X_03_Cobra_guy

I have a 3250lb vette and have managed a 121MPH trap speed. The car is an Automatic with 3.42 gears. Is there a formula to calculate RWHP based on trap speed?

jleews6

iTrader: (2)

My 03 cobra went 121 with 440 rwhp @3700 pounds. i would say you are around 400 rwhp.
It takes 400 fwhp to go 120 mph @3000 pounds . The Moroso slide rule shows 440 hp for your car.

SSilver

hmm how about a 6 speed with 4.11's and 113 mph and 3500lbs..

CAT3

iTrader: (9)

Guys....Google....then enter horsepower calculator!

Should give you a bunch of pages to use... based off the 3250 race weight (with driver) at 121 you would have 449rwhp, thats from a few different sites, probably cuz they all use a similar logic.

rpmoutlet.com and the other is speedworldmotorplex.com

try em out!

Raptor99

I'm sorry, but that page has got to be wrong. According to the MPH and ET calculator, I'm making between 409-418 RWHP with a bolt-on only car. I shouldn't be much more than 340, if that. Where's the flaw

Roarin_8

iTrader: (5)

Don't use the ET calculator, that's all based on traction.

1ScrudeDude

I will agree for sure.

On a side note, I'm trapping 117-118 and it told me I was at 445 rwhp. I'm actually at 413 rwhp.

BADSZ28

iTrader: (39)

There are two kinds of calculators out there, one for trap and one for MPH. They will measure way different. What I do is add both numbers and divide by 2. This will be as close as you will get without a dyno. So 340+380+720/2=360.

Raptor99

I used both. The 418 was the ET calculator, and the 408 was the MPH calculator. So yeah, there's no way my bolt-on car is pushing that much to the wheels. It's 3440 pounds, and the trap speed was 115. Hmm, doesn't add up

BADSZ28

iTrader: (39)

Well you also have to keep in mind "ram air" or more abundant cold air due to the higher speeds. It does not show on the dyno, but you usually see a difference at the track. Do the same calculation minus .1 and 1mph and you are closer to what you would see on the dyno.

Raptor99

Actually, I just thought about something else... the day I did my 11.75@115, I also had two 113 mph runs, which would put me at 387 to the wheels and 457 at the flywheel. Hmmm, it's still a little off. OR... maybe my car just likes my mods

distortion_69

iTrader: (20)

A calculator like that doesn't account for great 60's, nor does losses in mph due to things like big tires, different convertors, etc show up. You could very easily run 2mph with just a convertor swap.. but your really not making anymore horsepower.. possibly not even at the wheel.. Just staying in your powerband better. I've found it works alot more accurately for a 6 speed car.

BIGBOS

I made about 460 rwhp through my TH400 a while back, car weighed close to 3700.....I went 122 mph...