Twin Turbo VS Single Turbo

[Frank@AMS]

Merv,

Its a commen misunderstanding that a ball bearing turbo will spool so much quicker. They do spool quicker but only 150-200rpms quicker. The ball bearing units are actually designed for efficincey in mind, while quicker spooler up is just a benifiting factor.

A GT3582R is rated at 640HP however im not sure if they off the .82A/R in a T4 housing. A T3 hot side would be much too small.
However I do know that they make a GT3568R .68 A/R with a T4 hot side using a V-Band clamp, You would see the same HP but quicker spool up.

[Frank@AMS]

Merv,

How do you plan to feed the water lines to the R series turbos see that the P-cars are air cooled?

[WydRyd]

I'm told they live OK being just oil cooled in a Porsche application. Some Porsche tuners actually run oil through the water jackets too, for added cooling, but I don't know.

What about a twin setup? How much are the smaller GT's for a twin config that'll support 300-325HP each?

[Frank@AMS]

Merv,

twin set-up=$$$$$$$$$$$$$$$$$$$$$$$$

We thought about it on my brothers car but its not worth it with the GT series turbos being available.

[TimT]

Why not a big single turbo, and a supercharger..

You get instant grunt from the supercharger, then when the turbo is making good boost, your putting HP back on the crank by overdriving the supercharger.

Yes expensive and complex.. but the cool factor "priceless"

[WydRyd]

Originally posted by TimT
Yes expensive and complex.. but the cool factor "priceless"

That's a lot of money for "cool factor"

Frank, is the GT35 you speak of above a GT35/40 unit?

[Frank@AMS]

No its GT35, a GT40 is a completly different turbo.

There is no such thing as a GT3540

[beepbeep]

Twin Garrett GT3040R's:



They spool surprizingly low down. Around 3400 RPM if my memory serves me correctly. GT series is way to go. Very very efficient and spool-friendly, especially R-series.

Unfortunately they are temp-sensitive so we intend to use small water-cooler loop this time.

[Frank@AMS]

I just dont see why you would go to twin's, there is no reason to when you get spool time and top end out of the gt series turbos

[RarlyL8]

There is one never-ending reason to go twins - the cool factor.

[Frank@AMS]

Originally posted by RarlyL8
There is one never-ending reason to go twins - the cool factor.

That is the olny reason I will except.

[WydRyd]

beepbeep, what a monster

I agree, having twins is sooo cool and they are pretty much non-existant down here, in the pre-993tt era cars that is.

[WydRyd]

[raceman]

go with the twins,because you can.Once l`m done with my single turbo system l may sell it off and go with twins using the NA 993 headers.Mike the Mechanic on this forum did it and it looks/works great.Sure it will cost a bit more but so what.What`s money at this point,we`re talking twins here.Twin Turbo Porsche....now how can that be bad?

[WydRyd]

Certainly sounds good, doesn't it? Twin Turbo Carrera. Hmmm...
If/when I do it, it'll be for optimum mid range streetability. Two small'ish turbo's that will spool real fast, yet deliver 550-600 max HP. That can't be bad

[ssetek]

Originally posted by Frank@AMS
No its GT35, a GT40 is a completly different turbo.

There is no such thing as a GT3540

the gt35 uses the smaller gt40 compressor wheel so ive heard some people say it that way.

if spool is a big factor with allot of you than i would just go with a journal bearing gt turbo with the inconnel turbine wheel and just run some antilag on it and spool it real early and than if you need to you can rebuld it for under $100 and get a new tubo again vs the bb units that you have to buy the center section

[WydRyd]

I was referring to the GT35/40R... it has the GT35 turbine and a 40R compressor

I still think two T3's with the smaller 0.48A/R turbine housings would be the way to go. Very quick spool and ~600HP capability

[ssetek]

you can run a single with a small backside as long as have enogh wastegate to get rid of the rest

ive run .63 backed single with twin 44mm tials had no boost creep issues and it spooled fast

its just another way to look outside the box

[Natchamp]

.

[Lukesportsman]

Mark:

Do you have a good picture of your turbo to tire clearance? Your turbos seems similarly placed to where my 993TT headers will position my turbos. I still have another engine in the car right now with full length HE's so hard to be accurate. I think it looks as if they'll clear to the inside, but I'm running near max backspacing on my car.

Did you simply run the air intake plumbing to the inside of the tires and through the "tin" or actual body metal?

TIA