octane booster

[James Weiler]

On Tue, 7 Jan 1997, tom cloud wrote:

>         [ snip ]
> 
> >Xylene and toluene are good but methyl-t-butyl ether is better and 
> >probably cheaper.  There are others that are potent but I'd have to look 
> >them up.  Undergrad chemistry was a while ago.
> >
> >Where will you get these from?
> >later
> >jw
> 
> can someone enlighten someone (me) who knows nothing about
> octane boosters ??
> 
> Tom Cloud <cloud at peaches.ph.utexas.edu>
> 
> 
I'll try to remember what I can.  There are several ways to boost 
octane.  There is research octane (R) and then motor octane (M) numbers.  
Lets not get in to strict definitions here (cuz I can't remember them)but 
one gives a resistance to 
ignition under a light load (such as cruise) and the other is relevant to 
ingnition under a heavy load.(I think?  maybe I should shut up and go 
look at my old notes before I start babling)
Sometimes you might see at the gas pump (R+M)/2. This is the 
average of research + motor octane numbers.  One gas companys 91 octane 
is probably not the same as another.  Before I show more ignorance I'm 
going to find my notes at home but one more thing.  Toluene and xylene 
are molecules very close to benzene in structure.  Benzene is a very 
potent carcinogen so I would caution it's use.  Use a carcoal filtered 
mask and rubber gloves.  Store and deliver these in a well ventalated area.
Methyl-t-butyl ether (MTBE) is not nearly as toxic.  Actually I'm not 
sure it has much of any risks associated with it. I would use MTBE at 1 
part to 100 parts gas. That should be about a 10 point boost in octane 
rating.
Another problem with Toluene or xylene is that when they evaporate they 
leave a thick film.  These are the gums that we see on our carbs.  A carb 
is easy to dismantle and clean.  I have no idea as to how serious a 
problem they would be for an injector, but I would be concerned.
I used to have some MTBE and tried it in a friends car.  He had a 351C 
with 13:1 compression and a pretty square cam.  With 93 octane pump gas 
(~15 gallons) spiked with 350-400 ml (~coke can full) of MTBE it ran 
better than race gas which had an octane rating of about 115.  He used this 
formula for the rest of the season and had no carb gumming problems.
MTBE would also help out for emissions as well since it is an oxygenating 
agent.  As all ethers are.  MTBE is one of the reagents used by gas 
companies in there O2 enriched fuels.
Anyway I'm going to refresh my brain and hopefully add to this tomorrow 
if you like.
later
jw
P.S. Finnally something I can contribute to this list.