Timing - Educate Me. Am I Running To Much? To Little?
05-29-2006, 12:32 PM
#11
0.0 BAR
Join Date: Feb 2003
Posts: 0
Re: Timing - Educate Me. Am I Running To Much? To Little?
I haven't tuned an A6, but I'm wierded out by the timing values in both the maps displayed based on Y8 and Z6 experience.
Like SOHC MShue, I've found best timing on Z6 @ 10 psi to be in the 14-15 degree range. Matt tells me he recently swapped for an STi turbo, and now his setup likes 16 or so. Stuff varies around, but within a certain very small ballpark *unless* you've gotten completely crazy with CR, cam profile, turbo selection, etc.
A6 isn't Z6, but the combustion chambers are similar. The timing running all over the place works okay for a stock NA vehicle, but when heat + load build up under boost you end up with a really volatile setup. Change most (mid-upper rpm range) of those columns under boost to the same value, and until you get dyno time to see how power vs timing manifests, don't change them.
Like anhything, timing can be empirically deduced - you only have to stop being intimidated with a new experience and go slow and think your way out of the box. Monitoring CTS logs during a pull tells a lot. When I had Steve's Y8 on the dyno, and the other's Steve's H22 on the street, I was able to drop timing and coolant temps while not losing any power whatsoever. In the case of Steve/Y8 the ambient air temps increased as the day progressed (15 degrees F!) and his engine was pretty heatsoaked when it made peak power, but the timing and coolant temps dropped in relation to each other until I started drawing out too much timing and the temps stayed steady and after more timing taken out (and power loss) they went back up a smidge.
Like SOHC MShue, I've found best timing on Z6 @ 10 psi to be in the 14-15 degree range. Matt tells me he recently swapped for an STi turbo, and now his setup likes 16 or so. Stuff varies around, but within a certain very small ballpark *unless* you've gotten completely crazy with CR, cam profile, turbo selection, etc.
A6 isn't Z6, but the combustion chambers are similar. The timing running all over the place works okay for a stock NA vehicle, but when heat + load build up under boost you end up with a really volatile setup. Change most (mid-upper rpm range) of those columns under boost to the same value, and until you get dyno time to see how power vs timing manifests, don't change them.
Like anhything, timing can be empirically deduced - you only have to stop being intimidated with a new experience and go slow and think your way out of the box. Monitoring CTS logs during a pull tells a lot. When I had Steve's Y8 on the dyno, and the other's Steve's H22 on the street, I was able to drop timing and coolant temps while not losing any power whatsoever. In the case of Steve/Y8 the ambient air temps increased as the day progressed (15 degrees F!) and his engine was pretty heatsoaked when it made peak power, but the timing and coolant temps dropped in relation to each other until I started drawing out too much timing and the temps stayed steady and after more timing taken out (and power loss) they went back up a smidge.
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