The only correction I can make is that most 2.0L VW in-line 4 motors also
use knock sensors (I wouldn't exactly call all of them "high
performance"). I know my TiiCo motor uses one. I think the main 2 reasons
to use a knock sensor are 9:1 and higher compression, and use of forced
induction (turbo/supercharger). Most automaker these days are probably
using knock sensors just to keep their supposed "high efficiency" (high
compression) motors from blowing up when you get a batch of bad gas.

Sean B.
'90 V'gon, "Happy Bus", pseudo Wolfy
Torrance, CA
Join the TiiCo registry at
HTTP://www.vgonman.com

On Fri, 28 Dec 2001 19:47:43 +0000 Paul Mayfield
<paulmayfield@EARTHLINK.NET> writes:
> Please correct me if any of this is untrue/incorrect!
>
<SNIP>
> I've heard some high performance
> high compression engines have preignition sensors
> that adjust to lower power levels when 87 octane is used.
> (porsche,corvette?)
<SNIP>