Will Garrett GT35r work in air cooled 930 motor

[kenny3737]

I am looking to change out my Kokeln ball bearing to a turbo that will provide more power. What is best replacement? Will a Garrett GT 35r work on a air cooled motor? I see that it needs water cooling? What gives when I see the 35r in somebody's parts list on this site?

[kenikh]

Yes. I think DonE uses one with great success.

[tarheelturbo]

yes it works wonderfully... i have one on my 930 CIS car.. and they can be water or oil cooled to my understanding as i use oil to cool mine.. the performance of it really puts a kkk to shame in under the curve power, spool, responsiveness, and top end..
definitely the route to go!!

[RarlyL8]

kkk what? There are many forms of K27 turbochargers.

[tarheelturbo]

im just making a general statement about modern ball bearing vs. old school kkk k27 style units.. i'm not saying that a kkk can't have the same atributes, but it will never have all of them.. a 35r is big enough to make serious power, spools fast, and has great under the curve power,
if you go to a big k27 you might have top end but you will lose the under the curve power and responsiveness, i can see that from my experience with a 7006, i can't imagine dealing with a bigger unit!!
and if you want faster spool like that of a 7200, it has been said over and over again it wlll run out of steam up top, period, and a 35r can handle more up top that we can give it.. in fact the part thats most ashame is at the boost levels we run in these cars you never get to a 35r sweet spot, and it still is pretty amazing... i'm just giving my .02 nothing more nothing less

[TroyN]

Brian, which kkk's would you say are better? I have the S variant, so just curious.

[RarlyL8]

The GT35R is too big for most applications. You need EFI and 500WHP.
The K27-7006 is old school and not in the same league.
The K27HFS is capable of 1800rpm boost threshold, 1.0bar in by 2600prm and pulls 1.0bar through redline while supporting 400+WHP on a CIS engine.

[kenikh]

Originally Posted by RarlyL8

The K27HFS is capable of 1800rpm boost threshold, 1.0bar in by 2600prm

This is of course displacement dependent; this would slide up and down from a 3.0L to a 3.6L.

[RarlyL8]

It's dependent on a lot of things - proper AFRs, timing, cams, intercooler, etc. I used the word capable due to the turbo being only part of the equation for low boost threshold. This holds for any turbo.

[kenikh]

You would be amazed by how much more quickly you get full boost on e85 with an e85 tune...but that requires EFI.

[DonE]

Originally Posted by kenny3737

I am looking to change out my Kokeln ball bearing to a turbo that will provide more power. What is best replacement? Will a Garrett GT 35r work on a air cooled motor? I see that it needs water cooling? What gives when I see the 35r in somebody's parts list on this site?

To answer your question, I have a GT35r on my car and do not use any center cooling. This is not a direct bolt on turbo and can not use the stock turbo support bracket, but if you like working and fabricating parts for your car, this is a great turbo. There are numerous combinations of turbines and compressors and turbine configurations, so you must do your homework.

I don't think it provides more power, as boost is boost. It just depends when it comes in and if the turbo can support 1 bar all the way to red line. The problem with CIS (among other things) is your inability to manage timing and this is fairly important in getting a turbo spinning quickly. The other issue is getting a quick shot of fuel in the chamber rather than waiting for the CIS system to react.

In short, is the GT35r a great turbo? Yes. Is it effective in a CIS car? Probably with the right fabrication, but there are other bolt-on turbos out there that will do well with CIS cars but at a price. Does it work well with cars that have ECU's? Oh ya - it's a top rated turbo in this application. Do you need to cool the center section in some way? No, but ideally I think its a good idea.

[sjf911]

Originally Posted by DonE

I don't think it provides more power, as boost is boost. It just depends when it comes in and if the turbo can support 1 bar all the way to red line. The problem with CIS (among other things) is your inability to manage timing and this is fairly important in getting a turbo spinning quickly. The other issue is getting a quick shot of fuel in the chamber rather than waiting for the CIS system to react.

What does your timing map look like for increasing early boost?

[JBL930]

I went through 3 of these turbos on my 3.3 engine in 13,000 miles. Nothing to do with the turbo, to do with the clown that was fitting them. I'm sure Don will correct me, but the way i understand it is they need much less oil feed than the KKK, therefore you need to run a restriction in the oil line, basically so that the bearing gets a spray of oil as opposed to a bath of oil. That way they will live, the other way they don't last long at all. Mine ran oil through the water cooling jacket i was told.

[beepbeep]

Turbo isn't dependent on fuel injection. With other words, turbo doesn't care if it EFI or CIS that injects the fuel.

I believe that GT35R can be a good turbo even on a CIS car, if you plan to raise the boost somewhat. It will probably make 10-15hp more than corresponding 3DLZ solely trough being more efficient at top end. it will also have significantly higher margins left.

If you don't plan to tune the car GT30R is probably enough. Otherwise, GT35R is a great turbo! I've been involved in a project where two(!) GT35R's were being run on 3.6L engine and it worked as a charm...

[911nut]

Using a calculated maximum mass flow of 49 lb/min (based on a displacement of 3.3 L and 80% engine efficiency at max engine speed) and absolute pressure of 2.1 bar the GT35R is running at 78% efficiency whereas the K 27-7200 is at 60% (and also it's right at the choke point of the compressor).
Bottom line is that the GT35R will provide more air (as in denser air) to the engine than a K27-7200, which is why the performance of the GT35R is better than that of the K27-7200 as both approach maximum engine speed (confirming Goran's statement with the math).
Of course, with CIS how does one fuel all that air that the GT35R is delivering?
At the moment my cars' AFR is 12.5 at max engine speed using the stock K 27-7200 but I'm sure that I'd be in trouble if I made the switch to the GT35R.
Having said all that, if I were upgrading my turbo I would feel more comfortable with the Garrett as the compressor map is available to study before I plunk down the money for it. As we all know this isn't the case for the updated K 27 variants.

[kenny3737]

Don E,
I have a MoTec in the car. Will that help with installing a GT 35R. What do you think would be the right combination given the following mods listed below:
MoTec
3.4 liters
Pauter Rods
BB Headers
GHL exhaust
Niresist Rings
Evo Cams
964 plastic intake manifold with Mustang 80 mm throttle body
1.2 bar boost / 490 rwhp
Full width intercooler
Kokeln ball bearing turbocharger which I think is the K27 variety

[kenny3737]

Hello Again,
My engine is not twin plugged and I think the heads are stock. What I meant by the right combination are turbine wheels.
Thanks Ken

[beepbeep]

3DLZ:



GT35R:

[RarlyL8]

I completely agree with Don's take on the GT35R.

The K27 equivalent to the GT35R is not the 3LDZ or the K27-7200 but the K27HF and K27HFS.

If your heads are stock that is where you need to go to gain power. I don't know anything about the Kokeln turbo, are you certain it is running out of steam at your present level?

[beepbeep]

Originally Posted by RarlyL8

I completely agree with Don's take on the GT35R.

The K27 equivalent to the GT35R is not the 3LDZ or the K27-7200 but the K27HF and K27HFS.

If your heads are stock that is where you need to go to gain power. I don't know anything about the Kokeln turbo, are you certain it is running out of steam at your present level?

Would you be kind and post the compressor map of K27HF and/or K27HFS? Then we can compare apples to apples. Without maps, it's all shooting in the dark.