1995 z32 TT
1992 z32 TT
Accent Stripe
AIV Delete
Badgeless Rear Panel
Battery Optima Red Top
Big Brakes
Boost Gauge
Boost Sensor Hose
Boost Jets
Brake Idiot Light
Brake Master Cylinder
Butterfly Throttle Body
Carbon Canister Delete
Carpet Hole Repair
Center Console Removal
Classified ad
Clutch MC and Bleed
Cone Air Filter Placement
Connectors Under Hood
Delete & Bypass
Dyno Runs
Earthing Kit
Engine Pull
EGR Delete
Front Fascia
Fuel Line Clamps
Funky Fuses
Gear Shift Knob
Hatch Lock Stuck
Hella Horns
Hood Squeak
Idle Air Adjustment
Injector Dremel
Injector Testing
Interior Hatch Trim Repair
Jacking Car
Manual Boost Controller
Molding Replacement
Nose Panel
Parking Brake
Plenum Pull
PRVR Removal and Bypass
Pressure Wash
Radiator Hard Pipe Leak
Radiator Howe
Rear Interior Trim
Robo's Rules of Z-Dom
Seat Removal
Shock Install
Spare Tire
Speedometer 180 mph
Stereo Installation
Taillights JDM
Temperature Gauge
Throttle Sticking
Vacuum Lines
When TT.net Goes Down
1987 z31 T
2004 Tacoma
2011 Tacoma
1974 Mercedes 450 SL
12 Hours of Sebring
24 Hours of Le Mans
AACA 2004 Hershey
Garage Remodel
Misc Album Pics
Misc Linked Pics
Numidia Raceway
Watkins Glen
Interesting Links
For Sale
Contact & Feedback

When I first wrote this article back in 2003, gas was less than $2 a gallon, and I was able to buy toluene for less than $9 per gallon in individual cans.  For the two gallons in the pic below, I paid $14 each, plus tax in upstate New York during August, 2005.  The price of toluene follows the price of gas. I don't expect the price to be coming back down to the $9 level any time soon.  The older this article gets, the more ridiculous the price of toluene.  However, there is a "wow" factor there that makes trying toluene worth it, IMO. 

This article is about using toluene, a solvent that can be purchased at paint and hardware stores, as a gasoline additive to raise the octane of pump fuel. 

These cans of toluene are branded by Sherwin Williams, who have their own independent paint stores.  Not all the Sherwin Williams stores carry toluene.   Yes, I am stupid for putting metal cans on my glass T-tops. 

If we assume toluene to have an octane of 114 (as defined by R + M/2), and you can get hold of some 93 octane gas, then a ten percent mix of toluene to gas will yield,

(9 gallons x 93 octane) + (1 gallon x 114 octane) / 10 gallons = 95.1 octane.

Using the same calculations, a 20 percent mix of toluene yields an octane of 97.2.  So each ten percent addition of toluene roughly adds a little over two full octane points to the mix.  A petroleum chemical engineer wrote me after reading this.  He said that toluene does not mix in a linear fashion, so these calculations are really only rough aproximations.  The exact numbers are not critical.  Running too much toluene is not inherently dangerous.  Toluene is harder to ignite than gasoline and running higher concentrations will lead to poor cold starting and eventually rough running, but the engine will not "blow up" if the toluene percentage is too high. 

The 1980's were the "turbo era" of Formula 1 racing.  Those cars ran on 84% toluene.  The engines also needed to have hot radiator air diverted to heat the fuel tanks in order to make the toluene more combustible.  I have run as much as 30 percent toluene with 94 octane gas without any problems.  I usually go with a 20 percent mix.  I have found that once I drop below ten percent, that the "seat of the pants" improvement loses its "wow" factor.

Toluene is one of the most potent octane boosters you can buy, although  it takes a significant  volume to get the job done, compared to the small bottles of mystery booster on the shelf at the auto parts stores.  There have been reports in the enthusiast's magazines of some off-the-shelf octane boosters DECREASING the octane level of the fuel, which is not desirable.  In the "Octane Olympics" article below, labels claiming to raise octane a certain number of points could often only manage a few tenths of an increase in the RON octane rating, raising the question, "What exactly is an octane point?"  I have also noticed that none of the proprietary bottles of octane boosters list their ingredients.  At least with toluene, you know what you are getting.

In theory, simply raising the octane of gasoline should not make a car run better, faster or stronger unless the engine is already experiencing problems with detonation.  The octane rating of the fuel is nothing more than its ability to resist detonation. Detonation is one of the most damaging phenomenon that can happen inside an engine.  Basically, detonation is abnormal, spontaneous combustion of the air-fuel mixture inside the cylinder due to heat and pressure.  This can lead to serious damage of the internal engine parts, literally blowing them apart. 

If the engine were optimally tuned, and not detonating, then raising the octane should not make any difference.  Yet is does, or at least I believe it does based on my "seat of the pants" dyno.  The difference is not subtle.  Also, reading the testimonials in the article below seems to indicate that there is something real, and something more than just a placebo effect occurring.  I am usually not a fan of this type of empirical evidence, but IMO the difference when running a 20% mix of toluene is too obvious to ignore. 

