Hi Guys, would Like to get your input on what I'm working on.

So my project car is a 1981 Porsche 924 TURBO. This is an 4cyl 2.0L 8v.

Now the two issues are the turbo is a KKK K26, BUT it has Specific 3 bolt mount to the manifold, which ONLY fits these cars. So i can't take other Hotsides and swap them out. So i am building a custom header to mount a t3 or t25 housing.

and secondly, I don't seem to find a comparable turbo in any more common turbos as far as turbine/compressor sizes.

Here are the specs on the factory turbo.
compressor exducer= 66mm
compressor inducer= 42.24mm
trim= 41

inducer 54.6 (2.15")
exducer 63.4 (2.5")

Turbine housing difficult to say but its a #4 which from what I understand means 4cm^3. It looks similar in size to a T3 .48, but the on the .48 T3, the Id/wheel size is significantly smaller.


Now what im wanting to achieve is better boost response/pressure with out more lag than it currently has. Im looking for about 300hp, max 325, But I really dont want to run more than 17psi.

If I went with a t3 .48 the outlet size is smaller than the original size. But if I go with a .63 the wheel size is similar to the Stock wheel, but im afraid of more lag due to the larger A/R.
Also on a turbo such as the T04e the compressor size is notably bigger 66mm vs 76mm

One shop recommended the GT28R (disco potato), but im worried that might be too small, and the Turbine size is much smaller than stock. Plus the factory set up uses an external wastegate.
ALSO, the T3 centers with the offset mounting bolts are the same as the KKK turbos, so it mounts directly to the Stock turbo Mount. but the gt28's have a symmetrical bolt pattern and would make mounting more difficult.

(I will say, I always thought the stock turbo was just a little too big, especially for an 8v engine)

thanks guys!