what can it hold???

[reborngarcia]

i am in the planing stages of doing a turbo build in my 02 grand am. and i would like to know what is the highest power out put i maybe able to put out. before something goes wrong. like trans, or something in the motor??? if i do this build the motor is going to stay stock. that means everything stock for now.

[bszopi]

Welcome to the site! In your car, the tranny is going to be the limiting factor. The engine itself, in stock form, will be good up to 8-10psi on a turbo. You will start having tranny issues at levels lower than that unfortunately.

[robertisaar]

X2....

with a good tune, the engine will FAR outlive thr tranny....

[reborngarcia]

i know that the stock motor makes somewhere around 130-140 to the wheels(i hope) so what can i look at before the trans goes bye bye. and what in the trans does go? i know a few ppl in my area that could help with not only a rebuild but a build up also.

[Azrael]

There are a few people who've built up the 4t4xE transmissions. But I haven't heard how well they hold up in the long term though.

[AaronGTR]

The 3400 in the GA with the 4T45E typically puts out 140-145 HP at the wheels, assuming there are no issues and everything is running good and not a tired motor. You can easily put down over 300whp with the stock engine as long as it's tuned properly and has enough fuel. I would recommend bigger injectors of course, and stiffer valve springs. It really benefits from a bigger throttle body at those power levels too.

Biggest problem is the trans. Clutch plates start burning up around 220whp+. Nothing really breaks unless you are doing peg leg burnouts then the diff sometimes shatters. Mostly though the slip in the torque converter and the clutch plates helps isolate the gears, drive chain, axles etc from shock and breakage. You can upgrade the diff, the clutches, the valve body, the accumulator pistons, TC, and a bunch of other little internal parts. Plan on spending a couple grand though for a complete build up, even if you are doing it yourself/with help. Once that is done you can program the pcm for more aggressive shifting. No one who has built one has broken it yet, but they haven't been pushed to the limit either power wise to see how much they can handle. 300-350whp is no problem though.

Other thing you can do is swap in a 5spd or 6spd manual, but those have a whole other set of issues to address to install them.

[reborngarcia]

so which one would be the best set up then to hold 300+ hp to the wheels. that is my goal. and also to get this car into the 13s also. i would like to keep it auto but if it is going to cost me more with the auto then what other options do i really have. i have read up on the 5 or 6 speed swaps and they do look to hard. but i know that i could find an other auto in the junk yard and just build that one. but if i could get close to that with a manual tranny that i am better off that way. or is there an other auto trans that i can put in that i can hold that power? so many options and it is looking like i will have a lot of planing ahead of me.

[AaronGTR]

There's no really solid answer there. It IS possible to swap in a 4T65E-HD also from the grand prix GTP... but that also requires custom work and some re-wiring and re-programming to make it work, and I'm not sure exactly how it's done. I've only ever heard of 1-2 people who have done it, and they didn't tell anyone how they did it. Most of the manuals will definitely hold that power, but you'll probably need an upgraded clutch and fly wheel. And the built 4T45E will hold the power too.

Problem is, not enough people have done all these things and totally disclosed the process and costs to be able to determine which one is cheaper or better. There just isn't enough info out there. It's not like modifying a Honda. When you dig into these cars, it's almost like breaking new ground sometimes. In the end it's going to come down to which you want more, an auto or a manual, and which one you think is going to be easier to do.

[reborngarcia]

so this is going to make for a long and hard build then for me. i really want to do a turbo on this car. but it looks like i am going to have to get an other dd to be able to do this. i am going to have to keep looking around and keep reading on as much as i can to go there with it all. but i am going to keep at it. this is the first American car that i am going to try to do a build on. thank god i work at a shop and that i have ppl to help me with it all.

aarongtr your grand am is not white 2dr is it???

[TurboGTU]

Honestly, you don't even need to open up the engine. Just boost it. Bigger problem is putting it to the ground. Yes trans issues , but traction is the other. Get quality AA traction tires. Most of your money is going to the trans.

[AaronGTR]

Yeah, pretty sure you're the guy I met at the Moe's meet saturday night right? Whats up man