Mondragon

Hi guys, im in the process of a full engine rebuild, nothing radical rebuilt heads, new rings bearings, 964 cams, 3.2 Carrera manifold, autronic SM4, multi coil CTI, ceramic coated pistons valves and heads, water methanol injection and Garrett GT35R turbo.
which brings me to the question, has any one of you fitted a water cooled turbo. if so what did you do about the water side of things. I am thinking of purchasing a water to air radiator from a suzuki motor cycle 12"h x 4"w x 2"thick, and fitting it in the passanger side rear wheel well (left side in Australia) with a small thermo fan and a Davies Craig water pump. Have any of you done this simpler?

regards,
Alex...

ngoldrich

Alex,

My 993 GT2 racecar has two Garret GT ball bearing turbos. They are supposed to be water cooled. However, nothing was connected to the water cooling jacket. Meaning that only air and the bearing oil was cooling the turbo.

That was the way the car was setup when I purchased it. I ran it two years that way.
However, I had to replace both turbos every 6 hours of use which was no fun from a cost or effort standpoint. I do have about 20 nearly new GT turbos that have leaking cold side seals :-)
Unfortunately there are no GT rebuild kits for these ball bearing turbos.

Anyway, I spoke with one of the design engineers at Garret and they told me that the problem was not actually the bearings, it is a small c-type seal clip at the end of the bearing cartridge that is melting. That was causing the seal to leak.

I looked at the options putting a whole water cooling system in. However, after talking with the Garret engineer, he said that would only be marginally better than simply cooling the turbo jacket with oil.

So I did do all the plumbing on the supply and return side of each cooling jacket and it does work well (at least in my setup).

The turbo center section, by the bearings, no longer turns blue after running a short while. So far everything has worked great.

So at least in my setup, the oil cooling seems to work well...

Norm

PorschePhD

Norm,

Do you run a pump after the motor is shut down? Like the 951, Audis etc? This also would prolong the life. Hot shut downs kill although your situation is a tad different. I too run Garretts on my twin without the water cooling. I am religious about shut downs though. I can go about 15K on the pair I have. Basically every year I do the cartridges

Mondragon

Thanks for the info guys, i should have said my car is street driven. i am going to hook up the water cooling system as i cant afford to be rebuilding the turbos every 10 minutes like you guys.

thanks.

Alex...

ngoldrich

Stephen,

I do not run a pump. However, I always let the engine cool down for a few minutes at idle when I come in. Everything works fine now since I started oil cooling the jacket.

Thx,
Norm

special tool

Norm - I would suggest that you have a real turbo guy spec your turbos.
This is elementary stuff.
Whoever set up your car originally was lacking in turbocharger experience.
You do not need to use a Garret center - we need to think outside the box!