Winter gas vs summer gas

[944 at technologist.com]

True and a correction. It should read 2% More BTUs of heat energy in the
winter than summer. In octane, you trade Heptane versus Octane or Isooctane.
Heptane is the smaller molecule but has a higher BTU count per gallon. Its
flaw. It ignites at a lower temperature than desirable.  Mixed with
isooctane, the temperature of combustion goes up but the BTUs per gallon
actually drop.slightly in the summer.

Back to James, I understand that California "Fuel" is about 4% low in BTUs
to that of a gallon of gasoline. Feel free to dispute that number because I
only found that in one sight last year. 4% is probably a good estimate. FI
meter liquid and not BTUs. O2 sensors force you to Stoich and not to max
horsepower. My BOSCH ML1.2 fuel map forces me to 1.01 which was slightly
rich (O2 deactivate). The results is 3-4% less power than it did a few years
back when oxygenated fuel appeared and they took our tetraethyl lead away.
Sob.

Additives are usually alcohols and keytones and the like. Again, much less
heat energy than a gallon of old fashion leaded gasoline. Methanol has about
half the BTUs of a gallon of gas.

FR Wilk
I was without email for 5 weeks if anyone had tried to contact me.
DSL!!!!!!!!!!!!
____________________________


> This brings up an interesting point.  Higher grades of gasoline actually
> have lower energy content due to the larger amount of additives (which do
> not contribute to the energy of the fuel) which bring up the ignition
point,
> right?
>
> James Ballenger
>
> >-----Original Message-----
> >From: owner-diy_efi at diy-efi.org [mailto:owner-diy_efi at diy-efi.org]On
> >Behalf Of 944 at technologist.com
> >Sent: Tuesday, March 13, 2001 11:21 PM
> >To: diy_efi at diy-efi.org
> >Subject: Re: Winter gas vs summer gas
> >
> >
> >> problems with "winter" gas?
> >
> >That is normal. I am not sure what rules they are running
> >these days but you
> >could count on about 2% fewer BTUs of heat energy in the winter and the
> >knocking in warm LA, CA. Cold fuel in the snow must ignite and
> >there are few
> >choices on how to do that. Hence, the trade-off. Some people notice the
> >knocking. Just go up a grade for a few months.
> >
> >FR Wilk
> >___________________________________________________
> >
> >
> >> Has anyone here experienced problems with "winter" gas?
> >Especially the
> >> oxygenated, reformulated, winter gas sold in California in (I think)
> >> November, December, and January?
> >>
> >> The previous two winters, the winter gas caused two of my vehicles to
> >> occasionally ping under mild throttle conditions.  Each year, by the
> >> time the weather warmed up enough (February) to consider
> >diagnosing the
> >> pinging, the problem went away.  One vehicle is PFI and the
> >other has a
> >> computer-carb.  A neighbor reported similar problems with a
> >TBI engine.
> >>
> >> This winter, I didn't have the pinging.  Instead, the carb
> >vehicle liked
> >> to stall when the engine was cool.  The engine acted/sounded like it
> >> went totally pig rich, the rpms dropped, it started rich
> >misfiring, and
> >> eventually stalled.  I replaced a few "iffy" parts, but
> >couldn't fully
> >> solve the problem.  I've been driving around for several weeks with a
> >> DVM hooked to the O2 sensor.  The DVM showed that the cool
> >engine wasn't
> >> nearly as rich as it sometimes got when fully warmed up.
> >>
> >> A few days ago, I filled up with gas for the first time
> >since January.
> >> (30 gallon gas tank...)  Problem solved.  Hrmph!
> >>
> >> --
> >> Ludis Langens                               ludis (at)
> >cruzers (dot) com
> >> Mac, Fiero, & engine controller goodies:
> >http://www.cruzers.com/~ludis/
> >>
> >>
> >>
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