Thread: Advance Curves
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les_garten les_garten is offline
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Join Date: Jun 2003
Location: PSL, FL
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Originally Posted by 89turbocabmike View Post
Les, keep in mind that Porsche's timing specs at idle are guided in part by the limitations of a mechanical distributor and the timing curve/advance it is going to need over the rev range. With a stand alone, you can break out of those limitations/mindset. For example, I often add a couple degrees more timing at the lowest expected cell, in your case 800rpm, to help stabilize the idle. Exactly what is the idle issue your having?
Hi Mike,
I've got a lot of idle issues! Wandering idle, cold idle, hot idle, blah. blah, blah. I have the workshop manuals and there is no easy way for me to reconcile the mechanical advance curve, vacuum, advance, and vacuum retard curves to get some idea of what the cell timing should be in the "ballpark" of. I'm trying to land on a decent timing setting from 800-1200, so that I can say, that;s reasonable, look elsewhere for your idle issues.

I figure if I can eliminate that variable than I can look at the other variables. That should be the easiest one to eliminate. I might have it now, just would like to see some curves that are well sorted out. I realize all curves under load and higher up in the rpm system will be custom, but even those portions should show trends.

I had a great conversation with DonE recently, and he brought up a very valid point. The reason why a factory EFI car runs so flawlessly is that their R&D depts spend more than a few Dyno hours getting them to run right.

I don't know if anybody with an EFI car has one that is "perfectly" sorted out. But somebody here probably has one that is 99% sorted out. That's the curves I'd like to see. Not to use them, just to look them over for patterns. Mine is going on the Dyno next week where we'll do our own timing curve. I'd like to have some patterns in the back of my mind while I'm doing it. So, I'm not just interested in Idle, but he whole range.

I got some tuning info from a few people, but you wouldn't believe some of the differences, even in the idle areas. I thought the more stuff I could see, some of it may make sense in time. Does that sound like it makes sense?

---Les Garten---85 930, Andial IC, GHL Headers, Fabspeed Dual, K-27 HF2, 3.4 JE Full Finned 7.5:1 CR, 964 CAM'd, Carerra 3.2 Manifold Cut/Flipped, Tec3r, Siemans 55#, GSF Fuel Rails, Clewett Crank Trigger, Clewett Cam Trigger,Dual Plugged, ARP Head Studs/Rod Bolts, Clewett Wires.Tial 46mm WG, Tial 50mm BOV, WEVO Shifter,934 Boost Gauge, Wideband EGO Sensor/Gauge, C2T Head Gaskets, '88 MB 300TE,BMW R100RT
Old 01-05-2008, 05:32 PM
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