Thread: Grand Prix GXP build questions

Hello. Im David Thomas. I have lurked around here for a while but haven't said anything. I am getting ready to start a new job soon and in about 9 to 10 months after I start it, I should have enough moolah saved up to get a decent GXP with low mileage. I am looking at ways to beef it up and I would like everyone's thoughts on it. I should have about $25,000 left after I get the car and that would be my starting budget. Any ideas on how to get to a minimum of 400whp on a 2008 Grand Prix GXP? One more thing. Does anyone here know of a good place to get a custom gas tank for these cars? Thanks.

If you want 400whp your only real option is cartuning turbo kit priced around $5000. I also recommend DOD delete, and bigger trans cooler upgrade. And with that amount of power your gonna want a new trans or get your stock one rebuilt.

With that amount of money why not buy a G8 or a GTO? Im not trying to hate on the GXP, but those would just be better platforms for that amount of power.

Originally Posted by 05GXPBeast

If you want 400whp your only real option is cartuning turbo kit priced around $5000. I also recommend DOD delete, and bigger trans cooler upgrade. And with that amount of power your gonna want a new trans or get your stock one rebuilt.

Originally Posted by 05GXPBeast

With that amount of money why not buy a G8 or a GTO? Im not trying to hate on the GXP, but those would just be better platforms for that amount of power.

I was kinda figuring on the turbo bit and the trans. The 04 GTP I had souped up to close to 400whp got about 60000 miles on the stock trans with just a stock rebuild and a good tune. As for the G8 or GTO, I don't want one of those cause they look like rice burners that just wanna be american muscle. Not knocking them. Just don't like their looks.

Originally Posted by ItHurtz

How does it take almost 1 year to be able to buy a car, but yet have 25k to spend? Gtp will stomp on Gxp's all day anyway!

You are probably right. As I mentioned, I had few 3800 v6's. Two NA and one Supercharged. They were great engines. However, I want the V8 growl now. All I have ever driven are v6 cars, except the two foxbody mustangs, which were four bangers. They were good cars too. The 1999 Grand Prix I had came with a NA 3800 and it was a very good car. The only weak points I had with it were the trans and them pesky coolant elbows. I spewed out a bunch of cuss words over those. The 2004 Grand Prix with the NA 3800 was a piece of junk. The abs system was crap. I took the and module off to find that the valve actuators we're very rusty, which led me to believe that it was a flood car. Then, comes the 2004 Grand Prix GTP. That was a fun car all the way around. Plenty of get up and go from the start. Then getting it souped up after having it for about a year really made her shine. I did the engine work and trans work at the same time. She was a brute. However, there was one thing missing. The V8 growl and grumble. Sure, the supercharged 3800 sounded great and all, but it just ain't the same. Anyway, let me finish my reply. As for your comment about taking almost a year to buy a car and still have 25k, the job I am getting is going to be involving 18 wheelers. Starting out at 58k a year before taxes and probably wind up getting more. I can get a 2008 GXP with 30000 miles for about 10k. With me not having much in the way of bills as of right now, I can see paying 10k for the car in cash, and still have 25k left over. Now the car itself ain't gonna be a track beater, even after I get it souped up. It will be my daily driver, even after I get squared away enough to get a Hellcat. I just want it the way I want it. Simple as that. I am a quirky fellow. I am not satisfied with the average. I like pushing the limits of something.

Originally Posted by DTJ122389

I was kinda figuring on the turbo bit and the trans. The 04 GTP I had souped up to close to 400whp got about 60000 miles on the stock trans with just a stock rebuild and a good tune. As for the G8 or GTO, I don't want one of those cause they look like rice burners that just wanna be american muscle. Not knocking them. Just don't like their looks.

The v8 is just too much for a stock spec 4t65e. If your gonna build your stock trans I recommend upgrades from Triple Edge Performance.

Originally Posted by DTJ122389

Hello. Im David Thomas. I have lurked around here for a while but haven't said anything. I am getting ready to start a new job soon and in about 9 to 10 months after I start it, I should have enough moolah saved up to get a decent GXP with low mileage. I am looking at ways to beef it up and I would like everyone's thoughts on it. I should have about $25,000 left after I get the car and that would be my starting budget. Any ideas on how to get to a minimum of 400whp on a 2008 Grand Prix GXP? One more thing. Does anyone here know of a good place to get a custom gas tank for these cars? Thanks.

I'm not knocking your choice as I have the GXP as well as a 2004 Comp G, but this in my opinion is not going to be money well spent. You like what you like, but that's a lot of money and once its gone regret will most likely set in as it will be a fun car but you will have paid good money for a car that really isn't that fast per dollar spent. A few have built really fast LS4's, I believe all were turbo . You don't say how you are mechanically, if you are paying for the work that money will be gone quickly. Not trying to hijack this thread, there is another site with lots of info on these cars and a search should find you all the answers you are looking for but the site has very littly activity compared to this so dont hold your breath for any answers. Good luck whatever you choose. Here is the site

LS4 Performance - LS1TECH - Camaro and Firebird Forum Discussion

Originally Posted by 05GXPBeast

If you want 400whp your only real option is cartuning turbo kit priced around $5000. I also recommend DOD delete, and bigger trans cooler upgrade. And with that amount of power your gonna want a new trans or get your stock one rebuilt.

BTW, I almost forgot to mention that I'm not looking for 400whp. I'm looking for 400hp at the crank. I apologise for the misunderstanding. This would be my daily driver as my nieces would be riding in this car. 400whp and kids are not a good mix, especially if one is already a speed demon anyway. 😁

Originally Posted by 05GXPBeast

If you want 400whp your only real option is cartuning turbo kit priced around $5000. I also recommend DOD delete, and bigger trans cooler upgrade. And with that amount of power your gonna want a new trans or get your stock one rebuilt.

And I just realized that I typed in whp. I meant bhp. Again, I apologise for the misunderstanding.