Thread: Results Are In! Turbo GTP

Well many of you know that I recently bought a 1998 Grand Prix GTP 4-Dr with 74,000 miles on it as my new daily driver. When I bought the car it was totally bone stock….even down to the original spark plug wires (which had to be replaced within 30 mins of owning the car…Thanks to the help of “scottydoggs”). Well long story short I had planned on doing some simple flow mods and running a simple 3.4 pulley setup (Headers, 1.9 RR, GenV) but lets face it, that quickly snowballed due to running across a deal on a turbo kit I couldn’t turn down. So the car ended up going from bone stock to a full blown cammed turbo build thanks to the help of Jason “hitman92499”, the peer pressure of Bill “no name required”, and for Brian “Swiggles” who called dibs on supervisor during the build process.

Now that the back story is out of the way it’s time for the reason of the post. I’m going to have the car up on the dyno this next week and wanted people to chime in on what numbers you think it will put down on low boost and what it will be on high boost.

Mod List:
Cartuning Turbo Kit w/PT61 Turbo
Cartuning Intercooler Kit
Stattama ST2
L26 Intake
Crow Cam 105#
Manley Retainers
Racetronix Fuel Pump
60# Injectors
NGK TR6 spark plugs
180 t-stat
Stock exhaust manifold
Stock cat-back
Everything else stock unless specified

Dyno will be done on 2 different settings and will be done with 93 Octane pump gas:
Low Boost – 9psi-10psi running off WG spring alone
High Boost – Not sure but my guess is going to be 15psi-17psi


Let the guessing begin.

cam'd, intercooled, turbo setup, stock exhaust after the downpipe.

it's gonna put down about ~380ish, i'd hope.

395/450

9/10psi: 335/395~
15-17psi: 400/450~

Then, transmission explosion

Ill 348/386 low boost and 404/455 high boost.

If you don't make at least 350whp on wastegate something isn't right.

EDIT: okay I see you dont have a plog or HV insert, but you do have 60's, a cam, and custom tune?

So factoring in that bit of info I still think you will be around 330ish whp or damn close to it on wastegate.

With that power isn't it time for an exhaust?

Originally Posted by Sudden

With that power isn't it time for an exhaust?

I'm not planning on it. Remember this is going to be my DD....want it nice and quiet and I'm not worried about getting every last bit of HP out of it that I can.

That's exactly how I feel..i'm planning on going turbo eventually...but plan on leaving the factory cat back on.

Edited my orginal post.

If you could please make sure to post your reaults in the turbo sticky in the turbo section it would be appreciated. I would love to add your results with mine so we have some data to compare our results with.

Originally Posted by Greg Badass

I'm not planning on it. Remember this is going to be my DD....want is nice and quiet and I'm not worried about getting every last bit of HP out of it that I can.

You could always run an electric cutout for when you want to go balls to the wall.

Originally Posted by Greg Badass

I'm not planning on it. Remember this is going to be my DD....want is nice and quiet and I'm not worried about getting every last bit of HP out of it that I can.

Why don't you just put square wheels on her while you at it, seeing as you wish to buck conventional wisdom... Lol, just kidding!

No hating, BUT if you're gonna increase the INTAKE you must do likewise to the exhaust. I know it's yours and you can do what you want, but spending all that on the Turbo, IC, etc and nothing opening the exhaust is a waste IMO.

Good luck with her and remember the 20-HP you're leaving behind by not opening up that exhaust. Lolz...


Regards...

The stock cat back is good for 350whp. He MIGHT loose 10hp it he makes 400 at the wheels. I'll sacrifice 10hp to know my car doesn't sound like ****

Originally Posted by 4THGENCAMAROFAN

The stock cat back is good for 350whp. He MIGHT loose 10hp it he makes 400 at the wheels. I'll sacrifice 10hp to know my car doesn't sound like ****

Yup. It's not going to be a big loss if anything plus he wants a somewhat stock car not a chatter all your teeth kind of DD

9psi- 340/375
15psi- 410/450

Then as someone said... trans goes boom

Originally Posted by 4THGENCAMAROFAN

The stock cat back is good for 350whp. He MIGHT loose 10hp it he makes 400 at the wheels. I'll sacrifice 10hp to know my car doesn't sound like ****

You would be surprised how much exhaust of some kind will wake a turbo car up. It's also not just about power it helps with spool time as well.