09-25-2009, 09:23 AM
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CC Member
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Join Date: Apr 2007
Cobra Make, Engine:
Posts: 1,009
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Quote:
Originally Posted by fkemmerer
Interesting, what are your thoughts as to why retarding the ignition above 7000 RPM helped the power output with EFI? How much retard did you use?
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I am not really sure, I think it might be related to cylinder pressure going up with rpm because the intake duration is pretty high (292@.050). Total advance was reduced from 32 to 29.5 degrees, the cylinder heads are very good and compression, 14.7 is pretty high. The earlier engine had Edelbrock heads that were highly modified but that engine peaked at 35 degrees advance because the chambers were still basically an FE. It seems that the more advance you need, the poorer the heads are and the less power you make. NASCAR engines are all in the 20's and as you know, very efficient.
As to EFI, I am not sure that it would not have worked with the carb. too, we were out of time and just thrashing the EFI at that point so we did not check it. |
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