What is the Drive Train loss %?

[USCG CHARGER]

What % is our drive train loss? I have a 727, 8.75 (4.10 gears)... I heard it's as much as 20% and as low as 12%.. does anyone know?

 

[1970Duster]

about 20 % or so. Now that you bring that up I think a current issue of a car mag deals with this subject, which one I can't remember but I do remember a 1970 LS6 Chevelle being tested in it. (They were looking at rear wheel power, both horse and torque)

 

[fishy68]

My thought is there's no absolute loss figure because there can be variations in any given trans. or rearend. I always figure about 18% as a general rule of thumb when you have a 727 and 8-3/4.

 

[superdart]

I figure 20% for some fudge factor.

I dynoed my Dakota and figured the loss on it to be about 25%, assuming the factory 220hp rating was correct. (4.7L Flex Fuel)

(166 RWHP * 100)/220 = 75% (25% loss)

Keep in mind that is a 4.7 with the 545RFE trans and a 9.25" truck rear end with 18" wheels, so I would expect the percentage loss to be a bit higher.

I think the 18-20% range is reasonable for a car based setup.

 

[moper]

I use 18% for auto, 15% for stick, regardless of the components. GM auto trannys take a lot more power so if you read 20% it's probably for them.