Friday, April 27 and Saturday, April 28

ZZP is setting aside two days for an LNF gathering. This is for the Cobalt, Redline, G5, and HHR. We will have a full mod day on Saturday the 28th, starting at 9AM. Dyno pulls will be offered at a discount and run Friday afternoon and all day Saturday. Parts will also be discounted during this time. Friday and Saturday nights should both be good nights to cruise and hit the local hang-outs. We are also planning a tuning discussion based on LNF tuning through HP tuners. This will take place on Saturday at 1 PM and should provide some insight for anyone tackling their own tune or shopping for an LNF tuner.

While this gathering is based on the LNF engine, we welcome all of our customers to show up. We will gladly dyno LSJ, LE5, L61, etc… All Ecotec platform vehicles can participate in modding as well.

Friday November 25^th, 2011

Starting at 12am EST

Sales will be given through our Facebook and Twitter pages and in our news & info section on our website.

Each sale will be for a limited time or quantity.

Payment must be collected at the time of the sale for the sale to count. No sale will be given outside of its given time frame/date. Unpaid orders will not be processed at a later time/date.

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You will be able to use existing in store credits toward your Black Friday purchases but they must be updated to “in store credits” through our new website. Email kyla@zzperformance.com if you were issued an coupon code prior to the new website that is still valid that you would like be able to use during Black Friday Sales.

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Once you receive your tracking number for your purchase, we can no longer make adjustments, cancellations, or combine orders.

We will do our best to get all orders out as soon as possible. Due to the number of orders, there may be a delay in shipping orders. We appreciate your patience!

There will be a delay on orders that have a difference in billing and shipping addresses. Orders with a difference in billing and shipping may require further verification. For the quickest order processing, please have your orders shipped to your billing address.

If you have questions about orders placed during the sale, please include your order number in the subject line so that we can respond as quickly as possible.

New product pages will be generated for each sale item, so links to current items will not take you to the sale item. You will not be able to add items to your cart and have the discount applied when the sale is released. You must add the specific sale item to your cart in order to receive the discount.

If the sale item has a limited quantity and that quantity is already purchased you will not be able to checkout with the sale product. You will be returned back to your cart and you will receive and error stating :

Sorry, the item (item name) is not available at this time. The quantity requested of (item name) is unavailable at this time. 

If you receive this message, the item has sold out for that sale. You will need to empty your cart in order to purchase other items.

We will be taking a break from 3am to 8am EST. No sales will be posted during this time.

Email customerservice@zzperformance.com with any questions!

With the race season winding down, I wanted to get this car to the track to see what I could put down. I headed down to US131 Motorsports Park in Martin. The weather was great and the track was alright, but my slicks are 2 years old and not in the best shape anymore. All passes were made with 16-18psi in 1st gear and switched to the high boost setting down track.

For the 1st pass, I launched very conservatively and put down a 1.84 sixty foot. I switched to high boost- about 26psi towards the top of 2nd gear. I shifted pretty conservative and finished with an 11.2432 at 132.16

For the 2nd pass, I launched a little harder for a 1.78 sixty foot. Unfortunately, I forgot to switch to high boost until part way through 4th gear. This pass was a 11.30 at 130.

Pass #3 was a little better sixty foot at 1.77. I hit high boost(27psi) about half way through 2nd gear. This pass got it done with a 10.9985 @ 133.61!

Pass #4 was run the same way, but the sixty foot was a little slower at 1.80. This run was a 11.06 @ 134.40

For pass #5, I decided to turn it up a little(29psi on high) and also tried to launch harder. I also started no-lift shifting the 3-4 shift. Unfortunately it spun pretty bad on this run for a 1.88 sixty. The pass was 11.01 @ 136.85.

Pass #6 was run the same(29psi and nls 3-4). I got a better sixty foot at 1.81 and ran 11.00 @ 136.84.

For pass#7, I decided to nls 2-3 as well as 3-4. Unfortunately, thinking about this, I forgot to hit the high boost switch until 4th gear again. I finished with an 11.18 at 132mph.

At this point, I decided to call it a day because the track just wasn’t good enough to put down a good sixty foot any more. With a 1.68 sixty foot and 30psi on the high setting, we should be looking at a 10.6. Maybe next year…

-Matt

9.93@142.5 w/1.59 60′ followed up with a 9.82@141.64 w/1.55 60′!!!!! Congrats guys!

As the velocity of the pulse increase, the negative pressures also increase.  As you have an increase in velocity, the length of time that you have a negative pressure in the system is increased.

The net result of high velocity to assist in scavenging is increased performance of the intake and exhaust system.  Maintaining higher exhaust temperatures throughout the system increases performance in many ways.

Think of exhaust gases as a heavy liquid such as an oil additive.  If the liquid were traveling down a tubular system in a cold state, it would move very slowly.  If you heat the liquid, the density of the fluid changes.  The liquid responds to the heat increasing its velocity.

Exhaust gases respond in the same manner.  Higher temperatures in a system increase the flow of the system.  If the liquid is allowed to cool in the system, it slows the flow of the liquid.

By this illustration, you can now see the importance of maintaining higher temperatures in an exhaust system.

Ceramic coating the manifolds and crossover helps to maintain exhaust gas heat within the system. This translates into more exhaust flow due to maintaining exhaust temperatures as it flows out of the engine. By improving the scavenging of spent gases, the engine breathes more efficiently. This reduces contamination of gases, thus allowing the engine to develop more power.

By keeping the heat in the exhaust you will reduce under hood temps. This keeps you engine running cooler and the intake air charge denser. Cooler inlet air translates into more HP and reduced detonation.

• Lower the compression of the motor.

Without rebuilding my motor or at least taking off the heads I can’t change the compression so that’s out.

• Lower the boost level.

While this is a better option than water injection I don’t want to decrease the airflow by running a larger pulley to lower boost because then I would lose power.

• Decrease the explosiveness of the mixture.

To do this you can

1.Run high octane fuel but anything over 93 is expensive and hard to find.
2.Use octane booster but that is bad for your motor, expensive and not very effective.

3.Cool down the intake charge, or cool down the combustion chamber but most people can’t afford an intercooler, don’t want to tackle the difficult installation and aren’t willing to lose boost from the restrictiveness of the IC. Another way to cool the intake charge is to change to a centrifugal SC which is more efficient but that has the problem of being an expensive custom install.

Having looked at the 3 fixes above it would appear that we are out of practical options, but here is what I did to help eliminate my KR:

• Free flowing exhaust.

The exhaust is very important because the more air that you can get out of the combustion chamber quickly the less is left over to cause you power robbing problems. The exhaust gas is extremely hot and any left over in the cylinder will cause the chamber and the mixture to stay hot thus contributing to detonation and finally KR. Also with less exhaust in there, there is room for more fresh mixture and this will help prevent boost stacking. It will lower the manifold boosts slightly as well, which in this case is good.

I believe the biggest restrictions in the factory system are the downpipe and the manifolds. I had the ‘99’s downpipe replaced with 3″ tubing with the factory flex left in place. This goes into the factory cat, which is gutted. I want to add here that testing before and after gutting the cat produced results showing that the cat was not a restriction even while running 13.2’s. Even though I don’t think that the factory cat is much of a restriction the mod is free so hey it can’t hurt. Just make sure you have an O2 sim before doing this. From the cat I have 2 ½” mandrel bent pipe that goes into an SLP Y and from there into the factory mufflers. I kept these because I don’t see them as being any kind of a restriction and I wanted to keep the car quiet. Up front I upgraded the factory exhaust manifolds as shown here: ZZP Exhaust Manifold Porting. On the heads I removed all of the imperfections and burs right at the exit with a dremel. I didn’t want to take them off of the car so this was really all I could do.

• Fuel.

You must run the best gas that you can find, period. I only use Shell but any top brand gas 93 or higher should do. Running rich will also help you but only to the extent that you don’t start losing power from being so rich. In our GTPs .91 is about the perfect balance of removing KR vs. losing power from running too rich. Anything above .92 and you really start to slow down from the motor basically drowning in fuel. With race gas you want to be running around .88 depending on your boost & the fuel octane and with an IC or WI even lower .82-.86. The only time that you do need to be excessively rich .92-.94 is while you have the NOS spraying. To adjust the A/F ratio you can send in your MAF to have us mod it, get an FPR, or use a MAFT.

• Intake charge temp.

