Porsche-O-Phile

I've been told that later model 951s incorporated a larger turbine wheel on the hot side and this made higher horsepower by allowing the turbo to stay spooled longer and carry boost higher into the high-RPM regime. Is this true? What kinds of gains can be realized by doing this? Does it negatively affect drivability otherwise? Will I need different chips or injectors?

Of course, I really should get the car working properly before I tinker, but there's no harm in thinking about it, right?

streckfu's

The #8 turbine, when used the K26 compressor, will make more power but at the expense of increased turbo lag. I think the average power gain is in the 270-280rwhp range. Some claim around 300hp, but that would be at high boost levels.

If you are thinking of changing or converitng your turbo, search for archives for the K27/6. You can have your turbo converted economically and it's capable of over 300rwhp at modest boost levels and lag just slightly greater than stock.

Rage, has played with all this before and has posted extensively his knowledge.

Please search as this has been covered extensively. You'll learn more about turbos than you ever wanted to.....

Mike1982

Yea, I agree with the K27-6 upgrade. There was a post up not to long ago (within the last 2 weeks) about sure a upgrade. Just do a search, I have done TONS of research on this because I plan on doing it. A K27-6 is awesome from everyone I have heard, a K27-8 from what I have heard mostly will have TO much lag to make it worth it. Overall, you won't have the same powerband. With a 6 hotside you have much more area under a hp/tq graph then a 8 hotside but a 8 side will make more power. For any upgrade really, you want to increase the area under the graph not go for big numbers unless you just what big numbers and not a really fast car all around.

blitz951

I had them both. The K27/8 has a little more lag than the factory 89 K26/8 but if you want a significant difference in acceleration go with the #8. I didnt notice much of a difference from stock to #6 and will also say that when I raced a friend with my #6 we were even but with the #8 I was pulling away. All was kept constant with no other changes other than the turbo. People can talk all they want about the graphs but there is nothing like experiencing the two for yourself and thats what I did.
In addition, there is a dyno posted on the Rennlist, by Danno, of my friends car who has a k27/8 with a head and cam that was done by people(not a Porsche tuner) who really know how to make the 951 head come to life. He put down 370 rwhp and 370 torque @20 psi and the power never fell unlike all the other 951 dyno's I have seen and this car has no noticable lag! Bottom line, if you have your head, cam and the K27/8 work together you will have a car that is very fast and responsive.