the relationship between Horsepower and Torque

[Allnew2Me]

I found this article that explains the relationship between the two things that we are always seeking and talking about. http://www.4x4abc.com/jeep101/torque.html I thought some of you might find it interesting. The formula works as stated.



My truck stock is 235 HP X 5252 =1234220/2700RPM=457. 118. or 460ft. lbs as stated by the specs for my truck.



If you know your engine HP you can use the formula to see how much torque you have, it varies by which RPM you choose. I used 2700 because that is when my engine reaches the peak of both HP and torque.

 

[HeberRam]

try this formula, easier on the brain????

The quick and dirty method is for a Diesel is : 1 to 2. each Hp = approx. 2 torque. example 235hp = 470 torque. With gassers, it's almost 1 to 1.

 

[RonA]

Unfortunately the 2 to 1 method is quite flawed. Depending on how it's set up, my truck has made 1220ft/lbs at 2050rpm=476hp=2. 56 to 1. It has also done 1080ft/lbs at 3300=678=1. 6 to 1. The numbers only work out if your peak hp is made at 2626rpm. Ballpark, but different tuning can raise or lower substantially. A duramax or navistar will be different than a cummins.

 

[rbattelle]

The quick and dirty method is for a Diesel is : 1 to 2. each Hp = approx. 2 torque. example 235hp = 470 torque. With gassers, it's almost 1 to 1.

It's true this method is highly flawed for modified engines, but I use it all the time mentally for regular production engines. People like to talk horsepower, but I prefer talking torque. When someone tells me their car as 300 hp, I always mentally figure it's roughly going to be 300 ft-lb.



Similarly, for medium-sized highway diesels, if you double the horsepower you get a ballpark estimate of torque.



This only works for English units, and falls apart if you get into modifications, off-highway engines, very large engines, or very small engines.



Ryan