If you know your 1/4 mile time, MPH and vehicle weight, this site will tell you how much HP you are making.

Click on 1/4 mile based dyno's

http://www.corral.net/tech/

Based on my best run, says I was making 225 HP (with k&n Panel)


--Ray

 

Here's another one...
http://www.aspracing.com/dyno.htm

 

I assume for the vehicle weight it's vehicle+driver right?

 

Hey did you find a way to drive your car w/o being in it?

I know, I know what a smart @ss! Seems like it would be skewed a bit with driver weight.

 

Colonel---><---Me

Well it's SUPOSEDLY calculating rear wheel horsepower such as measured on a dyno. However, your not actually MOVING on a dyno.

If your using 1/4-mile times for the base calculation, your/my FAT @SS is work the car's engine must overcome in the 1/4-mile NOT on a dyno.

So do you see my question now?

 

I would assume w/driver if you are doing the 1/4 and trapspeed off dyno numbers.

Not sure what to do with the first caculation on that page though... I would do w/driver.

 

LOL Nah...I saw your question...just getting you all riled up!

I agree with the fat @ss point. My weight would definately skew the results! I am not sure what % the weight would effect the numbers though....

 

I know.

Check out these differences(with a 200lb. driver):
1) 3200lb. car, 89.8mph trap = 180.85whp
3200lb. car, 180.85whp = 15.1788sec. 1/4-mile

2) 3400lb. car, 89.8mph trap = 192.158whp
3400lb. car, 192.158whp = 15.1787sec. 1/4-mile

So ROUGHLY a 200lb. driver makes an 11.3hp difference going from a 1/4-mile trap speed to a dyno measurement, but the 1/4-mile time difference is NEGLIGIBLE.

 

Your skull slap boys are funny.

Reverse engineering is good and all, but I would like someone put a dyno next to the theory because if weight makes THAT much difference...I am not confident in the equation.

 

The horsepower and 1/4-mile times are very close to my slips and GUESStimated dyno hp numbers based on other peoples dynos for a stock 2K1 5-speed.

However, I KNOW FOR A FACT I can improve on that trap speed, so I doubt it will be as accurate once I go back to the track.

It was my first and only time at the track. I was shifting 300-400rpms early for the 1st-2nd AND 2nd-3rd shift, so I know my traps will reflect this.

 

in my opinion they were both way off. the #s just dont seem right.

also, trap speed and ET depend on how much traction you get at the start. if i spin my tires for 4 seconds with a 2.6 60' and end up getting a 15.3 @ 92 MPH that doesnt mean i have any less HP than i did when i DIDNT spin my tires and got a 2.2 69' and ran a 14.3 @ 96 mph. (those are fictional senarios just for example) seems to me like the 60' should be calculated in there somehow, someway.

 

My trap speeds are almost always the same. In the max I ran anywhere from 15.3 - 16.1 depending on traction all within 1 mph of each other.

I know people on here had dyno test and ran at the track. Someone input your info and let me know how close (or far) it was.

--Ray

 

This don't seem real accurate. Using my best time back when I was stock (15.6@88.6) and my driving weight (figured about 3500), the Corral one says I am putting out about 194 hp and should be running a 15.27 stock, while the rpm outlet says I have 189.9 hp stock and should be running a 15.37@88.6. Being that I had a stock 2k1 max with auto, that would probably be the most efficient driveline ever. That's a 13 and a 15% loss respectively. Something don't add up to me. The ET's might be possible with perfect conditions, pefect launch, and perfect shifting, but the horsepower is way too high.

 

You have to also consider wind resistance on the 1/4 is not accounted for and that the "dyno equivalent" hp rating is NOT SAE corrected.

Therefore, these calculators are NOT going to be dead-on-accurate or even measure the same thing.

Each have their own positives or negatives.

Dyno:
-----
No ram air effect, variation between equipment and brands, etc..

1/4-mile:
---------
Driver error, NOT SAE corrected, includes wind resistance, etc..

G-Tech Pro:
-----------
Driver error, NOT SAE corrected, includes wind resistance, measures "trap speed" differently than 1/4, etc..

Hp Calculators from 1/4 Times:
------------------------------
Theoretical not real world(doesn't account for all variables), uses wind resistance in measurement for 1/4-mile trap which is not valid on dyno, not SAE corrected, etc..


Etc..etc..etc... Each has it's pluses and minus and differences. None will be 100% accurate 100% of the time. They are just all ROUGH tools used accurately when benchmarking variations between tests using the SAME tool.

 

I think that the times it gives you are under the absolute perfect conditions, perfect launch, no pinning, perfect shifting.

 

Well I had my car Dyno'd a few weeks ago, and I ran these calculations with the weights shown on edmunds.com + my current weight(bathroom scale). It says I'm thrown 210 down to the ground. IN MY DREAMS.

What does the SAE correction do?

 

It increases/decreases the hp/tq values depending on temp, barometric pressure(altitude difference), and more from the standard that SAE decided to use as a baseline. Basically, it levels the playing field, so dynos from different locations, temps, pressure, etc.. will be measured approximately the same. However, supposedly the farther you get away from the SAE values, the more correction that is necessary, which adds more variation.

What were the conditions when you dynoed? Does it say SAE hp and SAE tq on your dyno plot?