Dyno question

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Can someone please inform me on what a Dyno is, and how it is used?


posted by  jdubya

dynamometer: An electric or hydraulic machine used to measure the actual engine horsepower output and torque. An engine dynamometer measures horsepower at the crankshaft and a chassis dynamometer measures horsepower output at the wheels

posted by  NISSANSPDR

Heres a couple images of a chasis dyno:

And an engine dyno:

posted by  Zalight

Wrong. A dyno measures torque and torque only.

HP is acquired mathematically. Torque X RPM / 5252 = HP (Though that's just general, the equation doesn't work for EVERY vehicle, but works for most.)

Take my 2.8 for instence:

160lbs @ 3600

160 X 3600 / 5252 = 109.67hp @ 3600RPM

The dyno is doing this test all the way through so, every time torque increases or decreses it does this equation and eventually find peak HP. Which should be 130 @ 4800 for that motor.

"x" X 4800 / 5252 = 130
.91x = 130
130/.91 = 142

so it makes 142lbs @ 4800 RPM Now to verify that because my math skills are somewhat lacking...

142 X 4800 / 5252 = 130
129.77 = 130 (Correct, i rounded it off in the earlier equation)

So that's how you find out power at certain RPMs.

posted by  88GrandPrixSE

I said that...

posted by  NISSANSPDR

Though they don't measure horsepower...

posted by  88GrandPrixSE

they do actually, they do it all by themselves, hence why they are computers, to do everything man is too lazy to do by himself.

posted by  Inygknok

Or it would be just plain stupid to grab a pen and peice of paper when it can be done in a few millionths of a second by a computer. :mrgreen:

88GrandPrixSE is pretty much right. They don't directly measure horsepower. Like he said, it's calculated by torque & rpm.

posted by  DodgeRida67

I mean what dyno doesnt have a computer next to it? :banghead:

posted by  NISSANSPDR

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