OFFICIAL READ FIRST THREAD!!!!! I put the graphs back up for

L67 supercharged talk about modification, how to for making your car greater!

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OFFICIAL READ FIRST THREAD!!!!! I put the graphs back up for

Postby gtpforever » Wed Mar 14, 2007 2:34 am

Until you have a method to scan your car........ you will mod at your own risk!




For unlocking a factory deck.....



dealer code is - 02107#
Call 1-800-537-5140 206010#


Press and hold 2 and 3 -----write down #
press AM/FM button.....write down the next three. Done and done!!


1.) First you have to register with a free image and video hosting website. I use Photobucket. Here is a link...

You can also use Imageshack, Putfile etc.

2.) Upload your photo's and videos into your new online album. This is very easy and self explanatory once you register.

3.) Once you get your photo's/video's uploaded, underneath each picture you will see three boxes named "Url, Tag, and Img".

4.) To post one of these pictures on GTPWorld, You have to use the "image" button on the left side of where you type in your posts, under where it says 'Insert'.

5.) Click on the 'image' box. An Explorer User Prompt will pop up. There will be a white area where you can paste in text.

6.) In your online album, copy the text inside the "Img" box.

7.) Paste this text into the Explorer User Prompt text box.

8.) Click Okay.

9.) You will now see the picture code inside the body of your post. It will look like this.....
10.) You will notice that there is an additional htt p: / / at the front and [ img ] at the end. You have to backspace these out for your pic to show up. The correct code looks like this....
11.) Now you can click on the Add Reply button and your pics will be able to be viewed by everyone!

12.) If you want to post a video, just copy the 'Img' text in your album, and paste it directly into the body of your post.
Hopefully this helps people with adding pictures...this is how i have to do it with Photobucket anyway. It won't work for me any other way lol. Hope you all get it to work!

Quick example.....

The code you see below \/ \/ \/ \/ .......

........will show this picture \/ \/ \/ \/

And there you go! Now you try it!

Fuel Pump By-Pass

Make your own CAI.....



Make your own TB Heatshield......

Thanks for the info Arkanzan Wheeler!

1997-2003 Pontiac Grand Prix Consumer Guide

http://consumerguideauto.howstuffworks. ... prix-6.htm

Custom Lexan C

DIY MODS and MISC: ... 8a913e8b8b

HUD Solder Fix:

Radio Backlight Fix: ... p?t=662868

Trouble Codes: ... _codes.txt

GP Body Shop Book: ... s_List.pdf

Custom Mods:

SC Oil Change Write-Up: ... x.html#top

Torque Specs:

List of GM part numbers, Grand Prix specific:

How to Locate Your Paint Code: ... ontiac.htm

supercharger info:

Spark plug check: ... talog.html

Back In Blacks webpage...

Boost Bypass Valve Mod:
Read all before adjusting the valve either way

Cam Install: ... l_new.php/

Climate Control Diagnostic:
You must have a CJ2 unit (pictured below) to view this information. To enter diagnostics mode:
Press and hold both the Driver and Passenger knobs in simultaneously until the display changes to read "-00". To change position, turn the Driver knob to the desired number and turn the Passenger knob one click to view the data for that position.

Position Description US Observed on mine Canada
-00 Error codes (List of Trouble Codes Below!)
-01 (servo position) 103-107 43-162
-02 (servo position) 128 120-202
-03 (servo position) 150 162-194
-04 CJ2 Fan Speed Low=15, 29, 44, 58, 71, 86, 110=High, CJ2 Unit will adjust to other increments as needed
-05 (servo position) 93 88-191
-06 (servo position) -152 00-252
-07 (servo position) 00 0, 34-255
-08 (servo position) -155 00-255
-09 (servo position) 00 0, 23-255
-10 ? 04 04
-11 CJ2 Vent Mode 1=Def, 2=Bilevel, 3=Auto, 4=Lower, 5=Def+Lower
-12 Engine Coolant Temp -60 degrees 80=104, 95=131, 100=140 Peak@135F
-13 Actual Vehicle Speed in MPH
-14 (servo position) 00 21=0
-15 ? 39 44
-16 Radiator low fan turn on temp -106 207
-17 Radiator low fan turn off temp 196 199
-18 ? 50 51
-19 (servo position) 162-169 40-172
-20 Affected by cabin temp sensor 89 50-172
-21 (servo position) 00 ?
-22 Sunload Sensor -117 LIGHT=126, 218=DARK
To return to normal operation, press the MODE button next to the Passenger temperature knob.

