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911st 911st is offline
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Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Thanks much Speedy Squirrel

Good work on the drawings and thank you for confirming how the retard works on the different distributors. It helps me believe that I am on the right track on this stuff after all the effort we have put in on this topic.

Brian's running 26 deg on boost with no retard is a good data point. He dose have a more efficient intercooler, turbo, and is only running .75 bar. I do not know if one could run 1 bar on Calif fuel and get away with that at 100 deg day after sitting at a stop lite for several minutes with the A/C on. The factory has to build in room for this.

It is possible that if we are watching our EGT's and AFR's we might get away with a lot more aggressive ignition timing. There are clues out there that indicate these might be possible.

If Brian can run 26 deg with not boost retard then a properly working US dist might be able to run 34 deg and then pull back to about -25 on boost. Remember, the C2 turbo runs 40 deg under light load at cruse.

I am not saying we can, just that it might be possible.

Good work so far everyone.

Just a thought.
Another data point is the C2 turbo that runs 21 +/- deg timing depending on intake air temps.

It still amazes me that euro's do not seem to have any boost retard.

I see little issue with running without Vac-Retard on a 930, euro or US, as it is more for emissions.

I wish someone that knows how to program a turbo on a dyno would test at different advance levels and see where we make the most power. That is the only way to see how much advance we can run. Of course we would want to pull it back a bit to stay safe under varying conditions.
Old 04-01-2010, 09:49 PM
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