Which Is Faster - 600hp@6200 or 600hp@7100

[EngineTech1]

So you've never calibrated a dyno yourself then?

Yes. 901’s. Though that’s entirely beside the point.

[77cruiser]

When you calibrate your dyno with weight to give a torque reading, how fast does it go with no HP being produced?

[user-23911]

So you've never calibrated a dyno yourself then?

Yes. 901’s. Though that’s entirely beside the point.

It's not beside the point because the load cell reads torque directly.
It can't work out the power without first of all reading the torque and then inputting the RPM.

So saying that a dyno directly measures the power and then calculates the torque is back to front.

[EngineTech1]

So you've never calibrated a dyno yourself then?

Yes. 901’s. Though that’s entirely beside the point.

It's not beside the point because the load cell reads torque directly.
It can't work out the power without first of all reading the torque and then inputting the RPM.

So saying that a dyno directly measures the power and then calculates the torque is back to front.

It’s beside the point because it doesn’t disprove anything I’m saying. Just because a water brake and strain gauge dyno measures torque output and calculates hp that doesn’t mean all dynos work that way and it doesn’t mean you can’t calculate hp without a strain gauge or torque measurement.

[user-23911]

With an engine dyno you can measure mass fuel flow and mass air flow.
Knowing the calorific value of the fuel you can convert to Kw or HP and then apply an efficiency factor, maybe 40% if it's a clean diesel. Less for petrol.
That should tie up well with the calculated power from measuring torque.
But the efficiency factor is a guess.


Someone else might know a way to directly measure power without torque?


Now 23 pages of BS.

[EngineTech1]

[MadBill]

With an engine dyno you can measure mass fuel flow and mass air flow.
Knowing the calorific value of the fuel you can convert to Kw or HP and then apply an efficiency factor, maybe 40% if it's a clean diesel. Less for petrol.
That should tie up well with the calculated power from measuring torque.
But the efficiency factor is a guess.


Someone else might know a way to directly measure power without torque?


Now 23 pages of BS.

Absent an engine speed input, a chassis inertia dyno can still measure and graph a horsepower curve.

[user-23911]

Absent an engine speed input, a chassis inertia dyno can still measure and graph a horsepower curve.

Acceleration of the rollers is proportional to wheel torque......that's the direct measurement.
Wheel torque is proportional to roller torque.
It always has roller speed.
roller speed x roller torque = HP
The graph shows HP vs MPH.....RPM is missing.
To convert wheel torque to engine torque you need the gear ratio and wheel size.
To convert from MPH to RPM you also need gear ratio and wheel size.

HP vs MPH is worthless if you don't know which gear you're in.

[Geoff2]

Next.....

[digger]

both torque and horsepower are never directly measured they are both calculated from other data. so what does that mean? not much actually

[user-23911]

The very first time I had my car on the local dyno (dynapack)....the dyno man entered the wrong final drive ratio and the numbers came out wrong.
It's another nice easy way to cheat the numbers.

I know they're wrong because I've spent a long time figuring those things out.
I remember him saying to me at the time......while having a false grin on his face.........."you'll be happy with those numbers."
It drove like shit and I reverted to my previous road tune.
But I got good numbers for bragging rights.
That's what counts?

both torque and horsepower are never directly measured they are both calculated from other data. so what does that mean? not much actually

A few posts up........if you've got a water brake with a strain gauge then torque is a direct measurement.........calibrated with a weight of X Kg hanging on an arm of distance of Y metres from the centreline........will give KgM torque directly.
An arm of 1 meter......hang 45.45 Kg from it, times by 9.81 to get N, the dyno will read 445 nm.Add another 45.45Kg on top, it should read 890nm.
That simulates the loading that the waterbrake puts on the strain gauge.

Accuracy?
Didn't someone claim that a dyno measures power directly?


So anyway, I'm still waiting for someone to come up with a list of parts and a spec to build both of these engines to have a raceoff.
Mines got 4 small turbos on it rated 150HP each........the one that tops out at 6200.
Yours in the N/A one with a hot cam, tunnel ram and the twin 4s.

[digger]

The very first time I had my car on the local dyno (dynapack)....the dyno man entered the wrong final drive ratio and the numbers came out wrong.
It's another nice easy way to cheat the numbers.

I know they're wrong because I've spent a long time figuring those things out.
I remember him saying to me at the time......while having a false grin on his face.........."you'll be happy with those numbers."
It drove like shit and I reverted to my previous road tune.
But I got good numbers for bragging rights.
That's what counts?

both torque and horsepower are never directly measured they are both calculated from other data. so what does that mean? not much actually

A few posts up........if you've got a water brake with a strain gauge then torque is a direct measurement.........calibrated with a weight of X Kg hanging on an arm of distance of Y metres from the centreline........will give KgM torque directly.
An arm of 1 meter......hang 45.45 Kg from it, times by 9.81 to get N, the dyno will read 445 nm.Add another 45.45Kg on top, it should read 890nm.
That simulates the loading that the waterbrake puts on the strain gauge.

Accuracy?
Didn't someone claim that a dyno measures power directly?


So anyway, I'm still waiting for someone to come up with a list of parts and a spec to build both of these engines to have a raceoff.
Mines got 4 small turbos on it rated 150HP each........the one that tops out at 6200.
Yours in the N/A one with a hot cam, tunnel ram and the twin 4s.

last time i checked strain gauges dont measure torque directly

[user-23911]

Same as a weighing scale.
Does a weighing scale directly measure weight?
Depends on how deep you want to look into it?

[digger]

Same as a weighing scale.
Does a weighing scale directly measure weight?
Depends on how deep you want to look into it?

that's exactly my point.

you aren't measuring torque and calculating power or vice versa. you are calculating both

[user-23911]

I've got an old "vane" dyno.
It's pretty old and got rollers.
It's also got disc brakes with the pads mounted on a pivot with an arm on it. The end of the arm does the measurement ..or did.
The brakes are air operated with pressure controlled with a regulator.
It's been modded and it's now worse than when new.....as per normal.

When it was made, it would have had a fish scale like thing measuring weight.....taking a reading off the end of the arm, That would have given a direct ft lb output or nm.

Nowardays everything is driven by software so nothing is direct.
It's been modded with a flywheel so that changes things a bit.


But a weighing scale with a coil spring does the same thing.



So who want's to waste their money building a hot engine that makes 600 HP at 7100 RPM?