Olitho

Does anyone know what the approximate power train horsepower loss is through a stock differential vs. Quaife vs. OS Giken and other diffs. Is there much difference?

mgarfias

Depends on mass of the diff. Your frictional losses will all be in the gear set/trans/drive line, not the diff (assuming straight line, no slippage). I'd imagine the differences would be slight as the diff itself is fairly small diameter compared to, say, a wheel/tire combo.

Olitho

Yeah, I figure so, too, but I am wondering if the torson style gear diff of the Quaife I have sucks out more power that the stock or OS Giken clutch type.

My Quaife itself is rather heavy with all the gears inside. It sure does get hot, too.


Oli

RX-Ben

The Quaife should get hot when "working" (in turns). Otherwise I don't think it would eat more power since the spyder gears don't move when the wheels are at the same speed.

Olitho

Good point.

mgarfias

How often are you going perfectly straight though?

RX-Ben

Good point, but I think it is academic since corrections or passing maneuvers on a straight will not excite the diff much.

mgarfias

I know, I'm just being pedantic. Though i admit to now being curious about how much slipping the diffs do on the "straights" and how much power loss that amounts to.

Would a locker (wiessman or detroit) be different? Or how about going Mark Donohue style and running a spool?

Canam

Rule of thumb used to be 20 percent plus or minus. For example a stock LT1 Corvette at 300HP will put down between 247 and 257 on a dyno by the post information I have. Thats not 20 percent but you get the picture.

RX-Ben

I can't see how a properly functioning limited slip would cause hp loss since it is "locked" on a dyno.

drivinhard

I used to run a Quaife diff on a FWD car, it generated massive amounts of heat in the transaxle. It was also worth several seconds a lap compared to the stock open diff!

mgarfias

He's asking about loss from the differential unit itself, not from the entire driveline.