In a message dated 7/27/99 9:02:32 PM EST, bernd@texas.net writes:
>
> It's not like I really care that much...I'll try something to see if it
> works. If it does, great. If not, that's called trial and error. Getting
> the best combination won't always work for identical engines...as you
> probably already know...but the 180 seems to be the exception.
>
> With all the mods on the truck, it still gets 17-19mpg on
> average....15-16mpg if i'm lead-footing it.
>
> My old Javelin's mileage went down with a 160 but gets its best mileage
with
> a 180. (Stock is a 195). Same thing went for my old Camaro as well
> (R.I.P.).
>
>
>
>
> -----Original Message-----
> From: owner-dakota-truck@buffnet4.buffnet.net
> [mailto:owner-dakota-truck@buffnet4.buffnet.net]On Behalf Of Patrick
> Delgado
> Sent: Tuesday, July 27, 1999 4:03 PM
> To: dakota-truck@buffnet.net
> Subject: Re: DML: better mileage w/180 or 195 stat?
>
>
> Any ideas why?
> Dr. Pat
>
> ----------
> >From: "Bernd D. Ratsch" <bernd@texas.net>
> >Subject: RE: DML: better mileage w/180 or 195 stat?
>
> > Funny, My mileage went UP with the 180.
> >
> > -----Original Message-----
>
> >> Nope, if anything it will make your mileage worse. The purpose of using
a
> > lower stat is to help pull heat out of the combustion chamber so that it
> > won't ping. This is usually because of advanced timing. Heat is power. If
> > you get rid of heat you're wasting power(and fuel).
> > Dr. Pat
>
>
>
OK here is the deal. THe reason all vehicles use a 195 is that a hotter
engine burns cleaner. Emissions! So when you put a lower degree T stat in
the engine runs cooler. Its and inverse relationship. The cooler you run,
the more HP you have, however, the cooler you run the gas you use, and hence
the more HC's you emit. OUR TRUCKS run two systems according to temp. Open
loop is the "warm-up" mode. The O2 sensor(s) have no input on mixture
ratios. its ;ike choke on a carb., but without the high revvs. Once the
engine hits about 175 deg (F), the computer switches to closed loop. This is
where the O2 sensor comes in. It will feed back info to the computer and
adjust the mixture of fuel and air (via tps and IAC, etc..) to get the best
combo. When you put a 180 in, yeah it opens at 180 but may fall below 175
(avg) and the computer goes back into open loop. A pre-set fuel/air mix.
This causes shitty gas milage, but HP is there (remember the relationship).
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