Online Horsepower Calculators

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I am pretty sure the Wallace calculator is all based off data he collected for Pontiac race car. If you race a Pontiac with a similar drive train and similar hp/weight ratios that the data is based on, then the results are close. You plug in data for a flyweight Fox, it all falls apart.

dyno 304 RWHP, race weight 3080, shift 5,800RPM, 26" tall tire, 4.10 gear

What Wallace calculates:
Power to Weight Ratio: 10.13
60 Foot E.T. : 1.75
1/8 Mile E.T. : 7.95
1/8 Mile Trap Speed : 85.47
1/4 Mile E.T. : 12.60
1/4 Mile Trap Speed : 106
1/4 Mile Trap RPM : 5,637

Real time slip
60ft 1.565
330ft 4.746
660ft 7.447
MPH 90.86
1000 9.775
1320 11.756
MPH 113.28

So Wallace is definitely not calculating based on RWHP

Plugging in an estimated 375 FWHP has Wallace calculate:
Power to Weight Ratio: 8.21
60 Foot E.T. : 1.63
1/8 Mile E.T. : 7.42
1/8 Mile Trap Speed : 91.66
1/4 Mile E.T. : 11.75
1/4 Mile Trap Speed : 114
1/4 Mile Trap RPM : 6,046

Bottom line, the closer your combination is to the combo he used to generate his data the more accurate the results.
 
sledger46 said:
I am pretty sure the Wallace calculator is all based off data he collected for Pontiac race car. If you race a Pontiac with a similar drive train and similar hp/weight ratios that the data is based on, then the results are close. You plug in data for a flyweight Fox, it all falls apart.

dyno 304 RWHP, race weight 3080, shift 5,800RPM, 26" tall tire, 4.10 gear

What Wallace calculates:
Power to Weight Ratio: 10.13
60 Foot E.T. : 1.75
1/8 Mile E.T. : 7.95
1/8 Mile Trap Speed : 85.47
1/4 Mile E.T. : 12.60
1/4 Mile Trap Speed : 106
1/4 Mile Trap RPM : 5,637

Real time slip
60ft 1.565
330ft 4.746
660ft 7.447
MPH 90.86
1000 9.775
1320 11.756
MPH 113.28

So Wallace is definitely not calculating based on RWHP

Plugging in an estimated 375 FWHP has Wallace calculate:
Power to Weight Ratio: 8.21
60 Foot E.T. : 1.63
1/8 Mile E.T. : 7.42
1/8 Mile Trap Speed : 91.66
1/4 Mile E.T. : 11.75
1/4 Mile Trap Speed : 114
1/4 Mile Trap RPM : 6,046

Bottom line, the closer your combination is to the combo he used to generate his data the more accurate the results.
Click to expand...

Yep, was just thinking about something along those lines that it has to be the type of cars the data was compiled from.........so there obviously wasn't many cars in that group that could leave like a Stocker then!!
 
clinteg said:
I always use the track time when people ask how fast it is. That's a sure indication of how it runs. It's those who ask how much power it makes that I don't know how to answer. Typically I just say around 550. But I try not to get too caught up in the dyno/calculator numbers much. I used the Wallace calculator that had inputs for hp, weight, gears, tire height and it came up with this:

Power to Weight Ratio: 6.24
60 Foot E.T. : 1.49
1/8 Mile E.T. : 6.77
1/8 Mile Trap Speed : 100.45
1/4 Mile E.T. : 10.72
1/4 Mile Trap Speed : 125
1/4 Mile Trap RPM : 5940

Those numbers are damn near spot on what I run except the rpm is about 1000 less than what I go through the traps at. That's guessing on my weight of 3370 with me in it too. Thanks for the input so far!
Click to expand...

I put your numbers into my "Drag Racing Workbench" app on my android phone and it came out almost spot on to what your times are. I was told this was supposed to be used with whp not chp so I am confused as well. If you do not have the app its worth checking out though!
 
junior636 said:
I put your numbers into my "Drag Racing Workbench" app on my android phone and it came out almost spot on to what your times are. I was told this was supposed to be used with whp not chp so I am confused as well. If you do not have the app its worth checking out though!
Click to expand...

Use the first link to work out fly and rwhp but the rwhp won't be accurate as a 10% drivetrain loss is not a standard for all cars.

The 2nd link is the one I've always been using and that IS fly hp, that matches with the 1st calcs numbers fly figs.

http://www.wallaceracing.com/hpcalculatorquarter.php rw/fly

http://www.wallaceracing.com/accel-calc.php fly hp only

Should sort it all out.
 
You know what. There is another piece of the puzzle that is not being figured in as well.

