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356-930 356-930 is offline
Acceleration Junkie
Join Date: Aug 2007
Location: Laguna Beach, CA
Posts: 263
Originally Posted by RarlyL8 View Post
356-930, I carefully re-read your post and see what you were doing on the Sun.
I do recall reading in the factory manual about the actual reduction of advance during boost on specific distributor models vs the lack of advance on others. I believe they were later model 930. I also recall that there were switching devices in play that allowed for different events to occur at different engine loads. The manual described a boost retard situation but how that retard came about was not by simple reaction of the pot to the signal. Do you have that information? If not I can look it up in my notes and send it to you. We are not allowed to post pages of the manual here on the board.
Thanks for the study and info. I appreciate your offer of factory manual data. Thankfully, I have access to the factory manuals.
My donor engine was a '79 3.3 liter and it didn't have any of the switching controls you note were employed by Porsche. That's why I ran the Sun tests, to see how the distributor behaved without vacuum/pressure switching control. I'm satisfied it's ok as is. My only concern is potential damage to the control diaphragms seeing vac/press they might not see if the controls were in place. If the engine starts to mis behave in the future, I'll look first at the distributor.
I run an MSD ignition with an MSD boost retard module and can pull out an additional 15-deg of timing if needed. (It's really advantageous to low end performance to run substantial advance. I presently pull out 3-deg with the MSD - helping to keep the pin in the grenade handle.)
Again, Thanks.
Old 04-07-2008, 09:50 AM
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