Formula: Converting to MPH

[1996 Bravada]

any one know the formula to how fast your going in a 1/4 mile time (if a car goes down 1/4 mile track in 10 sec. what would be the MPH) what is the math.

[duffy]

Unfortunately, there is no math to convert to what you're looking for.
I guess you should look at NHRA records to get a "good idea", however
it'll only give you an educated guess.... You have seen dragsters blow an engine 300 feet from the starting line, their ET is approximately 10 seconds, but, their MPH is only about 89....
just Google "NHRA records" as a phrase, and see what you get.
here's a sample:
B/SA 9.98 130.40 10/09/05 Keith Lynch - West Jordan, UT '70 Chevy Camaro
A/S 9.99 133.72 04/16/05 Tom Baird - Blue Point, NY '69 Chevy Camaro
as you can see, the quicker ET doesn't necessarily equal higher MPH. and, these are current RECORDS !

[dougbfresh]

http://tutor4physics.com/formulas.htm (1 dimesional motion) are the basic equations BUT, you have NON-uniform acceleration so some calculus is involved. You can get approximations for other LIKE cars doing 10sec qt's. Duffy is correct, without something describing the acceleration you can't know for surre.

[Porcupine]

That's not all entirely true. If you own an Aerostar you can average out between two dates on the calander. If you leave the start line on Friday, I guarentee, you'll be at the end by Saturday, just not sure what time.

Vetteonr's Vette and Duffy's Buke has been know to arrive sometime the same day of lift off.

[Saltmine]

So THAT'S why they had a calendar in the timing tower at LACR last year!

[Saltmine]

Zero-to-sixty in one afternoon...

[danny]

the timing traps are set up so that e.t.'s are recorded from the start line to the finish line and the mph traps are set up on each side of the finish line. the e.t. doesn't equate to the speed of the vehicle.

[Daniel Wood]

Everyone is right with the exception of Porcupine. I didn't know the bucket would go that fast.

You can have the quickest ET but a slower speed then the person you're against.

Click on this link Funny Car

Just look at the difference between these two. This is from 2004

Gary Densham
4.955-327.11
Jerry Toliver
4.821-319.29

[olddog]

I found these two formulas, a while back. They are reasonable estamates, as this is not an exact science.

These formulas are for 1/4 mile track

Hp = weight / (ET / 5.825)^3

Hp = weight * (speed / 234)^3

By using simple algebra you can manipulate these two formulas to calculate ET and speed by entering a wieght and Hp. I built an Excel spread sheet to do this, if anyone is interested.

For instance my spread sheet calculated that a 2200 lb car with 425 hp will run a 10.08 ET at 135.3 MPH. Pretty much what an A C Cobra did.

[olddog]

PS
The two formulas combined could be used to derive a formula to calculate speed from ET, but I have a cold and headache and I'm too lazy to do it right now.

Granted this is only going to give a ballpark number assuming decent traction and continuously getting the HP to the pavement. If not, all the comments above come into play.

[duffy]

Originally Posted by Porcupine

That's not all entirely true. If you own an Aerostar you can average out between two dates on the calander. If you leave the start line on Friday, I guarentee, you'll be at the end by Saturday, just not sure what time.

Timing the Aero-bucket requires someone familiar with the phases of the moon, and a really good tide chart.

[vetteonr]

But when he turns on the "blower", you have to time it with a sun dial.

[duffy]

Originally Posted by vetteonr

But when he turns on the "blower", you have to time it with a sun dial.

YIKES.. I forgot all about the blower...

[danny]

Originally Posted by duffy

YIKES.. I forgot all about the blower...

and the whitewalls-lol-

[duffy]

do you mean dem?


HOW COULD ANYONE FORGET???