air fuel blues!

[Blown353]

I bet your exhaust valves are hating life-- being that rich a ton of fuel is probably burning out the exhaust ports. That rich can also lead to excessive carbon deposits which bring on detonation earlier... and some is probably sneaking past the rings and diluting your oil. Running really rich is not good any way you look at it.

I'd set the thing for about 36 degrees total timing with the mechanical advance all in and begin by pulling about 1.1-1.2 degrees of timing per pound of boost (assuming you have a BTM or something similar.) That should be very safe on pump gas.



Next, work your A/F ratio leaner. You'll probably end up somewhere in the 11.4-11.8:1 range.

Then go back and start adding timing in a little at a time keeping a very close eye on the plugs.

Also, you are running vacuum advance... right? If not you may have a hard time achieving a good cruise mixture & mileage and also have difficulty keeping the plugs clean during normal driving. Supercharged motors by nature are overcammed/undercompressed when out of the boost and thus need lots of timing to keep the fires hot at light load. That's where vacuum advance comes in. With 8.4:1 compression I wouldn't doubt the thing will take all of 48-50 degrees of timing at steady state light load.

Are you running blowthrough or EFI? If blowthrough, who did your carb prep and what hat are you running?