[T3] great weekend drive

[Jim Adney]

On 5 Sep 2011 at 23:12, Bryon Garvin wrote:

> I did have the 12 point star driver and a torque wrench and did them to 25
> ft-lbs.  I think I read that right in the Bentley.  If did that wrong,
> please tell me.

I just checked, too, and that's exactly right.  ;-)

> I felt that it was tremendous mileage and much better than I expected.  But
> I guess if it matters, remember that it was ethanol-free, 92, and I was
> driving no more than 60 mph because of the roads that I take to get there
> and probably 1/3 of it was around 50 mph.  There was a somewhat of a
> tail-wind on the way, but really, I was fighting some buffeting from the
> side most of the way there.  I'd basically say "no" to having a tailwind.

Your 34 mi/gal still seems high. I did tests a few years ago driving 
at 65 and 60 and got about 28 and about 29 respectively (with gasohol 
in an AT '73) but I was driving the same cars in the 70s when almost 
all gas was ethanol free and never got close to 30 unless I had a 
tailwind. Ethanol has about 10% less energy content and there's maybe 
10% ethanol in your gas, so the overall difference in energy content 
is 10% of 10%, which is only 1%, or less than we can usually measure.

The change in energy content only becomes noticable with high 
concentrations of ethanol, like E85, which you shouldn't be using.

If your odometer was slipping, that would reduce your mileage, not 
increase it. Filling the gas tank to the same level, before and 
after, is critical to this measurement.

> I'm interested to hear your response Jim because currently, this would be
> the best mileage I get out of any of my cars on the highway and that
> includes my 96 Jetta.

I'm surprised, but pleased, that your Jetta doesn't do better. Which 
engine does it have? If it usually goes on trips where you can travel 
at 70 mi/hr +, then that makes a significant difference.

> I'm going to keep driving to this station and running 92 ethanol-free just
> to see what the around-the-town mileage is.  I don't mind paying that money
> at this point if I'm getting that kind of return on the investment.

The 21 mi/gal you get around town is exactly what I get around town, 
so that seems to indicate that there's nothing really wrong with your 
car. If your car is an MT, then that would give you a couple mi/gal 
edge, especially on the road.

I hope you'll do more trips and get us more data. I'll be pleasantly 
surprised if the 34 mi/gal number holds up as a long term average.

-- 
*******************************
Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
*******************************