Fuel Econ and Hiway Mode

[Mark S. Riley]

----- Original Message -----
From: "Bruce Plecan" <nacelp at bright.net>
To: <gmecm at diy-efi.org>
Sent: Tuesday, October 10, 2000 4:38 PM
Subject: Re: Fuel Econ and Hiway Mode


>
>
> > Like Jim Testa, I also "mess" with a bunch of GN TType Buicks and simply
> > raise the enable on the EGR to never, never land so that it keeps the #3
> > cylinder the same temperature as the other 5 and consequently doesn't
blow
> > the #3 head gasket into orbit or wrap the fire ring backwards around the
> > head bolts. I've seen more head gaskets blown on Buick v6's at light
> > throttle in 5:00 pm traffic than at wide open anywhere else. Deleting
the
> > EGR usually causes a mpg loss which careful driving doesn't quite get
> back.
>
> I'd be alot more predesposed to think the #3 gasket problems are a problem
> with the exhuast porting to the intake face rather then the EGR itself.
> There are 3 exhuast ports leading from the center exhuast valve pocket.
By
> allowing the EGR to work then that passageway gets alot more thermal
> loading, so it's just the way the design is executed rather then the
> principal that is wrong.  IMHO.
>   I really think the problem with EGR is cheap poorly designed executions
> rather then the design.
> Bruce

Well spoken. I think there is a place for EGR on a street driven vehicle in
the pursuit of high performance and MPG. The execution on the turbo regals
is just a bad design causing other problems.

Mark Riley

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