Thread: best upgrades for 2006 GXP ?

not a whole lot out there for these things. to my understanding, just your basic intake/exhaust stuff

Sell it...and get a GTP...you'll have money for school and mod money...plus a bunch of party money too. Picked the wrong car mang...there is hardly any aftermarket for the LS4 cars.

haha you didnt pick the wrong car unless you wanted to build a drag car, stock for stock i would pick the GXP all day.....stock for not stock i still would go with the GXP. you made a good choice and youll love it is my guess, just get u some loud exhaust on there so that all of the school will stare lol.

How to Mod a GXP..... SELL IT FOR A GTO OR G8 GT, GXP.

IMO, this car is fine to mod if you don't mind spending the $$$ to do a collection of mods. The cam is pretty small, and both the intake and exhaust manifolds are restrictive. You really need to upgrade all three to see big power in N/A trim. The only turbo kit is expensive ($5500 iirc), but you skip straight to 11s on slicks with it. No matter what you do, the stock engine produces enough torque that you'll have to upgrade your transmission after only a few mods if you want the transmission to last. It's fine for the stock engine, but the 3800 guys start fragging trannies if they get much above 300HP too.

But, compared to the GTP, you've already got premium brakes, lowering springs, performance shocks, 18" alloy wheels, performance tires, and an engine that produces as much power as a S/C 3800 does with your basic bolt-ons. Throw in all of the creature comforts like the premium seats (w/heaters), remote start, etc. and you'll have a lot of money in a GTP to get it to match the GXP across the board. That said, if you want to turn it into a race car, go with the GTP (or a GTO, G8, etc. because RWD>FWD for performance) because you'll be throwing out all of those premium parts for extreme parts, and then you are better of with the lower initial cost of the GTP.

Originally Posted by natefrog1990

Can u hook me up with links for cams I should get as well as intake n exhaust...u said I shoiuld get those right? After that stuff what kinda hp n stuff u think I'm looking at?

I've been busy lately, so sorry for not replying right away. It doesn't sound like you have a lot of experience with modifying engines (sorry if I'm wrong), so I wouldn't recommend starting out by changing your camshaft. You have to get the engine out (either by pulling it out the top or by dropping the subframe) to get access to the camshaft, and then you have to get it in and out, time it correctly, etc. It's not impossible, but it's definately not a bolt on.

Any cam for any LS engine will fit. I have the 07+ single bolt style camshaft, while you have the older three bolt style cam. If you change cams you'll need to swap out the lifters at the same time, because the DOD/AFM cylinders have different lifters and our cam is ground with a slightly different profile for those lobes (a little more lift). New Era Performance makes a DOD compatible cam, but it is for the G8 GT (08-09) so it has the single bolt style end. That cam is ground with a slightly smaller base circle, so you may want to get custom length lifters to reduce valvetrain noise.

If you change cams, you'll need to retune your engine or it will not run well, if at all. You'll something like HP Tuners or EFI Live; a pre-canned tune won't work.

I can't tell you how much power you'll make, because that will depend on the cam you chose and where it operates best, along with the rest of your combo. In general, you are moving the RPM where you engine makes peak torque when you change cams, and by moving it higher up in the RPM range you make more power at the expense of bottom end torque.

A better place to start modding, and learning, would be (in order) to add a cold air intake, cat back exhaust, Thorley headers or a Hogan downpipe, 1.8:1 rockers, and then either get your intake manifold ported or attempt to swap the LS6 on like I did. After that, you should probably learn to tune your car or get it dyno tuned. That will buy you some get up and go. If you want to go fast cheap, N20 (using a controller and the window switch feature) is the answer. The closest thing to a bolt on is the turbo kit, and it will also buy you the most power.

I posted this on LS1Tech, and I thought it might be good here too. The LQE/LM4 is basically a GEN III version of our engine, in that they are both all aluminum, 325ci, and have good stock heads. They were running dyno headers in the test too, and they went with Comp 918s once they upped the cam.

Stock LQE (300HP, 9.45:1 All Aluminum 5.3L used in the SSR):
Intake: Stock Truck
Heads: Stock (1.89 intake, 1.55 exhaust)
Cam: Stock (190/190, 114LSA, .456"/.464")
HP: 323@5200
TRQ: 355@4000
TRQ @2000RPM: 318
Vacuum: probably about 24" of mercury at idle

LQE with LPE GT2-3
Intake: Stock Truck
Heads: Stock (1.89 intake, 1.55 exhaust)
Cam: GT2-3 (206/220, 118.5LSA, .571"/.578")
HP: 378@6000
TRQ: 366@4800
TRQ @2000RPM: 308 (less than stock until 3300RPM)
Vacuum: 20.7" of mercury at idle

LQE with LPE GT1-1
Intake: Stock
Heads: Stock
Cam: GT1-1 (229/242, 114.5LSA, .631"/.631")
HP: 413@6600
TRQ: 369@4800
TRQ @2000RPM: 281 (less than stock until 4300RPM)
Vacuum: 10" of mercury at idle

LQE with LPE GT1-1, LSX Intake, Ported Heads
Intake: Comp Cams LSX
Heads: Ported Stockers (2.00 intake, 1.55 exhaust, bump to 10:1 compression)
Cam: GT1-1 (229/242, 114.5LSA, .631"/.631")
HP: 458@6600
TRQ: 392@5800
TRQ @2000RPM: 294 (less than stock until 3200RPM)
Vacuum: probably still 10" of mercury at idle


Notice when the compression comes up and the intake/heads match the cam, you pick up a lot of the midrange that was lost when just the cam was just a bit too big.

Here's a link to the second article in the series. You can read about them upgrading the injectors to match the big cam/intake too:
http://www.carcraft.com/techarticles...ine/index.html

I'd say #1 would be a GMPP extended warranty.