looking at dyno sheets

[92 mtechnic cabrio]

I just thought of something.

They say that on correctly scaled dyno sheets, the HP and TRQ lines always meet at 5252.

What if you're dyno'ing a diesel engine or something that doesn't rev up to 5252? Do the lines never meet?

Boggles my mind.

[kowalski]

never head of this... but if its true, i imagine that it only applied to gas engines.
somhow i think this theory is wrong tho....

[Brew]

never head of this... but if its true, i imagine that it only applied to gas engines.
somhow i think this theory is wrong tho....

Its no theory. Horsepower is calculated by taking RPM x torque and dividing it by 5252.

So HP = (RPM x Torque)/5252

(5252 x torque)/5252 = torque, so torque and hp are equal at 5252 rpm on ANY engine.

[palmfish]

I just thought of something.

They say that on correctly scaled dyno sheets, the HP and TRQ lines always meet at 5252.

What if you're dyno'ing a diesel engine or something that doesn't rev up to 5252? Do the lines never meet?

Boggles my mind.

Yup, that's right...

[Rigmaster]

TO answer your question about diesel engines, you are correct that if the engine does not rev to 5252rpm, the TQ + HP lines will not meet.


Bret.

[X2theZ3]

Its no theory. Horsepower is calculated by taking RPM x torque and dividing it by 5252.

So HP = (RPM x Torque)/5252

(5252 x torque)/5252 = torque, so torque and hp are equal at 5252 rpm on ANY engine.

Yup, what brew said. They are just functions of each other.

[PУCCKAЯ_e30ka]

is there any kind of formula to figure out hp at the wheels on E30? with milage (156k)? I searched but all I found was hp at the crank... I know that all the maintance shit has to add up to, but I've done most of the things on my thirty.

[92 mtechnic cabrio]

just do something like 15% of the crank hp, to accomodate for power lost through the drivetrain

so a brand new, stock E30, would do 142.8hp at the wheels. (168*0.15= 25.2, 168-25.2= 142.8)

a car similar to mine, stock with the exception of 19lb injectors, put down 140whp at around 120k miles.