I learned that heat is created from compressing air. Think of it like this: A given volume of air has heat in it. Say you take a gallon of 70 deg air and compress it down to an ounce. Well now you have a gallon of ‘air heat’ in the space of an ounce. The ounce will now be 1000’s of degrees! There is no way around this and when applying this principle to our cars – 14.9lbs of boost you are cutting the space that the air occupies in half! So you now have very hot air in the intake manifold. But that’s not all there is also heat that the SC makes just from being inefficient added to this. There is another physics principal at work here, something that we can do something about. The outlet temp of the SC can be determined by boost. But to calculate it you don’t just take your boost as it applies to atmospheric pressure, you have to take the difference of the SC outlet to the intake vacuum. So if you have a restrictive intake you might have some vacuum in the intake causing the SC outlet temps to be higher than they need to be. Not only will the vacuum cause your outlet temps to be higher it will also mean more hp robbed from the motor to turn the charger. This is why I started the throttle body project and spent hundreds of hours studying the intake design of our 3800 engines. Everyone has a decent air box but the TB is a restriction even with the stock pulley and becomes even more so as you start to run the smaller pulleys. If I had to guess I would say that having a mod’d TB is like getting an extra lb of boost for free (as it applies to KR). Not only that but most people don’t realize that the TB to SC gasket hangs in the airflow just a little bit causing more restriction. Cutting this gasket out 2mm bigger is a free mod.

• Combustion chamber temp.

The hotter that the combustion chamber is, the faster the explosion is going to take place and the less timing you can run. To cool down the combustion chamber without an intercooler or water injection you need to cool down the whole motor. To do this I removed the engine cover, removed the weather stripping on the back of the engine compartment, removed the thermal blanket on the underside of the hood, wrapped the exhaust manifolds, put in a modified stat, made a fan switch so that I can turn on both fans at any time from in the car and replaced ½ of the Dexcool with distilled water. Water while not having the heat range of coolant has much better thermal properties to cool the engine. For some people running the engine too cold will set an SES light. To get around this you can put a 16-20 k ohm resistor in place of the air intake temp sensor (Email me if you need one sent to you for free). I didn’t need to do this but some people with finicky computers will. As far as I’m concerned there is no way around running a very cold engine if you want to make power, period. It’s either doing these things, get an intercooler, or do a lot of internal motor work. The nonsense I hear about engine wear and oil sludge is just that, nonsense. I have the temp management down so good on my car that I can just about do laps at the drag strip and never have it heat up. Here is a pic of my temp gauge after driving 90 minutes to the track in the summer.

All of these little tricks do have their limits though. I can only run the * 3.1″ pulley with the outside temps being under 75 or so and then I start to get some decent KR.

Hope this helps with some of the questions that I’ve been getting.

* Update, with a modified blower on the car producing more boost than normally possible with a given pulley and the new info just coming into light about the PCM learning timing I have since switched to using the 3.4 and the 3.25 for daily driving.

It is a common misconception that spark plugs create heat. They don’t. A heat range refers to how much heat a spark plug is capable of removing from the combustion chamber. Selecting a spark plug with the proper heat range will insure that the tip will maintain a temperature high enough to prevent fouling yet be cool enough to prevent pre-ignition.

Spark plug gap and heat range should be paired with the power level of the car.  A car with basic bolt ons would want a 2 step colder plug with a gap around .055″.  A car with more than basic mods will want to run a plug about 3 steps colder than stock and a slightly smaller gap around .052-.050″.  Turbo, N20, and highly modified cars(500 hp) will run the smallest gaps around .048 or possibly even smaller.

There are many reasons that some people with similar mods run much faster than others in the ¼ mile. Some you can control while others you can’t.

• Driver skill

— This takes practice. Running a 2.0 60 instead of a 2.3 60 will drop you from a 14.9 to a 14.5 in the ¼ mile. This is because time dropped from your 60 equals a larger gain that that amount off of your ET. For tips on improving your launch click here.

— Driver weight, believe it or not but some member are over 200 lbs heavier than others. This means that the greatest improvement in this category would come from them going on a diet!

• Track preparation

— While some feel that you can’t do anything to your car and call it stock others do things like remove the spare tire and headlight. Others will race with only a small amount of fuel in the car. For tips on track prepping you car click here.

— Some tracks spray there launching section with VHT TrackBite, which greatly contributes to a car launching ability.

— The temperature of a track attributes to traction as well. Here is where warm weather can actually help you. A hot track sticks like glue.

• Weather

— The temperature of the outside is very critical. Members who live in the Southern states know that it is very difficult if not impossible to run the types of time that us Northern guys do. Cold air is more dense, holds more oxygen, resists detonation and usually is less humid than warm air.

— The humidity of air is another factor. Humid air does not hold as much oxygen and is a bad thing for going fast.

— The barometer can make more difference that a pulley swap in some cases. Trying to race in altitude is all but futile if you are trying to break some records. Even at the same track the air pressure can vary from day to day.

Now on to the interesting stuff.  Why is it that some cars just make more hp than others when they have the exact same mods and are in the exact same atmosphere conditions?

— When Eaton made the M90 they decided for one reason or another to machine the first ½” of the inlet of the SC housing. Unfortunately because of mass production this machining process isn’t perfect and some housings come out better than others. Below is a picture and you can see just how off center the machining was done on this particular blower.

— Eaton blower housings seem to prefer certain rotors to others. This means that when you take 2 brand new M90s one will inevitably produce slightly more boost than the other. Even when you switch housings from one to another there is no way to predict whether you will gain some output or lose a little.

The bypass plate varies from blower to blower as well. On some SCs the bypass seals much better than others producing more efficient operation and decreased outlet temps with higher boost.

• Exhaust

— The front exhaust manifold does not have large holes in it that just totally cover the head exhaust outlets. Instead they are shaped in a way that makes their placement affect performance. There is a little play in the mounting holes causing performance to vary from vehicle to vehicle. The front manifold is made of cast iron and this means that flow will vary just a little from car to car.

— The rear manifold is made of tubes kind of like a header. These are put together very fast and while doing the work on our ported manifolds we noticed that some cars were setup much better than others. This includes how far the #6 tube extends into the main piece and how far the O2 sensor mount extends into the factory header.

• Gaskets

— The intake manifold gaskets seem to vary wildly from car to car and this can make a big difference in how your ports will flow.

— The TB gasket is sometimes misaligned with how your blower has been machined.

— Checking your copper exhaust manifold gaskets for carbon deposits can reveal a misalignment.

— The HEAD GASKET is very critical on a GTP. In pulling a few heads off we noticed a few things about the L67. One is that the gaskets are not perfectly round. They have a strange shape to them. One can only speculate that this is to contour to the shape of the head. The other thing you notice is that each car’s gaskets look a little different and sometimes on certain cylinders the gasket come right up to the edge of the cylinder wall. This can cause detonation in a big way. The edge of the head gasket is very thin metal and doesn’t have a sink to dissipate the heat like the head does. A head gasket can glow red hot if it overhangs into the combustion chamber even a few thousandths. We believe that this is the biggest difference between GPs as to why some have so much more KR than others.

• Rocker arms

GM states that the rocker arm ratio on a Series II 3800 is 1.60. Now that we have modified rockers available we know how much difference in hp a different ratio can make. From the factory the rockers do not always come exactly 1.60, after measuring many we have found that each stock rocker’s ratio seems to be slightly different.

• Race weight

A stock GTP weighs about 3500 lbs. If you do some calculations for weight effect on GP performance you will find that every 8 pounds of weight on a stock GP is equal to around .01 in the ¼ mile. With the variances in driver weight, different levels of fuel or other fluids, and some people removing all the extra stuff in there cars times can vary as much as .3 or more. With a large stereo these differences can be even greater.

• Camshaft

After measuring the lobes on a cam we found that they can vary from lobe to lobe. This means that some cams are going to inevitably be better than others.

• Tires

Worn tires can sometimes be a good thing. They are slightly shorter and if they are less than a year old the rubber is still soft enough to give good traction. This added gearing as well as the tire being lighter will help with launching and trap speeds. Using different brands of tires can amplify the above differences.

• PCM

For some reason yet unknown to us certain PCM’s seem to reset and favor higher timing than others. Why this is we haven’t figured out yet but without doubt it could cause one car to have more hp than another.

• Knock sensors

Every Series II 3800 has two knock sensors, one on the front of the engine and one on the rear. Thanks to the wonders of mass production every knock sensor is going to have sensitivity variances. Because the knock sensors are used in determining timing this alone can cause vast differences in total advance.

• Fuel

Most people have a brand of gas they like to buy. For me it’s Shell but depending on where you buy your gas you are going to end up with a little higher or a little lower octane of fuel.

• Oil

Believe it or not but oil can make a difference. Using synthetic oil will reduce friction in your engine. This has many benefits including increased power output. The Viscosity of your oil will also determine how fast your lifters bleed down.

The graph (Graph 2) below shows what the knock sensor signal looks like at WOT with no KR. Notice again the scaling on the Y axis. This time it is VERY high. But of course I was careful to ensure that there would be no knock during this run. This is simply engine noise at high RPM.

The third graph below (Graph 3) shows what the PCM believes to be real knock (not just engine noise). This knock is indicated by the spikes in the signal along the graph. The largest spike by far is the one on the far left. Note the scales on BOTH axis. This is significant signal strength at VERY high frequencies. We are talking in the nanosecond range. Time separation between distinct knock pulses is about 23 microseconds.

