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dsiegel360 dsiegel360 is offline
Doug Siegel
 
Join Date: Oct 2007
Location: Bloomington, IN
Posts: 314
Quote:
Originally Posted by fredmeister View Post
Great thread guys.....
I am having similar issues with pinging last nite since I changed from a 0.8bar boost spring to a 1.0bar spring.
My car is a 79 930 with the dual port can, the boost retard is open to atmosphere. Vacuum side is connected as normal.
Checked timing and here is what I have which confuses me:
at idle of 1000rpm..... timing = (neg) 7 degrees BTDC VACUUM PORT CONNECTED
at idle of 1000rpm..... timing = (neg) 29 degrees BTDC VACUUM PORT DISCONNECTED
Honestly I was shocked because I thought that the 29 was aweful high at idle because as I rev to 4000rpm (NOT DONE AS YET, SO CANNOT REPORT RESULTS) I expect the mechanical advance to go even higher.
Now the safe limit from other posts I have read under full boost and high revs indicates 26-28 degrees max timing BTDC......I wonder what it will be when I run it up to 4000rpm with vacuum disconnected.
Questions:
1) In short, how much more advance does the mechanical advance add by itself?
2) Are my mechanical advance weights frozen at idle to explain the above results so far?
Meister,
When I told Brian Leask that I was ready to go to a 1 bar spring, he suggested purchasing a modified fuel head from IA. He said that I'd need the 20% extra fuel otherwise full boost enrichment would prove lean. I have the PLX afr gauge, thus I can tell you that at 1 bar WOT, I ain't lean. Along with the fuel head, I had to buy the rpm activated solenoid from Brian. Of course, the adjustable WUR is part of the equation too. I'm sure lots of people run 1 bar without the extra fuel, but I wonder what kind of readings they are getting, if any at all. I assume that with a 1 bar spring, an afr gauge is a must.
Old 04-10-2008, 08:19 PM
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