ET Vs. MPH

Let's say 2 different cars both run 12.5 seconds in the 1/4 mile but car A crosses the line at 106 mph and car B crosses the line at 115 mph.
What would cause the difference?
Cliff

 

Horsepower and torque, torque because car b probably spun like sob

 

Gear ratio, chassis set-up, tire hook-up, "torquey" engine vs a high rpm engine, light car vs heavy car etc. Lots of variables, but for the most part the expected mph usually doesn't change by more than 5 mph or so one way or the other for a given 1/4 mile e.t. unless the car in question has a LOT of power and a crappy chassis set-up.

 

I was running 12.80s at 107 with 2.56 gears. Switch to 3.90 gears and run 12.50s at 109. Not much mph difference but lots of ET.

 

So which is a the better run? and why?
Thanks
Cliff

 

The race is over so its a moot point. However the car with the faster speed is quicker. In your scenario the two cars cross the line at the same time. The faster trap speed indicates that car had to catch up to the lower speed car. If the race was longer the faster speed car would be pulling away...

 

You would want the one with the higher trap speed, if you're asking which car is potentially "better". The higher trap speed car would most likely have more power but probably is either spinning on take off or geared too high for optimum quarter mile performance, so it has more potential.

 

For winning a race, it's reaction time plus ET. That's what determines who crosses the line first. The MPH doesn't matter

 

I would like to put in for the car that hooks and runs the 12.50 and the lower mph. In a drag race or street race the participant/competitor that gets there first is the winner no matter how fast they are travelling at any part of the track/course.
if I can get the participant in the other lane to get rattled when I jump em out of the hole and hit is nitrous too soon and spin or put too much throttle into it and spin and I can get to the other end ahead of em . Yep, I win.

mph is a function of hp and if you can't get that power down it is worthless. Spinning ain't winning.

lots of ways to get the power down. Converter in am auto trans car, rear gears and tire height make a difference. Chassis setup with adjustable arms, moving the mounting points, different bushings and springs. Lots goes into getting the power down.

 

I had 70 Skylark street/strip car years ago that I street raced ALOT, it only ran 7.40's at 87 so by no means was it a beast, but back in 2003 to 05 it was a contender against 95% of the stuff out riding around, I out ran TRAINLOADS of LS powered Fbodies, Vettes, 03/04 cobras etc most if not all ran faster mph to the stripe but from a first gear roll I would eat their lunch once we would get up to 120 or so they would pull back up on me but I would be tached out so the race was over

 

I can tell you car b is a lot of fun on the street.
My 96 Vette ran bottom 12s at 116 mph. That thing was a blast on the street with the manual trans. Never got it to 60' better than 1.85 though.

 

https://www.google.com/search?q=hennessey+escalade+vs+camaro&ie=UTF-8&oe=UTF-8&hl=en&client=safari

Watch this video—the Camaro loses but had a higher trap speed.

 

It sounds to me like car A with the lower MPH is then getting more out of the car or closer to full potential while car B with the higher trap speed is leaving something on the table. Is this a correct assumption?
Cliff

 

Yes, exactly as I stated in post #7 .....

 

I have 3:08 gears but cross the line at 108+mph with like 2.1 60ft time (non-posi). One example is I raced a guy and I crossed at 12.90 and he crossed just after me at 13.11 but at over 110mph. He was running 4:56 gears and a hi-po dual quad 409. My guess would be that if I was runni9ng something other than the stoch converter and 3:08 non posi, I would be in at least mid to low 12's.

 

108 as follows:

1.71 60 ft
7.75 1/8 mi
88 mph
12.27 1/4 mi
108 mph

This is with great traction, 3.73 to 3.42 rear gear, well built 3200 to 3500 stall converter, etc.