Spud,
In reviewing this year's run data, I just realized that we ran quicker on 59% nitro than on 70%. Every place we ran we were pretty good right out of the trailer, but slowed down nearly every pass after that. Also nipped a few plugs in a way I haven't seen before. Historically, when we got a little lean it would take off a ground strap. Usually completely off and I believe in the last 200', as it did not affect E.T.
With this new tune up, twice I have just taken the very tip off, maybe .015-.025", and it did not affect E.T. or MPH. A couple of other times it took about .060-.070" off and E.T. and MPH were way down. Fortunately we haven't hurt any parts.
When you flowed my system (great job by the way, you were spot on with the numbers between the 110 and 990 pumps) you mentioned getting the tune up "wetter in the pipes" at idle by increasing the idle check. Is it possible that I am too lean at the hit and too rich down track? Can I be burning the plug tips in the first 60'? (NGK 10 plug) Should I try to increase the check from 6 lbs to 8 lbs? Do I increase the port check from 10lbs to 12lbs if I increase the idle?
I have been trying to launch at a lower RPM and have taken a few grams off the clutch to try to get the lockup RPM higher.
For ref: 401" Donovan hemi, 6-71 @ 33% over (25 lbs), 60-70% nitro, 990 pump, not using high speed right now, direct drive 3 disc pedal clutch, 4.10 gear. We ran 215 @ Bowling Green! Just need to get more consistent now.
Thanks,
Steve K.