I always thought there was a sensor at the 1260 mark and 1320 mark, and then averaged (if you could snap shot your speedo at the 1320 mark, it should theoretically read higher than the 1/4 trap on the timeslip). But if it's a 120 foot average (1260 and 1380), then I've been messing up something aweful

 

1/4 mile trap speeds are calculated 66' before the finish line to 66' after the finish line giving you 132', then the MPH in between is averaged for finis line MPH.

 

WTF!!!@

dang, I've been seriosuly messing up then. Wow, learn something everyday. I'm staying in the throttle out at hrp until I reach I-10, dogone-it...who cares about netting and a sand box :o

 

This used to be the way they did it, but it changed a few years ago. Now they just do the 66' before the finish line to the finish line. They didn't want the top fuel guys staying in the throttle too long.

EDIT: I just Googled it and man, it's amazing how time flies. The NHRA made this change back in 1989! Here's the excerpt:

Previous to 1989, there were three timing lights at the end of the track; one AT the end of the quarter mile, and one 66 feet before, and one 66 feet after. The middle light was used to calculate the et of the run, and the time to travel the 132 feet at the end of the track was used to calculate the trap speed. This gave the average speed at the end of the track, but you can see what this lead to. Most of the racers stayed on the gas for an additional 66 feet past the quarter to get a consistent speed to evaluate their setup. The track's 'shut down area' of course is a fixed length, but the pro racers were starting to hit 300 mph plus by the end. In an attempt to get these guys off the gas 66 feet earlier and 'make' the cars appear slower, the NHRA stopped using the last light around August of 1989. Today, the trap speed is calculated between the light at the quarter mile and the one 66 feet before. So any timeslip after 1989 is really giving the average speed 33 feet from the finish, which is pretty close to one percent slower than before.

By the way, we can thank our fellow CF'er, Eddie Hill, for forcing this change. Mr. 300 was just going too fast back then!

 

ya, good catch, glenn. I just found it on nhra.com. Actually a pretty good site with alot of rule descriptions and history.

oh well, my cars a top end dog

 

all i know is i always let off at the finish line118-119, but when all this top mph started i held to way after 121. so even if its not their any moreit worked for me

 

Awesome MPH!

 

Any chance of me tapping on 11's with an 07 Z51 M6, 160 stat, 4.10's, optimal tune, Kooks LT's with X. Stinger CAI, Vette-Air scoop, and Bilsteins. I ran a 12.6 with just the CAI, never been on the dyno with this one, and I can up the tune for race gas if needed.

 

Nicely done Mikey! I'm gonna whip your butt this spring beatch!!

 

Oh its on. Got a buddy who will loan me his DR's when I need them. Makes me wonder what kind of times I could pull with those bad boys lol.

 

True

 

Yes, there is a VERY good chance actually if you're a decent driver.

 

Nice pass.

 

FWIW my 03 Cobra went 11.40 at the same mph so you should be able to get down there also. Very impressive MPH now just keep after it and you will see your times just keep falling. The ls3s are laying down the good MPH now we just need a couple of the A6 guys with good tires and a converter to lay down the quick ETs.

 

If ever there was incentive to go back for some more passes, that ET is it!

Nice runs, you'll get it next time.

 

That ET would drive me nuttz !

 

If you come run down at HRP (I see you're in texas) and you DONT run 11s with those mods then you need to learn to drive it

That's more than enough to go 11s at a good DA.

 

Thanks for rubbing it in guys

 

Time for MT ET Streets. I bought inexpensive 17" ZR1 wheels for my set up. About $650 total for 2 wheels & tires.

If you do a CAM remember to install Dual Springs as well. The OEM springs are the weak link.