This is a list of the Trouble Codes displayed by the CJ2 Unit.
A two digit code indicates a current fault while a three digit code indicates a historic fault.
Trouble Code Description
00 No System Fault
01 or 101 Inside Air Temperature Sensor Short
02 or 102 Inside Air Temperature Sensor Open
03 or 103 Ambient Outside Temperature Sensor Short
04 or 104 Ambient Outside Temperature Sensor Open
05 or 105 LH Electric Actuator Open or Short
06 or 106 RH Electric Actuator Open or Short
07 or 107 UART Serial Data Line Fault
08 or 108 Solar Sensor Open
To clear codes from the CJ2 Unit, press the A/C Mode button.

IMPORTANT: Before entering programming mode, have in possession all of the transmitters you will be using on the vehicle. Once you program the transmitter, all previous codes will be erased from the memory. The other transmitters will not be functional until you program the transmitters again.

1. Remove the key from the ignition.
2. Close all of the doors.
3. Remove the MALL PGM fuse from the fuse panel. Use the legend on the fuse panel or owners manual to properly locate the MALL PGM fuse.
4. Insert the keys into the ignition, and turn to the ACC position.
5. Turn the key to OFF and then back to ACC within 1 second.
6. Open and close any vehicle door. A chime will be heard when the system enters the programming mode.
7. Press and hold the transmitter LOCK and UNLOCK buttons simultaneously for 14 seconds. IMPORTANT: After 7 seconds, a chime may be heard confirming successful synchronization. It is necessary to wait approximately 14 seconds for a second chime that will confirm successful programming.
8. Repeat the previous step on each additional transmitter to be programmed (including any existing remotes).
9. Remove the key from the ignition.
10. Install the MALL PGM fuse.

(just so everyone knows if you use a remote that was already used on another vehicle it will lock and unlock and pop the trunk on both vehicles)


VENDORS: (No longer in business) ... Store.html ... oducts.htm ... tegoryId=3 ... 358129612c ... prix.shtml ... tegory=191
Now fixing....1998 Silvermist GTP with about 182,000 miles! Dead till fixed!!!!
Current Mods: XPZ, Stage 3 heads 150int/130exh, IRC bar/plate I/C, N*, 85mm maf, ZZP billet fuel logs, PRJ wires, 2.55, 2.8, 3.25, 3.4 pulleys and might have spun a bearing while dynoing!!!!! Worlds fastest GTP to get in the driveway to get rebuilt. No one comes close.
Image <<<<<Its BACK so watch out!
Good-luck to everyone who is true to the M90.....its like having a fat wife, sure a turbo (hot 120lb blond is better, but the M90 (fat wife) will be there forever!
GTP World Blower Freak (4000 club)
Posts: 4515
Joined: Mon Aug 07, 2006 12:00 am
Location: Detroit, MI

OFFICIAL READ FIRST THREAD!!!!! I put the graphs back up for

Postby 1BADPRIX » Wed Mar 14, 2007 6:08 am

Knock retard Article by Bill Hooper.

Knock Retard

What is Knock Retard?

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.

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 propogating toward each other, thus the collision. Real KR does NOT occur without detonation occurring FIRST.

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.

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.

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.

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.

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.

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.

What is REAL KR and what is FALSE KR?

Real KR is KR that grows with engine RPM and engine load. It depends entirely on detonation, which is dependant upon throttle position, MAF, MAP, engine load, engine temperature, and RPM. As RPM and engine load increase, the chance for KR (or higher KR) increases. As the vehicle shifts to the next gear, KR will usually make a small jump up as well due to the higher engine load.

False knock is characterized by a sharp spike to an immediately high value of KR followed instantly by the KR Recovery Rate. It doesn't grow with engine RPM or load, it jumps to a high value on throttle input and then recovers to a low value, or zero perhaps, as engine RPM continues to increase. Note that this is exactly opposite to the characterization of REAL KR. Remember, knock is simply specific noise detected by engine microphones. Because it happens to fall with in the frequency of real KR does not necessarily mean that it IS real KR.

What can cause FALSE KR?

Outlined below is a list of things that can cause false knock.

1. Sway bar hitting exhaust downpipe - This happens typically with the downpipe of headers because that configuration puts the downpipe in very close proximity to the sway bar much closer than the stock downpipe. The banging noise from the two metal objects hitting may resonate through the frequency band that the PCM detects as knock through the knock sensors. The solution to this is to flip the swap bar over. Because of the curvature of the sway bar near the downpipe, flipping it will allow the sway bar to curve AWAY from the downpipe rather than toward it.

