Re: How can I run on unleaded.

[rlgreen <rlgreen@ibm.net>]

Kenik Hassel wrote:
> 
> I heard a horrible rumor that aviation fuel is not good for cars.  The
> octane ratio is computed differently (noy and RON standard), so the
> computations don't cross apply.  I remeber reading somewhere that 100
> octane aviation fuel is actually equivalent to auto fuel of a low 80's
> octane.  Be careful, I'd cry if we lost another one of our type 3
> brethren to misinformation.
> 
> Kenik Hassel
> 71 fastback
> 
> On Tue, 23 Sep 1997 Sppinner@aol.com wrote:
> 
> > >  You can't make adjustments since the lead in the fuel was used to increase
> >
> > > the
> > >  octane of the fuel and as a lubricant/cushion for the valves.
> >
> > I have been using leaded aviation fuel (100 octane) in my '63 notch and '56
> > oval. Has anyone heard of a good reason NOT to do this ? It is called 100LL,
> > i.e. 100oct Low Lead. Being low lead doesn't mean it has less lead than
> > leaded auto fuel though. As a matter of fact, it has more lead than non-low
> > lead avgas, like 80oct. I usually mix it with 93oct auto gas like
> > 70%avgas/30% 93oct autogas. Am I going to cause any damage by this ? I
> > wouldn' t think so. I asked a guy who used to mix race fuel for us and he
> > joking said it'll fly (hehehe). The timing is set 10'BTDC, and it seems to
> > love it.
> >
> > kevin chapman
> > '63 jet-fueled notch
> >
My recollection on avgas is 81 ron or 87 ron.  Its been 15 years since I
pumped any avgas.  Last fuel I used in an aircraft was jp4.  

Piston engine airplanes have complete engine management systems.  Which
control manifold pressure, ignition timing(yes you can advance and
retard from the cockpit),fuel mixture(yes you can lean or richen your
fuel and air) etc.etc..  It has dual magnetos and a host of other
devices for safety and engine cooling equipment

Now avgas burns hotter than auto gas because it is lower octane, but
with the systems in place you can control your head temp and oil temp
through the use of system controls.  In a car you cannot.  Yes the
gauges are extremely accurate.   An aircarft engine operates at low
rpm's, usually between 1700, 2500.  Avgas works in a whole diferent and
narrow pressure range.

An engine (4cyl) aircooled jsut like a vw cost $25000 new and over
$10,000 to rebuild at 2000hrs of use.  With a whole lot of dollars spent
in between rebuilds.   

Avgas is under going the same changes as autogas.  120/140 were ready
available but no more.  120 would be equal to 91 ron  The octanes have
been lowered severely and many engine changes have been made.  Engines
use ceramic and chrome cylinders.  Valves for unleaded fuels and all the
ills we suffer from.

I can go into more detail but i would bore you to death.  Remember this
is fifteen year old memory I could be completely wrong.

Ron....
69 squareback