quattro Digest, Vol 10, Issue 86

[sdewitt at stx.rr.com]

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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