By expanding the time base of Graph 3, we can zoom in on the large spike to the left as shown in Graph 4. This is what the actual knock pulse looks like. It is a high frequency, very short burst with one occurring every 23 ms as shown in Graph 3. Within the burst, the waveform cycle varies anywhere between 120 ns (yes NANOseconds) and 300 ns, but is consistently within those time frames in the testing that I’ve done. The actual frequency range of this corresponds from 8.3 MHz (120ns) to 3.3 MHz (300ns). The actual pulse frequency does not matter so much, except to know that it is a VERY high frequency. We aren’t talking microseconds here: we are talking NANOseconds and megahertz. Look at the voltage on that initial spike. It is nearly 16 volts!

So What’s The Bottom line: why do I want to change the KR noise floor?
The point to all of this really is to show where the knock voltage is at idle, which in my car is at about 1V Peak. Prior to DHP changing my noise floor, I was getting HEAVY KR by just accelerating away from a stop normally. It was terrible. Every time I accelerated: even lightly, I got substantial KR (10-15 degrees). I never had it that bad until right after my trans was rebuilt. Since then it has been very bad. DHP asked me what my noise floor was on the knock sensors, and from my scope shots, I was able to tell him approximately 1 volt. Dave then raised the stock setting of 0.5 volts up to 1.0 volts. Since then, I have to REALLY work at getting KR. I have learned since then exactly what I have to do to get this kind of KR to occur. Thankfully, this fix in the PCM has prevented me from seeing KR under normal driving, spirited driving and racing. However, if I perform the right circumstances, I can repeatedly get KR. Fortunately, it is something that I have to really work at to have happen.

• Reduce boost – Boost is a direct reason for increased cylinder temperatures and thus detonation.
• Reduce timing (if added) - Timing advance is another direct reason for increased cylinder temperatures.
• Install an intercooler – This is the best solution of all, no doubt. This will reduce the intake charge temperature by approximately 100 degrees F (results vary among intercooler manufacturers).
• Add water injection – While much harder to tune, this is still an option for reducing charge temps.
• Run race gas (or at least the highest available octane gas) – Always a solution, high octane gas slows the burn rate of the combustion, thus acting inherently as a cooling agent.
• Keep your engine running cool - A cool engine helps to reduce the chance for ‘hot spots’. Things like lower temperature thermostats, larger radiators, etc will help.
• Free intake and exhaust restrictions – i.e cold air intakes, cams, headers, cat-back exhausts, larger throttle bodies, etc.
• Prevent parts from hitting (i.e. header downpipe with front swaybar)
• Add more fuel (to a point).

But there is much more to many of these and MANY necessary explanations and modifications that can help reduce KR … but most of them fall under one of these categories. What none of these address is what the PCM can do to help reduce or eliminate knock altogether or help to decrease the affect KR has on vehicle performance. Before we get into the PCM, let’s talk about each of the solutions in the list individually.

I will NOT talk about how good or bad a particular product is or compare them to other similar products across manufacturers. That is not the purpose of this document. The purpose is to talk about KR and how to reduce or eliminate it.

Maximum timing advance allowed by the stock cals is 17 degrees. Typical values seen at WOT is 15 degrees. Adding timing on top of this will only improve power, assuming you have no KR. This is one good reason why it is important to have something like an intercooler to control KR. With KR under control, a substantial amount of hp can be added by spark advance. The amount possible is under some scrutiny, but everyone agrees that it is not less than 1hp per degree, and not more than 3 hp per degree of added timing. This means that by adding a maximum of 10 degrees of timing, 10-30 hp will be seen by nearly everyone who is successful at implementing it WITHOUT KR.

• Install Intercooler – This is the most reliable and recommended solution to KR in a force fed application. The available intercoolers for the L67 (Thrasher, ZZP) will drop about 100 degrees off the lower intake manifold air temperature. There is some consequence though. You will drop some boost across the intercooler (either intercooler) as it IS a restriction. The gains you will see are instantaneous if you had KR previously. If you did not have KR previously, you may not see any initial gains. The REAL gains to the intercooler are what it ALLOWS you to do as later mods. For instance, with an intercooler KR is MUCH less an issue, therefore running smaller pullies is MUCH easier. Additionally, timing can now be added to the engine, again without as much worry for KR. Intercoolers are self-contained so you don’t have to worry about depleting or adding anything to it later, unlike water injection. The bottom line to this solution is, this is the ideal way to go!
• Install Water Injection – Not as many Grand Prix owners have done this. While some have been successful, others have struggled to tune it such that the car runs well. The idea is to inject a small, very fine mist of water into the air as it passes through the intake, or into the lower intake manifold after it has already passed through the supercharger. The water will absorb the heat in the air, thus cooling it, and then become vaporized in the cylinder and pass harmlessly out the exhaust as steam. The amount of water we are talking about here is very small. A negative effect of running any liquid in the air stream prior to the supercharger is its affect on the SC rotors. They are teflon coated in the Series Two engine and some have experienced de-lamination of the teflon from the rotor and ultimately damaged their SC, so BE CAREFUL. The bottom line to this solution is: it is viable and can work, but can take time to tune and should only be used in the air stream AFTER the SC.
• Run Race Gas - This is a GREAT solution that has EXCELLENT results in fighting KR. High octane gas slows the burn rate of the combustion mixture, thus reducing the rate of heat build up which helps to cause ‘hot spots’. The downfall to this is cost. At an average price of $4.00 per gallon, it is not a realistic choice for everyday use. Bottomline to this solution is: very good results against KR but NOT cost effective. Save it for the track.
• Keep Your Engine Running Cool – Since detonation is typically caused by ‘hot spots’ in one or more of the engine’s cylinders, running the engine cooler can help reduce the chance for a ‘hot spot’ to occur. Simple ways to do this is to run a lower temperature thermostat (more on this is a second), a larger radiator, an intercooler, water injection, and to lesser extents headers, cold air intakes, less restrictive exhausts and so forth.
  Lowering the thermostat temperature to a 160 or 180 can help some. As I remember, a local club member tested this mod and found an average gain of 2.5 hp by lowering the temperature. This is roughly equivalent to a little over one degree of KR. Of course, even with a lower temp thermostat, it is likely that your engine temp will STILL go well above that temperature simply because the radiator does not have the capacity and heat dissipation ability to keep the coolant THAT cool. You may not see that problem during the winter months, but during the summer, and in a lot of stop and go traffic, that temperature is going to climb regardless. So don’t expect it to stay at 160 degrees just because you install a 160 thermostat. Bottom line on this mod is it is so inexpensive and easy to do, it is well worth it to save a degree of KR.

• Another way to run your engine cooler is to install a larger radiator. With additional capacity for cooling, this can go a long way toward controlling your engine temperatures. This combined with the thermostat mod is worth the effort. The radiator will help to keep engine temperatures down near the thermostat temperature during those times when it wants to creep well past the thermostat temperature. Bottom line for this solution is that it is definitely a worth while effort, but the radiator does take a fair amount of time to install.

  Additionally, running a cooler spark plug will help. Autolite 103′s, for example, are three heat ranges colder and make an excellent choice for highly modified 3800 engines. These colder spark plugs have less area exposed to the combustion chamber and do not heat up nearly as quickly as hotter plugs.

• Free Intake and Exhaust Restrictions - Allowing your engine to breathe more easily will help. Installing headers, removing the U-bend, removing the resonator, installing a cat-back exhaust system, cam shafts, cold air intake, and ported & polished throttle bodies or larger throttle bodies from other vehicles like the Corvette (75 mm LS1 TB) can help. All have the same effect, but to varying degrees. The engine has to work LESS to breath in MORE air and pump out MORE exhaust. Less work equals less heat over the same period. A local club member ran dyno tests regarding the U-bend (installed and then removed) and found that removed, 5 hp was gained across most of the RPM band along with 2.5 lb-ft of torque!!! Bottom line is these are ALL excellent mods to do and are the kind you should be considering.

• Prevent Parts From Hitting – This has already been discussed in the “What can cause FALSE KR” section. See that section for more detail.

• Add More Fuel – The best way to tune your vehicle when adjusting your air/fuel ratio is on a dyno. Most dynos have a wideband O2 sensor that can reliably measure your engine’s actual air fuel ratio across your entire dynoed RPM band and displays it on the computer for your analysis.

Fuel Background
The stoichiometric ratio for any internal combustion four stroke gas engine is 14.7:1. That means 14.7 units of air to one unit of gas. This is the perfect combination of air and gas AT IDLE. The PCM will command this combination. Due to inherent inefficiencies in the engine, the PCM can’t simply command 14.7:1 and leave it at that. The engine will naturally drift a little in one direction (more rich or more lean) based on the last commanded a/f value. To control this drift, the PCM actually needs to MONITOR the oxygen content of the exhaust gas so that it knows when the engine drifts off of 14.7:1 and by how much. This information is used by the PCM to counter those drifts by commanding more or less gas depending on the direction of drift. This whole procedure is indicated by the PCM parameter ID (PID) called LTFT or Long Term Fuel Trim (and STFT or Short Term Fuel Trim). This parameter indicates how much the PCM is adding or deleting fuel to/from the engine over the long term (and short term for STFT). A value of 0% indicates that the PCM does not have to make any adjustments. A positive value indicates that the PCM is adding fuel because it is running lean, and a negative value means the PCM is removing fuel because of a rich condition. The PCM IS limited, however and can only adjust up to 16% additional fuel or 23% less fuel.

