[s-cars] Dyno Day/O2 sensor-related question

[Jim Green]

On 2/11/06, Joseph Pizzimenti <joe at betterbuildingservices.com> wrote:
>
> If you read it after the cat, the AF won't be accurate, but the HP
> readings won't be affected.
>
> Joe
> -----Original Message-----
> From: Dave Forgie <forgied at direct.ca>
> Date: Sat, 11 Feb 2006 10:50:02
> To:s-cars <s-car-list at audifans.com>
> Subject: [s-cars] Dyno Day/O2 sensor-related question
>
> I am organizing the first ever dyno day for our Vancouver UrS-car club
> on March 11th.  We have seven people signed up.
>
> We never had a four wheel dyno in the area until late in the fall when
> Patrick Richard of Subaru rally racing fame installed one at his shop
> (Rocket Rally Racing)  in Squamish (between Vancouver and Whistler).
> I've only talked to them and haven't seen their O2 sensor set-up (yet).
> From what I have been told, they use a "sniffer" tube stuck in the
> tailpipe.  When I told them that we all run cats, they said the A/F
> results won't be correct but they will be able to tell if we are rich or
> lean (but not the exact ratio, I guess).
>


Hmm, I've never thought about this when I run because I don't have a cat.
However this would explain why newer cars always seem rediculously lean on
the dyno.  Mainly B5 s4's from what I've seen.  Of the 10+ I've seen on the
dyno, they always read ~15:1 which is scary at first, but if all the cats on
that car are working right I guess that's where they should be!


--
Jim Green
'89 90tq
'89 80q
http://www.mswanson.com/~jgreen/car_home.html