[911st]

So what is our timing like and what would a more ideal look like?

For a stock US 930 I believe our timing looks approximately like this.

+1 (1 deg ATDC) at idle (quickly jumping to apx -8 with acceleration),
-26 (26 deg BTDC) at cruse above 3000rpm,
-16 to -17 on boost.

This comes from a combination of the following:

-Vacuum-Retard of about 9 deg. When this goes away with acceleration and effectively advances timing. There is no vac-advance on 3.3 Turbos. In general I belive vac-advance is to increase economy and vac-retard it to benefit emissions.
-Mechanical Advance of about 18 deg that is full in by about 3000rpm.
-Boost-Retard of about 9 deg. that is full in by about 5 psi.


What would a more ideal timing look like”?

I would love to see more input on this but one EFI turbo ignition timing table reviewed leads me to think it might look more like the following:

-15 (or more) at idle (w aggressive advance by 2500rpm)
-35 on cruse (seen reference up to -42 w little load)
-16 on boost

Our net on-boost timing seems good. We come up short with on cruse timing. However, cruse timing dose not seem hurt our performance to a significant deg. It dose however cost us, by one report, about 5% in fuel economy. Our best and most usable opportunity seems to be to improve idle and pre-boost acceleration. More low-end could also mean earlier boost onset. Further, our boost-retard seems to be all in with about 5 lbs of boost. Bringing this in, in a more progressive manner might reduce spool time.

Thus, we can do better!