At WOT (wide open throttle), the story is completely different. The PCM relies on static fuel tables to determine what a/f ratio to command. The PCM never uses the oxygen sensor under WOT conditions. As a result also, the LTFT is never used under WOT. This is when it is necessary to use a wideband O2 to determine your true a/f ratio and tune accordingly. The O2 sensors used by the engine are in their nonlinear region at those O2 voltage levels which is why they are not used. However, as a RELATIVE value for YOUR car, YOU CAN use them to get an idea of where you are at RELATIVE to previously known GOOD values that you may have correlated to a dyno.

As such, adding fuel under the right circumstances can have a positive impact on KR. There is no clear cut formula for the do-it-yourselfer because of the unique conditions that everyone’s vehicle is running under. Fuel can be added through several methods such as the MAF Translator, a DHP PCM, the ZZP Mini-AFC, the ZZP ICCU, or simply increasing the fuel pressure at the rail through an adjustable fuel pressure regulator.

What should I monitor with a scan tool?
The following values, at a minimum, should be monitored with an Autotap, Tech 2, or Scan Master (some parameters may not be available with the Scan Master) when tuning your car for spark or fuel:

What can the PCM do for me in the fight against KR?
Ok, now that we have covered the introductory pieces that were needed, we can proceed to the question that you have read through six pages to get to.

There are a LOT of calibrations in the PCM. I might say thousands. It is a whole sea in itself of parameters, many with meaningless descriptions, and some with very meaningFUL descriptions, and some you wonder why they are even there. The following outlines some of the important parameters that DHP adjusts (in a more descriptive format) that can affect KR:

There is even the ability to ignore KR at specific RPM values. For instance, some individuals have had very strange KR occurrences. One example is the unexplainable instantaneous 15 degrees of KR at exactly 6000 rpm. It would happen pretty consistently and only instantaneously. Once the engine pushed through 100 or so rpm starting at 6000 where the 15 degrees occurred, it would recover to 0 and the engine continued on normally with no KR. After much investigation, the decision was made to simply ignore any KR that occurred at exactly 6000 rpm. It is amazing what you can do with the PCM.

Ok, let’s take an individual look at each of the seven items from the list above.

AE
Acceleration Enrichment is that little splash of gas that is provided during throttle movement. The idea here is that you add a splash of gas right at the moment you press the throttle so that any detonation that MIGHT have developed is less likely due to the cooling effect of the AE splash. One of the parameters in the PCM allows this amount of splash to be changed. This has been a very effective countermeasure in the battle against KR and is used widely in DHP PCMs.

PE
These tables provide the fuel for the engine at WOT. This is where some magic can be worked for additional horsepower gains, a/f ratio tuning and so forth. PE = Power Enrichment.

KR Attack Rate
Like the title sounds, this is how aggressively KR is instituted.

KR Recovery Rate
Like the title sounds, this is the rate at which KR recovers from its peak knock level down to 0. For the stock PCM, this rate is 0.8 degrees per second. This means that with 15 degrees of KR, it would take nearly 19 seconds to recover to 0. This recovery rate can be changed to any value. Some PCMs have this value set to 2.5, while others have it set to 5.0. At a recovery rate of 5.0 degrees per second, it would take only 3 seconds to recover from 15 degrees of KR to 0. This is a VERY nice change to have in the PCM!!!

Capping Maximum KR
Simply put, this parameter limits the amount of KR that can be invoked by the PCM. For a stock PCM, KR is limited to 25.5 degrees. Many DHP PCMs have this value set to 15 degrees of KR.

Disabling Knock Sensors
DON’T DO THIS!!! Not that I would know anything about this, but I strongly urge any idiot that is even thinking about doing this to reconsider! The knock sensors are there for a reason. If you have knock, KR is there to PROTECT your engine. This is its ONLY function, period! It takes only 3ms for your engine to be damaged by detonation if the knock sensors are not enabled to protect it. Typical damage is indicated by a chunk of your piston (usually cylinder 1 or 3) breaking off and ‘banging’ around inside your cylinder. You will be lucky if your cylinder does not become scored so that you only have to change a piston. Otherwise, you are looking at a whole new short block.

KR Starting Voltage Level (Noise Floor)
OK, this is the one that I wanted to really make mention of. For those of you that were following the thread on ClubGP about the LS1 throttle body kit from ZZP know that I mentioned a particular modification that was done in the PCM to help keep my most recent KR issues at bay. I mentioned that I needed to get some scope shots to help better illustrate what I wanted to talk about. I also mentioned that I wanted it in a different thread so that the information would not be lost or buried in the LS1 thread. So here we are.

The noise floor for KR is the voltage at the PCM will start to recognize knock, at least this is the theory. I say ‘theory’ because noone is 100% sure what EXACTLY this parameter does, but given the description and the results, we have ideas. The stock setting for this parameter is 0.5 volts. This means that anything below this value will be ignored by the PCM. The normal idle knock sensor signal level on MY car was closer to 1.0 volts. Since my idle signal levels were 0.5 volts HIGHER than the stock detection settings, DHP raised that value from 0.5 volts to 1.0 volts. The results were ASTONISHING to say the LEAST. I will get into these results in a moment.

Before we get into the graphs, let me explain what I did. I connected a wire from the front cylinder bank knock sensor and routed it into the cabin and terminated it with a female BNC connector so that it could be connected to one channel of a dual channel oscilloscope. I connected a wire from the rear cylinder bank knock sensor, and in the same way as the front, I routed it into the cabin and terminated it also with a BNC for use with channel two on the scope. I took readings at idle, at cruise and at WOT with and without KR, and repeated them MANY times. The particular scope I used has a built in floppy disk drive and selections for converting the scope shot into an Excel CSV file. For each scope shot, I saved it to the floppy as a CSV file AND as the proprietary scope file so that I could also call it back up on the scope later. I set the scope up to trigger on the leading edge of any positive going AC voltage level that exceeded 14.1 volts. Because of this, I had to generate KR that would exceed this value. If this value was not exceed, the scope would show nothing … it would still just sit there and wait for the trigger voltage. In this way, I could correlate KR readings from the Tech 2 with a TRIGGERED scope shot. I also wanted to trigger high KR at LOW RPM so that the actual knock signal would not be hard to find buried in high engine noise. Since I know my car very well, I knew what I needed to do to generate KR under these circumstances. During these tests, whenever my KR exceed 14.1 volts, the scope was triggered and the signal snap shot was captured instantly on the pulse that exceeded 14.1 volts. Each time I successfully triggered a scope shot that I wanted to save, I exited the highway, pulled into a gas station and saved the signal to the floppy disk. The I resetup the scope for the next trigger and started again. The idle shots were taken while idling in the gas station. The weather was cold (28 degrees) under mostly cloudy night-time skies. The time was between 2:00AM and 4:00AM when there would be the least amount of traffic on the highway.

For reference purposes, my car has the following engine and trans mods:

Note – Since I have control over the timing, and I was NOT running race gas, I did not have the extra degrees of timing dialed in. I was running the stock 17 degrees of ignition timing.

Knock Retard (hereafter referred to as KR) is the response from the PCM to cylinder detonation. KR is the measure of the number of degrees of overall ignition timing advance that must be removed from the engine to prevent detonation from continuing, thus protecting the engine from damage.

Q:What is detonation?

KR is a result of detonation. To have ‘real’ (more on ‘real’ vs ‘false’ KR later) KR, you MUST have detonation. Detonation is the uncontrolled combustion of the intake charge. “Uncontrolled” means that the mixture ignites via a means other than the spark from the spark plug. In most cases, the uncontrolled ignition is due to a ‘hot spot’ in the cylinder. Hot spots can be caused by uneven combustion, spark plugs that are rated too ‘hot’, lean fuel conditions, breathing restrictions (exhaust / intake), bad gas and so forth. One problem in particular that came to light for me was the head gaskets. During one of my engine teardowns, Zooomer from ZZP pointed out that, while my cylinder bores are perfectly round, the head gaskets are NOT made perfectly round. Some of the gasket material actually protrudes slightly into the combustion chamber. Since the head gasket bore linings are made of metal, that little bit that protrudes into the cylinder glows red hot, thus creating the potential for a nasty ‘hot spot’. This is a good area to check and perhaps replace with an aftermarket head gasket. In other cases, the ‘hot spot’ is due to unreasonably high cylinder compression. Either way, the ‘pinging’ or ‘rattling’ sound you hear is the result of the actual collision of the flame front produced by the ‘hot spot’ and the normal flame front produced by the spark plug. Typically, these two flame fronts are opposing fronts, meaning that they are expanding, or propagating toward each other, thus the collision. Real KR does NOT occur without detonation occurring FIRST.