2. Transmission oil stick hitting exhaust crossover pipe - This typically happens with the crossover pipe of headers due to their large size and proximity as opposed to the stock crossover. The banging noise from the two metal objects hitting may resonate through the frequency band that the PCM detects as knock through the knock sensors. The solution to this is to carefully bend the trans oil stick away from the crossover pipe so that the two do not touch.

3. 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.

4. Loose knock sensors, or knock sensors that are too tight. Double check that your knock sensors are torqued to spec (14 lbft).

How do I FIGHT KR?

The simple and most basic answer is in one of the following (in no particular order):

1. Reduce boost - Boost is a direct reason for increased cylinder temperatures and thus detonation.

2. Reduce timing (if added) - Timing advance is another direct reason for increased cylinder temperatures.

3. 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).

4. Add water injection - While much harder to tune, this is still an option for reducing charge temps.

5. 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.

6. 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.

7. Free intake and exhaust restrictions - i.e cold air intakes, cams, headers, cat-back exhausts, larger throttle bodies, etc.

8. Prevent parts from hitting (i.e. header downpipe with front swaybar)

9. 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.

1. Reduce Boost - As you increase boost, cylinder pressures will increase because more air is being forced into the engine. As pressures increase, the temperatures will naturally increase as well and will lead to detonation. By lowering boost, you lower the cylinder pressure and temperature and thus deter the likelihood of detonation. The bottomline to this solution is since we are all enthusiasts and want more power, this will be our LAST solution.

2. Reduce Timing - If you are experiencing KR and you want to get rid of some (perhaps all) of it, AND you have the ability to add/retard timing to the engine (via a MAF Translator Plus, a DHP PCM, a ZZP Mini-AFC, or the ZZP ICCU), then start by reducing to 0 (or until KR is gone) the added ignition timing. If you still have some KR, you can then start RETARDING the timing some until KR has been eliminated. Unfortunately, if you are on the edge of having KR then adding timing is the FASTEST way to get KR and a LOT of it.

It is common knowledge that KR is not exactly a one-to-one ratio to the amount of corresponding ignition timing that is pulled. In my experience, for 5 degrees of KR 6-7 degrees of ignition timing is pulled. The bottomline to this solution is since we are all enthusiasts and want more power, this will be our second to last solution.

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.

3. 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 bottomline to this solution is this is the ideal way to go!

4. 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 delamination of the teflon from the rotor and ultimately damaged their SC so BE CAREFUL. The bottomline 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.

5. 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.

6. 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. Bottomline 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 creap well past the thermostat temperature. Bottomline 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.

7. 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 lbft of torque!!! Bottomline is these are ALL excellent mods to do and are the kind you should be considering.

8. Prevent Parts From Hitting - This has already been discussed in the "What can cause FALSE KR" section. See that section for more detail.

9. 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:

Engine RPM - Useful for monitoring your ICCU various fuel and spark segmentations if you have a ZZP ICCU, or if KR is occurring at only certain RPMS and so forth.
B1S1 O2 Sensor - For WOT adjustment. Typical accepted values range between 0.88 - 0.93 volts. Higher values indicate a richer mixture, while lower values indicate a leaner mixture.
Injector Pulse Width - Must be less than 23ms at 5200 rpm, 21.4 ms at 5600 rpm, and 20ms at 6000rpm. Anything equaling or greater than these values at these RPMs indicate that your stock injectors have gone static (i.e. always on at WOT).
Spark Advance - Look for values from 15-17 with no knock on a stock PCM. Values below 15 will likely have knock associated.
Knock Retard - Best is obviously 0. Most authorities agree that approximately 2 hp per degree of knock retard is lost. An intercooler is the best choice to take care of this.
Long Term Fuel Trim - Used to determine if your engine is running within the adjustable limits of the PCM. LTFT should never read as low as -23%, nor as high as +16%. Anything between means that the PCM is able to correctly adjust for engine input/output variations.
Throttle Position - Used to see when you have gone to WOT, at idle, or at cruise. Range should run from 0 to 100%.

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:

AE (acceleration enrichment)
PE (power enrichment)
KR attack rate
KR recovery rate
KR starting voltage level (noise floor)
Capping maximum KR
Disabling knock sensors.

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.


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.