There are several ways that raising the octane with toluene could help a Z run stronger.   Like most cars built in the computer age, the Z uses a computer management system to control many of the engine functions.  The car's central computer, called the Engine Control Unit (ECU), can retard the timing of the engine if the octane of the fuel is too low.  The ECU can also put the car into "safety boost" which will seriously cut the power of the engine by dropping the turbos' boost pressure.  These conditions are the ECU's way of protecting the engine from detonation.  Using fuel with too low of an octane rating is one of the common causes of detonation, depending on how the engine is set-up or tuned.  Even the stock ECU is programmed to take advantage of high octane fuel, higher than the "super unleaded" pump gas some folks are lucky enough to obtain.  So raising the octane by adding toluene can unleash more of the engine's potential, even with the stock ECU. 

One of my personal theories is that with lower octane fuel, the flash point of the fuel vapor occurs over a wider time range during the compression cycle, well before any audible detonation occurs.  I'm talking milliseconds, here.  Raise the octane, and the cylinders are igniting within a narrower, more consistent time range during the compression stroke, which translates to a smoother, more powerful engine.  Naturally, this assumes that the timing of the engine is optimally set.

Another difference could be from the chemical compostion of toluene compared to the typical gasoline blend.  Toluene is denser at 0.87 g/mL compared to 0.72-0.74 g/mL for gasoline.  This implies that toluene has more energy per unit volume.  Thus, the combustion of toluene, a pure aromatic hydrocarbon containing only hydrogen and carbon atoms, should lead to more energy being liberated and more power generated. 

More energy means toluene burns hotter than gasoline.  Therefore, the exhaust gases contain more kinetic energy, which in turn means that there is more energy to spin the turbos.  In practical terms this translates to quicker spool-up and more turbo boost.  The engine can handle this since the toluene is also raising the octane which allows for a wider margin of safety in preventing detonation.      

Admittedly, these theories are mostly conjecture and probably simplistic since I am neither a chemical or mechanical engineer.  However, based on the empirical evidence of having run scores of gallons of toluene through my engine, SOMETHING noticeably different, fun, and better happens each and every time.    

An easy way to "gauge" how much toluene to mix in a Z fuel tank is to go by the reserve fuel light.  There is a little picture of a fuel pump above the fuel gauge that lights up once the needle gets below E.   Some people have never witnessed this in their Z because they don't run their tank down that low.  Other folks say running the tank down too low is not good for the fuel pump.  That is another topic that I won't go into here, other than to say I don't worry about it.  There are about five gallons left in my tank when this reserve light comes on, more than I would've guessed.  That is the amount on which I base my toluene mix. 

I believe most Z's will be very close, but since I've only checked my gas tank, I suggest others verify the amount of gas left in their tanks when the reserve light comes on.    A Z can go a lot further on E than most folks probably thought.  I don't begin to get nervous about running out of motion lotion unless I've driven more than 50 miles on reserve, longer on the highway.  There's usually no reason to run the tank down that low, but it's nice to know.    

To see how much gas in left in reserve, fill the gas tank as soon as the warning light comes on, and subtract that amount from the known, nineteen gallon capacity of the z32 gas tank.  These numbers can be rounded to the nearest gallon.  The point is to have a close guesstimation, and to not worry about two decimal places.  

I use toluene when my tank is near empty.  Once the reserve light comes on, I head straight for the gas station.  The reserve light will flicker on and off for about twenty miles before staying constantly on.  I pour in my single gallon of toluene using a long funnel (don't get it on the paint), and then I add four more gallons of gasoline.  Voila', a ten percent mix, since there was still about five gallons in reserve.  For roughly a twenty percent mix, I add another gallon of toluene.  I personally have not run higher than a thirty percent mix.  The improvement between twenty and thirty percent was not so great which led me to believe that pushing much beyond thirty percent was not worth the trouble and expense.   

Of course, one could work the toluene percentage from a near full tank, but I like to work from the empty side of the tank.  That way, I don't have to buy as much toluene at one time to experience the thrill.  Plus, in the beginning when I was first experimenting with toluene, I didn't want a full tank of "rocket fuel" in case something went wrong.  Nothing ever did.   

I've observed one slightly unusual effect.  When running higher concentrations of toluene, my idle goes up to around 1500 RPM.  Another Z owner reported the same thing to me.  Usually my idle is right on spec, at about 750 RPM.  When I push my toluene concentration higher than 20%, the idle temporarily goes up, then goes back down after the toluene runs through the engine.  I believe this is due to the ECU making adjustments for the higher octane, or possibly just from the increased energy toluene releases when burned, but I'm not really sure.

Sometimes I add two to four ounces of Marvel Mystery Oil (MMO) to each gallon of toluene, although I don't consider the MMO to be absolutely necessary.  I believe this combination of toluene and MMO to be about the best possible fuel injector cleaner money can buy, but that is strictly my own biased, non-scientific opinion.  I have read about other folks using automatic transmission fluid instead of MMO.  Another gang I know adds two-cycle motor oil.  I've had folks tell me that all the injector cleaner addtives are basically kerosene.  I don't know.   

In case it isn't obvious by now, the gasoline to which the toluene is being added should be the highest octane premium available on the street.  There's no point in raising 87 octane to 89 octane if 94 octane is available two pumps over.  Duh.

