Need an accurate Drivetrain power Loss figure thru A727 trans with Loose 5500 stall converter & Dana 60 4:56 Trak-Loc 30 inch tall slicks. Have seen estimate numbers from 10 to >37 % !! ..30 % seems/feels about right to me. Thx for any help.

 

The first thing I would do is figure out how efficient your converter is by looking at your trap speed and rpm. Using a speed power calculator it will give you an rpm for a stick car with the same gears and tire size to compair yours to. It's not uncommon for a converter to give up 20 percent or only be 80 percent efficient.

 

I Agree. Find and use a performance Calculator.... Lots of variable.... Wish it was that easy...
But Could be tight on one side and loose on the other... Hope you get you answer...

 

Thanks, guys, for the info...I know the converter losses are a wild card but was trying to nail down the 727 & big heavy Dana 60 Hp losses.

 

I'd say 15 persent.........the 727 is not an efficient transmission, heavy rotating mass, I've heard the Dana is no better or worse than other axle assemblys.