On Fri, 20 Jun 2008 07:07:06 -0700, Built_Well wrote:

> Hachiroku wrote:
>>
>> OK: 27-29MPG with the Mazda running Ethanol-laced gas, 23-25 with
>> 'real' gas from Vermont.
>>
>> 29-31 MPG with the Scion on E-10, 27 with 'real' gas.
> ========
>
> Now I've heard of different weights of oil improving your gas mileage,
> like switching from 5w-30 to 5w-20, but I'm really not familiar with
> different brands of gasoline improving your mileage by 2 or 3-plus miles
> per gallon :-)
>
> Plus I'm sure you know that it's notoriously difficult to accurately
> assess your MPG's between tankfuls as driving routes change between
> tanks, and so do weather conditions and driving styles.
>
> By the way, I've read that switching to 20-weight oil from 30-weight
> really isn't going to save you much at the gas pump. Your mileage might
> improve one-half of one percent. So say, if you get 400 miles on a
> tankful of gas, you'll eeke out an extra 2 miles. You'll travel 402
> miles on a tank, instead of 400. All the while, you may have been using
> a weight of oil not spec'ed by your manual.
>
> If your manual specs 5w-30, it can be a great idea to switch to 0w-30
> under the right conditions, but I'd be hesitant to switch to a 20-weight
> oil just to save 6 dollars a year.
>
> Hachi, keep us updated on your gasoline brand experiments :-)

Hmmmm...why do I get the impression I'm being toyed with here?

One thing I do know: Particularly on my long-term cars (1980 Corolla SR5
and the GTS) it was easy to watch trends with my little notebook. The SR5
got 33 MPG in the end, and the GTS averages about 36. The 80 had a 1.8
Carbed engine and the GTS a 1.6 TC injected engine.

I still don't really have the tC dialed in yet. I don't drive it enough.

But, I drove the car in Vermont the first year I drove it, and I did
notice an increase switching from Shell to the Ethanol fuel sold in Mass.
About 2 MPG consistently.

However, I also had my Grand Voyager and the LHS at this time. The Gr
Vger had a pushrod 3.3 liter and the LHS had an OHC 3.5 liter: the LHS
also suffered (~2 MPG) on Vt gas, while the Vger was unaffected (27 MPG
overall).

BTW, I use Shell and Gulf. Gulf is the 'lowest' brand I will put in my
car, but it seems to work well. Now, ~15-20 years ago I was using Mobil
in the GTS, and it developed pre-ignition. I ran two tanks of Techron and
switched to Chevron and Amoco (when we still had them here) and the
problem stopped.