Anyone running 3.5L 964 cams with CIS

[flightlead404]

Gents

I'm considering some slight tweaking and wanted to see if anyone is running a similar setup AS A STREET CAR and wanted to get driving impressions. This is 1986 US 930 stock fuel head, lines, injectors, CIS with FrankenCIS managing the mixture via the lambda valve.

-3.5L 8:1 compression
-964 cams
-Lightweight clutch
-ported intake possibly as much as 40mm
-1.2 bar w/g
-twin plug w/ distributorless ign, COP in a wasted spark config
-Stock exhaust port
-RarlyL8 headers + hooligan

If anyone has done anything similar I'd like to head impressions on driveability, and gotchas you ran into, or would-do-it-differently-next-time's.

Thanks

[prschmn]

I'd talk to maybe DC or Web about the cam choice-964 is not ideal for force fed engines.
And I would NOT used wasted spark with COP-the spark at overlap causes reversion that prevents the turbo from spooling efficiently.
Course ther's a million possible combinations to ponder!

[Steve@Rennsport]

FWIW,.....

I've used 964 cams in a Turbo motor quite a few times over the past 25 years and its based on how the car will be used. For street cars, I prefer SC cams in these things.

You may have more experience than I do, but I've never, ever gotten sufficient fuel flow into a CIS Turbo motor to safely run 1.2 bar. There is far more to this, however I'd certainly re-think that much boost without running Engine Management to accurately (safely) control AFR's and timing.

[Jeff Alton]

The 965 S2 was a 3.3 with 964 NA cams (I had them mapped) and a few other bits. It didn't run 1.2 bar mind you, but made for a very good engine. The cam choice you made will be fine in a 3.5. Not sure about 1.2 bar with CIS, I will defer to Steve here as we don't try to run more than 1.0 bar CIS.

[Tippy]

Originally Posted by prschmn

And I would NOT used wasted spark with COP-the spark at overlap causes reversion that prevents the turbo from spooling efficiently.

I have never heard about this?? I'm wasted spark, but a 3.2 platform (higher flowing heads and intake over a 930). Spooling a fairly large 66mm turbo just fine (Borg-Warner S300-S366). As long as it's slightly rich on the punch, it lights pretty quick.

Curious if running sequential would enhance?

[prschmn]

Tippy, Dont be getting too worried here since turbos aren't as sensitive as blowers.
But, I watched a supercharged engine break belts on a dyno clearly due to the wasted spark setup. But it was a clear indicator for sure.
COP is great but I'd strongly advise not using wasted spark if it can be avoided.
Gains from sequential vs semi are not a ton-doubt it will help much since at higher RPM events are happening too fast.
Stay rich-fats where its at but lean is mean-----