These figures are AT SEA level HP.
 
http://www.dragtimes.com/da-density-altitude-calculator.php

this one will give you the weather at any drag strip for the day...and lets you convert your time to a sea level with standard baro and humidity like the dyno does...


more eye candy...

the 71 Dart on 10-4-14 at Famoso Raceway 10.31 @ 127.22 converts to

Stock and Mildly Modified Naturally Aspirated Engines
10.068 @ 130.459 MPH

Extensively Modified Naturally Aspirated Engines
10.16 @ 129.34 MPH
 
Hot Metal said:
Thats its p/w potential, the fact that it has 2.76 gears and probably a stock verter and therefore wouldn't launch worth a damn....it probably wouldn't run anywhere near that. But, if you put in 3.91 gears with 26" tyres that hooked, and upgrade the converter, if that motor made its 260hp at 5000rpm it could run a 13.72 shifting and trapping in the power band in top gear....yes its possible. The chassis is as important as the hp for a car to ET, as is the gearing/tyre to keep the car in the power band, thats what the calc helps you with and is exactly how I just used it.

I will give you another real world example close to that, and that was my all steel full interior street/strip '71 Cuda 340. 3600lbs, 3.55 gears 8x26" slicks, stock 2.02 heads, Hdrs., DC..484 hyd. purple, 750DP 3500 stall verter. Wallace has it at 300hp for this run>
60 Foot E.T. : 1.85
1/8 Mile E.T. : 8.41
1/8 Mile Trap Speed : 80.80
1/4 Mile E.T. : 13.33
1/4 Mile Trap Speed : 100
It ran [email protected]
Click to expand...

My point! If I had, If I had..... But see, I entered 2.76 gears, not 3.91s. It asked hp, weight, gears, ... Just for kicks I put 260, 3400, 2.76 and it said 13.72. It didn't say if you add gears, converter, slicks, you could potentially run 13.7's. It said 13.72 with 2.76 gears at 3400 lbs. with 260 hp. I guess it works for some, but it's not for me.
 
Yes I understand what your saying, unfortunately with software its black and white, it will spit out its numbers no matter. All you need for an ET prediction is weight/hp. The gearing tyre size inputs do not affect ET as far as the software goes (although on track it will make all the difference), its not designed to tell you what gears to run, its there to give you the trap rpm that your motor will be turning in 3rd gear which is what it assumes will happen. For those that know how much and where their engine makes its peak power it is a useful tool in determining tyre height/g-ratio to keep the motor at its peak hp throughout the run. The torque your engine makes will give you your converter choice along with the gearing weight tyre hp etc. etc. for optimum 60ft and 1/4 performance.

Basically as I said before, a stock street car cannot use the calculator to any effect as you are not set up for the 1/4 mile. No amount of HP will enable you to run what the calc suggests unless you have the chassis (gears/tyres/converter/suspension) to propel the car to the 60ft times and therefore the ET it will spit out for a given hp/weight combo. I hope that makes things somewhat clearer for you.
 
I would think the ET it predicts is if you car has the optimum converter and gears without wheel spin. If you have the wrong converter or gears or spinning your ET would not match the prediction.
 
D-50394 said:
I would think the ET it predicts is if you car has the optimum converter and gears without wheel spin. If you have the wrong converter or gears or spinning your ET would not match the prediction.
Click to expand...

^^ This ^^
 
These calculators should be used primarily for HORSEPOWER calculations, as known weight and MPH figures will be very close in showing actual power. NO WAY to estimate ET, due to chassis/tire varience.
 
replicaracer43 said:
These calculators should be used primarily for HORSEPOWER calculations, as known weight and MPH figures will be very close in showing actual power. NO WAY to estimate ET, due to chassis/tire varience.
Click to expand...

If you change gear ratio it changes mph so that changes how much hp the calculators show you are making. So really it is all a guess.
 
D-50394 said:
If you change gear ratio it changes mph so that changes how much hp the calculators show you are making. So really it is all a guess.
Click to expand...
If your MPH goes up with a gear change, it means your gear was "possably" wrong to start with, but basically, it takes "X" amount of power to run "X" MPH at a certain weight. That's where the calculators are good
 
I think I said that to start with when i said if you don't have the right parts you want run the ET the calculator estimated.
I went from a 5.14 to a 3.50 and gained 1 mph in the 1/8 and I was in second gear with the 3.50 when I crossed the finish line. 108 mph/ 5.14 gear and 109 mph/3.50 gear in 2nd.
I probably need about a 6.00 gear ratio.
 
junior636 said:
I put your numbers into my "Drag Racing Workbench" app on my android phone and it came out almost spot on to what your times are. I was told this was supposed to be used with whp not chp so I am confused as well. If you do not have the app its worth checking out though!
Click to expand...

Freakin apple doesn't seem to have that, but yes confusion everywhere lol! I highly doubt the engine is making 500+ to the wheels though. Was just trying to get an idea of what the car was really making (roughly) either at the crank or at the wheels.
 
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