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Pontiac Grand Prix Performance Modifications

gxpdadgxpdad Member Posts: 2
I recently purchased a 2006 GXP loaded . The question I have is what tweaking can I do to get a bit more HP. I did purchase a KN Filter and I am looking for some advice.


  • rmozolrmozol Member Posts: 124
    Try and get the magazine "Chevy HiPerformance" over the last 8 - 9 months? They did a buildup on a 5.3, in a truck though. They did rocker arms, cold air, reprogram, and got another 40? horses, and 60? ft/# of torque. They did more, and got more, I just can't rememeber the details. It had a step-by-step buildup though.
  • gxpdadgxpdad Member Posts: 2
    thanks for the info I'll ck it out. My gxp is black with the leather/suede combo, DVD Nav ,sunroof, Monsoon speaker system etc... I get a lot of compliments the 18 chrome wheels really make it stand out
  • rmozolrmozol Member Posts: 124
    As far as the additive, it's kind of a wash for price. Unless you can get it VERY cheaply, it costs more actually. Figure $6 for a bottle, and 17 gallons, and that works out to an extra 35 cents a gallon. Around here, premium doesn't have the 10 cent jump like regular to mid-grade. It's only about 13 to 15 cents a gallon more than regular. I found pads I'm getting too. EBC makes a "red" series for our cars. They bill them for "fast street driving and heavy braking" which MIGHT fit! :) They are said to reduce brake dust a LOT, according to the manufacturer. They're only $80 a front set, including shipping. I just ordered a set!
  • eagle75eagle75 Member Posts: 16
    Be interested to hear how the pads work out for you. The original front pads on my former '04 Bonneville GXP were replaced by the dealer at 30k miles (they were about worn out) with ceramic pads, and that eliminated 90% of the brake dust. I should have done that early on.
  • smallegansmallegan Member Posts: 10
    Has anyone has their computer chip reprogrammed. I am interested in getting the rev limiter removed and possibly tweaking some of the other programs. I found a place where you can buy the programmer for the 05 GXP online but I have an 06. Will this work for me?

    Also has anyone modified their exhaust? I love the low end idle rumble but my GXP seems to lose it roar at higher speeds...

    And what about the potential of a supercharger or turbo? I have read that there is a possibility that the transmition can only handle the stock engine. Any thoughts?

    Lastly I asked before but got no we have anyone here who has put in aftermarket car audio equipment?

  • erichthecatterichthecatt Member Posts: 37
    (Also has anyone modified their exhaust? I love the low end idle rumble but my GXP seems to lose it roar at higher speeds(

    I took the stock mufflers off of my 05 bonneville gxp, and put on the flowmaster "hush power 2" Wow, what a differance. Has a great low rumble tone, and a great sound on take-off, depending on how heavy your foot is. Ive had people back off at a green light, and i know its the intimidation of the growl. check out their website, and you can actually hear the mufflers. I was really surprised because the sound was pretty much identical to the way mine sounds. GAry
  • tlaurotlauro Member Posts: 504
    I would caution you against any after market chip reprogramers for the LS4 as I've yet to see any real results from them So far the only two companies doing any program tweaking have to have the original PCM's and they reprogram them from there. Both have worked very well and result in about a 15hp increase and of course tranny shifting and limiter changes/removal. Basically the LS4 runs a [non-permissible content removed] rich and of course lean is mean as they say.

    No one to date has had any issues and we're looking at some with 8mos of use and many track miles on them. Feel free to email me for pointers to other boards that will allow you to study this more.

    Tranny wise, you won't have a problem. Not sure if the tranny will handle the constant power, but IMO, I'd go turbo. Better gains, more power and easier on the tranny in terms of power delivery.

    Exhaust wise, the best results I've seen while not turing it too loud is the removal of the resonator. Deeper growl and throatier up top. Here's a sound clip of a friend with it removed.
  • smallegansmallegan Member Posts: 10
    Thanks for all of the information! I am a bit confused regarding the the chip reprogramming. You said you would caution against them but they do work and put out an additional 15HP? One of the main things I would like to do is remove the rev limit, it annoys the hell out of me!

