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les_garten les_garten is offline
Macht Schnell
 
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Join Date: Jun 2003
Location: PSL, FL
Posts: 861
Hi,
The Porsche head is a large deep bowl with the plug off to one side. You time a certain amount of degrees BTDC to give the flame time to travel across the head to light the mixture. This wouldn't be as big a problem if the spark plug was centrally located and there was a "squish" area to light.

The two flames of the dual spark help out with these issues. That is why you can actually retard from the normal timing.

Soon, some of the Engineers on the Forum will come in and correct or shore up my statements.

I'm just a shadetree after all.
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---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 03-04-2008, 11:20 AM
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