How safe is it to be around toulene?  I have some professional experience working with Material Safety Data Sheets (MSDS).  People who aren't used to reading these get scared when they read the warnings about toluene.  For this concern, I would simply say Google the MSDS sheet for gasoline, which reads much worse than toluene.  For example, gasoline contains known carcinogens, specifically benzene.  There has never been any proven link between toluene and cancer.  Bottom line, if you're not afraid to fill up your car with gas, which you will handle thousands of more times in your life, then don't be afraid of toluene.   

While all the other pages on this site are written by me, I did not see the purpose of researching and rewriting an entire article on toluene when I based 90% of what I knew about the subject on these two articles.  The content of these articles is reposted here in its entirety.  I made some minor formatting changes to make reading the articles easier.  Any editorial comments I made are bracketed and in italics.

This first article originally appeared on an Audi Forum web site.  The article appears to be  well written and researched.  The authors mention paying $2-3 per gallon for toluene when buying in bulk.  Those days are gone.       

<i.e. in this case, Audi's>

Cost...$2.50/gal <if purchased in 55 gallon drums, which is not likely for the casual user>
Mixtures with 92 Octane Premium
10%...94.2 Octane
20%...96.4 Octane
30%...98.6 Octane

Notes: Common ingredient in Octane Boosters in a can. 12-16 ounces will only raise octane 2-3 *points*, i.e. from 92 to 92.3. Often costs $3-5 for 12-16 ounces, when it can be purchased for less than $3/gal at chemical supply houses or paint stores.

Rocket fuel FAQ
Copyright © 1999, 2000 by Eliot Lim.  This paper may be freely distributed, provided it is distributed in its entirety
Last revised by Eliot Lim: February 8, 2000
Last augmented by Charles Smith: January 6, 2003


In late 1997 I became the lucky owner of 1 out of 150 1998 Porsche 993 Targa, the very last of the air cooled classics. As I drove it through the winter of 1997 and into the spring of 1998 I noticed that the engine lost some of its sweetness. Since this behavior was strongly related to ambient and engine temperature I suspected that the engine electronics were retarding its ignition timing due to insufficient fuel octane.

I started experimenting with octane boosting by first adding small doses of over the counter octane boosters and noticed immediate improvement. The engine ran smoother and quieter, was more willing to rev and had noticeably sharper throttle response. The octane shortage was confirmed by the sticker on the filler cap that stated that 93 octane fuel was needed. Since the highest octane rated fuel that was commonly available in Washington state is 92, I decided to investigate long term cost effective octane boosting so that I could fully enjoy the performance that this car offered.

My other car at the time, a 1990 Audi V8 quattro had an even more dramatic response to octane boosting. I managed to convince a few good friends to try it and the reaction was overwhelmingly positive. When I attempted a broader based dissemination of this exciting find, I was greeted largely by broad unyielding skepticism and plenty of FUD (fear, uncertainty, doubt) regarding toxicity, safety and engine damage. There arose a need to more clearly explain the details of octane boosting, hence giving rise to this article.

Q: Will my car benefit from octane boosting?

A: Consumer organizations have effectively emphasized the larger markups that oil companies charge for high octane gasoline, implying that for most vehicles higher octane fuel is a complete waste of money. It has been quite a long time since the consumer alert was issued. Since then engine technology has evolved greatly, while people's perceptions generally have not.

Modern vehicles now use computerized engine management systems that can react to engine knock and retard ignition timing if low octane fuel is being used. Consequently cars are now being manufactured with very high compression ratios that appear to give good fuel economy and at the same time good performance. This combination does assume that fuel of adequate octane is being used.

Q: Why bother to boost octane at all since my engine can run just fine on lower octane fuel?

A: For a high compression engine to run on low octane fuel, the engine management system will need to retard the ignition timing to prevent preignition or pinging. Retarding the ignition timing means that the firing of the spark plug is delayed until a later moment in the compression stroke. It does not take much to see that a later onset of combustion means that the combustion is less complete, which in turn mean less power and poorer fuel economy. It is possible that the casual driver will still come out ahead in terms of saving money by using low octane fuel, but the retarded ignition advance also means a rougher running engine and a much duller throttle response. Thus octane boosting is not necessarily of interest to all motorists but rather the enthusiasts.

For turbocharged or supercharged engines, insufficient octane will also lead the engine management system to curtail the amount of boost which in turn defeats the purpose of these engines.

Q: How did you discover using toluene?

A: Someone came across a web page that described various DIY home brew octane booster formulas. One of which used toluene as its main ingredient. As a Formula 1 racing fan of many years, I recalled that toluene was used extensively in the turbo era in the 1980s by all the Formula 1 teams. The 1.5 liter turbocharged engines ran as much as 5 bars of boost (73 psi) in qualifying and 4 bars (59 psi) in the actual race. Power output exceeded 1500 BHP, which translates into 1000 BHP/liter, an astronomical figure.

A motorsports journalist, Ian Bamsey, was able to obtain Honda's cooperation for his book "McLaren Honda Turbo, a Technical Appraisal". The book documents the key role that the toluene fuel played in allowing these tiny engines to run so much turbo boost without detonation. The term "rocket fuel" originated from the Formula 1 fraternity as an affectionate nickname to describe its devastating potency. Thus I concluded that I should focus my research on using toluene for my octane boosting project.

Individuals with good long term memory will recall that when unleaded gasoline was first introduced, only low octane grades were available. While it is not entirely clear that high octane super unleaded gas came about as a result of the advances in fuel technology in Formula 1, there is every reason to suspect that this is indeed the case, since many of the major oil companies were involved in the escalating race to develop increasingly potent racing fuel during this era.

