Every tenth in the sixty foot will usually be worth 2-3 tenths lower ET.
Your MPH can be affected by many things, mostly tirespin. The more you spin your tires, the faster your trap speed will be, but your ET will rise, because you're spinning your tires.
My car makes waay more power now than before, but only traps like 2 MPH more in the quarter off the nitrous than before, but that's after adding drag radials. So if I still had street tires I'd be spinning more and probably trapping like 105 MPH, instead of 101 N/A.
Your staging behavior can also affect MPH. Deep staging will get you lower MPH than shallow staging. Made a 2 MPH difference on my car. It ran
[email protected] MPH, and
[email protected] MPH within half hour of the runs, similar 60' (both in the 1.90s) and the biggest difference was I launched a little higher the second time, and deep staged the second time. The 12.78 run was barely tripping the stage bulb... (they were having an RT competition, deep staging netted me a .505 light and a pair of tickets to Dragstock).