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:

Intercooler LS1 throttle body kit Ported and Polished SC Custom PCM

Custom CAI Mild CAM Headers Offroad Pipe

No Ubend No Cat 2.6" Pulley 3.29 Gears

LSD Raybestos Clutches Mild Shift Kit 10 Deg Added Timing

38lb Injectors Mini-AFC

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.

The Knock Graphs

The graph below (Graph 1) shows the knock sensor voltage level of my car at idle. Essentially, the signal is simple engine noise, but note the scaling on the Y axis. There are some peaks up near two volts, but the bulk of all of them are down near a volt or below. There is no actual knock in this particular signal. The X axis is scaled in units of time.
Graph 1

The next 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.

Graph 2

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 Bottomline 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.
Graph 3 What the PCM believes to be real knock.
Graph 4

Now, is this noise floor parameter REALLY "fixing" KR? Is it really ELIMINATING KR? No. Absolutely not. What it is doing is simply masking KR up to a 1 volt. Notice that these graphs indicate by definition that this is FALSE KR. It is KR that jumps immediately to a BIG value and then recovers to 0 as engine RPM increases. It appears that this parameter does MORE than just mask KR up to 1 volt because it is SO much harder for KR to be generated in the car. Unfortunately, information about this particular parameter is limited, and it is currently unknown what it really does. I can say, that the system still detects knock at all levels above a volt (I can generate KR from 1 degree up to 15 degrees). When I add timing without race gas, I start to see KR at around 6 added degrees pretty easily (23 degrees overall ignition timing), so the system is working and working well. I have had this change to the PCM since October of 2002 with no ill effects in about 5,000 miles of driving (I put on a lot of miles). The fact that my heavy KR started immediately after my trans rebuild also lends itself to false knock (extra noise generated by the trans).

So, the bottomline to this mod is this . it should NOT be your first mod, but if you have tried everything else and have similar KR issues that I have described (large KR spikes in small pedal travel that recovers as engine RPM increases), then you may want to look into this one. If I didn't have THIS one done, I would not be able to run at the track very well at all. With the help of this PCM change by DHP, my vehicle is running between 12.62 and 12.84 at the track.

Good luck to everyone, and I sincerely hope something out of this crazy document helps somebody out there.

Bill Hooper
Joe McCann
President / M.C.C.G.P.
Intercooled 2K3 Blue-Black Metallic GTX
13.024@107.92 MPH
317.5 FWHP / 424.1 ft lbs
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Postby ArkanzanWheeler » Tue Jun 05, 2007 6:15 pm

Your Supercharger (SC) pulley is pressed onto the SC shaft. There is only one way to safely take that pulley off and that is with a special puller that is designed for these pullies. You can get them through ....... ... &catid=111 ... +Tool.html ... puller.htm ... -p-51.html
Most of these places will rent them out to you and send them in the mail for alot cheaper also, so there is no excuse as to why you do not use one.
There are many different ways that people have tried to take these pullies off, 2 or 3 arm standard pulley pulers only bend the backside of the pulley and if you do it wrong you can mess up your SC shaft which gets pricey to replace.
The idea that started this post was just using a hammer to hit it off. It was said a rubber mallet would take it off, but these things are pressed on the shaft with alot of force (when you take one of these pullies off and put one one you will know what I am talking about). Even if you try using a rubber mallet you take a chance of missing the little pulley and hitting something that you need like the fuse box that is right after the pulley. When you realize that the rubber mallet is not even making it budge you might get the idea that bigger is better and go get a metal hammer. Now all you are going to do is bend the pulley and possiblly the SC shaft and you could miss, not only hitting the fuse box like I mentioned before but now you can actually crack the case on the SC snout!
Do yourself a favor and get the right tool for the job...
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Postby DarkRelic » Tue Jun 19, 2007 11:36 am

Installing your boost Gauge.
(easier to perform on a cold engine)
you need:
9' or more plastice 5/8" tubing (purchase at an parts store)
Rubber "T" fitting, and rubber vaccum line "unions"
Boost Gauge
Electrical connectors or wire splices (18-22 gauge)

-Remove your engine cover if installed
--Follow the Plastic Vaccum line comming from a "T" fitting underneath your supercharger snout to the back of the engine



- I actually cut the existing Black vaccume line and installed a rubber "T" fitting

-Route the plastic hose from the inside of the car, underneath the carpet of the passenger side back-wall under the glove box. ( you may need to poke a hole in the rubber grommet that seals the hole to the engine firewall)
- connect the plastic hose to the "T" fitting you previously installed
-Route the other end of the plastic hose under the dash, but over the steering wheel linkage cover

Most Boost Gauge Kits only come with 6' of plastic hose. you can purchase a second one at any autoparts store.

