Why turbos after DME still used CIS

[Kurt B]

DME is a programmable system, I do not understand why CIS was still used. Does anyone know?

If you put a turbo on a 3.2, then you have to convert it to CIS or what?

[Early_S_Man]

Kurt,

Practicalities of production ... the CIS engine was already fully-developed, and it did an adequate job! New development costs would have been incurred to adapt the DME to a turbo engine, with very limited gains! IIRC, it was the mid-90's before the turbo version of the 964 engine was offered! The '84 - '89 Turbos didn't really undergo many changes from the '78 version ... except for the transaxle change!

With your high-compression pistons ... you can't just 'add' a turbo to your engine!

[Kurt B]

Warren:
Couldn't I just run lower boost...like .5 or .4 bar? I agree, I get spark knock as it is with 91 from time to time...can't imagine a turbo, but if I used minimal boost, you'd think I could slap a turbo on there....
No?

[sammyg2]

You can run a turbo on high compression motors, you just have to make some compromises. One is lower boost levels as you said, another would be higher octane (not feasable to most of us) and/or run a little less ignition advance along with a richer mixture.

under full boost the combustion temperatures get much higher when lean than when rich. If you are willing to give up some mileage for horsepower, all you have to do is to cobble up a 7th injector that kicks in at a certain boost level. You could probably even use your cold start injector or whatever the heck it's called on Carreras :-)

Obviously intercooling makes a big difference also.

[juan ruiz]

Hummmmmmmmm..................

[ChrisBennet]

Ruf has Motronic turbos in the '80's but the 1994 3.6 Turbo was still using K Jetronic (CIS).
-Chris