I was reading an article about trap speed calculations and it made mention of the old way trap speed was calculated vs the new way trapspeed is calculated. Prior to ~1988, the NHRA set the trap speed boxes at the finish line and 60' past the finish line. This is why you'll notice 1988-prior timeslips having fairly high traps in relation to ET. After too many wrecks from drivers staying in the throttle way past the trap, the NHRA decided to move the boxes to 60' before the finish and at finish line to take away the driver's need to stay in the throttle as long. There was no change in ET, but trap speed changed by ~3-4mph on average. What's interesting is that some tracks are still using the old style calculations since it has no affect on ET. The old style trap speed calculations are very accurate in terms of your true finishing speed, but the new way is a bit safer. On a side note, G-Tech style performance meters and onboard units the magazines use show true finishing trap speed, not the current NHRA calculated trap speed.

Just thought I'd share.


Dave

 

I was aware that they used to calculate trapspeed from the finish to 60' after the finish in the 'old days' but I didn't know that the 'old days' were so recent or that some tracks still used that method. That would explain trapspeed variations from track to track.

 

Magazines can either use the 60' averaged trap speed like how it's done at the track, or use the true right at the line speed. They can do whatever they want pretty much, and even do it both ways in the same comparison depending on what kind of result they're trying to get, or sponsors they're trying to please.

But thanks for the post, Dave. I didn't know that.