Track MPH

BluThnder99

New Member
Aug 29, 2003
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St. Louis
I don't understand how cars can run a 14.4 at 99-98 mph and everytime I run a 14.4 my mph is like 95-96mph how does this happen. I have a auto but I don't get it how a 14.4 time can very so much with the MPH. Please explain
 
This is a GREAT question. Trap speed depends opn many factors, not the least of which is climate and altitude.

If you get more tire spin on launch, your trap will be at a higher rpm and thus speed all other things being equal.

I saw a Z-28 run a 14.4 last week and trap at 112 mph. That was really wierd, but the guy was most likely spinning through second gear.

Also, remember it is a race. Trap speeds should be used for trouble shooting. The winner is the guy who gets the the 1/4 mile the soonest, not the guy with the highest speed.

When you launch, you want a little spin, but not too much. Spinning is better than bogging.

What is your 60 foot times? If your are getting 2.4 as an example, and you get a better launch with a little spin and your 60 foot drops to 2.0-2.1, I would expect something like a 13.9 at 99 mph. I mention this only as an example so you can see some realistic numbers.

Most likely, you are bogging your launch a bit.
 
My 60' times are consistantly 2.1's and 2.2's but I do get a little tire spin. without that tire spin what numbers do think I would put for 60' and 1/4 times. See my goal is to brake into the 13's with stock rearended auto on street tires. But I was just wondering about the MPH cause I always see guys posting there times and it'll be a 14.4 or something like that at a faster mph than me and I'm like what the hell.
 
You 60 foot's are pretty good for a stock auto. If you say you are getting some spin, I believe ya. If you did not get ANY spin, your 60 foot times would probably get a little worse and then loose a little trap speed. This would put you in the wrong direction.

Are you taking your passenger head light out? This creates a ram air effect and will get you 1 - 2 mph. Most guys do this on their stangs and has been pretty much accepted as gospel.

Your 60 foot goal with a near stock car, on stock tires should be about 2.0.

Aslo, what is the altitude of the track? Have you corrected your times for altitude and barametric pressure and humidity. This might tell us a lot.

Every 1,000 feet in altitude will cost you about 0.50 seconds in the quarter and about a 1.5 mph loss in trap speed with a near-stock stang.

So, be careful comparing your times to guys on the net w/o looking at where they live. Also, some guys cheat and list their corrected times. This is fine, as long as it is stated.
 
My personal best e.t is 14.0 @ at 100 mph. Im trapping a higher mph then people who have had lower e.t's. I should be trapping a higher mph, and a lower et, however the humidity was high (98%), and the temperature was in the high 70's. These are horrible conditions for drag racing. My best 60 was a 2.1 on street tires, so my e.t was more a result of the lower hp caused by the air, rather then my launching. With better air, and lower humidity, i should be in the higher/mid13's. All of this was before the 4.10's. Therefor, dont be disapointed with your mph, rather, work on your e.ts's. mph is greatly affected by the settings of the race. Ideal racing temp and humidity, as well as alt., will most definitly have a noticable effect on your mph, as well as your e.t.
What was the temp, humidity, and alt when you raced? that might help us tell if your mph is actually low, or if its just a product of the track.
Mike
 
I don't know what altitude I am at but I can tell you I live in St. louis if that helps. The day I ran my 14.4 @ 95 it was a pretty cool day with low humidty. Go Ho To why would my 60' times get worse with less tire spin? thought the name of the game was traction you know better traction better times? I'm confused. How would I go about correcting my times, is there a website I can go to?
 
spinning can be a factor as stated before...I've spun first through the 60ft and when I finally got traction I trapped at 14.4 @ 104mph...If I hadn't spun like that, it would've been an mid 13 second pass that time...
 
BluThnder99 said:
I don't know what altitude I am at but I can tell you I live in St. louis if that helps. The day I ran my 14.4 @ 95 it was a pretty cool day with low humidty. Go Ho To why would my 60' times get worse with less tire spin? thought the name of the game was traction you know better traction better times? I'm confused. How would I go about correcting my times, is there a website I can go to?

http://www.modulardepot.com/density.php
 
How accurate is that site for correcting et's? Do most people correct theirs (meaning in their sigs/when talking about their times)? or just leave them as what you got at the track that day?
Mike
 
BullittStangV8 said:
How accurate is that site for correcting et's? Do most people correct theirs (meaning in their sigs/when talking about their times)? or just leave them as what you got at the track that day?
Mike
The site I posted is very accurate. I think most people just put down what they actually ran. Most people that go for TnT or street legal drags dont keep track of the DA.
 
Track mph is an indication of how much power you have available on a given run.

Track time is an indication of how efficently you put that power to use on that given run.

So if you have one car that runs a 13.80 at 99 mph and another car that runs a 14.00 at 99 mph, we can analyze the numbers and see that the slower car (mr. 14.00) would have slower 60' or 330' or 1/8 mile numbers or what have you. SOmethign in his run let him only go 14.00 while the other guy did somethgin better and that let him run 13.80. Could be better traction, better shifting, or any of a lot of other factors.