[quote=Alchemi]I know nothing of engines at this level, but are those normal bsfc figures for this sort of monster? they look really high?
Might be some more tune left in it? [/quot
We made several pulls, adding fuel (methanol) each pull. It just kept making more power the more fuel we threw at it. The bsfc numbers said it was fat, but the power just kept going up. We finally hit a point where peak torque stayed the same.
This shows the value of dynoing a motor. I was certain i knew roughly where the tune should be. I had run a calculation on a web site that said a .117 main bypass would be close. I started at .108 and ended at .092! That means i pushed about 16 percent more fuel at it than my already supposedly rich point of .108.
Also we found and fixed oil leaks that could have cost me a weekend.
Without seeing the results of the unexpected high horse power at 7200, i could have chased the tuneup at the track and never figured it out because of false assumptions i had about what the motor wanted and how high it would make power.
You will still have to tune it at the track. Different situation in the car.
I just dynoed my engine last friday and to get the AFR right on the dyno I was 10 pill sizes off from where I have ran it for years at the track. And that was verified by the ET slips.
We tried 33,34,35 degrees total timing. It lost a touch of power at 33 and 35. 34 is my magic number!
As to tuning at the track, i agree. With alky i can start fat and get a baseline, then take away some to see where i am at. The biggest deal to me was getting the high speed lean out figured out. It starts opening at about 6,000 rpm and keeps the fuel curve very consistant all the way to 7200 rather than go fat on the top end.
