Toulene

Has anybody ever used toulene as an octane booster? I've heard good and bad about it.

[c4c5specialist]

HI there,
That chemical is known to short out injector winding and should not be used in fuel injection systems or systems with o2 sensors.
Allthebest, c4c5

Wait a minute, that's the primary ingredient in some off the shelf octane booster and is found in many fuels. Toluene is a regular component of pump gas and is available in various grades at chemical supply stores. Premium street gasoline carries roughly toluene, which partially helps octane characteristics. Unocal's 100-octane race gas has almost 25% toluene.

I've used it for 10 years now up to a 20% mix and never had an issue. Actually, I use xylene these days because it has a higher octane rating @ 117 compared to 113 of T. Higher concetrations can change the flame speed to it's not a good idea to mix more then 20%.

Here's a link to a MSDS for gasoline. Take a llok at the ingriedents and weights.

http://www.hess.com/EHS/msds/gasolin...rades-9950.pdf

[c4c5specialist]

HI there.
Thats the first reason why octane booster is NEVER recommended in injection equipped cars.
Race gas is NEVER recommended for street driven vehicles with fuel injection.
Yes, Toluene is always in gas, HOWEVER, only in certain percentages.
And, the actual use of octane boosters, such as Toluene and ETHANOL are never above 10%.
Now, if someone adds MORE than that, this is where problems occur.
While the MSDS shows 1-25% by weight, it is NOT stipulated how much, because its ALL gasolines, which may include racing fuel.
Even Ethanol, has been shown to create injector problems, because of the CORROSIVENESS OF IT.
That is why the E85 equipped vehicles require different fuel systems.
Just because you can purchase it, DOESNT mean you should use it.
Alltehbest, c4c5

Originally Posted by c4c5specialist

HI there.
Thats the first reason why octane booster is NEVER recommended in injection equipped cars.
Race gas is NEVER recommended for street driven vehicles with fuel injection.
Yes, Toluene is always in gas, HOWEVER, only in certain percentages.
And, the actual use of octane boosters, such as Toluene and ETHANOL are never above 10%.
Now, if someone adds MORE than that, this is where problems occur.
While the MSDS shows 1-25% by weight, it is NOT stipulated how much, because its ALL gasolines, which may include racing fuel.
Even Ethanol, has been shown to create injector problems, because of the CORROSIVENESS OF IT.
That is why the E85 equipped vehicles require different fuel systems.
Just because you can purchase it, DOESNT mean you should use it.
Alltehbest, c4c5

I think you’re getting some thing inappropriately grouped together so maybe I can clear up some confusion without typing a book.

In a nutshell, there are three types of octane boosting chemicals/methods (organo-metallics, ethers/alcohols, and aromatics) each has its own setbacks.

OM’s are really used in many “race” and Av gases which has TEL (Tetra Ethyl Lead), which is the 02 and catalytic killers. In automotive use, MMT (methylcyclopentadienyl manganese tricarbonyl) is substituted for TELl because it’s of a similar structure but uses manganese at the substitute for lead. While the MMT will work in FI cars, they can leave deposits in your engine because of the high metallic content. Most of the off the shelf octane boosters use this method and adds mineral spirits to try and dissolve the deposits and then add things like ATF as a lubricant to help the rings slide over these deposits (while selling you on the ATF cleaning the valves). Overall, a bad choice for octane booster but cost effective to produce and not noticeable to the average consumer. This is why I never recommend octane boosters until I understand the specific mixtures and chemicals.

Oxygenates are the ether/alcohols which are very corrosive and yes, in E85 applications can destroy fuel system components (particularly plastic and rubber fuel lines) unless they are coated/lined. Ethanol is a good booster but is its high volatility makes it a bad choice in emissions controls in warm climates. MTBE is usually the emmisions friendly ethanol replacement that get’s added to pump gas but has a significantly lower octane rating.

The third are the aromatics. While I wouldn’t describe them as the best of both worlds, they are better then the others for “our applications” because they are safe to use in standard fuel systems, leave no nasty deposits, and are have relatibly high octane ratings. They are have a lower volatility, and are less reactive, and are chemically stable. Again, they will NOT eat fuel system components like the oxygenates will. In Europe you’ll find that fuels have up to 40 to 45% aromatics.

So the real questions is if it’s so great why doesn’t everyone use it in higher concentrations????? In California, law restricts aromatics to 35% of a gasoline blend (Primarily because Benzene is a cheaper aromatic and also a nasty carcinogen). Elsewhere it may be as much as 40%. Toluene and Xylene are the not so cost effective replacements for Benzene. The proceed with caution side to the aromatics (we’re talking only Xylene and Toulene here), besides cost, is Toluene and Xylene have specific gravities higher than pump gas so the more of them you add, it will not only increase the octane numbers of the gasoline, but when you get above 50 or 60% total aromatics, throttle response can become poor because the flame speed is reduced to where increasing amounts of fuel are still burning as combustion gases are forced out the exhaust valve (essentially you need a leaner A/F mixture to run beyond 50% aromatics). Once this threshold is passed power is lost, not gained.

Basically compared to gasoline's specfic-gravity of 0.751-g/cc, toluene is about 0.881-g/cc and xylene is around 0.871-g/cc. This means they have more hydrogens and carbons to combust per gallon with the O2 in the air that's being pumped through the engine. The results of using large-percentage mixtures of these aromatics in your fuel is a richer mixture than before with just pure pump gas. This will be safer than using the other common OM’s additives or 100LL Av/race gas which is lighter than gasoline and will result in lean mixtures and melted catalytics and deposited O2-sensors.

In my personally experience I’ve run up to 20% additional toluene in high HP per liter and forced induction applications, in both race and street environments without an issue. This includes my 02 Z06 in 110 degree weather. If you’re looking for a just few octane points (91 to 94 bump), its much cheaper and completely safe to toss in a gallon of Toluene then use the over the counter octane boosters but be careful of the upper limits otherwise you’re just wasting money and power.

[c4c5specialist]

HI there,
The recommendation I have stated comes directly from GM service information files.
Obviously, you are a chemist, or something along those lines.
I am not an engineer, nor a chemist, my job is to maintain GM vehicles per THEIR GUIDELINES.
Nothing more and nothing less.
Your personal experience is great.
But I only follow what the people at GM, who engineer and build these vehicles say.
They say, "Using toluene or alcohol based fuel injection additives will shorten the life of fuel injector coil windings."
That is what I stand by.
Allthebest, c4c5

I’m not doubting you nor am I not trying to imply you’re being untruthful so I hope you don’t take it that way. I truly appreciate this discussion. I have no doubt that you have that information from GM them but I really question why they recommend that because from an engineering/design standpoint it doesn’t make sense. I didn’t go geek for argumentative purposes but, like many other things in the automotive world, I sometimes question the thinking even though I understand the rational when it comes to reliability, recall issues, “stupid consumers” and overall liability. Me, you, and GM are on the same page when it comes to off the shelf octane boosters and to a certain degree the misuse of Toluene. Ironically large percentage of fuel injector cleaners and treatments, including techron (which contains xylene to boost the octane of the bottle), is petroleum distillates which helps remove deposits and sulfurs left behind from organo-metallics.

I’m making an assumption that GM issued that information as a knee jerk reaction to the TSB Below and it was easier to rule out everything including Toulene.
http://acdelcotechconnect.com/pdf/tsb/tsb_05D-105.pdf

I do want to clarify that Toluene and Xylene can me mis/overused.

[c4c5specialist]

HI there,
EXCELLENT discussion.
Thank you.
Allthebest, c4c5