How much power is lost in the drivetrain ?

Wow!! Could this be that the 456 driveline is so efficient Han's?

RWD cars usuall suck up around 30% drivetrain loss. My 348 was put on the dyno over a year ago and I recall around 10-15% drivetrain loss.

7% is really good, if it has been calculated correctly by the dyno.

Thanks for sharing mate, very interesting stuff.

 

This stuff always fascinates me....I'm in agreement that "average" power losses are 15% to about 25% or so. I don't think it's possible to have a loss of only 7%. This does bring up a BASIC question:

HOW are they determining the power loss? Are they comparing the MEASURED power against the FACTORY RATED power?

 

I believe drivetrain power loss to be linear and not an even number all across the rpm range. With how high Ferrari engines spin, I imagine the power loss in the drivetrain to be substantial at high rpms (different with each model obviously). An article was written in a hot rod magazine a few years ago, and I recall it being named, "the Horrible truth" or something to that effect.

The purpose of this article was to determine exact drivetrain loss for this particular manual transmission '60s Ford drivetrain. The engine flywheel dyno'd at 355bhp or so. I cannot recall the exact figures, but the engine was reinstalled and then dyno'd at the rear wheels and loss an enormous 27-28% at the rear wheels. Peak power was made just over 5kRPM.

I would think F* engines would have severe drivetrain penalties as well considering how high they produce their peak power.

 

I actually believe its just the opposite. That you start out with high drag, high HP loss, and it begins to flatline as power goes up. But there really isnt a lot of data out there thats readily available.

I will say though that I find a 7% loss at the wheels almost impossible.

 

AWDs are notorious for horrendous drivetrain losses.

But for a comparison, google for an "EVO MIEV" -- a "Mitsubishi In-wheel Electric Vehicle". Mitsu took an EVO IX and removed the engine and drivetrain, and installed four electric motors inside the wheels.

Four 50 Kw electric motors total only 6 Kw less than the gas powered (JDM) EVO, and with 518 Nm at each wheel, the electric adds up to an insane amount of torque (compared to 355 Nm total on the gas engine). It only weighs about 100kg more than a standard EVO, too.

And no drivetrain losses.

So why is the electric almost 2 sec slower to 100kph than the gas car, despite all the AWD power losses in the gas machine?

I'd say it's the unsprung mass. The gas car can put all 206 Kw (minus all those drivetrain losses) to a single wheel, if need be. The electric tops off at 50Kw per wheel, so any wheel not nailed down subtracts from the total power. And with all that mass in the wheels, when it comes unstuck, it's not coming back any time soon. (I'd guess it's a gold-plated b**ch to drive at the limits.)

Neat concept, though. But an interesting comparison as to what we get for all those drivetrain losses.

 

Large mining trucks have used this system for years. Obviously on a MUCH larger scale.




Darrell.

 

You shouldn't post drivetrainloss in %. F.e. a drivetrain rwd for arround 250-400hp / 500nm has a loss of ~30-40hp at 7500rpm. Drivetrainloss depends on the rpm and for wich performance they are made. The drivetrainloss comes from the friction of the material because that it is a exponential curve over the rpm band, it has nothing to do with the engine power output. You can't say the 100hp engine has a drivetrainlos of 10% 10hp. Because it would have 10hp on 7000rpm but 20hp loss on 8000rpm and 5hp on 4000rpm. And if you mod that engine to 200hp it would have still 10hp on 7000rpm and not 20hp.