What is your Horsepower? How is it determined?

[FLX109]

This may sound dumb but Peak Torque and HP vs rpm, with your torque and horsepower figures, what is considered your Horsepower, say you have 630tq and 546hp, when asked what is your horsepower, is it 546? How is 450HP determined in our GTS?

 

[ruckdr]

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How is 450HP determined in our GTS?
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Conservatively - Go to a Dyno.
Later,

 

[SingleMalt]

Well, if those are dyno numbers, you're talking rear wheel horsepower. If you want flywheel horsepower, factor in about a 17-19% driveline loss. That'd make a 546HP figure more like 625 or so at the flywheel. I'm too lazy to actually open calc and do the math.

Mike

 

[99 R/T 10]

Most use a 12-15% loss of HP through the drive train.

 

[Viper Specialty]

I am not sure what you are asking, but if you mean what exactly "IS" Horsepower, I can sum it up in the following way:

Horsepower is a function of Torque at RPM. Meaning, it is the amount of total WORK and engine has done- whether it is by the amount of "Twisting force" it can exert (Torque), or the speed at which the engine turns.

For example: You can have an 2 engines that make the same HP, but one makes considerably less TQ. This is because the engine that makes more TQ doesnt have the ability to make the High TQ as LONG as the other engine- which in turn makes less TQ than the stronger engine, but can make it for a longer period of time. (Higher RPM limit) The two engines can do the same amount of "Work", but one of the engines needs to be rev'd out very far, the other does not for the same amount of work to be done. HP is just what the engine CAN put down, in total.

HP can be related to electricity very easily. Amperage is the "Torque", Voltage is the "RPM", and Wattage is the total work being done by the combination of both- or Horsepower.

Horsepower is figured by how fast the car on the Dynomometer can spin up the drums in the Dyno, from one RPM to another. Both the Accelleration of the drums, and the speed at which the start and end at come into effect. These drums have a set mass known by the computer.

 

[DChan415]

Someone somewhere somehow one day figured out that one horse can move 33,000 pounds a distance of 1 foot in 1 minute. 1 horsepower.

 

[FLX109]

Thanks everyone for trying to understand me but what I was trying to find out is the 450HP that is used for the horsepower figure on the GTS, is this flywheel horsepower or rear wheel? and how is this determined? Looks like my question was answered when you have a 12-15% driveline loss, so all you do is add 12-15% to your dyno figures to get your flywheel horsepower. So rear wheel HP on a stock GTS would be aprox 390? my #s from the dyno ended up at 680tq and 585HP, I was looking to determine the flywheel HP from these figures.
thankyou
everyone

FLX109

 

[RedEnuf93]

Fly wheel is 450HP.This is what Auto makers use to categorize HP. We usually measure it from rearwheels, since you can only strap car on a dyno and do the measurements. To measure the flywheel HP, youll have to pull motor out and run it in a motordyno.

Rear wheel typically 10-15% less = 391 rear wheel (13% loss)

In you car using the 13% loss, it would come to a 662HP. Thats one really healthy Viper there!!!