How much HP could I expect from these mods???

[90TGP]

I wonder how much it would cost to have custom headers made for the TGP.

[Chris A]

FDP Performance 62mm throttle body.
-Not as signifigant on a turbo
FFD under drive pully.
-Don't recommend, false HP
Plenum ported to match throttle body.
-not needed, however, smoothing intake will help
Plenum to lower intake gasket matched.
-By iteself not much
Lower intake to head gasket matched.
-Ditto
Jeff M. Cross-X pipe.
-back to stock
Jeff M. TopGun chip.
- My guess is 35 hp??
2 1/2" exhaust with dynomax super turbo mufflers.
-10 maybe, go bigger
Car Sound high-flow 2 1/2" cat.
K&N filter on turbo.
-10, but not w/ chip, chip requires filter so 0 w/chip
Port&Polish heads.
- LOTS. This is where most of the flow improvements can be made. You might be able to get another 15 to 20 in the heads, but it aint cheap
3-5 angle valve job.
-not much over porting, but for best results use this twice a day with a P&P
New timing chain.
-none
Either stock replacement cam, or a mild cam [www.w-body.com].
-probably pickup more torque than anything
Either stock replacement or 1.6 rollor rockers.
-maybe some hp with the other mods
Front mount intercooler.
-and retune for better cooling and pressure drop, this can support other mods and bigger turbos more than it will make HP. Maybe 10 hp by iteself


Combine the intake mods w/ P&P for 20hp, 30 for the chip w/ heads, and 10 for everything else. So 60 hp gain which about maxes the flow capacity of the turbo.

Chris

[Black Pheonix]

the interior on that prototype is tight. I take it the seats are out of a bonnevile or something. (correct if they just like ours) Same goes for the door molding. did they go on any other cars, did newer grand prix's have the leather steering wheel ever? Are those rims chromed!

[Chris A]

No, they're GP seats. They are a little different, but they are GP seats. The trim is just vinyl/leather instead of cloth, some cars were like this. I think the 89's looked more like the prototype than the 90's interior wise. I don't know of any GP that got a Tan leather steering wheel though. The rims are just polished, its  not that hard to do it to regular rims.

[1trucavalier]

sorry! i didn't mean to hijack but I just don't like auto's :D !

[1trucavalier]

you spend that kind of money and pick up only 60hp then you should be thinking of getting another turbo vehicle!!!!

[no1kicker]

Maybe my eyes are bad, but does it look like there is no hose going into the turbo in the first pic?

[turby]

You mean on the prototype? I think what you see is the gold canister on the turbo. The turbo itself looks to be in a shadow and not visible.

[Chris A]

Maybe my eyes are bad, but does it look like there is no hose going into the turbo in the first pic?

There isn't, the airbox sits right in front of the turbo. Not sure exactly how they did it, but thats what it is.

[Chris A]

you spend that kind of money and pick up only 60hp then you should be thinking of getting another turbo vehicle!!!!

He didn't ask about a bigger turbo which would make the most out of those mods. Everything works toghether, you crank up the boost on a restrictive intake and you will get more boost but not more flow. Crank it up on a good flowing intake tract and the boost will be able to do better. Now in fact if you crank the boost, then do all the intake smoothing, you might observe lower max boost levels. This is because the air can flow more easily, and is actually making more power.

As it is, bigger injectors don't MAKE more power, but they support changes that do. just like forged pistons, rods and hardened cranks don't really make power either. The intake work make not make a huge amount of power, but when other things are changed, the work will be much more apparent.

Heck, on my pickup truck, I could spend $1300 on a banks exhaust system and ONLY pickup 25hp.

[eclipse5302]

Does anyone know what turbo the prototype used?  Chris A?  What else about the engine is known?

Jason

[1trucavalier]

i guess its a little harder for me to understand I am broke :cry: !

[1trucavalier]

why is it these cars can supposedly only take 11.5-12lbs of boost safely?

[eclipse5302]

I don't think it's a matter of these engines only taking 11-12 psi safely...it's more of a matter of the T25 being able to supply good quality boost above 12 psi to a 191cid engine.  I'm sure with a larger turbo/headwork/injectors/tuning the engine would safely take upwards of 17-18 psi (hey, it's a guess).

But you must remember, if there is headwork done and a larger turbo is installed, the boost might still be only 12 psi--but it's making lots more power.  Just like what Chris A was talking about above.  So the smarter move for this engine would be to make it breathe better, before stuffing more air into it.

Jason

[skalor]

Yeah, if you look at a compressor map for the T-2small T-25 that they put on the TGP you will see that the efficiency takes a dive over 12 psi.  There's no point to run more boost if the air is superheated to such an extent that you'll probably make less power if the detonation doesn't kill the motor.  Here's an example, my friend has a stick '88 Ford turbocoupe with a 3" exhaust and a mildly ported head, ranger roller cam w/roller followers.  The stick turbocoupes have an IHI while the auto have a bigger T-3.  He was runing 18-19 psi on the tiny turbo with race gas(109).  His best on that setup was somewhere in the 15.00 range, and he had a bunch of 15.0's.  I talked to him about his car and he turned down the boost to 16 psi, but he still ran race gas and on his first run on that setup he ran a 14.7.  Point in case....more boost is not necessarily a good thing :D