This was brought up in a prior post....here's how it works:
Corrected wheel power is the measured wheel power corrected to "standard" atmospheric conditions. This is the power that the vehicle would put to the ground if tested under standard atmospheric conditions. This type of correction can only be controlled effectively during wide open throttle tests.
A variety of correction factors exist, the most accepted here is SAE.
Formula for SAE correction:
The SAE standard generally corrects power to reference conditions of 29.23InHg(99KPA) of dry air and 77 deg. Farenheit (25 C). This is the default correction on many dynos.
What does all this mean?
Lets say it's a hot, muggy day with a 90 degree Intake Are Temp...and your car put down a "true" 430 HP to the wheel.
Under "SAE conditions" the car would have made more power with the drier air and mild 77 degree temperature.
The SAE correction may say 460 HP......
It isn't making 460 HP today, but would under SAE conditions...therefore it's a true 460 SAE hp. No bs.
Heres where the user can screw with it:
The dyno has a temp sensor to test Intake Air Temperature.
If It's actually a 90 degree IAT, but you put the IAT sensor somewhere warmer (on the engine block, near the headers, etc....) it will cause the SAE correction to make a higher number because it thinks the "430 actual hp" it's making is occurring at a much hotter temp than it really is.
SAE correction says "oh 'Kiss Me''Kiss Me''Kiss Me''Kiss Me'.....if it's making 430 HP with 150 degree IAT, then at the SAE standard conditions, it will make 490 hp!"
In reality it's making 430 HP at 90 degree IAT,a dn the correction should bring it to 460 if the sensor was properly located.
These are nonsense numbers of course (except the the correction formula), but they give you an idea of how a dyno operator can make their dyno read whatever they want.
Corrected wheel power is the measured wheel power corrected to "standard" atmospheric conditions. This is the power that the vehicle would put to the ground if tested under standard atmospheric conditions. This type of correction can only be controlled effectively during wide open throttle tests.
A variety of correction factors exist, the most accepted here is SAE.
Formula for SAE correction:
The SAE standard generally corrects power to reference conditions of 29.23InHg(99KPA) of dry air and 77 deg. Farenheit (25 C). This is the default correction on many dynos.
What does all this mean?
Lets say it's a hot, muggy day with a 90 degree Intake Are Temp...and your car put down a "true" 430 HP to the wheel.
Under "SAE conditions" the car would have made more power with the drier air and mild 77 degree temperature.
The SAE correction may say 460 HP......
It isn't making 460 HP today, but would under SAE conditions...therefore it's a true 460 SAE hp. No bs.
Heres where the user can screw with it:
The dyno has a temp sensor to test Intake Air Temperature.
If It's actually a 90 degree IAT, but you put the IAT sensor somewhere warmer (on the engine block, near the headers, etc....) it will cause the SAE correction to make a higher number because it thinks the "430 actual hp" it's making is occurring at a much hotter temp than it really is.
SAE correction says "oh 'Kiss Me''Kiss Me''Kiss Me''Kiss Me'.....if it's making 430 HP with 150 degree IAT, then at the SAE standard conditions, it will make 490 hp!"
In reality it's making 430 HP at 90 degree IAT,a dn the correction should bring it to 460 if the sensor was properly located.
These are nonsense numbers of course (except the the correction formula), but they give you an idea of how a dyno operator can make their dyno read whatever they want.
