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Old 04-03-2024, 02:14 PM   #18
JP1738
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Default Re: RPM dip doing onto stop, w/ racepak graphs

I go on at .30, cruise at 4250-4300 with a CO2 stop and a really fat 30 year old carburetor. That set-up has been pretty good to me in 1/4 mile SST. 383 sbc at 2830lbs (6.30s W/O at that weight), usually 137 mph depending on weather and track.

I change mine to shift on RPM when I run 1/8th mile SST or any S/G, but I use the same .30 on and cruise speed, just add numbers on the back end. Just changing the shift to RPM usually gets me close to 6.90 given I have to go around 7.25 to the 1/8 to get me 10.90 in the 1/4 when shifting on time.

It does dip a bit, but not enough to hear or affect much. I can see it on my Mega 400 RPM playback but the resolution is not very fine. Might be worse than I think it is but I think I'd rather just not know. Ignorance is bliss.

Despite being slow, I'm more of a "get me close and figure it out before the finish line" kinda guy. Also never really had a T-stop ratio, I just try to get it close.
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#2827 S/ST 1978 Mazda RX7 w/ 383 sbc/glide
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