off topic / traction control

Programmer nwester at eidnet.org
Thu Jan 11 19:30:59 GMT 2001



> I have found that it doesn't always follow logic.  Spend some time
> in a car with an EVA, Electronic Vibration Analysis tool and you'll see.

Wish I had an EVA...someday perhaps.

> Lowering tire pressure in some cases makes a car not feel as smooth.

The Ford TSB's refer to harshness--first step is lowering tire pressure.

> The eva will still show the same normal road vibration magnitude, however
> raising the tire pressure raises the frequency so your buns don't feel it
as
> much.  (My experience on one type of vehicle).

Yes--there's a change in frequency--sometimes it just raises the vibration
speed. Fords' fix is either an exhaust change or shock absorber change.
Found that rather interesting as I read further into the 4 door and 2 door
problem on the '91+ Explorer.

> Also if you read the Ford doc or any document that explains turning, not
> drag strip racing, lower the tire pressure decreases the grip at the end
> of the vehicle that the tire pressure is being lowered on.

Well--yeah...the tire face is distorted and deflected. The sidewall flexes
more than normal, and I can't see how the centre of gravity is better-I
guess I'd have to see their tests. I just find it strange. Thanks Mark !!

Lyndon.
> ----- Original Message -----
> From: "Programmer" <nwester at eidnet.org>
> To: <diy_efi at diy-efi.org>
> Sent: Thursday, January 11, 2001 7:12 AM
> Subject: Re: off topic / traction control
>
>
> > Hmmm....that seems ag'nst all logic. Normally, you lower tire pressure
for
> > traction and the result is also instability <g>. They had balance
> harmonics
> > in those things  that resulted in the inability to get the vibration out
> of
> > the chassis at 34 psi pressure. They found that lowered tire pressure
took
> > out the vibes--and gave you a smooooth ride. Unfortunately--this also
> > creates more tire heat.
> >
> > Lyndon
> >
> > ----- Original Message -----
> > From: Romans, Mark <romans at starstream.net>
> > To: <diy_efi at diy-efi.org>
> > Sent: Wednesday, January 10, 2001 10:48 PM
> > Subject: Re: off topic / traction control
> >
> >
> > > The newspaper article I read stated that the internal Ford Docs stated
> > > that Ford's own internal testing showed the Explorer wasn't very
stable
> > > and that Ford decreased the tire pressure not for ride quality but to
> make
> > > the tires have less grip so it wouldn't roll as easily.  When the
> dropped
> > > the
> > > tire pressure it would pass Ford's own internal stability test, with
the
> > > tire pressure
> > > raised it was not stable enough.
> > >
> > > That's why I would sell a jeep or other really capable off road
vehicle
> > > before allowing
> > > my kids to drive it because by design what makes a vehicle capable off
> > road
> > > makes it less stable on road.
> > > (Narrow track, High CG).
> > > Mark
> > >
> >
>
> --------------------------------------------------------------------------
> > --
> > > To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the
> > quotes)
> > > in the body of a message (not the subject) to
> majordomo at lists.diy-efi.org
> > >
> >
>
> --------------------------------------------------------------------------
> --
> > To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the
> quotes)
> > in the body of a message (not the subject) to
majordomo at lists.diy-efi.org
> >
> >
>
> --------------------------------------------------------------------------
--
> To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the
quotes)
> in the body of a message (not the subject) to majordomo at lists.diy-efi.org
>

----------------------------------------------------------------------------
To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org




More information about the Diy_efi mailing list