[s-cars] Belly pan blues (95 S6A)

[Douglas Fifield]

What is it about Friday's?

D.

On 1/11/07, Taka Mizutani <t44tqtro at gmail.com> wrote:
> I agree about using the OE pan. I've never had a problem with the OE pan.
>
> Now if other listers want to make a metal belly pan for whatever reason,
> well
> so be it. I doubt that it would cause any aerodynamic issues due to the
> nature
> of the UrS, but that is an educated guess. I think rather than lift, the
> more important
> thing to consider are the cooling issues:
>
> 1. the belly pan affects intercooler efficiency w/ the stock intercooler
> 2. the belly pan may affect oil cooler and radiator efficiency
> 3. the belly pan may affect airflow through the engine compartment, hence
> points 1 and 2
>
> Cleaning up the air underneath the car would, IMO, actually improve gas
> mileage. This
> has been proven with the WRX and the STi, using the OEM aero pieces from the
> later
> model on the earlier cars. I know that these pieces were definitely tested
> in a wind tunnel,
> but they are basically completely flat.
>
> My hypothesis is that by cleaning up the airflow underneath the car, you
> would be able to
> reduce drag enough to see a 1-2 mpg improvement on the highway. Rather than
> reinventing
> the wheel with the belly pan, I'd look at fabbing some flat-bottomed pieces
> for the rest of
> the floorpan and cleaning up the undercarriage on the back end of the car.
> With the brick-like
> aero of the STi (big hood scoop and big wing) seeing a big improvement, the
> much slicker
> UrS should see an improvement- some STi owners were reporting as much as
> 4mpg difference
> on the highway, which would result in a halfway respectable 26-27mpg.
>
>
> Taka
>
>
> On 1/11/07, Dave Forgie <forgied at ae.ca> wrote:
> >
> > Taka: You are taking this beyond all belief. It was a causual comment
> > meant to suggest, there are consequences of lift and that the metal
> > belly pan designers should consider that because I can guarantee that
> > the plastic belly pan designers did.
> >
> > I like said, just use the OE plastic pan. It is well designed and will
> > be
> > proven to be reasonably priced after the aluminum pan design is
> > completed and installed. (The is an OPINION)
> >
> > Dave F.
> > >>> "Taka Mizutani" <t44tqtro at gmail.com> 01/11/07 11:36AM >>>
> > Dave-
> > What is your evidence that a belly pan made of metal would cause
> > excessive
> > lift?
> >
> > At what speeds?
> >
> > How much lift?
> >
> > What is the differential between the OEM plastic belly pan's generated
> > lift/downforce vs. the metal one?
> >
> > How do you know that lift is even generated and if so, that it is due
> > to the
> > belly pan?
> >
> > Did you or did you not take into consideration the fact that the MBZ
> > race
> > car generates downforce?
> > That said downforce being disrupted by the bumpy road caused excessive
> > air
> > to flow underneath the
> > car, something that apparently was not anticipated?
> >
> > Audi UrS cars do not generate significant downforce. Your hypothesis
> > that a
> > metal belly pan would
> > cause lift at all, much less lift significant enough to lose control of
> > the
> > car is not based on sound
> > principles.
> >
> > Taka
> >
> >
> > On 1/11/07, Dave Forgie <forgied at ae.ca> wrote:
> > >
> > > I knew somebody would take exception to my "back flip" hyperbole.
> > My
> > > point was if you go out and reinvent the wheel without the proper
> > > tools,
> > > e.g. a wind tunnel, then there could be bad consequences.
> > Admittedly,
> > >
> > > not as extreme as in my example, but nevertheless, added lift can,
> > in
> > > no
> > > way, be a good thing.
> > >
> > > On the Mercedes thing, who do you think said "OH, SH*T!!" first, the
> > > driver or the engineers?   I think the engineers watching the race
> > live
> > > or
> > > on TV. They would see what was happening earlier than the poor
> > > driver who was very likely very confused why there was no road noise
> > > and the steering suddenly became very light while the rev limiter
> > was
> > > being hit.
> > >
> > > Dave F., P.Eng.
> > >
> > > >>> "Taka Mizutani" <t44tqtro at gmail.com> 01/11/07 10:32AM >>>
> > > I think equating a metal belly pan to the back flip action of the
> > Benz
> > > you
> > > mention
> > > is a little bit beyond hyperbole and is overly alarmist.
> > >
> > > I agree that the OE belly pan is probably the best solution, esp.
> > > taking
> > > into account
> > > cost.
> > >
> > > Taka
> > >
> >
> _______________________________________________
> S-CAR-List mailing list
> S-CAR-List at audifans.com
> http://www.audifans.com/mailman/listinfo/s-car-list
>


-- 
Douglas in MN
95.5 Audi S//6 Avant
73 BMW R60/5 mit Toaster Tank