Wheel hp (to) Crank hp Translation?
Nov 7, 2003, 06:26 AM
#1
Wheel hp (to) Crank hp Translation?
Is there a formula for figuring out what crank hp is represented by one's wheel hp for the Evo? For example; what does a 300whp Evo make at the crank? (I know this is a little different b/c the Evo is a FI car and the same translation can't be calculated as on a NA car). Thanks in advance, just curious.
4-BNGR
4-BNGR
Nov 7, 2003, 08:42 AM
#3
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It's impossible to accurately represent the driveline loss, which is what you'd need. Each car is different, and even the same car can be different day to day. As a real general rule of thumb though, AWD cars typically loose 22-27% of power at the wheels.
Nov 7, 2003, 09:10 AM
#6
http://vishnutuning.com/How_Big_Is_Your_Horsepower.xls
Not perfect but better than the answers your getting here
Not perfect but better than the answers your getting here
Nov 7, 2003, 09:21 AM
#7
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the only way to truely figure out crank vs. wheel HP is to dyno your car on a chassis dyno and then remove your engine from your car and dyno it on a engine dyno. Then you need to account for elevation, heat, fuel grade, air flow etc etc.
the best thing you can do is to chassis dyno your car stock and get a baseline and then duplicate the settings on the same dyno as you mod your car. Even then, there are factors beyond your control that can effect your HP numbers (though probably not much)
the best thing you can do is to chassis dyno your car stock and get a baseline and then duplicate the settings on the same dyno as you mod your car. Even then, there are factors beyond your control that can effect your HP numbers (though probably not much)
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Nov 7, 2003, 09:28 AM
#8
300whp
AWD Dyno Dynamics 420 flywheel hp
AWD Dynapack 357 flywheel hp
Dynamic Testing 309 flywheel hp
AWD Dynojet ???
So about 357 crank hp rather than the 366. Would the Dynapack Chassis dyno be the most accurate measurement of whp since it measures the actual power at the chassis?
AWD Dyno Dynamics 420 flywheel hp
AWD Dynapack 357 flywheel hp
Dynamic Testing 309 flywheel hp
AWD Dynojet ???
So about 357 crank hp rather than the 366. Would the Dynapack Chassis dyno be the most accurate measurement of whp since it measures the actual power at the chassis?
Nov 7, 2003, 09:34 AM
#9
Originally posted by 4-BNGR
300whp
AWD Dyno Dynamics 420 flywheel hp
AWD Dynapack 357 flywheel hp
Dynamic Testing 309 flywheel hp
AWD Dynojet ???
So about 357 crank hp rather than the 366. Would the Dynapack Chassis dyno be the most accurate measurement of whp since it measures the actual power at the chassis?
300whp
AWD Dyno Dynamics 420 flywheel hp
AWD Dynapack 357 flywheel hp
Dynamic Testing 309 flywheel hp
AWD Dynojet ???
So about 357 crank hp rather than the 366. Would the Dynapack Chassis dyno be the most accurate measurement of whp since it measures the actual power at the chassis?
Nov 7, 2003, 10:06 AM
#11
Originally posted by 4-BNGR
What's that ZO6 putting down? The ZO6 is that car that I'm after aswell. But I think that it's badged 405 crank hp is well underrated and it makes close to that on a dyno...
4-BNGR
What's that ZO6 putting down? The ZO6 is that car that I'm after aswell. But I think that it's badged 405 crank hp is well underrated and it makes close to that on a dyno...
4-BNGR
295-305 on a DD
Stout bastard indeed
Nov 7, 2003, 10:18 AM
#12
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Originally posted by Fireball
It's impossible to accurately represent the driveline loss, which is what you'd need. Each car is different, and even the same car can be different day to day. As a real general rule of thumb though, AWD cars typically loose 22-27% of power at the wheels.
It's impossible to accurately represent the driveline loss, which is what you'd need. Each car is different, and even the same car can be different day to day. As a real general rule of thumb though, AWD cars typically loose 22-27% of power at the wheels.
As Fireball said, it is impossible to represent the driveline loss, and the % formula generally gets you close when talking stock numbers but, IMHO, it becomes less accurate as HP increases.
Nov 7, 2003, 10:20 AM
#13
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Originally posted by MP5
295-305 on a DD Stout bastard indeed
295-305 on a DD
Stout bastard indeed
Nov 7, 2003, 10:21 AM
#14
Sure its prolly a combination of the two but rest assured we will never know or need to know unless NASA gets on it- even then I dont know if their results would be right 
Originally posted by UFO
I've never really gone for the percentage theory, and there are some tuners who agree with me too. For example, let's say we take a 100 HP car with 15% loss, and it loses 15 WHP. Now, if we take the same car and do things that are nigh on impossible to do (but for the sake of this argument we'll do them anyway) and up that horsepower to 1,000 HP at the crank then, using the percentage formula, we would now lose 150 WHP as opposed to 15 WHP. In the real world it doesn't work like that.
As Fireball said, it is impossible to represent the driveline loss, and the % formula generally gets you close when talking stock numbers but, IMHO, it becomes less accurate as HP increases.
I've never really gone for the percentage theory, and there are some tuners who agree with me too. For example, let's say we take a 100 HP car with 15% loss, and it loses 15 WHP. Now, if we take the same car and do things that are nigh on impossible to do (but for the sake of this argument we'll do them anyway) and up that horsepower to 1,000 HP at the crank then, using the percentage formula, we would now lose 150 WHP as opposed to 15 WHP. In the real world it doesn't work like that.
As Fireball said, it is impossible to represent the driveline loss, and the % formula generally gets you close when talking stock numbers but, IMHO, it becomes less accurate as HP increases.
Nov 7, 2003, 10:24 AM
#15
Originally posted by UFO
Friend of mine ran 11.9 in his with just BFG DRs and a K&N. Ran low 12s stock. I think he runs 11.4s now.
Friend of mine ran 11.9 in his with just BFG DRs and a K&N. Ran low 12s stock. I think he runs 11.4s now.