What size of turbo should I choose? (for p10)

[radicalG20]

As some of you already know, hot shot performance is putting together a sponsored turbo kit for my p10. They asked me what size turbo I wanted. I can choose from either a turbonetics T3, a T3/T4, or a T4. I was told a T3/T4 will spool up quicker than a T3. By the way, whatever turbo I go with will be mated to a turbonetics adjustable wastegate, blow-off valve, and front mount intercooler. Any suggestions for which turbo to go with? Any help would be appreciated.

[jayntguru]

How fast do you want to go?
What sort of fuel system will you be running?
How much money do you have to spend?

[radicalG20]

1. My goal is around 225 to 250 whp.
2. stock w/370 injectors, JWT fuel rail
3. money, really no object, half of the stuff I'm getting free, the rest is at wholesale/dealer cost.

[b-b00gie]

If you only want 250whp you may want to go w/ a T28, extrude honed, BB center.

Definately search the SE-R archives for stuff by Rob Cadle and Mike Kojima.

[radicalG20]

T28 is not an option. The smallest I will go with is a T3. The 225 to 250 whp is my initial goal, followed by increasing the boost and doing a little internal work.

[b-b00gie]

Well then your goal isnt 250whp is it?

You need to decide on your ultimate goal in order to properly size your turbo...

It's not only a question of your turbo type. The specs on the turbo are equally important, which all depends on your final goal.

[radicalG20]

OK, 225-250=initial goal
around 300 whp=final goal (Or enough to beat my dad's Mustang Cobra )

[b-b00gie]

OK then...

T3/T04E Stage III
50 Trim Compressor Wheel
.63 A/R Turbine Housing

The boost will start coming on @3500 (pretty good). If you want to lower the spool time (you do! ) Get a Ball Bearing center for an extra $500. Also get the exhaust housing extrude honed which will run you about $100. You should then start spooling at 2500 or 2700 rpms. ...what lag???

This turbo is good for up to 325whp. It costs around $850, or $1300 if you get the BB center.


This info is coming from Rob Cadle, a Garrett engineer and SE-R owner.

[jayntguru]

You dodn't state if your power goals were pump gas or race gas...

50 trim compressor wheel I would spec more along the lines of a 400 WHP motor. If you are only going for 300, use a smaller wheel. I like the way the 46 trim wheel looks on paper. It was good enough for 400 WHP in my 97 GSX. 11.7 @ 119.7 in the 1/4. It will easily make 300 HP on pump gas. (My numbers were on race gas.)

Don't get me wrong, the 50 trim is a good wheel, but it's powerful enough to propel a heavy DSM into the 10's. You don't need something that big for only 300 HP.

[b-b00gie]

I dont think it will be a race gas type vehicle from what I know of the car

Using a 46 trim compressor wheel would require cranking up the boost pretty damn high. I'm not sure he's planning on bottom end work, etc...


BTW... using a 50 trim compressor wheel you will NOT see 400whp with .63 A/R turbine housing. With a 50 trim .82 A/R you will see 400whp but there will be close to another 1000 rpms of lag.

Of course there are mutliple setups to get to 300whp, but the turbo I listed above has been known as the best way of getting there with the least amount of lag and boost levels that arent borderlining on detonation.

[jayntguru]

I'm looking at the maps, don't see what you mean about high boost with the 46 trim. I've had both turbos on a car. 50 trim sweet spot is about 27 PSI, 46 trim is about 24 PSI. Neither will be realized on this car it looks like.

Wanna bet about making more than 400HP on an AR that small?

(Go look at what a 7cm Mitsu housing's AR works out to be. You'll be surprised what power you can make with a small AR.)

[b-b00gie]

BTW...

You will need 50lb/hr injectors, Cobra MAF (your dad will like that!), Walbro or 300ZX fuel pump, new fuel rail along with the other turbo "stuff"

[b-b00gie]

Originally posted by jayntguru
I'm looking at the maps, don't see what you mean about high boost with the 46 trim. I've had both turbos on a car. 50 trim sweet spot is about 27 PSI, 46 trim is about 24 PSI. Neither will be realized on this car it looks like.

Wanna bet about making more than 400HP on an AR that small?

(Go look at what a 7cm Mitsu housing's AR works out to be. You'll be surprised what power you can make with a small AR.)

You are talking about boosting over 20 psi on a stock internal engine street car. Can we say detonation?

[jayntguru]

Quoting myself:

"50 trim sweet spot is about 27 PSI, 46 trim is about 24 PSI. Neither will be realized on this car it looks like. "

Ask Jay H how much boost you can run on a stock motor. 22 PSI plus.

[b-b00gie]

I know Hass's old car pretty good.

He was running that boost with water injection. And even at that boost he laid down 409whp w/ a 76 trim .82 A/R


Running more than 18psi is just plain dumb without race gas or water injection or lowered compression and bottom end work.