Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Question about Drivetrain Parasitic Loss

From UK Dyno results it looks like we have about the following losses

Zetec 2L ~ 27 BHP
Duratec ~ 45 BHP

Seen on several cars now. You guess is a good as mine as to why the 6 pot looses so much more

"Zetec 2L ~ 27 BHP
Duratec ~ 45 BHP
Seen on several cars now. You guess is a good as mine as to why the 6 pot looses so much more"

Probably because (as stated above) it IS a % of power loss. Like taxes, the more you make, the more you pay.

Parasitic losses due to the drivetrain are a percentage of total transmitted power. Most loss factors (gear tooth friction, bearing friction, shaft friction) increase linearly with load. This is why towing packages on trucks often include a transmission cooler, to dissipate the extra friction that is produced under higher load. In a similar way, adding HP increases the tranny load (friction losses) and therefore robs more power.

Here at work we design transmissions for Aerospace applications and we typically use
1% loss per gear mesh. HTH

flyer

That's a pretty good gear efficiency. In a typical auotmotive trans, you'll see about 94% - 96% efficiency on the gears themselves, ~97% on the final drive. By the way, each gear (1st, 2nd, 3rd, etc) has a different efficiency in many transmissions. The tires are a huge loss too.