-Using the second plastic vaccume hose feed it through the top of your dash underneath where your HUD pod is located (if using HUD pod)


- connect both vaccum lines utilizing the rubber vaccum union (cut away excess vaccum line)

-If your boost Gauge is not lighted and does not require electrical power, install Gauge into desired opening in your Pod and connect the vaccum line you installed via 5/8" ID vaccum union.

-if you require electrical power than Tap into this wire from the harness on the back of your light selector switch

Open the driver's door, and pop off the trapezoidal panel that's there on the side.

Once off, unplug the wire harness connector that connects to the headlight dial and dimmer dial. Flip the connector so the top of it is facing downward, and locate the wire on the row nearest you, second from the right (click picture for larger view) as seen here and tap into it:


That's it for the dimmer circuit. Make sure to connect this line to the appropriate input on your gauges.

All that's left now is the ground. I used a connector and wire right under the bolt that connects the dash frame to the car's chassis, because there is already exposed metal there, and it was very convenient. Choose a good ground anywhere you feel comfortable, and connect the ground to your gauges.

(some of the info and pics were taken from Thanks Jerry.. LOL)


-250,xxx miles
3.4"pulley Gen V, SLP RR, SLP Headers/Cat-Back, ZZP PCM, Eibach/AGX suspension, GMPP full upgrade kit, GMPP rear STB, WBS Perf. control arms (all 4 corners), TEP 3.29 transmission, F-Body Brakes, Modified Projector Headlights, CAI, 180*therm, AL104, WBS OS Radiator, 18x7.5" Verde Protocol Wheels
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Postby slammedGP » Thu Oct 18, 2007 6:01 pm

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Postby slammedGP » Sun Dec 30, 2007 11:42 pm

Another good page.

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Postby Condore21 » Thu Jan 17, 2008 9:00 pm

Here is an install guide on how to install a pillar pod and aeroforce gauge into your 97-03 grand prix.
Suggested parts for install, add-a-circuit by littlefuse, about 10' of 16-18awg wire, one butt-splice, 10amp mini fuse.

Step 1: Locate fuse panel in glove compartment. (on far right side of glove box, pull out the little storage tray)

Step 2: Locate the "sunroof" fuse in the fuse block. (should be toward the lower right side of the block, also labeled on small tray piece that you removed to get to fuse block)

Step 3: Pull out sunroof fuse and plug the fuse into one of the slots on the add-a-circuit.

Step 4: Strip an end of 16-18awg wire and crimp it together with the add-a-circuit. (add-a-circuit already has a wire lead off of it with one end butt spliced)

Step 5: Plug in add-a-circuit to the open fuse block where you originally removed the "sunroof fuse" (note- if your car does not have a sunroof, any 20amp fuse block that does not have power at 'key off' will suffice)

Step 6: Remove the lower portion of the dash board directly under the glove box. (Three [3] black push-ins on passenger side) Don't forget to twist out the floor light from the lower dash portion.

Step 7: Remove lower portion of dash board on driver's side, directly above the gas/brake pedals. (Two [2] black push-ins hold this side in)

Step 8: Run other end of 10' wire through the back of the glove box and down into the passenger floor area.

Step 9: Pull back the carpet under the passenger area floor and run wire behind carpet. Continue to do this behind HVAC tubing located behind the front of the center console.

Step 10: Now that the wire is on the driver's side of the vehicle, pull back the carpet behind the gas/brake pedals and continue to run the wire back behind there.

Step 11: Now that the wire is halfway run, we are going to need to take off that pesky weather stripping and old pillar cover.

Step 12: Insert smoke break here.

Step 13: The weather stripping that runs along the top of the ceiling and down along the front A-pillar can simply just be pulled down. (it is only held in by glue, be careful, it is really sticky stuff)

Step 14: Now that the weather stripping is out of the way, be sure to remove the little screw on the bottom of the weather stripping near the door hinges to give yourself some extra slack to work with.

Step 15: The stock A-pillar cover is held in by 2 clips. It should take just a minimal amount of effort to "pop" it out of the A-pillar. Basically, just pull it off, but be gentle.

Step 16: Take new Pillar pod and position it in place where you would like it to be.

Step 17: Use the screws supplied with the pillar pod (if bought from lo-tek, zzp does not include screws) and mark the screw hole position on the cars A-pillar. Basically, take the screw or a nail and scratch the paint where the screws will go through the pillar pod screw holes. This gives you a reference point for you to drill the screw holes later.