Q: Why do you think toluene is better than other types of octane boosters?

A: Several reasons:

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.

Chevron's web site also describes the problems of ethanol being used in gasoline.

MTBE was heavily touted as a clean additive several years ago, and became a key ingredient in reformulated gasoline that is sold in California. But recently new studies arose that showed that MTBE was far more toxic than previously imagined. Organizations such as oxybusters have formed around the country to eliminate the use of MTBE in gasoline and several states, including California have passed new laws to eventually outlaw MTBE.

Q: How much toluene should I use per tank of gas?

A: 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.

Q: Will toluene damage my engine or other parts of my car?

A: A 5 or 10% increase in the aromatic content of gas will most likely be well within the refining specifications of gasoline defined by ASTM D4814, which specify an aromatic content of between 20% and 45%. What this means is that if the 92 octane gas that you started off with had an aromatic content of say 30% and you increased it by 10% to 40% you would still be left with a mix that meets the industry definition of gasoline. So the above question would amount to: "Will gasoline damage my engine or other parts of my car?"

Even in the unlikely event that the 92 octane gas has a aromatic content of 45% the resulting mix would still be within the bounds of gasoline sold in other countries.

Q: Isn't toluene an extremely toxic substance?

A: The common perception of toluene's toxicity far exceeds reality. Fortunately there is an ample body of information available that specifically addresses this question. Toluene is more toxic than gasoline but it is certainly not agent orange or cyanide. See the Agency for Toxic Substances link below in the reference section.

US Environmental Protection Agency Chemical Summary

US Agency for Toxic Substances and Disease Registry (ATSDR)

National priority list of toxic substances
Note that the ATSDR also rates gasoline as a hazardous substance.

Mobil's spec sheet for toluene even goes as far as saying that "Based on available toxicological information, it has been determined that this product poses no significant health risk when used and handled properly."

Q: Isn't toluene an active ingredient of TNT (trinitrotoluene) and is thus deadly?

A: In the same way that cotton wool is the base ingredient of nitrocellulose (guncotton) which in turn is the main ingredient in modern smokeless gunpowder. Using this reasoning one could conclude that cotton wool is a deadly substance. This question reflects a poor understanding of basic chemistry but unfortunately it has been asked often enough.

Q: How much does toluene cost, and where can I buy some?

A: $10/gallon in a one gallon can at a hardware store, about $6/gallon in a 5 gallon can from a chemical supply or paint store, or $3/gallon in a 55 gallon drum from a chemical supply warehouse.

A2: Experience of Charlie Smith in 2002. Sherwin Williams paint stores have it for $5.00 in a gallon can. They can order it in a 5 gallon can at $4.00 / gallon. They can order 55 gallon drums for about the same cost per gallon, but you have to have a dock unloading facility to get the drum(s) off of the delivery truck.

Q: Can I just dump in 100% toluene into the tank like the F1 racers? vroom vroom vroom

A: First of all, the F1 racers did not use 100% toluene, but 84%. The other 16% in their brew is n-heptane, which has an octane rating of zero. The reason for this strange combination is because the F1 rocket fuel was limited to the rules to being of 102 RON octane. The n-heptane is "filler" to make the fuel comply with the rules.

Because toluene is such an effective anti knock fuel it also means that it is more difficult to ignite at low temperatures. The Formula 1 cars that ran on 84% toluene needed to have hot radiator air diverted to heat its fuel tank to 70C to assist its vaporization. Thus too strong a concentration of toluene will lead to poor cold start and running characteristics. I recommend that the concentration of toluene used to not exceed what the engine is capable of utilizing. Experiment with small increases in concentration until you can no longer detect an improvement.

Q: Why not simply use racing gasoline or aviation fuel?

A1: Most types of aviation fuel have very high lead content, which would rule out cars equipped with catalytic converters. Most piston engined aircraft burn leaded fuel. Also aviation fuel has a very different hydrocarbon mix to optimize volatility properties at high altitude.

A2: Racing gasoline could be a much more convenient way to run high octane fuel compared to having to constantly mix in toluene with each fill up. There are, however a few caveats:

You don't know for sure if you are really getting what is being advertised. You should find out if the fuel inspectors verify the actual octane of the racing gasoline in addition to ordinary gasoline. If you paid $3/gallon and only got 94 or 95 octane instead of 100 octane you may conclude erroneously that your car does not benefit from octane boosting.

You don't know what octane boosters are used in the racing gasoline. The worst case scenario is buying leaded racing gasoline without knowing it. Unleaded racing gasoline may still contain damaging octane boosters like MMT or methanol. A very high alcohol content will lead to fuel line erosion, accelerated fuel pump wear, very poor fuel economy and possibly lower performance, as alcohols have a less impressive MON rating than aromatics.

It takes smaller quantities of toluene to achieve the same octane boost compared to 100 octane racing gas. I have not seen unleaded racing gas for sale that exceeds the octane rating of toluene.

Since toluene is not officially sold as a fuel, gas taxes do not apply. Also racing gasoline tend to have higher markups being of interest to the performance minded enthusiast and thus is very likely to be more expensive to buy and use long term than toluene, which is typically used in more mundane applications like paint thinner.

