Back pressure and torque

[Corey L. Cole]

John Hess wrote:
> 
> I DID go to the books.  Back pressure (and flow) effects the exhaust
> temperature.  The exhaust temperature of a free flowing exhaust can have
> an effect on the O2 sensor, since most depend on the exhaust to heat
> them up into their operating range.  I have consistently had troubles
> with cars with header systems not going into closed loop, simply because
> the O2 sensor didn't get hot enough.  That is why I now install
> electrically heated O2 sensors on cars with headers.

I always thought that the problem with O2 sensors and fabricated manifolds
was that the thin wall tubing rejected heat much faster than the cast type.
Furthermore, I'd also heard that ceramic coatings and thermal wraps can
alleviate or eliminate those problems (plus keep you engine compartment
cooler)

-- 
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Corey L. Cole                     | I was standing on the side of the road, 
 M/S 19-HH                        |   rain falling on my shoe. 
 E-mail: corey.l.cole at boeing.com  | I was heading for the east coast,
 Phone: 206-662-3596              |   Lord knows I've paid some dues. 
				  | Tangled up in blue.
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Disclaimer:  If I'm not speaking FORTRAN, I'm not speaking for Boeing.