Engine set up for a twin turbo converted 1985 911 Carrera?

[TurboKraft]

Originally Posted by mamut

My plan is getting LN engineering 3.4 L cylinder and pistons, GT-2 EVO cam, race valve spring, twin plug, Pauter rods, raceware head studs. up the engine redline to 8000RPM.

IMHO, Still too big for that combination, a pair of gtx3071r's will do much better.,cheers,Stefan.[/QUOTE]

Done both of the above. Booooooooring. German Supra.
Want torque, response, and up to 650rwhp? Run GT28xxR turbos.

[911TT33]

Originally Posted by TurboKraft

IMHO, Still too big for that combination, a pair of gtx3071r's will do much better.,cheers,Stefan.

Done both of the above. Booooooooring. German Supra.
Want torque, response, and up to 650rwhp? Run GT28xxR turbos.

++1 on the GT28RS I *think* their compressors flow 35lb/min, so should be good for ~700HP

Sounds like Albert is aiming for BIG (1000+) numbers though

Each to their own... either way, I love seeing these unique configurations

P.S: Chris, have you ever fitted GT28RS turbo's on 993TT heat exchangers? Is it an easy mod?

[TurboKraft]

Yeah, twin GT35Rs did 819rwhp without much effort.

Yes, we have done the twin GT28xxR on 993TT heat exchangers many times:
Turbos & Manifolds Installed
New Header Flange Comparison
That 3.6L did over 700hp on MODE's dyno, later 645rwhp on Dynojet. Huge, wide torque band to work with.

[911TT33]

Originally Posted by TurboKraft

Yeah, twin GT35Rs did 819rwhp without much effort.

Yes, we have done the twin GT28xxR on 993TT heat exchangers many times:
Turbos & Manifolds Installed
New Header Flange Comparison
That 3.6L did over 700hp on MODE's dyno, later 645rwhp on Dynojet. Huge, wide torque band to work with.

WHOA, awesome numbers!

At what boost levels did you net those numbers? On pump fuel, or race?

[race911turbo]

Originally Posted by 911TT33

What A/R are you running in the hot housing on those GT35R's? 0.63?

What sort of HP are you aiming for? 1000+ HP?

I personally would prefer a twin GT28RS setup to make that car a LOT more enjoyable, and still have excellent response and tonnes of power

Also, the length of those headers won't help response times on those massive GT35R's

Single turbo A/R 0.84, for twin turbo I swap turbine housing to 0.63.

[spence88mph]

Originally Posted by TurboKraft

Yeah, twin GT35Rs did 819rwhp without much effort.

Yes, we have done the twin GT28xxR on 993TT heat exchangers many times:
Turbos & Manifolds Installed
New Header Flange Comparison
That 3.6L did over 700hp on MODE's dyno, later 645rwhp on Dynojet. Huge, wide torque band to work with.

Damn you do some awesome stuff Chris, I saw he retained the factory lid, did you put intercoolers in the guards? could this be done on a 930 and get enough airflow?

[TurboKraft]

Originally Posted by race911turbo

...for twin turbo I swap turbine housing to 0.63.

Major compressor surge!

[race911turbo]

Originally Posted by mamut

My plan is getting LN engineering 3.4 L cylinder and pistons, GT-2 EVO cam, race valve spring, twin plug, Pauter rods, raceware head studs. up the engine redline to 8000RPM.

IMHO, Still too big for that combination, a pair of gtx3071r's will do much better.,cheers,Stefan.[/QUOTE]


Think about what HP this setup would make at 8000 - 8200 RPM or just looking at the engine bay would make me excited.
GT-28, GT-30, GT-35 use same V-band flange, I can do a swap in 2 hours.
I don't try it I would never know twin GT-35R turbocharger would feel like....
6 individual throttle body on my shelf should look better in the engine bay!!!!!

[race911turbo]

Originally Posted by TurboKraft

Major compressor surge!

A/R 0.63x 2 = ?? compare with A/R 0.84x 1 = ??............
At idle air blow like hair drier...

[911TT33]

0.63 A/R is a good size for TT's... you can go down to 0.48 A/R and it will be VERY responsive, BUT it will choke the motor at the top end and limit HP output.

All depends how you use your car

[race911turbo]

Originally Posted by 911TT33

0.63 A/R is a good size for TT's... you can go down to 0.48 A/R and it will be VERY responsive, BUT it will choke the motor at the top end and limit HP output.

