John..

Anybody on here know the turbine size of the K-24s used on the GT2, or anybody have a set of triple K K-24s used on a 996 TT? I am working on a twin turbo 928 project and am seriously considering using the high flow K-24s off of the Audi 3B/ AAN 5 cylinder because of their size and flow range of the compressors. These units supported 230 HP on the AAN and could be run out to about 265 HP when chipped. I am looking to run them in the 200-230 HP range but don't want the back pressure to run up too high.

Thanks.

msindi

Not too sure by what you mean by "anybody have a set of triple K K-24s used on a 996 TT"??
The X50 996TT comes from factory with GT2 K24s if that is what you are asking....Good for 600HP with proper exhaust and ECU (headers help torque too)

John..

Yes, I have heard those were used, but what is the turbine size? There are lots of different options out there.

msindi

Best person to ask is probably Kevin (I think his username is also Kevin) - he is THE authority on turbochargers...

Kevin

And the measurements are:

57mm Major

52.80 Exducer

John..

This is great, thanks for the information. This sounds to be the same turbine size that is in the K-24 from the 3B/AAN 5 cylinders. These units spooled real fast in the AAN, so the same should be true in the 928. They have just about a perfect compressor for what I am doing, small inlet and outlet with the ability to flow lots of air at 76% efficiency. Don't you love it when you are running peak design boost at the peak compressor efficiency?

I have lots of design work to do, but in three months time I should have one heck of a setup for the 4.5/4.7 liter 928.

Thanks again.

Kevin

The stock Audi and GT2 or X50 compressor wheel trim is to small for your displacement.. You need a larger wheel.

John..

I have thought about a larger turbine. The turbine wheel is 58 mm major, but you are right the exducer is smaller at about 42 mm or so. What is your recommendation? I'm not convinced these won't work well, because I am building a 4.5 liter and this turbo came off of a 2.2 liter, so I am asking it to support just 50 more ccs per bank. The displacement is about the same, but if I could have my wish I would go a little bit larger on the outlet size. As usual, the cost comes into play. The compressors are really perfect on these little guys.

ebaker

What size turbos did Callaway use?

John..

Callaway used an IHI RHB-6. The K-24 has a much better compressor map and about the same flow capacity or slightly more, but the IHI has a slightly larger exducer. I know these K-24s will work, but my wish list would be to have about a 50 mm on the exducer bore to allow for greater flow up top.

I may look into using these compressors with a larger k-26 hot side from the Audi line. Space is at a premium.