Q:How is knock detected?

Since detonation results in noise (the rattling or pinging sound of the two colliding flame fronts), it can easily be detected through the use of microphones attached to the engine in key locations. On both the L36 and L67 3800 engines, there are two microphones. Each one is located immediately beneath a cylinder bank and are mounted in the block of the engine directly into the cylinder water jacket. As the sound of detonation occurs, the noise is ‘heard’ by the microphones and the signal is carried to the PCM where it is analyzed. The PCM determines whether or not the signal provided by the microphones is knock or just normal engine noise. Knock is detected by the frequency of the signal. The severity of the knock is determined by the voltage level of the signal. Another way to say it is the voltage level of the signal will determine the level of KR. The PCM is tuned to responded ONLY to those signal frequencies that it has been programmed to recognize as knock. Anything else is engine noise.

Q:How does the PCM respond to knock ?

Engineers designed into our engines a safety mechanism for protecting our engines from KR. To do so, the PCM must respond electronically somehow to the knock signal. To electronically eliminate KR, and thus detonation, it is necessary to reduce the heat in the cylinders. Heat is a byproduct of power, so to reduce heat … power must be reduced. The PCM can reduce power electronically by retarding the overall ignition timing. The PCM converts the voltage level to a corresponding spark timing degree (KR) by which the engine should be retarded so that the detonation is naturally eliminated. The higher the voltage, the higher the KR. By doing this, the spark ignition of the combustion mixture occurs much later in the cycle of the piston compression stroke, thus reducing the effort the piston undergoes in compressing an explosion that has occurred ~15 degrees prior to TDC (top dead center). The later the ignition occurs, the less combustion that is compressed, and the less work the engine has to do. The effect of this is to cause the engine to lose power; a noticeable amount of power. The other effect of this is reduced cylinder temperatures which immediately dissipates cylinder ‘hot spots’. With temperatures down and ‘hot spots’ gone, detonation has been eliminated. The KR response by the PCM is limited to not exceed 25.5 degrees.

Q:What does the PCM do immediately after the detonation levels begin to fall?

Once the PCM has retarded timing sufficiently to reduce knock below the currently detected peak level, a changeable parameter in the PCM governs how quickly the overall ignition timing can be restored to normal levels (more on this later). The engine could see a peak of 15 degrees of KR from which the originating detonation may immediately disappear. However, the PCM will not instantly restore timing to pre-detonation levels. Instead, the PCM cautiously and conservatively restores ignition timing at a rate of 0.8 degrees per second. In the event of a 15 degree KR event, it would take nearly 19 seconds for the ignition timing to be restored to pre-KR levels. By the time your car sees full power again, the race is already over. This ‘time’ that the PCM takes to restore the ignition timing is called the Recovery Rate (more on this later). The Recovery Rate will continue in this slow fashion until KR reaches zero, KR increases back above the current recovery value, or the throttle is released.

Q:How much horsepower do I actually lose with KR?

Approximately 2 hp per degree. At 15 degrees of KR, you are subject to lose 30 hp. At 25 degrees of KR, you lose approximately 50 hp. Yes, it is VERY substantial and VERY noticeable. Please note that this is not EXACT hp lost … it is approximate.

Q:Why do I NOT want to have KR (why is it bad)?

Due to the retardation of the ignition timing, KR causes the vehicle to lose substantial power. More importantly, though, the flame front collisions are EXTREMELY harmful to the pistons. These highly volatile areas in the cylinder can cause stress cracks in your piston, which will eventually give way causing an entire CHUNK of your piston to lift right off and begin banging around inside the cylinder. This is why when the spark plug is removed after such an event, the plug end is bent all the way over. The broken piston can be VERY expensive to fix if you are not capable of doing the work yourself. DON’T EVER DISABLE YOUR KNOCK SENSORS. It takes less than 3ms to damage your engine due to knock.

Q:How do I know if I have KR?

KR is an electronically determined value based upon signal input from the knock sensors. As such, the best way to determine whether or not you have KR, and if so how much, is to use a scan tool to actually read that parameter ID (PID) from the PCM. There are three tools readily available : Autotap, Scan Master, and a Tech 2 that can show you your KR value.

• Anything loose in the engine or outside the engine may cause noises that drift through the frequency range that the PCM detects as KR. Carefully check your engine! This is very vague and is intended to be vague because just about anything loose in or out of your engine that is making noise could cause this. This includes loose or noisy components in your transmission as well.

• Loose knock sensors, or knock sensors that are too tight. Double check that your knock sensors are torqued to spec (14 lb-ft).

To fix this simply remove your Throttle Body; being careful enough to reuse the old gasket or better yet buy a new one. With the Throttle Body off of the car install the gasket onto the studs sticking out of the Super Charger. Then with a razor or trim knife trim the gasket material that overhangs the Super Charge inlet.

Carefully put the Throttle Body back on the engine.

New mods are posted frequently, so please check back often…

This filter is the same diameter and the same thread but is 1″ longer than a stock 3.8L filter.

This gives you longer life and better oil filtration performance.

A warning from one of our readers:

In the tech articles on your website (good reading, by
the way), you list running an oversize, longer oil
filter. Many people do, and in the past, I did as
well. I don’t anymore as a problem occured, and I
thought I would bring it to your attention so that
maybe you could add a word of warning to your tech
article.
Not too long ago, while I was running the larger oil
filter, my lower motor mount failed (possibly the
tranny mount as well…I have not checked it). I did
not notice it until my real problem occured. The
failed motor mount caused the engine to drop just
enough so that the oil filter was actually resting on
the cradle. One day when I pulled into work, after
hitting a not so major bump in the road, I parked my
car. When I came out of work later on, my oil was
everywhere. There was a trail from the entrance to the
parking lot to the spot I had parked in, and the
puddle of oil under my car was huge. That last bump
before pulling into work was enough to crack the oil
filter. I had to hacksaw the filter off as I had no
other way to remove it.
I just thought I would bring this to your attention,
so that maybe you could advise people to check their
lower motor mounts before upgrading to the larger oil
filter. The combination of bad mounts and larger
filter could have been quite a catastrophe for me had
it occured when on the highway and I may not have
noticed what had happened immediately. I don’t know if
this info matters to you at all or not, but I thought
that it was worth sharing.
-Matt

The stock pushrods are 7.020 and most companies list their aftermarket 7.050 pushrods as a “stock length” replacement. Comp cams measure their pushrods different than some companies by not taking into account the final radius on the ends of their pushrods. This makes their pushrods measure about ~.010 longer than some (like intense).  ZZPerformance likes to run our pushrods on the short side to avoid the chance of lifter pump up.  Lifter pump up is when the oil pressure raises so high that the lifter actually keeps the valve from closing all of the way to get the most compression in the cylinder as possible.

The stock head gaskets on a Grand Prix are .062 with most people running .052 as an aftermarket alternative. Some go as small as .045 and some as large as .074. These are all within range of what a lifter can accomodate for and do not usually require pushrod length change.

Some aftermarket cams can have a smaller base circle than the stock cam. This reduces lifter preload by the amount that the radius is smaller than the stock cam. Most aftermarket cams have the diameter .010 to .030 smaller than stock with the milder cams being closer to .010. The XPZ intake lobe with a very custom profile has the base circle diameter around .070 less than stock. When measuring the diameter of your aftermarket cam compared to a stock cam, keep in mind it’s the radius, not the diameter that you need to use in the math.

Aftermarket heads can have different valve lengths. There is no way around this if you recut the valve seats. If the valves have close to a stock tip height, then it probably doesn’t need to be factored in.

The ZZP heads use valves that are .100 longer than stock. We do this to correct for rocker angle when going to a larger cam. Normally the lift of a stock head is around .400 and most users of aftermarket heads have lifts around .550. Leaving the starting position of the rocker the same and opening the valve another .100-.200 causes and extreme angle on the rocker. Our use of longer valves allows higher valve lifts with correct rocker geometry, but requires the customer to use the supplied rocker shims to raise up the rockers with the valve tip.
If you were, for example running our heads with stock pushrods, lifters, rockers, and cam the additional valve tip height would use up the lifter ‘squish’ and hold the valves open all the time causing zero cylinder pressure and a no start condition. To properly set this up you need “rocker pedistal spacers”/”rocker shims” (supplied with our Stage heads), shorter pushrods, or finally a different rocker setup.

All said and done you need to add up the changes in head milling, block decking, head gasket thickness, pushrod length, valve tip height, camshaft base circle lobe diameter, and rocker arm type. This will allow you to calculate the length of pushrod needed.