Q: Ok, what is the catch?

A: It should be mentioned that in the US, efforts are underway to reduce the aromatic content of gasolines in general as a higher aromatic content leads to higher benzene emissions. Benzene is an extremely toxic substance. However it should also be noted that the proportions that is being discussed in this FAQ is relatively small and in the grand scheme of things is probably insignificant. Moreover, the industrial standard for defining gasoline composition allows plenty of leeway in aromatic content and the proportions present in US gas is already lower than most other countries. I therefore feel that the information provided here is useful to a performance minded car enthusiast while not being significantly detrimental to the environment.

Q: What safety measures can you recommend in handling toluene?

A: The following is a good reference guide: <answer is missing from the original post>

Q: Do you have testimonies of others who have tried this?

A: Some samples of feedback is reprinted with the names removed below. You may contact me if you wish to contact the respondents directly.


Since I didn't have any reference point for how much to use, I dumped about a half gallon of this mix into a mostly empty tank (the GT has a 16 gallon tank) and then filled up with Chevron 92 octane.  I didn't get to drive the car until PIR the next morning, (my GF doesn't like the 200; it's too big) but the report was that there was no change for a mile or so, and then all of a sudden, the engine seemed to smooth out and became quite eager to rev and run.  Well, by that calculation, I only managed to bump the octane to just shy of 93, but it seemed to make a big difference. I ran the car hard all day, (for reference, it's got an '87 MC turbo motor, K26, 12psi boost, and currently no intercooler) and even at 12 pounds of boost, I never once felt the ECU backing the timing off. Granted, the ambient temps never got above 50, and my water and oil temps were rock solid. (Oil just pushing above 100C)

The only cars that I had to get out of the way for was an Integra Type R and a couple of race-prepped P-cars. I even managed to lap the NSX once! It was a really good day!


Okay, kids, gather round. This is important: we spend lots of money for our car, lot of money modifying and taking care of it, lots of effort and pride in owning it. So if someone comes along and proposes to give you something that would increase your enjoyment in driving by exponential measures and it would only cost you two or three bucks per tank of gas, would you be suspicious like the 100MPG carburetors? Would you listen long enough to real-life testimonies to consider this improvement for yourself?

Well, this is the case for Toluene and what it can do for your V8Q if you been using anything less than 92+ octane. Get some.Try it. No harm, no risk. Use about 24-32 ounces per 1/2 to full tank. You will not look debonair. You will have to suspend your "cool" look. You may want to try this alone. YOU WILL HAVE THE SHITTEST, MOST PLASTER, GRIN ON YOUR FACE YOU HAVE EVER HAD! It won't come off. You'll tell the kids, daddy has his own "transformer". It will be like a new car...no, better than new!

I took my family out to dinner tonight and could hardly keep from dropping it into manual and showing off like some teenager (I don't think my 17 year old daughter was impressed). I wanna see some posts here with personal experiences by you guys using this stuff - I wanna know that my car is normal and hasn't been deprived ever since I've owned it.


I did the Rocket Fuel thing tonight on my Extremely Modified 5KCSTQ that runs 24 PSI of boost... And I can tell you not only does my ears and my butt say that the Rocket fuel is doing it's job but My ECU Data logger that gives me the timing value for all 5 cyls says it's working too.

Before Rocket Fuel I was running full retard (14 Deg of timing) on boost and would still on occasion get some knock, now I'm getting timing numbers around 22 Deg's with ZERO knock ever. I'm running 2 Gallons of Toluene 7oz of ATF and 17.5 gals of 93 oct gas for a net octane of 95.15. I'm next going to try 3 Gallons of Toluene (96.23 Octane) to see what timing numbers I get.


After being convinced that my car was running below it potential - Owners manual recommends octane rating between 95 and 99, although it_will_run on octane as low as 91 - I stopped by Sherwin Williams and picked up a gallon. It was on sale for $5.85! Anyway, head to the chevron and pour a half gallon into the tank before pumping in the premium. The car took 16 gallons so there was still 4 gallons in the tank. I take off....nothing (obviously burning the fuel still in the lines). About 10 miles later, HOLY SH*****T!!!!!!!!!! It really does everything advertised by the list. It is so much more responsive from a stop and low speed, it really is impressive. I would agree with the sentiment that it feels like a totally different car.
For the non believers, you really should try to get some higher octane fuel in your tank, whether through the use of Toluene or not. The owners manual recommends 95 to 99 octane** for optimal performance. With the half gallon of Toluene I added to the 92 octane, I was only running at approximately 92.6 octane and the difference was simply amazing!

If you haven't tried it, do yourself a favor and give it a whirl - I swear you'll be impressed.

(**note: this person confused RON octane mentioned in the owners manual with R+M/2 octane that is sold in the pump. 95-99 RON is roughly equivalent to 91-94 R+M/2)


After trying rocket fuel for two weeks, I can only say I love it.
The first tank, however, was a disappointment. I think I did not add enough of rocket fuel for the first tank. So I added a little more for my second tank, it ran better but not too much improvement. Then on my 3rd tank, what a difference, the car feels like a "Rocket" now, even though it is an "Auto". I always feel there is more power available for me.

