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mark houghton mark houghton is offline
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Join Date: Jul 2008
Location: Central Washington State
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Originally Posted by e170drvr View Post
My gut is telling my that my 87 US was designed to run at 26BTDC on .8 bar boost. However if this solenoid does indeed block the boost signal above 22 as Speedy says my thinking will change. Just find it hard to believe that the Porsche engineers are protecting this expensive motor with a cheap electrical solenoid, who's failure could result in a blown motor. Very interested in this detail.
Agreed on that. And for all the people who have ripped out all emissions stuff except for the Lambda frequency valve behind the fuel head, all those cars would be toast right now if that little solenoid was so important for retarding ignition.

I'll say it once again: I am running with 38 degrees advance at no-load 4000 rpms. My MSD BTM retards 12 degreess of that by the time I'm on full boost, and I have to trust that the rest of the timing (another 8-10 degrees) is coming off as a function of the distributor pot boost retard.

I do not have that silly solenoid in-line, never have had it. My car has not melted a piston, nor does it cry the death rattle. This either means that the solenoid is not an integral part of the equation, or it means that I'm running with 26 degrees advance on boost with no problems. You be the judge, 'cause I don't know.

If I ever get a wild hair, I will attach various vacuum and pressurized air sources to my distributor and see what's really happening beyond conjecture....and will share the results if/when I do it. Until then, happy motoring!!!
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 04-06-2010, 03:09 PM
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