Re: So what's good about FWD?

[shields@tembel.org (Michael Shields)]

> >1. Yes, FWD performs better in a low-traction situation purely because
> >   of the nose-heavy weight distribution.
> 
> Sooooo, lemme get it straight -- since it's nose heavy, FWD, front-engined
> vehicles can stop better and get better traction due to weight transfer.

Two people seem to have misunderstood this so I'll explain the basic
vehicle dynamics terms (real racers feel free to correct me):

One issue is "weight distribution".  This refers to how much weight rests
on each wheel when the car is parked on a level surface.  A FE/FWD car
has all the important parts up front and so will be nose-heavy.  A FE/RWD
car can have a 50/50 distribution if carefully designed (example: M3).

Another is "weight transfer".  When the car is accelerating (in the
vector sense, i.e. increasing or speed in any lateral or longitudinal
direction including cornering), some of the car's weight will shift.
This is because you control the car solely by the tire's contact patches,
which are at ground level, while the center of mass is above ground level.
Essentially when you drive you're trying to pull the tires out from
underneath the car.  This is why the nose dives in braking, &c.

When you are travelling in a straight line (the simplest case) and punch
the throttle, you're transferring weight to the rear wheels and away from
the front.  Since tires have more available traction when they have more
load, this is good.  That's why Corvettes have RWD.

In a low-traction situation, you ca'n't transfer as much weight.  So the
static weight distribution is more of a factor.

> Hmm... so why the fuss over q's??

Because when you distribute the engine forces across twice as much
tire you have more of its ability for cornering.  This is important
when accelerating out of the turn -- applying power doesn't ask the
wheels to do more than they can, causing you to slide.  On the street
you keep the same line and stay further within the envelope -- on the
track you take a later apex and accelerate better out of the turn.
(I think; I have neither a q nor race experience... JTH.)

This factor becomes important when you have a lot of power *relative*
to the available traction -- either because you're driving on snow or
ice or sand or dirt, or because you have a 993 or a Stealth tt or a
hyper-tweaked Audi.

My question was why FWD was better at all in the snow -- the only reason
I could think of was that it's nose-heavy.  Since yes, that's the whole
reason, I then asked why not just put the engine in the back.
-- 
Shields.