Step 17: Now that the drill spots are marked, take a punch or a nail and a hammer and punch the screw holes you marked out on the A-pillar. This is so that the drill bit will not jump around as you try to start to drill the hole.

Step 18: Use a smaller drill bit than the size of the screw and make a starter hole in all 2 or 3 "punched holes" (amount of starter holes depends on if you got a 2 pod or 3 pod pillar)

Step 19: After your starter holes are done, find a bit that matches the thickness of the screws you are using to hold the pillar pod in place. Now drill into the starter holes with the bigger bit until you are through.

Step 20: After your holes are drilled, try to screw the screws in place with a hand screwdriver to see if they are the proper size. If screw will not screw in, take the drill bit you just used and longate the holes. Basically, put the drill bit in the hole and move it up and down at an angle or side to side at an angle. Now test fit the screw to see how it screws in. Repeat until the screw threads in with no problems.

Step 21: Insert smoke break here.

Step 22: Once you have your holes drilled to your liking, it is now time to run the rest of the wire. Pop off the panel on the inside of the drivers side dahsboard.

Step 23: Now it is time to take the wire we ran earlier and run it up to our pillar pod.

Step 24: Run the wire up and over your steering column and then up and over your BCM (little black box under the left side of the dashboarrd)

Step 25: Now you can pull the wire through the little panel you popped off on the drivers side dash.

Step 26: GM was nice enough to put a hole or two in the top of our dashboards at the bottom of the A-pillar so we could run our wire through it.

Step 27: Snake a section of coat hanger through the hole at the bottom of the A-pillar that GM was nice enough to leave us as mentioned before. Attach coat hanger to end of the wire via the little panel we took the cover off of.

Step 28: Pull coat hanger up through hole and voila your power wire is now nearing the end of its run.

Step 29: Now take the gray cable which runs to the OBD II sensor and run it up and over the steering column like you did with your 16-18awg wire.

Step 30: Run gray cable up and over the BCM (little black box) and through the little panel hole on driver's side of dashboard.

Step 31: Snake wire through same hole as the power wire like we had just done previously. (Note - be careful not to pull too hard and destroy the plug at the end of the cable)

Step 32: Now that we have both wires ran to the location of the pillar pod, we have to decide which hole to use to house the Aeroforce gauge.

Step 33: Insert another smoke break

Step 34: The middle hole was chosen in this case because it was in perfect line with the driver's site.

Step 35: Now that your location is picked, we are going to connect the Aeroforce gauge harness wire to the wire that we have just ran. This includes stripping the other end of the wire (cutting back any extra wire that is not needed first)

Step 36: The RED wire is the only one we will be needing off of the Aeroforce gauge wire harness. (green and white are only used for analog inputs) Strip end of RED wire and connect the red wire from the gauge harness to the power which we just stripped previously. (DO NOT chop off the green and white wires, they can be rolled up and tucked out of the way incase you need them in the future)

Step 37: Take the silver U- bracket that comes with the Aeroforce gauge and keep it on the inside of the pillar pod. Insert Aeroforce gauge into front of pillar pod. Use the two (2) black plastic nuts to hold the bracket onto the gauge. (note - the bracket will fit either way, thanks Slammed GP)

Step 38: Once the gauge is in place you can connect the wires into the back of the gauge. (Note - next to where the two harnesses plug in you will see a red plastic square. That is a jumper for running the gauge without the external power wire. This MUST be removed in order to run the gauge off of the external power wire. When you remove it you will see the two [2] silver prongs like in the picture above, that's what it should look like)

Step 39: Put pillar pod in place and start putting the screws in, but only a couple of threads to hold it in place. You do this because the weather stripping we took off before sits inbetween the pillar pod and the pillar.

Step 40: Put weather stripping back in place, then finish tightening the screws on the pillar pod.

Don't forget to put that little screw back in the bottom of the weather strippipng.

Step 41: Once you have that done, you can plug in the big black connector into the ODB II port.

Step 42: Turn car on and look at your wonderful accomplishment.

Step 43: As long as everything appears to be in proper working order, you can put the two (2) lower dashboard pieces back in place. Remember two (2) black push-ins on driver's side, three (3) black push-ins on passenger side.

Step 44: Put little storage compartment back into the glove box. It just snaps back into place.


Step 45: Celebrate with JD IN THE HOUSE!

