Date:         Thu, 3 Oct 2002 15:38:23 -0400
Reply-To:     "G.M.Bulley" <gmbulley@BULLEY-HEWLETT.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         "G.M.Bulley" <gmbulley@BULLEY-HEWLETT.COM>
Organization: Bulley-Hewlett
Subject:      Re: High Octane was: what's the best kind of gasoline?
In-Reply-To:  <11232E890694F74893375BC7AD88A62DECD61C@MAINEX4.ASU.EDU>
Content-Type: text/plain; charset="us-ascii"

One shouldn't construe that at all. Keep in mind, except of Amoco
ultimate, Gas is gas. "premium" just means it has more anti-knock
compounds added, it DOES NOT mean that there is more potential energy
(BTU's per gallon). This used to be the case (back in the 1960s and
before) that premium had more BTU's per gallon. No longer. Just more
junk in it to slow down the burn.

The recommended for your 1982 is 87. If you run stock, or close to stock
cam, cylinders, rockers, etc. running 8.5 to 1 or less compression, you
should be fine with 87 at 7.5 degrees BTDC at 850 rpm (which is <30
total advance at 4500).

If you have some whack cam, and pop-top pistons, and huge valves, and
all that, you may be buying your gas out at the airport. I run flat-top
96mm cylinders at 8.3 to 1 with 7.5 degrees at 850 rpm and have no
problems.

The key is to listen for pinging. If you can't hear your motor very
well, try warming the motor up thoroughly, then take the motor cover
off, and drive up a fat hill in 4th. Ping? Retard the advance slightly.
No ping. No worries.

Bringing your ideas to life,
G. Matthew Bulley
Bulley-Hewlett
Business: www.bulley-hewlett.com
AIM = IExplain4u
Phone: +1.919.658.1278


-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf
Of Sean Garrett
Sent: Thursday, October 03, 2002 2:49 PM
To: vanagon@GERRY.VANAGON.COM
Subject: High Octane was: what's the best kind of gasoline?

So one might construe that the Air-cooled brethren ought to use higher
octane to prevent pre-ignition. We do have much higher head temps.

Sean Garrett
1981 Westy (his)
1995 Eurovan Camper (hers)
sean.garrett@asu.edu




> -----Original Message-----
> From: Matthew Libby [mailto:MLibby1@CFL.RR.COM]
> Sent: Thursday, October 03, 2002 11:41 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: what's the best kind of gasoline?
>
>
> This is a false conception about high octance/  Higher octane
> just means
> that the fuel is harder to ignite.   Only high temp and or
> high compression
> engines benefit at all from high octance.
> ----- Original Message -----
> From: "Malcolm Stebbins" <Malcolm.Stebbins@MSVU.CA>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Thursday, October 03, 2002 9:27 AM
> Subject: Re: what's the best kind of gasoline?
>
>
> > I dare not post anything w/o first doing an archive search :-)))
> >
> >  I did find that Joel Walker posted on this topic back on
> 17 Sep 94!  (
> > http://gerry.vanagon.com/cgi-
> > bin/wa.exe?A2=ind9409&L=vanagon&P=R17458 )
> >
> > I then did a google.com search related to this topic as I
> was trying to
> > find backing for what my mechanic tells me:  Premium gas is
> 'better' in
> > that one can go farther on a tank of premium than on a tank
> of regular
> > and that one should be looking at costs per kilometre/mile
> rather than
> > cost/litre (gallon).  He also suggests that since premium burns more
> > slowly (I'll assume that this is correct) that there is
> more of 'push' on
> > the piston and less of a 'slap' therefore being easier on
> the engine.
> >
> > So what did I find on Google?  Nothing.  I tried AAA and CAA too:
> > nothing.  Can anyone speak to this issue?  Malcolm
>