Timing setting
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Joined: May 2004
Posts: 87
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From: Hendersonvill TN
Timing setting
I have a '90 automatic with a 358 ci engine with 9 to 1 compression, medium comp cam, AFR 210 heads, mini-ram, 1 5/8 shortie headers, 1.6 roller rockers, ATI supercharger running 10 lbs of boost, Ed Wright (Fastchip) suggested stock timing but at 12 I'm getting backfire, at 15 it's better but still not right. From what I've seen on this forum some are running 23 to 40 degrees. My mechanic has not done many vettes but thought that was too much for a supercharged engine. Any suggestions. Everything else seems to be great. 
Melting Slicks
Joined: Mar 1999
Posts: 2,535
Likes: 2
From: Rochester NY
Timing for forced induction any where from 15-26 degree of timing. Definately not 40. Your backfire could be a few things,
1) your spark plug gaped properly with colder heat range
2) Your ignition system, stock or aftermarket type.
3) Your fuel system is good?
All the above can cause back fires at WOT.
Bruce
1) your spark plug gaped properly with colder heat range
2) Your ignition system, stock or aftermarket type.
3) Your fuel system is good?
All the above can cause back fires at WOT.
Bruce
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Advanced
Joined: May 2004
Posts: 87
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From: Hendersonvill TN
Thanks Bruce, the fuel system is new, the ignition system is new but stock, I'm using new MSD wires and Denso plugs. We think it is the timing because he had it at 12 and went to 15. Got better but still needed some help. 
