Welcome to Just Commodores, a site specifically designed for all people who share the same passion as yourself.

New Posts Contact us

Just Commodores Forum Community

It takes just a moment to join our fantastic community

Register

how do dynos work?

Immortality

Can't live without smoky bacon!
Staff member
Joined
Apr 15, 2006
Messages
22,472
Reaction score
19,901
Points
113
Location
Sth Auck, NZ
Members Ride
HSV VS Senator, VX Calais II L67
The best gift is the gift that keeps on giving :D
 

AirStrike

Well-Known Member
Joined
Jun 28, 2003
Messages
8,197
Reaction score
1,044
Points
113
Age
38
Location
Melbourne
Members Ride
91' VN SS

torana355

Member
Joined
Mar 24, 2009
Messages
889
Reaction score
3
Points
16
Location
Sydney
Members Ride
VE SERIES 2 MY11 SSV A6 in IVY GREEN
A dyno measures torque (twisting force) and RPM, power is how much work can be achieved in a specified time and is the relationship between Torque and RPM. The higher the RPM the higher the power depending on the torque at that RPM.

So for example if my SSV makes 400 foot pound of torque at 6000rpm You would calculate power in HP with this equation 400 * 6000 / 5252 = 456HP@ 6000rpm

If it was making 300 foot pound of torque at 4000rpm the equation would be 300*4000/5252 =228HP@4000rpm

This is why diesel cars have alot of torque but not much power, they only rev to around 4-5k and they make maximum torque at low RPM. This is also why rotarys are gutless at low rpm, they have a small amount of torque which means they need to use high rpm to make their power. On the other end of the spectrum a big 6L V8 makes alot of torque at low rpm so they don't need to rev as high to make the same power and if they are built to rev to high rpm they usually make very good power.

Here is a link that explains this very clearly Power and Torque: Understanding the Relationship Between the Two, by EPI Inc.
 
Last edited:

torana355

Member
Joined
Mar 24, 2009
Messages
889
Reaction score
3
Points
16
Location
Sydney
Members Ride
VE SERIES 2 MY11 SSV A6 in IVY GREEN
The point of the whole argument is what do dyno's measure, they can't measure power as power is only a calculation based on what is actually measured, which is torque. There is a thread on LS1 that explains it better.

Whatever applies the force is irrelevant as the dyno can't actually quantify it, it can only measure the torque required to spin the rollers.

No dynos measure torque and RPM. Torque on its own would not move a car very far or fast at all. Engines produce power but a dyno does not measure power, yes power has to be calculated but the engine is still producing it or your motor would spin for a few seconds then stop. I hope that made sense lol.
 

Not_An_Abba_Fan

Exhaust Guru
Joined
Aug 18, 2006
Messages
14,639
Reaction score
1,364
Points
113
Location
Bunbury, WA
Members Ride
Strange Rover
No dynos measure torque and RPM. Torque on its own would not move a car very far or fast at all. Engines produce power but a dyno does not measure power, yes power has to be calculated but the engine is still producing it or your motor would spin for a few seconds then stop. I hope that made sense lol.

Nobody is arguing that an engine doesn't produce power, the argument is, or my argument is, the power isn't MEASURED, it's calculated by a formula.
 

torana355

Member
Joined
Mar 24, 2009
Messages
889
Reaction score
3
Points
16
Location
Sydney
Members Ride
VE SERIES 2 MY11 SSV A6 in IVY GREEN
Nobody is arguing that an engine doesn't produce power, the argument is, or my argument is, the power isn't MEASURED, it's calculated by a formula.

In that case i agree 100%
 
Top