    I watched that movie and loved the way that sounds. How hard is it removing the resonator on the GXP?

    Also you said you know of some other boards that discuss these types of mods please feel free to shoot me a list ;-) I am looking for all of the info I can get.

  • smallegansmallegan Member Posts: 10
    hmm sounds nice, does the Bonnie GXP have a rev limiter?

  • erichthecatterichthecatt Member Posts: 37
    My 05 bonneville gxp has the rev limiter. I dont mind it being there though. My bonneville just had the two mufflers at the rear that i switched out for the "hush power" muffs. Is there somehow an internal resonator thats removable from the muffler? I kept my original muff's so maybe ill dig them out of the garage and see whats there....
  • smallegansmallegan Member Posts: 10
    I haven't been able to get fully underneath the GXP but the way I understand it there is a resonator that is a piece of the pipe on the GP GXP's I am not sure if the same resonator exists on the Bonneville.

    I went down and asked the the local exhaust shop what it would take to remove it and he said he would just patch it straight through for about $50.

    Also regarding the rev limiter, I had my dealer talk to his service team about removing it and they said it would void the warranty...Rats...
  • gpgt1gpgt1 Member Posts: 1
    I have installed alot of aftermarket car equipment. What questions do you have if you still have any?
  • cudaccudac Member Posts: 3
    hi i have a 03 grandprix why is it only my year you cant get a ipod connector for it all other years are listed at usa spec. any idea thks
  • cjnellycjnelly Member Posts: 1
    I have a 2000 GP/SE with a 3.1L. I was wondering if the 3.8L intake manifold off of a GT would fit on the 3.1 heads. If not, with the 3.8 heads bolt on to a 3.1? It is the same block isn't it?
  • cudaccudac Member Posts: 3
    does anyone know if you have to take the compressor off to put a new ac clutch on.
  • whosnextdclwhosnextdcl Member Posts: 2
    Thanks for your help with the info on the fenderwell intake. When you mentioned that there is a company that modifies the PCM, were you referring to the Vector, or another company? If another company does it, could you tell me their name? Thanks again.
  • rwassonrwasson Member Posts: 1
    As you can see form the title i just bought a 99 pontaic grand prix SE. Soon as i get it home i start to un-ravel its problems. First of all, the heat does not blow. At all, its indiana in the winter, heat is a must. None of the heat settings do anything. Not even sure where to start. Also sometimes when its idling it will rev up to about 3K RPM a couple times and then Die! Not sure what to do there either. Im a college student so taking it to a dealer isnt exactly an option . Any help at all would be greatly appreciated.

    I also am trying to install a new stereo, seeing as how the old one wont play CDs. Anyone know where i can get a wiring diagram for a 99 grand prix?


  • kbcobrakbcobra Member Posts: 2
  • kbcobrakbcobra Member Posts: 2
    Hi, I am looking at getting a grand prix GT, since I can get one cheaper than a GTP. I was wondering if you could just bolt on a 3800 supercharger without any mods? What would I have to do to do this? And also, I was looking at running nitrous. How much hp could I yeild with a s/c and a ZEP dry nitrous system?

