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 03-15-2005, 02:13 AM #1 jdubya CF Enthusiast     Join Date: Mar 2005 Location: MO Posts: 122 Dyno question Can someone please inform me on what a Dyno is, and how it is used? THANKS A LOT! JESSE __________________ PRELUDE POWER! Last edited by jdubya : 03-15-2005 at 02:21 AM.
 03-15-2005, 02:26 AM #2 NISSANSPDR and the Revolution     Join Date: Jan 2005 Location: Gainesville, FL Posts: 591 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 __________________ Yours truly, Gabriel
 03-15-2005, 03:28 AM #3 Zalight Who's house? Runs house.     Join Date: Mar 2004 Location: Albuquerque, New Mexico Posts: 2,264 Heres a couple images of a chasis dyno: And an engine dyno: __________________ 1999 BMW ///M3
03-15-2005, 04:57 AM   #4
88GrandPrixSE
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Join Date: Jan 2005
Posts: 581
Quote:
 Originally Posted by NISSANSPDR 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

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.
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Last edited by 88GrandPrixSE : 03-15-2005 at 05:18 AM.

03-15-2005, 05:37 AM   #5
NISSANSPDR
and the Revolution

Join Date: Jan 2005
Location: Gainesville, FL
Posts: 591
Quote:
 Originally Posted by 88GrandPrixSE Wrong. A dyno measures torque and torque only. .

I said that...

Quote:
 to measure the actual engine horsepower output and torque
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Yours truly,
Gabriel

03-15-2005, 02:44 PM   #6
88GrandPrixSE
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Quote:
 Originally Posted by NISSANSPDR I said that...

Though they don't measure horsepower...
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03-15-2005, 04:09 PM   #7
Inygknok
El del Supra

Join Date: May 2004
Location: Puerto Rico
Posts: 1,863
Quote:
 Originally Posted by 88GrandPrixSE Though they don't measure horsepower...

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.
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03-15-2005, 04:58 PM   #8
DodgeRida67
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Join Date: Feb 2004
Location: Jackson, Georgia
Posts: 2,056
Quote:
 Originally Posted by Inygknok 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.

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.

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

 03-15-2005, 06:32 PM #9 NISSANSPDR and the Revolution     Join Date: Jan 2005 Location: Gainesville, FL Posts: 591 I mean what dyno doesnt have a computer next to it? __________________ Yours truly, Gabriel