To check for lifter preload or lifter squish you need to first get to zero lash. Turn the engine over so that one valve on a cylinder is open. Because one is open, you know the other is closed, meaning the lifter is sitting on the base circle. With that lifter on the base circle loosen the rocker bolt and then retighten with one hand while spinning the pushrod with the other. This way you can tell when everything first makes contact (the valve is touching the rocker tip, the pushrod is touching the rocker & and lifter and the lifter is touching the cam). At this point of first contact you are at zero lash. Everything past this point is lifter preload. Continue to tighten the rocker bolt until the bolt hits its snug point. This is how much lifter preload you have. Each 1/2 turn of the rocker bolt is ~.050 of lifter preload. Your goal is to have between 1/2 turn and 1.5 turns if you have stock lifters or 3/8 turn to 1/2 turn if you have Comp lifters. As you can see the stockers have a lot more room for error.

If you have too much preload and you have exhausted the adjustment of the lifter, the valves will stay open and the car will not start due to lack of compression. If you have too little preload, the valve train will be noisy and you risk exploding a lifter and having a very costly repair.

Remember, once the engine is heated up things change a bit. Parts grow and you will have to calculate in ~.005 pushrod growth. Also each pushrod with vary +/- .005 making things critical in high performance applications.

For the 3800 there are a few choices of valve springs:

Stock “tested at ~70# pounds seat pressure @ install height of 1.72

LS1  “tested at ~70# seat pressure @ install height of 1.80

LS6 blue “tested at ~90# seat pressure @ install height of 1.80

LS6 yellow “tested at ~90# seat pressure @ install height of 1.80

Comp 105 “tested at ~108# seat pressure @ install height of 1.80

Comp 130 “tested at ~135# seat pressure @ install height of 1.80

Comp dual spring-tested at ~135# seat pressure @ install height of 1.80

Comp 150 -tested at 155# seat pressure @ install height of 1.90

Tested seat pressure is only at the seat, when the valve is closed. Our values are listed for springs that are brand new. When a spring is used, it will settle to a slightly lower pressure. The seat pressure rating of the spring does not determine how much lift the spring can handle, what the open pressure will be or how strong the spring is (strength meaning resistance to breaking).

Spring rate determines how much pressure the spring will have when the valve is open. This is very important because the spring pressure when the valve is opening determines the force needed to open the valve. The more force needed, the higher the stress on the timing chain system. In our case, the stock timing chain dampener. This means that the higher the spring pressure during valve opening the more wear on the stock timing dampener.

The LS6 spring increases in pressure faster than the Comp 105 or the Comp 130 (which has the same spring rate as the 105). By the time you get to .300 lift, the yellow LS6 spring has passed the Comp105 in pressure. At valve lifts of .500 (close to what a 1.9 rocker gives) the LS6 spring is up to 275#, while the Comp105 is only 250# and the Comp130  280#.

Valve float is bad. The resistance to valve float is determined by the seat pressure, not the spring rate. For the 3800 running a stock timing dampener, it makes sense to try and run the seat pressure you need to prevent valve float, coupled with the lowest spring rate to reduce dampener wear. Valve float comes from the spring’s inability to control the valve. High rpm, fast ramp rates, valve lift, valve train component weight all play a factor in how soon your setup will experience valve float.

 Performance: We recommend the Comp 105 spring over the LS6 spring because the 105 has a lower spring rate than the LS6. With a lower spring rate the dampener will not wear as fast. Another little known factor is rocker deflection. This is where the rocker actually bends as its being opened because of the massive force being applied to it by the spring. A stock rocker experiences this problem the worst and loses about 25 thousandths of valve lift due to deflection. This is the same as lowering the rocker ratio by .1 (turning a 1.9 into a 1.8 and so on). This is one of the reasons why HP gains from using high ratio rocker arms have been all over the spectrum. Using a modified 1.9 ratio rocker without changing the valve springs works well because the stock springs are light and you don’t get much rocker deflection. You do risk valve float this way but most people don’t have that problem. With a roller rocker you will get valve float with a 1.9 ratio rocker unless you use higher rate springs. This however costs you a small amount of lift and is why many people running 1.9 rollers, don’t see large gains over 1.8 ratio rollers using stock springs (which works w/o valve float). That certainly gives you a lot to think about but the bottom line is this: Using the Comp105s over the LS6 springs is a good idea if you don’t mind spending the extra money.

Retainers will determine your installed height. Using stock retainers gives you an installed height of 1.72 and using and LS1 or LS6 retainer (same part #) gives you an installed height of 1.80. If you use stock retainers with any of our LS1 style aftermarket springs, it will increase the seat pressure (by ~29# on an LS6, ~23# on a Comp105 or 130, and ~18# on a stock LS1 spring) This is because you are preloading the spring .080, so when you calculate total lift on the spring you have to add .080 to it. (Using stock 3800 retainer with LS6 spring and stock retainer with a .500 lift cam, compresses the spring as if you had a cam with .580 lift! There is no instance in which you should ever run stock 3800 retainers with an LS1 style spring meant for a 1.80 install height.

Maximum lift capability of a spring is not the same thing as coil bind. A spring has a rated maximum lift that is usually around 25 thousands lower than its coil bind point. Any vendor that gives you coil bind specs when you ask what lift is safe, does not have the knowledge to be giving advice.

Now that you know a little more about valve springs, we’ll explore the problems in the 3800 community.

Wbody store:

They sell a light duty valve spring. These have a dealer cost of less than $2/spring and come stock on an LS1. Its maximum rated lift is ~.500 and it does not have any more seat pressure than a stock 3800 valve spring. If you use it with stock 3800 retainers, the maximum lift drops to .420 (1.9 rockers bring the lift to .490). This spring should not be considered for use in our market.

Anyone using stock retainers with these springs can expect the spring to fail, using LS1 retainers and you have the same valve float protection as your stock springs.

This store rates the maximum lift of the Comp 105 as .590 and the Comp130s as .630, both are actually rated from Comp at .600 and coil bind around .625

Spring rates for their light duty and medium duty (LS1 and LS6) springs are incorrect.

Intense:

When they originally offered the 85 pound springs, they used the blue LS6 springs. They have the same cost as the yellow but do not support the same lift. This shows a lack of testing and research. On the positive side, they now sell the yellow LS6 springs.

They currently list the LS6 spring for use with a stock retainer. This changes the maximum lift from .550 to .470. This also destroys the stock timing chain dampener in 5-10k miles when using 1.9 rockers or a small cam. They have this information listed on their site and on each box of springs send out. It is very, very bad information.

Intense springs package 

Failed LS6 spring with stock retainer and 1.9 rocker

Failure pic2 with stock retainer and 1.9 rocker

Picture of a stock and damaged timing chain dampener when you have too much spring pressure

At ZZPerformance, we believe in testing products and doing all the research before releasing them on the public. That is why we have taken the time to work with Comp cams, educate ourselves, inspect engines that have been run under various conditions and share the information with you.

http://www.zzperformance.com/miscftp/spring%20testing01.jpg

http://www.zzperformance.com/miscftp/spring%20testing02.jpg

http://www.zzperformance.com/miscftp/spring%20testing03.jpg

http://www.zzperformance.com/miscftp/spring%20testing04.jpg

http://www.zzperformance.com/miscftp/spring%20testing05.jpg 

http://www.zzperformance.com/miscftp/spring%20testing06.jpg

The roots blower found on our cars is very good at moving air, but not very good at producing pressure. In fact the higher the pressure, the less efficient your supercharger becomes. In turbo or centrifugal power adders, the unit can actually become more efficient with boost, but more on that later.

As the pressure differential from the blower inlet to the blower outlet increases, more air begins to seep around the rotors causing a loss in efficiency. At some point, it actually costs you more power to produce the boost than the HP you gain by the increase in airflow to the engine. For the older Eaton blowers, this point wasn’t much over 10psi. Once Eaton added the Teflon on the rotors around 1995, the efficiency of the blower increased and the maximum usable boost pressure also increased. In 2004 some of the blowers were redone with a new epoxy rotor coating and tighter lobe to case tolerances. This further increased efficiency and became know as the Gen 5 blower. Now gains can be had with boost pressures up to around 15-16 pounds. Since the M90 is capable of producing 15 pounds with a small pulley, there isn’t much reason to switch to an M112 blower because the increased boost isn’t going to make more HP.

 Are their any gains to be made with a larger blower?

 Yes. The larger MP112 blower can produce the same boost level and airflow as the M90 while spinning slower. The slower spinning lobes create less heat, which means more efficiency. At the same boost level the 112 will make around 5% more power from that increased efficiency. Whether a 5% gain in HP is worth the upgrade cost, is up to you. We don’t feel it is because of the other alternatives.

 What about running two blowers?

If both blowers were attached to the same intake plenum, then you could expect the same type of situation as described above. Two blowers would simply behave like a larger blower and give gains as such. High boost levels would hurt both blowers in the same way that hurts one. There is an alternative that no one has tried yet and that is to feed one blowers outlet to the inlet of the other blower. This would result in possible gains well over 20psi. This would also solve the belt slip issue and give you the opportunity to dual intercool. Of course you’d have to be crazy to go through all the work involved with custom plumbing and mounting. I wonder if anyone or any company will ever build a setup like that. I wonder who would try such a crazy thing:

 So what about a twin screw blower?