All depends how you use your car

Yes, 0.63 is good for 930 twin TT. Half of 3.3 Liter = 1650cc , each turbo with A/R 0.63 handle 1.65 liter.

[911TT33]

The problem with running a big compressor wheel is the exhaust turbine has more mass to get spinning, which = more LAG, but once it's get spinning, it can flow huge amounts of air.

Smaller compressor wheel = quicker boost onset = fatter torque/power band = more fun

Chris, how does the boost characteristics differ between the GT28RS vs K16/24 or K16/16G in a TT configuration?

[TurboKraft]

Originally Posted by MrShades

I want a intercooler that looks something like this or this

:-) Thanks!

Getting back to the original topic:
A very nice looking car. Do you have any specifications on the turbochargers? There is a tag on each, between the top oil inlet fitting and the side coolant port, with a part number XXXXXX-xxxx.
Any photos of the exhaust?

The 0.6bar sounds very conservative, but a lot depends on the tuning, and how much your 915 clutch can withstand.

[MrShades]

I did not convert the car but it is Garrett M27 AR 48 turbo`s after what i can see

Is that not called the T series turbo?

Originally Posted by 911TT33

Yep, on a 3.8 or 4.0 big bore motor they'd be OK, but on a 3.3, they're too big

When do you get full boost, Albert? Way past 4K RPM I would think

MrShades, what size Garretts do you have on your TT setup? T3's?

[TurboKraft]

M27 -- is that cast on the compressor cover? There should also be an ID tag on the bearing housing.
The only reference to "Garrett M27" I find is a small GT15 turbocharger, OEM for 2.0L Saab Turbo, etc.
We've used two for a twin turbo before, but on a smaller displacement engine <3.0L.



Even on the small engine, these turbos were a little too small, too much turbine back pressure. Went with a pair of bigger turbochargers and didn't lose any response, and gains in performance.

[MrShades]

TurboKraft
I just wrote down what i could see when the car was taken apart when we restored the car
The turbos on your picture looks a bit smaller than the ones on my car(it might just be the picture)but the turbos works very well
I will have a better look when i have the car on a lift
There is no turbo badge on the car and even if i put in bigger turbos it still will not have turbo badges. I might go for a 911 badge but that is all.

Never thought about the turbos but now i have to see what the tag says. If i remember right it is a blue tag on the turbos and the tag was hard to read without taking off a turbo but
i need to know even if that mean to take one off
The brakes on the car i Brembo big reds

One qustion about the length of the exhaust pipes i have seen some that use long exhaust pipes and some that use short pipes. What is the best on a 911?

This is how the set up looks(i need to wipe/sand off the the dirt and surface rust on the exhaust) It is the only picture i took before painting of the car
You can see the intercooler under the masking paper. It for sure sound loud when you use the car

[911TT33]

Originally Posted by MrShades

One qustion about the length of the exhaust pipes i have seen some that use long exhaust pipes and some that use short pipes. What is the best on a 911?

I assume you mean the exhaust pipe before the turbo?

If so, shorter exhaust pipes are best to minimize lag.

[MrShades]

No i have heard about the length after the turbos will affect the cars performance.
After what i understood is that there is some benefits with long pipes and also some other benefits with short pipes

[911TT33]

Originally Posted by MrShades

No i have heard about the length after the turbos will affect the cars performance.
After what i understood is that there is some benefits with long pipes and also some other benefits with short pipes

AFTER the turbo, a shorter pipe is better as it results in less back-pressure on the turbo, and maximises boost response. You want to get rid of the exhaust gas as quickly as possible out of the exhaust.

BEFORE the turbo, you want shorter exhaust pipes (i.e. the primaries on the headers) to maximise exhaust gas velocity, which spools the turbo up quicker.

That's the theory anyway

[race911turbo]

Originally Posted by 911TT33

AFTER the turbo, a shorter pipe is better as it results in less back-pressure on the turbo, and maximises boost response. You want to get rid of the exhaust gas as quickly as possible out of the exhaust.

BEFORE the turbo, you want shorter exhaust pipes (i.e. the primaries on the headers) to maximise exhaust gas velocity, which spools the turbo up quicker.

That's the theory anyway

This is my theory..

Longer equal length header will give out smoother exhaust energy to turbocharger.
Heat = energy, longer pipe = heat lost before turbocharger, some use thermal barrier coating or header wrap to keep heat in the piping. Some use thicker 3mm stainless steel pipes.

Short unequal length header give out fast respond, but cancel some of energy between cylinders.

Long equal length header = higher HP number.
Short equal length header = faster turbo respond.