problem with performance calculators

[skorpion317]

i've been toying around with those "performance calculators" floating around on the 'Net...mainly the one's that calculate horsepower and E/T. now, the problem is, i get two different HP ratings by using two different calculators. the first calculator uses vehicle weight and 1/4 trap speed to calculate RWHP, while the 2nd calculator uses the weight and the E/T to figure out RWHP.

with the 1st calc, i come up with 176 RWHP, or 208 at the crank. with the 2nd calc, i come up with 186 RWHP, or 219 at the crank. NOTE: i'm not substituing this for a dyno, i'm just wondering why there's a 10 HP difference between formulas.

[WishIHad$$$]

Originally posted by skorpion317:
NOTE: i'm not substituing this for a dyno, i'm just wondering why there's a 10 HP difference between formulas.

Because they are not accurate. If you want to know truly what your rwhp is, go to a real dyno. I used one of those formulas before and told me I have 225 fwhp or something like that. 25 horsepower from a flowmaster muffler? I don't think so.

There are many other factors that determine how fast a car is other than horsepower and weight.

[OneQuickV6]

I'd almost trsut the one that uses trap speeds over the ET one. This is because ET calcs count on you being able to drive the car to its potential. Trap speeds are the true indication of what power you're making, regardless of whether or not yo can launch the car.

Again, these calculators suck, get on a dyno if you wanna know how much power you're making.

[WickEdSix9838]

the MPH calculator will definately be more accurate because ET relies on traction, driver, the gear ratio, etc...

[12secondv6]

True, MPH does reflect a vehicle's "true" horsepower.

all of those HP/ ET calculators you find give you an "idea" of what the car should make.

The only TRUE way is a legit dyno.

Don't go by ET's for true hp.

Look at my ET's, then think about my 180 RWHP
Look at my mph, then think about my 180 RWHP

Probably makes a bit better sense with that reference... maybe