I think for my 1st and 2nd tank, I did not have enough rocket fuel in it, even though I added one gallon per tank. Then, on my 3rd tank, I had enough because of the left overs from my 1st and 2nd tank. (I fill up my tank at about the 1/4 mark). Now I only have about 2 gallons of rocket fuel left, I better get more now!!! :-)
Reference materials:

1. Gasoline FAQ

2. McLaren Honda Turbo - a technical appraisal
Ian Bamsey
ISBN 0-85429-840-1, published 1990

3. Chevron's excellent Motor Gasolines Technical Review

4. Agency for Toxic Substances FAQ on Toluene
    In summary:
    Use in a well ventilated area, don't drink even a little of it, and
    report spills of more than 1000 pounds to the National Response Center

5. Toxic Chemicals in your Environment (Australia) FAQ on Toluene
    In summary:
    this "Total Environment Center" likes a totally chemical free environment,
    and even at that they can't find fault about much more than acute exposure
    cases, and they also say not to drink any of it.

6. Exxon Chemical Americas - Toluene, Technical Material Safety Data Sheet

7. Recicladora Temarry de Mexico - Recycling Processor
    Recycling information and Material Safety Data Sheets on numerous chemicals including Toluene.    

Top of Audi page
Mail to Charlie

<end of "Rocket Fuel" article>

This next article about different octane boosters was copied from automotiveforums.com, and was supposedly retyped from an article orginally published in Fast Fours Magazine Nov/Dec 1999.  Toluene finished second out of thirteen contenders.  Here is the article reposted in its entirety.

Octane boosters are popular in the performance scene because they often regain power last through detonation. Sold for around $25 in a handy bottle, they’re a convenient fuel additive and horsepower helper. But with so much brands on the market, you may be fooled into thinking they’re all as effective as each other. Which they’re not! Differing chemical compounds, additives and even volumes, mixed in with a good percentage of advertising, ‘independent" testing and testimonials all conspire to confuse the consumer away from the single most important point: does it improve the octane rating?

Let’s see what’s worth it in octane boosters.


The boys at "The Macquarie Library" describe detonation as: "Excessively rapid burning of the fuel mixture, often caused by auto-ignition due to excessive temperatures in the combustion chamber, incorrect ignition timing, lean mixtures, too high a compression ratio or unsuitable fuel," – as in too-low an octane rating.

Heard as a faint, metallic rattle, detonation is accompanied by a loss of power and can cause serious damage to piston crowns.

The significance of detonation is such that many companies produce fuel additives designed to increase the inherent octane rating of a given fuel. The proliferation of octane boosters has in part come about in recent times thanks to low quality Australian fuels. White or "Super" leaded fuel has been reduced from 98 to 95-96 octane, Premium Unleaded has also dropped to a minimum of 95 octane. And this presents a problem for high-performance cars designed to run on higher octane European or 100 octane Japanese fuel. Japanese import performance cars, Subaru’s STI WRX for example, runs an ECU program for 100 octane, but sometimes detonates on our Australian PULP.

All engines are different though and with Honda’s S2000 2.0-litre engine running a high 11.0:1 compression ratio, it relies on advanced engine management as much as quality fuel. But it can sustain its power on PULP. And of course any turbo owner who has experimented with boost will know if you run too much, it will detonate, so improving the octane is vital for maximum performance.

We must state that unless an engine is detonation through low RON fuel, octane boosters have little use. However, in a turbo or high compression application, the inclusion of a better grade of fuel allows the engine management system to optimize ignition timing and fueling.


For this test we tracked down nine different makes and models of octane boosters, two fuel "additive," a straight race fuel and a drum of Toluene. Where there were several different "levels" of octane boosters in the one brand, we chose the strongest version.

The biggest claims the bottles have is the amount of "points" they claim to increase. This is ambiguous as a "point" can relate to either 1.0 RON (Research Octane Number) octane points, or 0.1RON octane points.

The list of entrants in our octane Olympics included:

  • STP Octane Booster
  • Wynns Octane 10+ Power Booster
  • Amsoil Series 2000 Octane Boost
  • Super 104+ Octane Booster
  • VP C5 Fuel Additive
  • ELF HTX 330 Racing Fuel Stabilizer
  • Nulon Pro Strength Octane Booster
  • PowerFuel Super Street Nitro Based
  • PowerFuel Max Race Nitro Based
  • NF Octane Booster Racing Formula
  • NOS Octane Booster Racing Formula
  • Toluene
  • VP Motorsport 103 Unleaded Racing Fuel 


To conduct these tests we contracted independent laboratory Intertek Testing Services, who would test our products on a knock engine.

We had to also find a base fuel to add our boosters to so we went to the closest public petrol station, a Shell on the outward-bound side of the Westgate Bridge in Melbourne.

Being a performance-based test, we chose premium unleaded fuel as this represents the most common high performance fuel (ie: if you start with regular unleaded, you’re wasting money!). We should add that "some" boosters would have improved the octane rating of regular unleaded proportionately more than our tests with PULP.

With a RON rating at a minimum of 95, we first established the exact octane of the PULP. The biggest surprise was our randomly select Shell resulted in a quite high 96-8 RON.

We precisely measured and mixed each additive to the PULP, according to each manufacturer’s recommendations and specs and poured each into the knock engine's tank. The compression ratio was then slowly increased until it started to knock, gaining a threshold of detonation and subsequently a maximum RON rating.

