Hoon
Autocross Champion
- Location
- Rhode Island
On a dynojet, horsepower is measured and torque is calculated.
Still not sure where you're going with this.
7
curious real HP
- Thread starter maic
- Start date
On a dynojet, horsepower is measured and torque is calculated.
Still not sure where you're going with this.
Same is true on a mustang dyno. In fact, when the software spazzes out, sometimes you get a HP curve with no torque values.
I think it's one of those "common internet knowledge" things that everyone gets wrong that you can't measure horsepower because it's an abstract concept. But in reality, it's easy to measure. Torque and horsepower are mathmatically linked, if you have either and the engine speed, you have both.
JerseyDrew77
Autocross Champion
- Location
- Virginia & NC
- Car(s)
- 2016 TR GTI S 6MT
I think his dementia has kicked in.
The winner! HP cannot be directly measured, only torque can. HP is calculated from torque. I did like the pulling against a horse answers.
Not a nice thing to say about Hoon.
Rafiki76
Ready to race!
- Location
- Los Angeles
- Car(s)
- MKVII GTI
Horsepower is the rate of work, acceleration of a mass at a speed really. The derivative of that will be jerk/surge or the rate of change for acceleration.
I was waiting for someone to throw the incorrect internet answer out...
You can measure HP, it's not black magic, it's a rate of work. You can calculate it from torque OR you can measure it directly by recording actual energy output from a generator (watts) while the car spins it or calculate it from drum speed (without knowing the torque).
Strange Mud
Autocross Champion
- Location
- Small Town CT
- Car(s)
- Assorted
I know the strain on the cables are carefully monitored, I was just referring to, using they changed, why they just don't use an electric motor. They use a variable swash plate radial hydraulic pump (motor, like our air conditioning compressor) driven by an electric motor so they can maintain similar torque throughout the RPM range. Must have been one the worst jobs operating them when the water was rough.
As you know, electric motors develop their maximum torque at the instant of starting, and varying the swash plate lets the electric motor run at a constant speed and torque while letting the hydraulic motor control the RRM . I hated to work on them. Oil and me don't mix.
HP is derived from torque if you use a dynometer:
How Does The Dyno Work?
Although due to the miracles of technology it only takes milliseconds for the computer to calculate your horsepower and torque it is not as simple as it may look. It is all just basic laws of physics applied with one another to calculate the measurements. This is a very basic explanation of what goes on inside the computer when you are making a dyno pull, there are a few more details but these are the main points. Lets get started...
First The Computer Must Calculate The Force Force = Mass x Acceleration
"The force required to accelerate an object is proportional to the mass of the object and the acceleration given it."
NEWTON'S SECOND LAW OF MOTION
The torque is the rotational Force the computer is calculating here. The first variable, Mass, is the rotational mass of the two 2700 lb. drums. This is programmed in the computer by Dynojet and due to fact that it is a inertia-type dyno it is a standard variable that can not be changed. The second variable is the acceleration, this is simply how fast you turn over the drums. Just multiply the two together and you have the Force.
Second The Computer Has To Calculate The Work Work = Force x Distance
It is very easy to now find the Work. The computer simply takes the force is has just calculated and multiplies it be the distance you have gone. The distance is nothing more than the circumference of the drum multiplied by how many times it has rotated.
Third The Computer Can Calculate The Power
Power = Work / Time
Now the computer takes that Work and divides it by the time taken and you then have your Power or Horsepower as we call it.
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Oldschoolmk7
Go Kart Champion
- Location
- Yonder
With dp, ebay IC, intake mods on stock boost 245/290 whp dynojet.
Hoon
Autocross Champion
- Location
- Rhode Island
Im not going to bother reading the Google results you just posted. A dyno measures horsepower.
If you do a dyno pull without a tach signal you get horsepower (work / time).
Add the tach signal and you can then calculate torque.
Diggs24
Autocross Champion
- Location
- de plains! de plains!
- Car(s)
- 2015 GTI
Don't argue with old people. I wish the ignore list would also ignore when said people are quoted. Frankly just wish it wiped their existence altogether so you couldn't even see threads they start but I guess that's wishful thinking....