crispeed

For all you people out there with horsepower calculators here's a quiz for you!
How much RWHP is required for a 2400lb car to run 8.05 at 167mph in the 1/4 mile?
I know the answer already but I just want to see how accurate those calculators are with cars running that quick.

crispeed
87 Rx-7 TII
9.204@150.47mph
2600lbs
un-tubbed

peejay

Using my favorite formulas...

Roughly 880-900hp at the flywheel (909hp via ET, 872hp via MPH) which is, what, 750ish at the wheels?

I use the calculator at DSM.org. I've seen the formulae a decade or so ago in an issue of Car Craft and they said they calculated flywheel HP, not wheel HP as DSM.org erroneously states.

crispeed

You're very correct!
The car made 760 RWHP at 36psi on alcohol!
From what I've experience with the above calculator it seems to be correct for wheel power on cars running up to 9.00 seconds in the 1/4 approx. I know of many cars running in the 8 second zone and the calculator always give the approximate correct flywheel power but not the wheel power.
I did it for my car and Nero's(Titan's Supra) by the mph vs weight and it came up right on the money.
But who really knows!

crispeed

crispeed
87 Rx-7 TII
9.204@150.47mph

peejay

Plug in a 2550lb car that runs 17.0 at 80. You get roughly 100hp, which is the weight, 1/4mi time, trap speed, and flywheel HP of a '79 RX-7

silvr94r2

iTrader: (3)

I got the same exact results!!! Cool.....so mine are right just like i thought.

jspecracer7

That site's down I think...or maybe I just suck at internet crap What's the web address?

RETed

Try this one?
http://www.turbofast.com.au/Drag.html
(HP numbers are RW.)


-Ted

silvr94r2

iTrader: (3)

the one i use and is always deadnuts on is Ray Hall Turbocharging. I don't remember the exact address.....but that's the name. I has alot of very good info! Enjoy!

matty

according to that web site a car that weighs 2900 with 300rwhp should run 12.4. I ran 13.3 with shitty 60' times. Trap speed is dead on though. I doubt even with an excellent launch i could run 12.4 however

silvr94r2

iTrader: (3)

matty: which website? I've found that the e.t. will be a little off.....but the trap speed will always be deadnuts on! I haven't been off with a single car.....and i've tested it on about 15 different cars.

Felix Wankel

Cause the ET's are based on basically a perfect driver.

peejay

Not really! If they were then that doesn't explain how ET can calc out to a HIGHER power than MPH!

silvr94r2

iTrader: (3)

I meant it (website) has alot of good info.....not me.

jspecracer7

thanks!

matty

yeah i have to agree ...ET is more driver dependant than trap speeds. Drag racing is all about launch and 60' times.
Thus utilizing the programs to calculate mph works but when calculating ET it only shows what a terible driver you are.

matt

mp

peejay

That's an advantage though! It tells you if you're having problems! (Like when I was running only 15.7 but at 89mph!)

matty

what was the problem?

protlewski

Well with that DSM says I should be able to run 12's with my corvair when its done.