quattro Digest, Vol 10, Issue 86 - drivetrain losses

[Larry C Leung]

Ahh, yes, Piech's argument back in 1980 when quattro was
intro'd. Of course the advantage is rather nullified by the additional
drivetrain friction (extra CV's, vibration, noise, etc, losses) and 
additional weight, which is a transverse force, increasing frictional
loads on the axles. Add to this the effect weight has on the tire
hysterisis, and the end result is a greater percentile driveline loss.
Unfortunately, ya still can't get something for nothing....

LL - NY


On Thu, 26 Aug 2004 10:19:52 -0500 sdewitt at stx.rr.com writes:
> Don't forget that there is less rolling resistance in a wheel that 
> transmits torque versus one that does not.
> 
> ----- Original Message -----
> From: Larry C Leung <l.leung at juno.com>
> Date: Thursday, August 26, 2004 9:08 am
> Subject: Re: quattro Digest, Vol 10, Issue 86
> 
> > Mike,
> > 
> > The energy goes into various places besides making the car go 
> > forwards (or backwards!), mostly due to what is generally called
> > frictional losses. Potential energy sinks:
> > 
> > Heat (into the drivetrain parts, air, lubes in the driveline, etc. 
> 
> > -
> > largest of the losses)
> > Sound (all that whirring noise, that's losses!)
> > Vibration (essentially work that's wasted in making parts vibrate 
> 
> > up and
> > down or whatever)
> > Hysterisis (flexural absorbtion in the tires)
> > Other mechanical losses (now we're getting into minor bits, shock
> > absorber heat, spring flex, etc)
> > 
> > Since there are more bits to absorb in an AWD car vs. 2WD, there 
> > tends to
> > be greater losses. 
> > Don't know what losses are caused by the diffy fluids that shall 
> > remainnameless in the center of post
> > '89 quattros......, although my understanding of those particular 
> 
> > diffs(also known as Quaiffe's) is it's
> > mostly a mechanical set-up, with lot's of little bits, allowing 
> > for much
> > of the same losses as the overall,
> > just on a much smaller scale....
> > 
> > LL - NY - a.k.a. the Physics Teacher
> > 
> > 
> > > ------------------------------
> > > 
> > > Date: Thu, 26 Aug 2004 08:27:17 -0400
> > > From: Mike Arman <armanmik at earthlink.net>
> > > Subject: drive train losses
> > > To: quattro at audifans.com
> > > Message-ID: 
> <4.2.0.58.20040826073546.00ad7bb8 at mail.earthlink.net>
> > > Content-Type: text/plain; charset="us-ascii"
> > > 
> > > 
> > > 
> > > I have to take issue with the idea that you can "lose" 100 hp in 
> 
> > the 
> > > drive 
> > > train.
> > > 
> > > Where does this energy go? 100 hp is (at 33,000 ft. lbs per hp) 
> 
> > over 
> > > 3 
> > > million foot pounds, at 746 watts per hp, it is 74.6 KW, enough 
> 
> > to 
> > > run your 
> > > whole house, central A/C, big screen TV and all. This energy 
> > simply 
> > > does 
> > > NOT "disappear" in the drive train.
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> > 
> 
> 
>