    KB cobra
  • swampbluesswampblues Member Posts: 1
    i have an 07 grand prix gt, and im looking for a good performance chip if there is one, anybody have any suggestions?
  • fandfprixxfandfprixx Member Posts: 1
    Hey. Brand new to this forum and pretty new to the car world itself. I have a 1999 pontiac grand prix GT and so far all i have done is put in a cool air intake system but i was wondering what else i could do to the car to enhance performance and not spend alot of money. Anyone with any suggestions please let me know or e-mail me [email protected] thanks!
  • mawdeucemawdeuce Member Posts: 2
    Hi, I've recently purchased a 2006 Grand Prix, SE trim with the 3.8L Series III engine. I would like to locate and purchase a K&N Filtercharger or other K&N airbox replacements for minor horsepower gains, and was wondering if there's anything I'd need to know about the emissions controls and how they would work with the system that's already in the vehicle, I'm trying to avoid the "Service Engine Soon" light if at all possible. Also I'd like to install a CryO2 system but wonder if it's even worth it with an engine that's naturally aspirated. Thanks!
  • mawdeucemawdeuce Member Posts: 2
    I've heard that the Tornado brand intake tube inserts can increase both horsepower and fuel mileage, and cost under $30 in most auto parts stores, if that helps any....I also had a 1997 Bonneville that experienced quicker throttle response and possibly a power boost with Bosch Platinum +4 spark plugs.....but then again I also combined that with fully synthetic Castrol Syntec oil, a K&N Performance Gold oil filter, a Fram Airhog air filter and 93 octane or higher fuel at all times, I know it'll be hard to do now though cause of the outrageous gas prices, and I never ever ever had any even slight problems with performance or emissions.....had some "gitupandgo" right up till the day I traded it for the Grand Prix I'm driving now, the Bonneville had over 160,000 miles on it but ran like a dream, but figured that since it had the same engine as your 1999 Grand Prix that you may get some use out of that info. Hope I helped a little!
  • greasemonkeyscgreasemonkeysc Member Posts: 3
    go to they offer verious parts for performance increases and they are very reasonable in price i get all my parts from them
  • greasemonkeyscgreasemonkeysc Member Posts: 3
    if u bolt on a supercharger to a gt engine YOU WILL BLOW A PISTON!!!! the bottom end of a gt motor cant handle the boost the rods are not strong enough and will bend or a piston top will just be destroyed they do make stronger rods and pistons for non supercharged motors
  • greasemonkeyscgreasemonkeysc Member Posts: 3
    k&n filters are great and will now set a "check light" on the dash just...DONT USE THE OIL!!! the k&n oil is not friendly to GM mass air flow sensors. the oil with get coated on the sensor "hot" wire and get cooked on making then sensor not read correctly and will cause the light to come on you can find filter kits and numerous other performance parts at
  • jpfjpf Member Posts: 496
    You should check on e-bay or with a Pontiac GP car club. Good luck.
  • motorcity6motorcity6 Member Posts: 427
    2006 GPGT using a K&N filter, really didn't notice much performance difference..It's been on for about 30k miles and I may just replace it with a std air filter..Not interested in quick acceleration, high speed interstate cruising is my bag..

    At 60k miles the engine has been what all 3.8s do, reliable, however the the ISS shafts, engine and tranny mounts, and batteries have been the problem..3 ISS's, 4 batteries, and 12 tires later..Fla car, heat is killing the batteries, steering has been great for the last 30k miles..All ISS were free, and I paid for the last battery, next one is free..All Deco crap..

    Car is always garaged if not in use, and probably the cast iron engine retains the heat too long..My previous car was a 2002 Olds Intigue with the alum 3.5 engine and the orig battery went 100k in all Fla driving..

    Had 3 Intrigues, 98, 99, and 02..GM bought the 98 back after 26k miles due to brake and steering issues. My 99 w/3.5 engine was a winner, did 80k miles, and the 02 was broomed after 120k..Had the SLP catback exhaust on the 99 and 02..great system..

    Having owned 53 cars to date, 34 GM, I can say the "W" body GM configuration of the GP and Impala series is junk..The engine/tranny mounting system is "junk." I had 2 mounts collapse..never floored from a stand still..go figure...........

    Any clue on cleaning K&N filter??? Lub for S/C??? All work is now performed by a high-priced 2 person shop..GM experts!!!!
  • 03compg03compg Member Posts: 2
    Not necessarily true.
    I've been into GPs for the last 11 years and I've seen some pretty radical setups. Just slapping a supercharger onto an L36 will be bad, as was said. But if you do a top swap, which is more involved, and a job not for the meek, you will have a beast. The higher compression and RPMs will grenade a motor, but the pistons, rods, and crank are fine as is. Just search Top Swap on and see for yourself. Maybe you'll get the mod bug like the rest of us. See you at the track!
  • 03compg03compg Member Posts: 2
    Good luck with the Prix.
    Go to and get the Diablo programmer. It ain't cheap, but its what you want. I have a GTP anf I got my computer reprogrammed to work with my mods by a guy called Overkill. Check, troll the boards.
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