RE: Speed Limiter

["Timothy Wise" <twise@discretelogic.net>]

I suspect that the car is limited to 130 MPH, but the dealer likely doesn't
know the reasons.  The engine would likely disintergrate if all fuel was cut
off at a reasonably high load (at a speed such as 130MPH).  Its likely a
soft revolution limiter that is mapped to vehicle speed instead of directly
to engine RPMs.  A soft revolution limiter generally retards and then cuts
spark while reducing fuel flow (I believe this latter part is considered a
hard limiter, have to check).  Bouncing onto a rev limiter occaisionaly is
not all that damaging, staying hard against the rev limiter is.

I suspect that the salesperson was just looking to get buy in from you by
giving you the tire story.  There are probably lots of other legal liability
reasons for the car being speed limited.  Analogous to why does the BMW Z3
have that stupid roll bar above each seat that most everyone sits above
anyways...

ECU's that I've dealt with have flash eeproms that allow you to change this
field quite simply, provided you have the software.  The Dealer might, but
liability again would prohibit him doing it; also, the A4 ECU may not be
flashable.  A replacment chip may do this, but it depends if it changes
anything other than the fuel/air/speed/throttle acceleration tables.

Tim

> -----Original Message-----
> From: owner-quattro@coimbra.ans.net
> [mailto:owner-quattro@coimbra.ans.net]On Behalf Of David Lola
> Sent: Wednesday, February 17, 1999 9:30 AM
> To: quattro@coimbra.ans.net
> Subject: Speed Limiter
>
>
> Do the fuel injectors on 99A4Q really shut off at the speed that
> corresponds to
> the tire rating.  When I purchased my new A4 the dealer told me
> that the fuel
> injectors automatically shut off at 130 mph.  They said that this
> was the case
> because the tires equipped from the factory were only rated to
> 130.  This would
> correspond to the tire having an "H" rating.  However, I have the
> sport package
> on my A4Q and the tires that are on my car now, from the factory,
>  have a "Z"
> rating.  This rating corresponds to a speed of 150+.  So, will my
> fuel injectors
> still shut off at 130?  I'm trying to make a little extra time on
> the way to
> work.
>
>