View Full Version : Where does calculated Torque and rear wheel kW come from?
4wheelin
December 7th, 2007, 12:47 AM
How does the scan tool come up with calculated engine torque and rear wheel kW? Mine is logging 770 Nm and 800 rwkW to which I am very sceptical as the dyno is showing me 325 rwkW. Its an LS1, 212 cam, TO4ZR turbo at 8.9psi through a 4L80E.
Anyone used this function before?
Joel
2002_z28_six_speed
December 13th, 2007, 04:11 PM
It comes from accerlation of the rear wheels which will be incorrect unless you are in direct drive, have full traction, and on a flat surface.
If you are in 1st then your numbers will be inflated.
4wheelin
December 14th, 2007, 08:02 PM
Would that vary based on the drive train also? Mine is a Nissan Patrol with 31 inch tyres and a transfere case. If they are measuring rate of acceleration of the wheel they wouldn't need to know the mass of the wheel at the least?
2002_z28_six_speed
December 15th, 2007, 09:38 AM
For crank HP, yes. They would have to put a factor into it to estimate those losses or do some real caculations.
Which exact pid are you looking at? CALC.POWER_RW? For the real HP pushing the car down the road after all loses, you don't have to consider much.
I am half-trying to make a Calc PID to show Crank HP but it isn't really my job/half interested. Since it wouldn't do much for society I haven't worked on it much. :)
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