Best 1/4 Mile Trap Speed


My best 1/4 mile trap occurred during a mini-Stealth gathering at Lapeer Dragway on October 16th, 1999.  It was a mild day (low 70's) with 17.5psi dialed in and Torco 104 octane in the tank.



4.902 second 60ft

11.226 second 1/8 mile @ 90.44 mph

15.543 second 1/4 mile @ 118.80 mph


What the heck, a 15.543 ?!?


Here is what happened, I was lined up by myself on the inside lane and didn't take off when the light flashed green.  Instead I concentrated on watching the tach and nailed it when I was ready.  In the meantime, my car tripped the starting line beam (slight down-slope at the start - I hate the inside lane) and the clock started a couple seconds before I did.  If I assume a 1.800 second 60ft (typical), then each time is off by 3.102 seconds.


With this assumption (3.102 second correction factor):

1.800 second 60ft

8.124 second 1/8 mile @ 90.44 mph

12.441 second 1/4 mile @ 118.80 mph


Because I don't know the 60ft for sure, I cannot say with any certainty what the 1/4 mile E.T. actually was (wouldn't have been a personal best anyways), but the speeds measured at the 1/8 and 1/4 are accurate with the 1/4 mile trap showing here being my best.


My best 1/8 mph of 92.83 mph occurred 10/30/99 at Lapeer dragway on 17 psi boost.



Starting with the launch,  the datalog shows I released the clutch at 5,100 rpm.  I reached WOT in about 1.4 seconds and it took the clutch ~ 2.0 seconds to stop slipping (not good - too much slippage due to slow release of clutch).  I struggled all day getting the new RPS clutch to bite without bogging the engine (either excessive slippage or bog).  On this run, engine speed did not drop below 4,100 rpm on the launch.


Overall, the shifts were decent.  The longest shift, 2-3, kept me off the gas for 0.6 seconds.  Note that I didn't have to shift into 4th,  I can hit 120 mph in 3rd.  Also note the fluctuating O2 voltage which I felt in the car as a hesitation.  For discussion of the hesitation, visit my "Best ET" datalog.


Again, as usual, the knock sum was kept in check.  The 104 octane fuel and 73 degree F ambient kept the knock sum at or below 6.  The 550cc injectors did not exceed 78% IDC yet kept the O2 voltage at or above .80 volts (ignoring the hesitation).  I could have added more fuel via VPC/GCC but opted not to since the knock sum was low (no spark retard).



Well, most of you are probably wondering why I don't have an 11 second pass by now with the traps my car is capable of.  I don't have a good answer other than my limited "problem free" runs down the quarter and the fact that I'm still learning how to drive the car.  This run at 17.5 psi also represents the highest I've dialed the boost.  I believe many of the 11 second passes may be at higher boost.  I fully expect to improve my personal bests next year.  I am getting better at launches, shifts, and tuning in general.




since August 7th, 2002


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