Special thanks to ShadowGTP for letting us use his car for the install and to Babygirl for taking the pictures. More to come as soon as ShadowGTP gets his boost and Oil Pressure Gauges
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Postby gtpforever » Thu Feb 14, 2008 5:19 am

General word abreviations

A/F = Air Fuel Ratio

CEL= Check Engine Light

DHP = Digital Horse Power

DP = Down Pipe

DTC = Diagnostic Trouble Code

EGR = Exhaust Gas Recirculation

FTW = For The Win

GMPP = General Motors Performance Parts

GP = Grand Prix

GTP = No one really knows

GTP FTW = GTP For The Win

IAC = Idle Air Control

IPW = Injector Pulse Width

IAT = Intake Air Temp

KR = Knock Retard

LTFT = Long Term Fuel Trim

MAP = Manifold Absolute Pressure

OBD II = On-Board Diagnostics

P&P = Port and Polish

PE = Power Enrichment

PW = Power Window

PFYC = Parts For your Car, An online parts store ( )

SES = Service Engine Soon

SLP = Street legal Performance ( )

STFT = Short Term Fuel Trim

STFU = Shut The F*** Up

S/C = Supercharger

TDC = Top Dead Center

WOT = Wide Open Throttle

ZZP = ZZPerformance ( )


Aeroforce = A gauge used to scan multiple parameters using OBD2. ( )

AFC = Air Fuel Controller

Autolites = Autolite spark plugs

CAI = Cold Air Intake

DHP PCM = Power train Control Module made by DHP

DHP P/T = Digital Horse Powers Power Tuner software, used to tune.

3" DP = Used for Mild Mods (gets rid of U-bend)

FWI = Fender Well Intake

IC = Intercooler

SSI/C = Short Stack Intercooler

ICCU = In Car Controller Unit

MPS = Modular Pulley System

N* TB = The NorthStar Throttle body out of a Cadillac.

PEM = Ported Exhaust Manifold

Plog = ZZPerformance's Power Log ( )

RR = Roller Rockers

T-stat = Thermostat

TB Spacer = Throttle Body Spacer

TOGs = The Other Guy Headers ( )

U-bend delete = A U shaped piece in the stock cat back that is very restrictive and is usually removed.

VOM = Volt Ohms Meter or Multi Meter

Wiz = Wizaired Intake ( )


BBV = Boost Bypass Valve

DIC = Driver Information Center

EGR valve = Exhaust Gas Recirculation valve

HUD = Heads Up Display

IAT = sensor Intake Air Temperature sensor

ICM = Ignition Control Module

MAF = sensor Mass Air Flow sensor

PCM = Power train Control Module

TCC = Torque Converter Clutch

TB = Throttle Body

TPS = Throttle Position Sensor
Now fixing....1998 Silvermist GTP with about 182,000 miles! Dead till fixed!!!!
Current Mods: XPZ, Stage 3 heads 150int/130exh, IRC bar/plate I/C, N*, 85mm maf, ZZP billet fuel logs, PRJ wires, 2.55, 2.8, 3.25, 3.4 pulleys and might have spun a bearing while dynoing!!!!! Worlds fastest GTP to get in the driveway to get rebuilt. No one comes close.
Image <<<<<Its BACK so watch out!
Good-luck to everyone who is true to the M90.....its like having a fat wife, sure a turbo (hot 120lb blond is better, but the M90 (fat wife) will be there forever!
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Postby gixer2000 » Thu Feb 21, 2008 5:00 pm

now i wont have to search for this pic next time someone needs it

L67 Pulley Diagram and locations
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Postby Condore21 » Sat Mar 08, 2008 2:47 am

This should be a quick down and dirty to the ever present question. When can I run a 3.4, 3.25, 3.0 etc.... Take into account this write up will be on the more conservative side and I think everyone will agree that this aplies to 95% of GTP's. Obviously that 5% applies to people with already hurt motors or if you have 150k miles, have gone 10's of thousands of miles between oil changes etc... you may want to rethink modding at all and start fresh. With this list you should be knock free, however its always a good idea to either buy a scantool or join one of your local chapters and find someone close by with one to scan for kr, however like I said this list is designed to almost guarntee 0 KR. Anyone please feel free to addin suggestions or comments and I will adjust this accordingly.

Well start with the 3.4 pulley as it usually starts the majority of these questions. Below you will find a list of supporting mods that should be in place prior to installing that 3.4. Can you get away with less? Possibly. Have people gotten away with less? Yes. Do you want to take the chance? Enough said.

