Date:         Sun, 15 Dec 2013 12:16:04 -0500
Reply-To:     Marc Perdue <mcperdue@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Marc Perdue <mcperdue@GMAIL.COM>
Subject:      Re: Gas question, seriously folks
In-Reply-To:  <064E9AA5-4E6C-4E93-9E94-ACF77D57A100@gmail.com>
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It seems that everybody, including me, has an opinion on gasoline, some
based on anecdote, some based on what USED to happen back in the 60s and
70s, some based on a different engine than you're running . . . Sigh . . .

I have an '87 Westy with a Boston Bob big valve engine. It's NOT stock. Bob
Donalds told me that I should always run premium gas in it, ergo, I do.
Here is a nice article that Bob wrote a number of years ago. Keep in mind
that it leans heavily toward the air-cooled engines, but the information in
it is useful to us just the same, even though there are some different
blends now and even ethanol-free fuel available.
http://www.suburbanengine.com/articles/todaysfuels.html
Another thing that's important to note is that the tendency for an engine
to incur pre-ignition is higher with lower octane fuels AT LOAD. I consider
a Westfalia full camper to always be at load, more so when I'm taking it
camping. All of this is to say that if I were going to switch between
different grades of gas, I would use the lower octane gas for everyday
driving wherein I'm running an empty van and use the higher octane gas for
camping trips or any other time when I'm putting a serious load on the van,
i.e., driving up to the mountains.

Many have made different claims about Stabil (pronounced stay bill--I don't
know if you use a reader, Eric). I don't know enough about it to make any
substantial claims. What I have read is in alignment with what Stuart said,
I think, that it's basically more useful in circumstances where an engine
and/or fuel tank is likely to be sitting awhile, thus allowing the
separation of components of the gasoline, absorption of water and such. I
should be using it in my van right now . . . :(

An interesting note relevant to the last paragraph that Paul shared from
the GoWesty pages: Bob Donalds talked about lowering the compression ratio
in his air-cooled engines he built for Zambonis. This kept the head temps
cooler. I'm imagining the scenario where somebody made a connection between
a high compression ratio engine having hotter running heads and using
higher octane fuel and thinking the higher octane fuel was the CAUSE of the
higher temps. Correlation does not equal causation.

Interesting thread, to me anyway . . .
Marc P.


On Sun, Dec 15, 2013 at 10:58 AM, Paul Rogers <wognacious@gmail.com> wrote:

>  This is from the GoWesty site. After spending over $3K+, plus countless
> hours, on my "new to me engine" I follow this philosophy
>
>
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> Gasoline Grade: Which Should I Use in My VW Van?
> Gasoline is rated by its octane level. The higher the octane, the more
> stable the fuel is, and the less likely it is to prematurely ignite and
> cause the engine to “knock,” which usually results in a pinging sound. This
> can lead to catastrophic engine failure in a surprisingly short amount of
> time, with very little notice. Pre-ignition can occur in a particular
> engine design for various reasons. For whatever reason it occurs, high
> octane fuel can prevent it from happening.
>
> Higher performance engines typically have higher compression ratios (CR)
> and are more susceptible to knocking than lower CR engines. Those of us who
> grew up in the '60s and '70s are accustomed to this reality, and as a
> matter of course listened for pinging whenever driving a vehicle with a
> high performance engine. Pinging occurs only at high power demand (high
> load). That is, if you are just cruising down the road, rarely if ever
> using full throttle, and don’t need all of the power the engine is capable
> of producing—pinging does not occur. "Old-schoolers" like me know when to
> listen. To this day, on long trips in my Bus or Vanagon, I ALWAYS listen
> for pinging after each tank fill-up. I simply turn down the radio, roll
> down the window, and listen. If the engine is going to ping, it will do so
> on a long grade at above 80% throttle-especially at altitudes uner 3000
> feet. If I got a tank of bad gas, I know that for at least that tank of
> fuel, I gotta keep my foot off of it, and stay below 80% throttle. This
> happens a lot in Mexico.
>
> In the late 1980s, Bosch came up with a “knock sensor” feature, whereby
> the engine management system senses knocking and automatically makes
> adjustments to timing and/or fuel delivery and/or valve timing so the
> knocking stops. The result is that the engine simply produces less power in
> exchange for staying in one piece. It is realy no different than what us
> old-schoolers have been doing all along, except it is done automatically
> for you by a device that does not have to turn the radio down or roll down
> the window, or even stop to eat or pee.
>
> Eurovans: Having been designed in the late '80s, all Eurovans are equipped
> with a knock sensor system. You can run low octane in a Eurovan, and the
> engine will adjust if knocking occurs. So, it makes no difference what
> grade fuel you are using—the engine management system will make the
> necessary adjustment. If you need more power—if you plan on towing, for
> example— you should buy the higher octane fuel. The bottom line, though, is
> that neither is likely to hurt the engine.
>
> VW Buses and Vanagons:  By contrast, Buses and Vanagons were designed in
> the '60s and '70s and DO NOT HAVE knock sensing capability. That is, if you
> decide to use low-grade fuel, or end up with some bad gas by mistake, the
> engine has no way of adapting to it. The little engine will try to push
> that big box around with all its might, knocking or not, until it pukes.
> And unlike the newer Eurovans—with their larger, more sturdy engines—the
> engine in a Bus or Vanagon is BARELY able to push it down the road even
> under ideal circumstances. Anyone who has spent any time behind the wheel
> of one of these vehicles, even one fitted with a GoWesty high performance
> 2.5 liter engine, finds themselves trying to push the accelerator pedal
> through the floor without realizing it. So: Always run premium in any Bus
> or Vanagon, or you will risk destroying the engine. And even with known
> good fuel, it is a good idea to experiment a little, learn what pinging
> sounds like, and make changes in your driving habbits as needed to avoid it
> from happening.
>
> What about the cost? Well, at $3-5 per gallon, what is another twenty
> cents? A lot less than another engine, that’s for sure.
>
> What about MPG? Don’t you get better MPG with higher octane fuel? Baloney!
> Don’t believe it! It is just not true. You can run regular in any Eurovan
> without hurting it and get the same MPG.
>
> What about running hotter? Doesn’t my engine run at a HIGHER temperature
> with HIGHER octane gasoline? Baloney! Don’t believe it! It is just not true.