Real Fiero Tech

D1S used that because of fitment issues. I dotn' think its that bad of a design for the space constraints in a fiero. You also have to remember the Miller woods kit(d1S) kit came out backin 87. It wasnt' bad for its day. It can be improved upon. The only drawback right now is the excessivly small turbo. i think Kevin should try and fit a larger one on there with a new intake or exh setup. It would totally rock then. Update it a bit for the times I say. Oh well

Shaun41178(2) wrote:BB turbos are not necessary unless you are going racing and need to have spool 300 rpm sooner then a non BB turbo

Don't forget that BB turbos build back their boost a lot faster after a shift as well. Friend of mine has an AWD 2G Talon with T3/TO4B hybrid with plain bearings. After power shifting that thing, there's a definite wait while the turbo spools back up. I can totally see why automatic turbo cars are faster in a straight line.

I alwasy thought powershifting meant you dont' lift off the throttle when you shift? At least thats what I call it.

I do that when I race. I dont' lift!!! I just bang gears.

I drove a wrx last week and powershifted that thing a few times. It never dropped out of boost. Also what effects "spool" time is how long the intake piping is from teh turbo to the TB. The longer the pipe is the logner it takes to fill which just makes it feel laggy.

That's very hard on synchros and clutch (and rev-limiter too).
I shift dam fast, but I still lift for the sake of transmission life.

I have a garrett turbo for my 3.4dohc and was wondering if someone could map it.

Its a T3/4, A/R hot is .63 Cold is .60 and its a 57 trim.

Was going to buy a T61 but this turbo fell into my lap at a awesome price.

I could map it but I think there is debate about the VE the engine may have that are material enough to throw off the plot.

The Dark Side of Will wrote:That's very hard on synchros and clutch (and rev-limiter too).
I shift dam fast, but I still lift for the sake of transmission life.

You are correct Will. But when I race I dont' care!!! I am a crazy MOFO!!!

I think the stock fiero tranny can hold powershifts with the power I am putting down. I also have a stronger then stock clutch. 12k miles and still grips hard. I still stall it once in a while from it grabbing too quickly.

Oh yea just to clarify on my last statement about spool and such. I meant to say that ANOTHER reason for lag is long intake routing. Not the only reason for it. Just thuoght I wuold clarify so I dont' look like a toolebag more then I already do.

KTHX

Pretend the VE is 85%. This motor also revs to 7200rpm, a few more cfm than a pushrod.

I got that map from turbocalculator.com

http://www.howard.saturnet.net/turboInf ... rkbook.htm tells me that at .90 VE and at half a bar, the 3.4TDC will want 43.1lbs/min at 7k RPM.

there is a user editable excel version at http://www.howard.saturnet.net/turboInf ... rkbook.xls

It doesnt look like a good match to me. Seems to want a higher pressure ratio.

As a minor update to this thread, I have a friend from college that now works for Garrett that has told me she will put me in contact with one of their engineers to discuss the right way to calculate VE on boosted engines. Hopefully, next week I will have some good information to post.

crzyone, double check the AR on that turbo compressor side.

On the compressor it says

A/R .60
M 10

On the hot side it says

A/R .63
M3
61

Crzyone. MINE is BIGGER than YOURS!

The suggestion from Garrett is to hook up a large unmodified MAF sensor to the engine and calculate the VE using that. . . .

Whos good with hardware?

Donk, its how you use it that counts!

The Dark Side of Will wrote:That's very hard on synchros and clutch (and rev-limiter too).
I shift dam fast, but I still lift for the sake of transmission life.

It's ok thou...he doesn't own the WRX.... (haha)

eHoward wrote:The suggestion from Garrett is to hook up a large unmodified MAF sensor to the engine and calculate the VE using that. . . .

Whos good with hardware?

Well if you have a data logging system on a MAF based car, you can do some dyno runs and match up airflow to RPM to RWTQ and come up with a pretty good relationship that way... just gotta guestimate driveline loss.

A manual transmission Fiero or FWD car would be a better candidate for this than a longitudinal car because there's less drivetrain loss in the transverse gearboxes.

I guess when I go to an IAC TB and different computer, I could keep the MAF part of the TB and have a stand-alone logger log MAF freq, but then I'd need to scale according to factory Northstar MAF tables, which I don't have...

just gotta guestimate driveline loss.

Your idea just tanked right there, Will.

275 HP Northstar puts 250 to the ground through a 282. I can guesstimate pretty close...

Will, why do you want to come up with a relationship between torque and VE?

The MAF method will allow you to calculate VE without going to a dyno.

Its just that for engines like the 2.8 or in my case a B16, you will have to get a MAF from another car and come up with some sort of interface for it to datalog to.

Also, if you get a really large MAF, like one from an LS2, you can put it upstream of a smaller turbo once that is installed and compare intake temps to pressure ratio to CFM which would be cool.

This is how you do it.
Take your engine, or car to the appropriate dyno.
Not an inertial dyno, a real dyno, that holds the engine at a fixed RPM under load.
Hook up the intake side to a mass airflow meter.
Run the engine up to the specific RPM point that you're interested in, at full throttle.
Start the MAF readings and a stopwatch at the same time.
Stop the MAF readings and a stopwatch at the same time.
-----------------
Since you now know the volume of air ingested by the engine, and you should know the swept volume of the cylinders, and the amount of time, which corresponds to the RPM (revolutions per minute)..
You can now calculate the VE of the engine knowing that you don't have to worry about internal engine drag, drivetrain losses, etc.
Ain't I smart?
BTW, I think this is the way the OEMs do it.....Ask Cali Kid, the doorknob guy.