1. PCM- standard v 1.0 will suffice at this level.
2. CAI/FWI- Cold Air Intake/ Fenderwell Intake, you can build your own or purchase one from a vendor.
3. Ported Exhaust Manifolds/ Headers/ ZZP Powerlog- your choice, at this level Pems or the Powerlog are fine, if your planning on further modding later you will need headers, only you know your budget.
4. 3" Downpipe- Crushbendt which most exhaust shops will do is unadvised, preferable to purchase an aftermarket from one of the vendors.
5. 1-2 Heat range colder plugs. i.e Autolite 104's or equivelent gapped in the .055-.060 range
6. Ubend delete- just after the cat, most exhaust shops will be able to remove this and put in a straight pipe.

Thats it, doesnt sound too hard right? Fortunatly your reading this, back when alot of us blew our motors there was no such write up and no such guidance. These 5 items are considered necissary, of course you can change your thermo to a 180 unit, also wouldnt hurt. Also quite a few people add a set of 1.9 ratio rockers to that list. If you plan on staying at this mod level, I agree, add the rockers, if your planning on continuing on in the quest of more speed and wont be at this level for very long skip the rockers.

Now onto the 3.2-3.25 Pulley. Obviously this is going to take more extensive supporting mods. Add all from above and include:

1. Camshaft- take your personnal pick, do a search these have been compared time and time again. Addin supporting components, i.e stiffer springs, new pushrods, check with the vendor for individual needs.
2. Ported and Polished heads, larger valves- check with the vendors on this one, will be your best bet to invest in a stage 2 or 3.
3. Headers- if you had Pems before your dangerously close to being out of their level, sell and get some headers.
4. Larger Throttle Body- again these have been compared, take your personnal pick.
5. 2-3 heat range cooler plugs, you can stay with 104's but may need to switch to 103's
6. Retuned PCM to add in the cam and free flowing heads etc....

3.0 Pulley needs extensive mods, and honestly you shouldnt even be considering if you have to read this, but just in case take all from above and add:

1. High flow Cat
2.Cat-Back system
3. 42.5# injectors (needed for 3.1" pulley and smaller)
4. Upgraded fuel system
5. Stage 4 heads
6.Powertuner/HPTuners or some other means to custom write onto your PCM during a dyno session.

Now yes notice I didnt say anything about Intercoolers in any of those combinations. Either a Short Stack or Full size intercooler obviously adjusts those combinations. However I dont agree with the idea of just slapping on an IC to address an issue. Can you run a 3.25 with a full size IC and no other supporting mods? Our vendors say yes. Will you get knock? No probably not. Is it a knucleheaded way of thinking? Abso***inglutely. Go ask people who have dealt with forced induction far longer than our motors have been around, if they would almost double the stock boost with just an IC backing it up, not a single one will say yes, Ill bet my next year salary on it. IC's are great, and have their uses, but you need to have a foundation first. Endeth the sermon.

*A method of scanning is ALWAYS recommended when modding your car. Whether it be an aeroforce gauge, tuning program, or other scan tool.*
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Postby gixer2000 » Tue Jun 24, 2008 2:12 pm

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Postby gixer2000 » Tue Nov 11, 2008 5:02 pm

How to change your flex plate without pulling the motor or trans
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OFFICIAL READ FIRST THREAD!!!!! I put the graphs back up for

Postby Gibby » Tue Feb 03, 2009 2:17 pm

I thought I would add this link it is good if your looking for any stock replacement parts..
gtpforever wrote:Now I know you live in Cali so thats complicates things for you compared to the rest of us who live where we have rights

NIC cam, tuned by me. Best time of 13.35 @107. Cant keep tires from spinning during WOT shifts, need slicks.
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OFFICIAL READ FIRST THREAD!!!!! I put the graphs back up for

Postby tomcat81970 » Sun Apr 05, 2009 9:35 pm

Vacuum lines:
Top of the Engine in exploded view, i got this from a dealership... This was in another thread, but im not sure where it went...
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Posts: 2363
Joined: Mon Jan 26, 2009 1:00 am
Location: Boise, ID

OFFICIAL READ FIRST THREAD!!!!! I put the graphs back up for

Postby Gibby » Wed Apr 29, 2009 1:31 am

Great fender well intake write up...... ... =5&smode=1
gtpforever wrote:Now I know you live in Cali so thats complicates things for you compared to the rest of us who live where we have rights

NIC cam, tuned by me. Best time of 13.35 @107. Cant keep tires from spinning during WOT shifts, need slicks.

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