I have looked all over the net for the equation to calculate torque. And I have Torque = HP x 5252 / rpm.
So lets say a motor has 270 rwhp @ 2000 rpm and the optimal torque rpm is 1600.
270 x 5252 = 1418040 / 1600 = 886.275 So this would mean that the engine is producing 886 ft/lbs of torque. This number does not match numbers that others have claimed for torque values. I hope someone can clear this up for me.

 

Here is the easy way to do it. http://www.21cgt.com/FMWebCatalog/frmConversion3.aspx

 

The horsepower wouldn't be 270 at 1600 RPMs. It would be lower, around 200.

 

Exactly!

PEAK horsepower and PEAK torque usually occur at very different RPM values!

 

It is my understanding that the only measurable force is torqe. horsepower is simply a mathematical derivation of torque. the the formula is


HP=(torque X rpm)/5252

which is algebraically the same as the original equation. This is why the torque is always greater until 5252 rpm and the HP is always greater after. Look at dyno charts, the crossover point is always there. this is also why the vast majority of our trucks will never at any time make more hp than torque. in case any one was wondering.

 

Seems to explain why this calculator does not work....

If you know that the peak torque occurs at 1600 rpms on a cummins per say, you would have to get the horsepower at that particular RPM to get peak torque...

That calculator tells me that my 348 horse run was only producing 553 ft lbs of tq...
Perhaps that is true at that particular point in the run, Now if the cummins has peak tq at 1600 rpms, if i put that HP of 348 rwhp and 1600 rpms i have well over 1100 ft lbs of tq.. again a number that does not make any sence....

This only tells me that for most accurate TQ reading you would need your HP at 1600 RPMS for the most accuracy.... diesels develop peak tq much sooner than gassers, gassers tq usually just grows as does the hp...

Well on edit playing around i figured this out.. 304.5 RWHP at 1600 RPMS will yield that magical 1000 RWTQ number... so if at 1600 RPMS you are producing 304 RWHP You should be very very close to that figure...



OK now to do this, this is just my stab at it... I am going by speed on the dyno run.. USING the final run, which was my strongest run, at 2000 RPMS i know that i was turning about 70 mph, so.. in the calculator i put in what seems to be about 320 rwhp at 2000 rpms, and i got 840 ft lbs of tq... now that number makes alot of sence to me actually, lets say using that same curve, i went back a little farther to about lets say 65 mph, i get about 275 rwhp according to my eyes. If I put in 1600 rpms, and 275 rwhp i get i get 903ft lbs of tq, I think that this is close to peak tq because that is about the speed on the highway taht im turning about 1600 rpm.. It seems to be a reasonable number for tq for a 12V as well..

Rick