'79 930 engine questions

[gumba]

What I have: '79 930, twin plug, Andial intercooler & fuel enrichment, stock heat exchangers, DP muffler, K27 turbo, Tial 46mm waste gate, gruppe b cams (?). I have Euro heat exchangers I will be putting on. The p/o put in a new/rebuilt fuel head, injectors & fuel accumulator. I would appreciate opinions and suggestions on the following items:
compression test: 130-140.
the a/f under idle and normal driving is 11.5-12.0/1.
I did 3 pulls from 2500-6500, went from 11.5 to 13.5 at the top end.
full boost at 3800-4000 rpm.
hot start problem from being flooded. A temporary fix was to shut off the fuel pumps when starting then turn them on after it started.
I'll do a leak down when I pull the motor. I don't plan on tracking the car and would be happy with 370-400 hp.

Is the rich a/f caused by the Andial unit? What's the fix.
How do I get full boost earlier?
Any opinions on the hot start problem?

Thanks,
Harold

[Rob 930]

Harold,

I can't answer all your questions, but I have a few thoughts. First, 11.5:1 under cruise is too rich. But I think you knew that. It will run better with AFRs in the 13s or even more if you're truly in a no load situation. But I'd be concerned about the AFRs during your "pulls." I assume these are full throttle acceleration runs. For those, 11.5:1 is not too rich for the initial part of the pull, and for a CIS car, is actually pretty good. But 13.5:1 at the top end is too lean and you're risking engine damage. At the top end, you generally want to see AFRs no higher than the low 12s. For now, I'd plan to short shift at whatever engine speed corresponds to 12.2 or12.3:1 in order to avoid ventilating your pistons.

As you may know, those Andial fuel enrichment devices have fallen from favor the last few years. There's lots of discussion here and on Rennlist about how to optimize the AFR curve for a CIS 930, and it usually involves a flow modification to CIS head and tweaks done to the warm up regulator. There are a number of CIS cars running around with well over 400 RWHP and safe AFRs throughout the range. Here's a thread I started years ago on this topic and it's still going:

Rennlist thread on CIS 930s

Good luck,

Rob