Re: Painting...and Gas Mileage...

[Jim Adney <jadney@vwtype3.org>]

On 22 Aug 2005 at 10:16, J. Jonik wrote:

> "Keith Park" <topnotch@nycap.rr.com> wrote:
> 
> > Ive found recently that modern Gas, here in the US
> anyway, it very problematic and wont give you the gas
> milage you used to get... especially the winter
> blends.......
> 
> ******   Is there any info out there about this
> possibility? With the gas price story, this would be a
> quite newsworthy scandal.

I don't think there's really any scandal here. It's all pretty much out in the 
open, although not much in the public awareness.

Alcohol has less energy content than gasoline, so gasohol gives less mileage 
than gasoline. I suspect that some of the special blends mandated by the EPA 
for certain geographical areas also have the similar effects.

Then there are summer and winter blends, with different levels of volatility. I 
think that longer chain hydrocarbons generally carry more energy, so the summer 
blends (lower volatility) should give better gas mileage. So winter brings us a 
double whammy with cold temps (which reduce our efficiency) plus gas with 
slightly less energy content.

To some extent, the higher energy content in summer gas may be partly 
responsible for the higher summer prices, but higher summer demand is probably 
the main contributor.

-- 
Jim Adney
jadney@vwtype3.org
Madison, WI 53711-3054
USA

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