I just paid $13/gallon at Sherwin Williams in Allston. Anybody know of a place cheaper?

(Why can't they just offer 95 octane at the pump?)

Not only is toluene highly carcinogenic, but it has additional pathophysiology as a chemical that is commonly abused ("huffing", "bagging") - it has become the model airplane glue of the 21st century. Many stores have stopped carrying the stuff. As an actane booster, it is challenge as it is dener than gasoline - and from what I understand, can settle and concentrate, where its highly corrosive nature can take a toll on tanks and plumbing. Keep it off your skin!

Best wishes
Eric

PS - it is a constituent of "Bouin's fixative" which is a solution for preserving tissue that we biologist's use (which is how I have my experience with toluene). I used it for years in the 1980's - but I won't use it now...

I am using it as a band-aid until I get a water injection setup working. The software in my S4 just doesn't seem to agree with the current crop of 93 octane gas here in Mass.

I was under the impression that the level of hazard of tolune is similar to gasoline.
<a href="http://www.atsdr.cdc.gov/tfacts56.html">This CDC site</a> doesn't seem too alarming. "The EPA has determined that the carcinogenicity of toluene can not be classified." Obviously "huffing" it is a different matter entirely. I did wear gloves while transferring it, as a precaution.

I noted that as well, but I am assuming it must be miscible with gasoline, since gasoline itself often already contains significant amounts of toluene.

<center><img src="http://www.racegas.com/images/racepump.gif"></center><p>I used to use VP Racing Fuel in my 66 GTO ( which is leaded), but on occasion used GT100 unleaded. May be a better alternative for you than toluene.

Sunoco GTTM 100, which has the highest octane rating of any street legal fuel, is now available at selected retail locations. Sunoco GT 100 is designed for high performance street cars, muscle cars, classics, street rods, motorcycles, karts and marine applications. Sunoco GT 100 contains no metallic compounds to harm catalytic converters or oxygen sensors. It contains a comprehensive additive package for greater engine protection and reduced fuel system deposits as measured by the BMW test. Sunoco GT 100 is also compatible with virtually all two-stroke synthetic and mineral based motor oils.

GT 100 Unleaded is available at selected locations throughout the U.S. In certain areas, GT 100 Unleaded is available under the CAM2 GTTM 100 label.

Brad's Service
817 Frank Street
Chicopee, MA 01020
413) 592-5187

Gas Express
52 Tarkin Hill Road
New Bedford, MA 02740
508) 995-0500

Main Street Sunoco
468 Main St
Leominster, MA 01453
978) 534-3433

W. Harwich Sunoco
Tre. 28 &amp; Division Street
West Harwich, MA 02671
508) 432-4344<ul><li><a href="http://www.racegas.com/gt100locals/default.asp">http://www.racegas.com/gt100locals/default.asp</a</li></ul>

Lexington store sells 5 gallon jugs but like $10 a gallon.

Other stores sell the smaller 1 gallon containers.

3 North to NH, Exit 6 make right at light at end of ramp. Make left into Sunoco station and they will pump 100 octane into your car for I think like $5.70 a gallon right now.

Andrew

...something is wrong with your car. All "93oct" software runs WELL within the limits of what you can do on 93octane fuel.

But yes, toluene is at least partially soluble in gasoline.

Have you seen what toluene does to gas lines?

Maybe you are thinking of typical software for the biturbo S4.

I have an ur-S4, running MTM "1+" software. It's known to be very aggressive, perhaps too much so.

I meant miscible. If this is incorrect, please explain why. Is gasoline not a homogeneous mixture?

I may be wrong here, but this is my logic:
- High octane gasoline often contains Toluene
- Gasoline is not generally considered to be at risk of "separating" due to heavier components settling out
- Fuel lines are designed to handle gasoline
Therefore, adding 5% additional toluene seems like a limited risk.

"From Al Powell's Audi FAQ"

Mindful of the evil reputation of octane boosters in general, toluene is a very safe choice because it is one of the main octane boosters used by oil companies in producing ordinary gasoline of all grades. Thus if toluene is indeed harmful to your engine as feared, your engine would have disintegrated long, long ago since ordinary pump gasoline can contain as much as 50% aromatic hydrocarbons.

Toluene is a pure hydrocarbon (C7H8). i.e. it contains only hydrogen and carbon atoms. It belongs to a particular category of hydrocarbons called aromatic hydrocarbons. Complete combustion of toluene yields CO2 and H2O. This fact ensures that the entire emission control system such as the catalyst and oxygen sensor of your car is unaffected. There are no metallic compounds (lead, magnesium etc), no nitro compounds and no oxygen atoms in toluene. It is made up of exactly the same ingredients as ordinary gasoline. In fact it is one of the main ingredients of gasoline.

Toluene has a RON octane rating of 121 and a MON rating of 107, leading to a (R+M)/2 rating of 114. (R+M)/2 is how ordinary fuels are rated in the US. Note that toluene has a sensitivity rating of 121-107=14. This compares favorably with alcohols which have sensitivities in the 20-30 range. The more sensitive a fuel is the more its performance degrades under load. Toluene's low sensitivity means that it is an excellent fuel for a heavily loaded engine.

Toluene is denser than ordinary gasoline (0.87 g/mL vs. 0.72-0.74) and contains more energy per unit volume. Thus combustion of toluene leads to more energy being liberated and thus more power generated. This is in contrast to oxygenated octane boosters like ethanol or MTBE which contain less energy per unit volume compared to gasoline. The higher heating value of toluene also means that the exhaust gases contain more kinetic energy, which in turn means that there is more energy to drive turbocharger vanes. In practical terms this is experienced as a faster onset of turbo boost.

Chevron's published composition of 100 octane aviation fuel shows that toluene comprises up to 14% alone and is the predominant aromatic hydrocarbon. Unfortunately composition specifications for automotive gasoline is harder to pin down due to constantly changing requirements.

Octane ratings can be very easily calculated by simple averaging. For example, the tank of an Audi A4 1.8TQ is 15.6 gallons. Filling it with 14.6 gallons of 92 octane and 1 gallon of toluene (114 octane) will yield a fuel mix of:

(14.6 * 92) + (1 * 114) / 15.6 = 93.4

The Audi A4 1.8T is a good example of a car that has very high octane needs if it has been modified to produce more turbo boost. The base compression ratio of this car is a very high 9.5:1 and when an additional 1 bar (14.7 psi) of turbo boost is applied on top of it, the resulting effective compression ratio is way beyond what 92 or 93 octane fuel can ever hope to cope with. Most modified 1.8Ts running without octane enhancement are running with severely retarded ignition timing and boost.<ul><li><a href="http://www.elektro.com/~audi/audi/toluene.html">http://www.elektro.com/~audi/audi/toluene.html</a</li></ul>