Of less importance but still worth mentioning is the design of the bottles: since most people will be pouring it straight into a tank, the design of a bottle is important to prevent any spillage on paintwork causing damage.

So let’s look at the results!



Octane points

It’s very easy to confuse octane ratings as there are a number of separate international standards. MON (Motor Octane Number) is the number derived from a fuel when it’s applied to a test engine run at 3000rpm rather than 600rpm and higher inlet temps and ignition advance. The Australian importer of 104+, Andrew Holdsworth, suggested MON is seen as a more real-world test.

Though none of the fuel companies promote the MON figure which is normally between 7 and 10 numbers less than RON (Research Octane Number).

Intertek’s Graeme Marks believes RON provides the general public with an idea of which additive works more effectively. And being the most commonly-used reference, we’ve used RON for all our tests.


PowerFuel Super Street Nitro Based

946ml treats 35 litres RRP: $35

Right from the start, we were told PowerFuel’s additives weren’t necessarily octane boosters, but horsepower helpers. We kept this in mind when testing both the products, but of the two only the Super Street claimed it was specifically designed to increase the octane rating of PULP. With a 20-percent nitro mix, Super Street Nitro-Based still improved octane ever so slightly (0.2RON) but the real test for these two would come on the dyno runs.



PowerFuel MaxRace Nitro Based

946ml treats 35 litres RRP: $45

Containing another 15 percent more nitromethane than the SuperStreet formula, MaxRace doesn’t claim to increase octane, but the verbal recommendation was the same, ie: its main characteristic is to boost horsepower, not octane. For a fair comparison of these two additives, you need to look at the power they produce. As for octane, it proved very similar toe the SuperStreet formula bumping up octane ever so slightly.



STP Octane Booster

350ml treats 57 litres RRP: $10.95

One of the cheapest of the group, the STP was also one of the hardest to find. Auto stores either didn’t stock it, or had simply run out! Claiming to increase the octane 2-5 points, in a well-designed-for-pouring bottle, the STP – used in the ratio determined by the label - improved the octane marginally by just over half a point. A little disappointing unless you interpret STP’s claim actually meant 0.2-0.5 points. Then it’s a good result!



Wynns Octane 10+ Power Booster

325ml treats 60 litres RRP: $10

The Wynns was the cheapest of the lot and claimed an increase between two and five points, again not actually listing what a "point" related to. Strangely though the 10+ could indicate 1 RON and if this is the case going by our tests it almost lived up to its name. It didn’t quite live up to its claims however, increasing the octane rating by 0.8 RON.



Super 104+ Octane Boost

473ml treats 83 litres RRP: $25.95

The acknowledged winner of all previous testing in this country, Super 104+’s bottle stated we should expect an increase between four and seven point. With a new formula introduced about 12 months ago, identified by an "Eagle" logo on the back of the bottle, the Super 104+ seems to have lost its edge with a marginal gain of just less than 1.0 RON.



VP Racing C5

355ml treats 75 litres RRP: $19.95

VP has a strong reputation with fuels and its high octane formulas are very popular (VP?) with drag racers. VP Racing’s C5 Fuel Additive lacked any indication of contents nor claims, but the C5 additive still provided a reasonable increase of 1.3 RON.



NOS Octane Booster Racing Formula

355ml treats 60 litres RRP: $28

NOS, a relatively new octane booster, comes in "1/10th" scale bottles designed to emulate the actual nitrous bottles of its successful NOS systems. The Racing Formula is the strongest of three concentrates and containing Hydrotreated Aliphatics and Methylcyclopentadienyl Manganese Tricarbonyl (try saying that 10 times in a row), it contains a lead replacement which NOS claims increases the octane rating by as much as seven points. Obviously not recommended for street use, it also included with a handy pouring spout. In testing, it proved a good result improving the octane rating by almost 2 RON.

OCTANE IMPROVEMENT: 98.6 (+1.8 RON) as much as 7 points


ELF 330 Fuel Stabilizer

1000ml treats 50 litres RRP: $45

"If you spill it on your paintwork, don’t rub it off – rinse it with water" were our works of warning. We were also told to "pre-mix" the ELF before adding it in a fuel tank (which with this test we were doing anyway) as the ELF has a tendency to settle to the bottom of fuel if it’s either not mixed properly or left to sit. This was made somewhat more difficult by the design of the bottle, which tends to drip when pouring. With some nasty stuff known as Aniline, the ELF doesn’t claim any numbers, and provided a decent 1.8 RON point improvement.



Amsoil Series 2000 Octane Boost

354ml treats 57 litres RRP: $23

Recommended for off-road and racing use, the Amsoil Series 2000 claimed to increase the octane rating by up to seven points. It came up a little short, but still proved surprisingly good with a full 2.0 RON improvement. And good enough for the bronze medal in our Octane Booster Olympics.



Toluene (Toluol)

20 litres treats 100 litres RRP: $48

Since toluene (pronounced toll-you-een – also known as methyl benzine) isn’t a commercially advertised octane booster, we were unsure of exactly what ratio to mix the clear Toluene to the fuel, with recommendations between 10 and 30 percent. From personal experience, we have seen high percentages increase octane even further, though 30 percent is considered the maximum. Available only from various fuel distributors (it is a special order through services stations), under advice we ran a 20 percent mix (quite a lot more than the others) and saw an impressive improvement of 2.5 RON, for the silver medal.



