Mods Available for '05-'08 Grand Prix GXP

'05-'08 Grand Prix GXP LS4 V8 Mods Suggestions w/ prices


CAI---K&N 63 Aircharger---select "click to see price" and it should be roughly $275 w/ free shipping.
http://www.autopartswarehouse.com/search/?N=0&Nr=AND(wpn_tl_name:Engine+%26+Drivetrain,wpn_cat_n ame:Air+Filters+%26+Intake+Systems,wpn_scat_name:C old+Air+Intakes+%26+Accessories,part:Cold+Air+Inta ke)


PCM Tuning
Vector Motorsports---$349.99 (15-20+ wheel HP claims)
http://www.vectormotorsports.com/index.php?page=shop.product_details&category_id=28&flypage=shop.flypage&product_id=10&option=com_virtuemart&Itemid=28


HP Tuners (VCM Suite)
http://www.hptuners.com/products/vcmsuite.php
Supported under Gen IV category....about $499 for the Standard Edition.


Magnaflow Cat-Back Exhaust (Part #16726)---$698.79 (other sites are about the same, it comes down to shipping for the best deal)
http://www.pfyc.com/pc/GP5902/04EXH/MagnaFlow+Cat-Back+Grand+Prix+GXP+16726.html


Hogan Downpipe (DP7S) comes with Magnaflow Super High-Flow Cat Converter ($289.95)
http://hoganperformance.com/DP7S.htm


Headers by Doug Thorley---$960--ceramic coated!
http://dougthorleyheaders.com/products/searchType/vehicleSearch/year/2008/make/PONTIAC/model/GRAND%20PRIX%20GXP/sfID1/9

Completed K&N Aircharger intake mod on my son's '08 Pontiac Grand Prix GXP. A few comments about the install. The pictorial instructions are comprehensive but vague on the hardware like washers, bolts, nuts, etc. so you have to reference the parts illustration which is hard to read at times. The rubber grommet fasteners for the two bolts that hold the heat shield and ECM tray to the inner fenderwell seem flaky but work. Overall the mod was time consuming but fairly easy to do. What real benefit remains to be seen until a power tune is done or a few runs at the dragstrip. If you like intake roar/noise then you will get plenty of that.

Also, the rubber seal needs to be cut to fit the heat shield but hi-temp RTV silicone sealant should be used to keep the seal intact. One pic shows we have 100 mph tape holding one part of the seal down.

Last comment. The ECM and TCM will be more exposed compared to the stock airbox.



http://i5.photobucket.com/albums/y186/lizzywiz/gxp_cai_03.jpg




http://i5.photobucket.com/albums/y186/lizzywiz/gxp_cai_02.jpg

Adding this. Superchips Cortex Programmer. Under $400 depending on supplier. Easier to use than the HP Tuners which also requires a laptop computer. My son purchased one and we are currently testing performance. From what I can see easy to use.

Superchips Cortex Programmer (http://www.autoanything.com/performance-chips/61A3685A0A0.aspx?kc=GOOGADW&app=1&s_kwcid=TC|5843|superchip%20cortex%20programmer||S |b|2880206648&gclid=CLS-vPnb8KMCFQ7u7QodJlCw3g)

Just an update to the Superchips Cortex programmer. An interesting feature is the ability to disable Active Fuel Management aka Displacement on Demand - DOD. Comes in handy when drag racing but I would recommend turning it back on for daily driving for fuel economy.

The upshifts feel much better in non TapShift mode with no rpm drop off, however, you will notice some more torque steer due to the extra power which could be good or bad. We still have to get it to the local drag strip for testing and timeslips.

Also, Superchips will allow you to tune another GXP (second car) for a $199 upgrade without having to purchase a complete tuner.

Do I still see stock manifolds in there Bob? When are you guys getting headers? (or are they available yet?)

Do I still see stock manifolds in there Bob? When are you guys getting headers? (or are they available yet?)

Doug Thorley now makes them but not sure how the horsepower and torque will be. I would like to see a Dyno test. On NA engines most headers shift the powerband from medium to high with low end suffering.

We're looking at a 3" Hogan downpipe with Magnaflow 3.0" hi-flow CAT for now and custom exhaust system versus canned CATBack.

wonder what it would take for a gxp to make a 12.9 sec pass....rockers/headers/chip?

Even with headers and a power program probably not. And I would not mess with rockers since it has the active fuel management system. All you need is at the link below and the 1/4 mile ET will be better than 12.9. This is a proven mod and plenty of You Tube videos supporting it.

Cartuning Turbo Kit for LS4 (http://www.cartuning.ca/products/product.php?model=grandprix&engine=ls4)

Thanks for this great post!

So far I have k&n intake and Gibson exhaust...sounds badass IMO but hopefully tune in near future

Here is a few more:

ECM/TCM Programming by Overkill (http://www.getoverkilled.ca/LS4.html)

Cold Air Intake (http://www.pfyc.com/pc/GP3018/04UNDER/Cold+Air+Induction+System+for+Grand+Prix+GXP.html)

Also, cheaper stainless steel headers may be coming out mid-fall for the LS4. In R&D and test phase now. Around $350.00.

did they come out with different headers for the LS4?