Horse Power conversion/calculation

[SSSSE YA]

Hi Everyone

I am looking for a reminder about how to convert rear wheel HP to crank HP on a Viper. It's been a while and I don't think I'm doing the math correctly. I am getting my GTS dyno'd next week in anticipation of reprogramming the computer (by Dan Cragin at DC Performance aka "The Viper Shop").

Thanks!!

 

[Snakester]

Most people simply divide the RWHP number by 0.85 to get crank HP. That assumes a 15% drivetrain loss.

But more measured tests show only a 13% driveline loss in Vipers, which means you would divide the RWHP number by 0.87.

For instance the 481RWHP/501RWTQ numbers from your signiture would translate to 553HP/576TQ at the crank, figuring a 13% driveline loss.

Remember most people use 15% loss to show higher HP, and some people use 20%, so don't sweat the final numbers.

The only really valuable info from the dynos is comparing baseline numbers with after-mod numbers. And even that is just a ballpark measurement as the power numbers even on the same dyno change with different conditions.

 

[STUGOTS]

Most people simply divide the RWHP number by 0.85 to get crank HP. That assumes a 15% drivetrain loss.

But more measured tests show only a 13% driveline loss in Vipers, which means you would divide the RWHP number by 0.87.

For instance the 481RWHP/501RWTQ numbers from your signiture would translate to 553HP/576TQ at the crank, figuring a 13% driveline loss.

Remember most people use 15% loss to show higher HP, and some people use 20%, so don't sweat the final numbers.

The only really valuable info from the dynos is comparing baseline numbers with after-mod numbers. And even that is just a ballpark measurement as the power numbers even on the same dyno change with different conditions.

thanks thanks some GREAT info