NF Octane Booster Racing Formula

250 ml treats 80 litres RRP: $29.95

Time for an Aussie-made product. From Perth, the NF Octane Booster Racing Formula was the smallest bottle in the field, but looking at the mixing ratio, also the strongest NF relies on an incredibly small dose – a mere 3 percent! Claiming to increase octane as much as 6.0 RON, NF took the gold medal in a surprising tie. If it were a split decision based on concentration though, it would be the clear winner.



Nulon Pro Strength Octane Booster

500 ml treats 60 litres RRP: $20.95

Note: Also available in four-litre container for $110

The Australian-made Nulon Pro Strength Octane Booster is the top of the range Nulon fuel product, claiming to boost octane "up to seven number". The Pro Strength gained a test-winning, gold-medal-gaining and Nf-equalling 2.8 RON increase. And at $21, it’s good value too!


VP Motorsport 103 fuel

Used straight fuel (20-litre minimum) RRP: $70

Purely for interest, we decided to also test a straight racing fuel. While there are a number available (such as ELF) for no particular reason we chose VP. The highest octane VP fuel which was still totally street-legal was the Motorsport 103. Working out at $3.50 per litre and "designed for maximum power and throttle response", the VP was very impressive with an octane rating of 107RON – more than 10RON points more than PULP. Obviously more expensive than the boosters, if octane is problem, racing fuel like VP may be the answer.


As the name suggests, a knock engine is designed to test the detonation or anti-knock rating of fuels and fuel additives. It’s a slow revving engine capable of running most fossil fuels through an adjustable compression ratio. As the comp ratio increases, it accurately measures the intensity of the knock and determines the fuel’s octane rating.

The world standard is a one-cylinder two-valve four-stroke engine with exposed valve gear. Archaic in appearance, a carby is fed from any one of three fuel bowls to allow three different fuels to be run back to back. The mixture is actually controlled via gravity feed and by raising or lowering the float level of each bowl!

Run under load via a belt-drive linking the flywheel and load system, it ensures a real world situation and ensuring minimal variation between tests, oil temperature, intake air density and air temperature are all monitored and controlled.

The engine is somewhat agricultural, however its unique ability to vary the compression ratio while running between 5.0:1 and 15.0:1 is quite amazing. The operator simply winds a handle and the entire head and cylinder assembly moves up and down relative to the crankshaft.

A knock sensor measures both the frequency and intensity of the ping (as displayed on a knock metre). Figures are then cross-referenced on a chart using the information provided by the knock meter, plus the height of the head and barrel.

Finally, knock intensity is figured in and the fuel’s octane rating determined.

Taking two hours to warm, this $200,000 engine is super robust and rarely needs rebuilding. Individual tests can then proceed at approximately $120 per test sample.

Being subjected to so much detonation, you can only imagine how much maintenance an engine of this nature must need. Interestingly, this isn’t the case as the piston and rod assembly are rejects from a monstrous ship engine (just kidding)! They’re frigging huge with the incredibly thick piston crown contributing to a combined gudgeon pin and piston weight of 1794 grams! Likewise, the rod weighs an astonishing 1929 grams. The bottom line is these engines which have replacement value of over $200,000 and almost never require rebuilding.


Ultimately, the role of an octane booster, is to regain horsepower lost through detonation or retarded ignition timing due to detonation. But two of our products, the nitro additives, weren’t specifically designed to increase octane. Instead, they contain a mix of nitromethane (the petrol Top Fuellers run) in a "percentage" concentrate. Power Fuel’s Super Street and Max Race additives has 20 percent and 35 percent nitro respectively, and the Australian importer specifically claimed they would increase power, not necessarily octane.

So, we took those two products, and the two best-performing octane boosters to MRT Performance for some Dyno Dynamics dyno testing. Interestingly, we were going to use MRT’s rally Civic, which normally runs on avgas. On PULP – even with the booster – it was pinging too much, so a Jap-spec EF Honda Civic was used with a 1.6-litre VTEC and about 10.0:1 comp ratio.

The graphs tell the story though, and to be fair to the products, with variables such as heat soak, the results weren’t as conclusive as could be gained from an engine dyno. But that is not to say the products don’t work. As our test prove, they do, but it’s not as easily measured on a chassis dyno. Plus the Civic had no detonation problems on PULP, further hampering the "apparent" effectiveness of the boosters.

With changes too small to accurately measure, we would suggest if your engine is sensitive to octane, a booster is for you. If not, try the nitro or racing fuels.


Both the Nulon Pro Strength and the NF Racing Formula rated the best octane boosters in our test. And considering that less NF was needed than Nulon, it evens out a little with a slightly higher cost. Still, both proved extremely effective at increasing octane, even outranking Toluene, which needs much higher levels of concentration. The VP Motorsport 103 fuel was an interesting exercise, and if a little more effort (ie: buying it from the selected outlets) is worth the octane, it’s a good representative of what to expect from straight racing fuel. As for the nitro additives, if you’re not experiencing any type of detonation, they’re definitely worth a try. So whether you detonate or not, we’ve found a fuel additive for you!

Material courtesy of Fast Fours Magazine Nov/Dec 1999. 

Content © 2000-2003 AutomotiveForums.comvBulletin v3.0.0 Beta 5, Copyright ©2000-2004, Jelsoft Enterprises Ltd.