 Whipple and Kenne Bell blowers use intermeshing ‘screws’ in a male/female pattern to move air. This design, unlike a roots blower, compresses the air inside of the blower. The design produces a steady flow of air, rather than ˜pulses’ of air created by an Eaton blower. This lends itself to more efficient operation, especially at the higher boost levels. However, this style of supercharger is not without its down sides. At low boost levels (1-6 psi) the charger doesn’t work quite as well as the roots blower. While under normal driving conditions the twin screw blowers rob slightly more HP than the Eaton blowers. The tolerances of the twin screw are much tighter and more critical. This makes the blower itself heat soak quicker. It also means a much higher failure rate than the nearly indestructible Eaton blowers. The twin screw does offer some HP gains over the Eaton blowers at the same boost levels but the real magic happens when you want to run boost levels at 15psi or higher. Unfortunately this means belt slippage issues. Most users will find that they have to run wider belts and/or custom tensioners. Depending on boost levels, a twin screw can make 5-20% more HP on a 3800 than an M90.

So what do you do for big power?

In short, run a turbo. Turbo have virtually no limit on boost level or HP level. Running off of the exhaust they don’t have any belt slip issues. Not that a turbo doesn’t have any downsides, it’s just that this article was written to answer the larger blower question:

No IC
Grand Prix
3.8 (Stock): 667
3.2-3.6: 660
2.85-3.1: 650
2.7-2.85: 642

Bonneville
Stock: 721
3.4: 716

With ZZP Stage 2 IC (2.25″€ tall Core)
6 Rib
3.3-3.8: 685
2.7-3.2: 680 (Note that the NAPA 680 may be too long for 2.8″ and smaller. Try a NAPA 672)
2.5-2.6: 672

8 Rib NOTE: For these belts the part numbers are 080 rather than 060…or K8 with the Duralast rather than K6.
3.0-3.2: 685
2.6-2.9: 680

Gen 5 Blower
2.9-3.1: 685
2.7-3.0: 680
2.4-2.6: 675

With ZZP Stage 3 IC (2.375″ Core)
6 Rib:
3.1-3.8: 685
2.6-3.0: 680

Gen 5 Blower
3.0-3.8: 685
2.6-2.9: 680
2.3-2.55: 675

With ZZP SSIC (1″€ tall Core)
3.2-3.8: 670
3.9-3.1: 667 (Stock belt)
2.8: 660

With MAP IC (2.0″ tall Core)
3.1-3.4: 680
2.8-3.0: 672

ZZP SS M90 Conversion
970 – SS M90 for 97/98
950 – 3.8-4.2 SS M90 for 99+
947 – 3.5-4.0 SS M90 for 99+

Other Belts

060915 – Stock accessory belt for 99+
-also works with either UD WP pulley or OD alt pulley but not both.

060923 – Accessory belt for 99+ with UD WP pulley and alt UD pulley.

4060935 – Stock accessory belt for 97/98 (94″).

4060938 – Accessory belt for 97/98 with underdrive pulleys.

]]> http://www.zzperformance.com/blog/belt-sizes-routing-and-pulley-diagram/feed/ 0 http://www.zzperformance.com/blog/torque-converter-stall-speed/?utm_source=rss&utm_medium=rss&utm_campaign=torque-converter-stall-speed http://www.zzperformance.com/blog/torque-converter-stall-speed/#comments Thu, 13 Oct 2011 23:01:03 +0000 ZZPerformance http://zzperformance.com/blog/?p=44 Continue reading →]]> With all the stall speeds available many people in our market ask “What stall speed is the best”. In short, there is no best, it’s about matching your needs to the right unit.

The next question, we get is “what does that stall speed number mean?” Specifically in our market, not much. ZZP and the other vendors in our market label converters whatever we want. ZZP based our labels on what people had come to expect the numbers to mean. In other words, there is no technical explanation for the labels on our converters. Because of this you may get some very strange responses from people not familiar with our market. “OMG, you can’t run a stall that high!” or “That’s not enough converter (referring to the stall speed not being high enough”.  Both of these responses are common by mechanics not familiar with our market. Neither means anything because they aren’t familiar with our rating system.

The technical explanation for stall speed is the amount of difference between the engine speed and transmission speed. But the problem with specific ratings is that, the stall speed changes based on the weight of the vehicle, speed of the transmission and most importantly, horsepower of the engine.

Higher stall converters allow better launches and more low end grunt because the engine can get higher into the power band while the transmission is still or at a lower speed. The sacrifice is in top end horsepower, gas mileage and heat. Below is a dyno of a maxed out M90 setup with and without the converter locked. It’s a ZZP 3500 stall converter. As you can see there is a lot of low end power gained by letting the converter slip but there is also a large penalty up top. On our 2500 stall converter the two lines wouldn’t be separated so far. We normally see only about 10HP lost up top. Because the 3800 with an M90 makes so much torque, we generally recommend our 2500 stall converter because more power at launch is not going to help as much as more top end power.

Having been a automobile enthusiast all my life and owning ZZP for 9 years, I can give some great advice on picking a shop. Here at ZZP roughly half of our work is redoing another persons or shops work. Often time redoing the work is more expensive than doing it from scratch. Here is my advice for having work done:

1. Choose a shop with a good reputation. If you don’t know anything about the business you are taking your car to, you are risking a lot. Every shop whether good or bad will usually tell you that they are the best. Do your homework and pick a place with experience.

Understand that shops do not charge you for a result, they charge you for working on the car. If you bring your car into a shop YOU are taking the responsibility to trust that they know what they are doing. If they do work that isn’t needed, you still have to pay for it. If there is a problem and they diagnose it wrong and start repairing things that don’t need to get done, you still have to pay for it. This is how all shops operate and no one would be able to stay in business working for free every time a customer felt they diagnosed the problem wrong. Every shop can make mistakes or diagnose issues wrong or recommend incorrect parts. The idea is to work with a shop that is knowledged enough to minimize this chance.

2. Have one company do all or as much of the work as possible. If you have multiple people or companies under the hood, no one will be responsible for anything. This will leave YOU as the person responsible for any and all problems and failures. It is not right to expect a shop to be responsible for a car that another shop was also working on. We deal with this issue often in that people do what they can themselves, then have us do a little that they can’t do and expect that we are going to warranty the entire car. Sorry guys, it doesn’t work this way.

3. Make sure the work is done by someone who is large enough to pay out a liability claim. What if your engine fails or car is heavily damaged or crashed during a test drive? Can the individual or shop cover this? Are they insured? Smaller places or backyard mechanics can be great to save a few dollars…until there is a problem.

4. Ask the shop “what if”  type questions. What if my engine fails after you work on it? What if there is a fluid leak? What does your warranty cover? Do you have a warranty?
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Real life horror stories

I am having starting issues with my Grand Prix GT.  I turn the key and it does one of two things:

1.       Shut off (the lights and everything are on)

2.       Start at 1500-2000 rpms and stays there ( I was able to go 4 miles without touching the gas pedal because it stayed at 2000 rpm)

When it shuts off, if I rev the motor it will eventually stay on, but it sounds like it is struggling to stay on, it would stay at about 700 rpm and go slightly up and down.

A customer purchased a ZZP catback exhaust. Then they went to Midas to have it installed because they were $75 and ZZP wanted $100 to put it on. Midas did the install and the customer left. Shortly later the gas tank melted and gas was leaking. The car was towed into ZZP with the customer demanding we pay the towing bill, replace the gas tank and repair the exhaust. We explained that we were not responsible because we didn’t install it. Midas claimed they were not responsible because it was a ZZP exhaust and didn’t fit correctly.

When ZZP got the car in, we discovered that Midas had taken off the heat shield, shoved the exhaust against the gas tank and bolted everything down. They installed a pre-fitted catback system as the customer had asked. Investigating we found that the engine in the car was a replacement from a Regal with a different rear manifold. This put the entire exhaust out of wack. The factory exhaust, being much smaller than the 3” ZZP exhaust didn’t have a problem.

A customer from VA had a coolant leak and the car ran poorly. He took it to the dealer who replaced the supercharger and intake gaskets. Gave it back but the problems persisted so he returned and they replaced a ‘cracked lower intake’. Gave the car back but it still had problems. They told him the head gaskets were bad and replaced them. The problem was still there and they said that the heads were cracked. They wanted to replace them and he called ZZP. They wanted so much for factory heads that he could buy ZZP ported heads and pay for us to install them. He shipped the car here. We found that they had lost one of the throttle body spacer studs and replaced it with a bolt. The bolt bottomed out just as it appeared to tighten the TB. This caused the throttle body to not seal properly. Coolant to the TB leaked and got ingested into the engine. Total cost to dealer? Close to 3 grand. Total cost to get his car here? Around $500. Repair bill at ZZP? Less than $200.

A car came in from CT that barely ran. Customer had been working on it for over a year with a friend who knows the car helping him. We discovered valve springs were installed with the wrong retainers giving him 55# of seat pressure. One injector connector had RTV in it and was not making connection to the injector causing it to run on 5 cylinders. Head gaskets had RTV on them causing a loss of seal. Once these issues were fixed this 3800 with an XP cam and intercooler only dyno’d ~220WHP, had KR and high boost. We determined that the double roller was installed too far advanced and tore it back down. We were incorrect and later discovered the exhaust was so restrictive that we picked up over 80WHP by changing the cat back to better stuff.

A customer from WI with every high end mod we sell for an M90 car could not run faster than mid 12’s. They spent nearly 15k in ZZP parts and did a meticulous job with the install. All scans seemed perfect but the car just didn’t run the times. We dyno’d it and it made ~300WHP. After some time we tried removing the RT cat to see if that would help. The car picked up 60WHP and we tuned from there.

I high end build that should have run low 11’s was stuck in high 11’s. The car had already dyno’d over 400WHP and we had not changed anything. It took 3 days to figure out that we had changed something. We had painted the alternator bracket and it wasn’t making a good ground with the engine. Adding a ground wire dropped 4 tenths off the car’s ET.

A customer with our centrifugal kit in Canada was having problems getting the power out of his car. He added a complex wet nitrous kit at an installed price of over 2k. The car ran 14’s. Taking a long drive to ZZP, we removed the nitrous kit, discovered the RT cat was not flowing well and removed it. We then invited our customer to come to the track with us and with our driver piloted the car to run 11.7.

Off brand and RT cats often don’t flow well on high HP builds. Many times these cats can still be seen through giving the impression of high flow and low restriction. Only dyno testing can often reveal the problem.

————————————–

After MANY MANY issues with this engine I’ve finally given up with this car.  I had to pull the motor apart Three times before my machine shop(s) could get it balanced “Right”.  And then a rod let go because one of my machine shops shaved material off the small end of the rod (to balance it) and it let go of the wrist pin at 6000 RPMS.  Made a mess of the Block, and the $900 JE piston set (4 pistons are still good).  As soon as I get it back together its getting sold.  Thanks for the help thus far, ill be looking into buying a G8 GT.

Buying a ZZP engine has its advantages. We recommend always using a shop you can trust with experience.

]]> http://www.zzperformance.com/blog/horror-stories-and-instructions-on-choosing-a-shop-to-work-on-your-car/feed/ 0 http://www.zzperformance.com/blog/engine-balance-and-deleting-the-balance-shaft/?utm_source=rss&utm_medium=rss&utm_campaign=engine-balance-and-deleting-the-balance-shaft http://www.zzperformance.com/blog/engine-balance-and-deleting-the-balance-shaft/#comments Thu, 13 Oct 2011 22:33:07 +0000 ZZPerformance http://zzperformance.com/blog/?p=40 Continue reading →]]> With any engine balance is important, especially for high rpm operation. It’s a common misconception that the balance shaft is used to balance the engine. It is not. An engine’s rotating assembly is balanced so that when the crank is spinning in a circle the weight at any one point is the same. This makes it so that no uneven forces to try and move the engine in a particular direction at any point in it’s rotation. Hence the spinning is ‘in balance’. A great example is a tire. Have you ever had tire shake or driven a car before the wheels were balanced? Same thing. These forces at high rpm turn into a vibration which literally shakes your engine apart. In a motor, you add or remove weight from the crank, make sure the rods and pistons weigh the same. The 3800 uses external balancing as well, with a weighted balancer and a weight on the flex plate. The better the balance, the higher the rpm the engine will survive at.

Consider the math. An imbalance of one ounce (the weight of a rod bolt) 1” away from center at 2,000 rpm will be subjecting a force of 7 lbs. At 4,000 rpm, the force grows to 23.5 lbs! Double the speed again to 8,000 rpm and the force becomes 114 lbs! Keep in mind, this is one 1” away from the center of rotation. The idea is to show why balance issues are negligible at low rpm but insanely important at high rpm.

The 3800 has 6 cylinders, two banks of 3, 90 deg apart (90 deg V6 engine). This engine is actually 2 inline 3 cylinder engines together. At any given time a cylinder on the front is in the same position as a cylinder in the rear. The crank shaft has 30 deg offsets for journals where rods are next to each other. This 30 deg, plus the 90 degree V gives you 120 degrees. 3 cylinders x 120 degrees gives you 360 degrees or a full circle.

This design has some inherent problems though. As the 3 cylinders on one bank move up and down a shock is generated as they change direction (at the top and bottom of stroke). This shock cannot be countered by the other bank because they are on a 90 deg plane from each other. This creates an annoying harmonic that doesn’t affect engine balance or performance but it is noticeable in the car. As the engine speed rises, so does the frequency of this shock and it’s not felt much as it’s absorbed through the mounts and chassis. A good example of this is a subwoofer vs. a tweeter. Bass is low frequency sound and you can hear it for a long ways, it shakes your car. But no one ever complains about a neighboring cars mids or tweeters because higher frequencies do not travel as well or shake other objects. Same principal.

The balance shaft is an out of balance rod that create a harmonic to counter the feel of the inherent engine shake. The balance shaft is statically balanced so it will roll smooth but it is dynamically out of balance with weight on one end and an apposing weight 180 deg off on the other. This is done on purpose to cancel out the vibration inherent to a 90 deg V6 cylinder engine. Mainly it does it’s work at idle and low engine speeds where vibrations are felt the most. It does not keep your engine in balance; in fact it is purposely out of dynamic balance which is bad for performance. This trade off is worth it for the average consumer. The real problem comes when you want to use the engine at high engine speeds. Remember the math above about forces as they relate to rpm? It just so happens that the radius of a factory balance shaft is just over an inch but the out of balance (counter weight) is a lot more than an ounce! This translates to terrible internal engine shake and HP being used to create this vibration. For high rpm engine operation, it is recommended to eliminate or disable the factory balance shaft.

ZZP 1.0 PCM
Year of your car:XXXX

Model:XXXX
Core charge:I am sending in my PCM first
Option 1:none selected
Option 2:stock gearing
Option 3:stock injectors
Option 4:Rear O2 deleted  

Wizaired Cold Air Induction System (+10hp)
Model:Standard
Option 1:Add 4 inch K&N filter  

HV3 High velocity intake insert (+20hp)
Option 1:Add throttle body rubber gasket
Option 2:none selected  

Water Pump Underdrive Pulley (+4hp)

High Velocity Throttle Body for the L36 (+5hp)
Year of your car:XXXX
Model:Stage 1
Core charge:I am sending in my TB first  

Thermostats
Model:180
Option 1:add thermostat gasket  

ER ratio rocker arms (+10hp)  OR
Core charge:I am sending in my rockers first
Option 1:None selected  

GT Camshafts (+30hp)
Model:GT1  

ZZP downpipes (+7hp)
Model:2.5 inch bolt in With Cat
Option 2:None selected
Option 3:Add front and rear gaskets
Option 4:I’m keeping my stock DP  

• You would not run rockers and a cam, it would be one or the other.  Rockers(+10-15hp) are approximately a 3 hour job, and a cam(+30hp) is about a 10 hour job.
• You would run a 2.5” downpipe on a L36 car, 3” is to big (you will sacrifice down low torque).  Also a catted downpipe would not sacrifice any HP.
• A pcm does not increase HP much than 5hp or so, but it increases your cars overall performance with, firmer shifts, raised shift points/limiters, lowers Torque Management, changes fueling/timing at WOT, and much more.
• If you have a car with a 3.05 final drive (04+ Grand Prix not supercharged, Monte Carlo LS or Impala LS)  The HD upgrade kit will convert your 3.05 final drive ratio to 3.29 and it would improve your cars acceleration.

Alternator Voltage Booster
Model:Stage 1  

High flow fuel filter
Model:ZZP unit  

ZZP Modular Pulley System
Size:3.4
Color:Black  

Serpentine belts
Size:658 (replaces 660)  

NGK Spark Plugs
Model:TR6  

Thermostats
Model:180
Option 1:add thermostat gasket  

Wizaired Cold Air Induction System
Model:Standard
Option 1:Add 4 inch K&N filter  

ZZP 1.0 PCM
VIN :XXXXXXXXXXXXXXXXX
Year of your car:select year
Model:XXXXX
Core charge:I am sending in my PCM first
Option 1:none selected
Option 2:stock gearing
Option 3:stock injectors
Option 4:none selected  

You must add a bolt in ZZP downpipe or Ubend delete to make this above list safe. 

You could also look into our Stage 1 and 2 Performance Packages under Products/Performance packages.

If you have a 04+ Supercharged Monte Carlo or Impala, then you would want to run a .1 larger supercharger pulley than a 97-03 superhcharged car.

This is a build up for a stock supercharged car. 

Bolts on about 50hp and gains about 2+ MPG.

If you want to go one step further here is a couple options:

You would not want to run rockers and a camshaft, you would want one or the other.  Rockers give up to 20hp, but a VS cam will give about 35-40hp, a XP camshaft would give about 45-50hp.  Email us for larger build sheets.