Home Brew Octane Booster

[blkfordsedan]

I had a "old timer" tell me you could raise the Octane rating of a tank of Premium (91 or 92) gas by mixing it with 89 Octane "Super Unleaded" (E10). He said you just fill approx half way up with E10 (89 Octane) and then fill it up with Premium. The 10% Ethanol in the E10 becomes 5% of the total mixture (10% of 50%), the base fuel used in the E10 becomes 45% of the total mixture and the 91 Octane Premium becomes the other 50%. His logic is that the 101 Octane Ethanol in a 5% blend will increase the Octane of the total mixture above 91.

Seems to me that what you're basically doing is raising the Octane of the base fuel used in the E10. If you did end up with higher than 91 Octane, I wouldn't think it would be much. I suppose using E85 in the same mixture would net better results. I did some searching on the subject and ran across the following info on a Buick GN site. I thought it would be interesting for those running boost.

Richard Lassiter's "How to Mix Your Own Brew"

FORMULA 1
Toulene
R+M/2...114
Cost...$2.50/gal
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.

FORMULA 2
Xylene
R+M/2...117
Cost...$2.75/gal
Mixtures with 92 Octane Premium
10%...94.5 Octane
20%...97.0 Octane
30%...99.5 Octane
Notes: Similar to Toulene. 12-16 ounces will only raise octane 2-3 *points*, I.e. from 92 to 92.3. Usually mixed with Toulene and advertised as *race formula*.
FORMULA 3
Methyl-tertiary-butyl-ether (MTBE)
R+M/2...118
Cost...$3.50/gal
Mixtures with 92 Octane Premium
10%...94.6 Octane
20%...97.2 Octane
30%...99.8 Octane
Notes: Oxygenate. Very common in octane booster products. Has lower BTU content than toulene or xylene, but oxygenate effect makes the gasoline burn better and produce more energy.
FORMULA 4
Methanol or Ethanol
R+M/2...101
Cost...$0.60 - $1.75/gal
Mixtures with 92 Octane Premium
10%...94.3 Octane (Methanol)
10%...94.7 Octane (Ethanol)
20%...Not Recommended
Notes: Methanol is wood alcohol. Ethanol is grain alcohol and found in Gasohol in 10% ratios. Both alcohols are mildly corrosive and will eat gas tank linings, rubber and aluminum if used in excessive ratios. Main ingredient in "Gas Dryers", combines with water.
FORMULA 5
Isopropyl Alcohol and Tertiary Butyl Alcohol
R+M/2...101
Cost...$0.60-$1.50/gal
Mixtures with 92 Octane Premium
10%...94.5 Octane
20%...Not Recommended
30%...Not Recommended
Notes: Similar to Methanol/Ethanol. Isopropyl Alcohol is simply rubbing alcohol.
MAKE YOUR OWN OCTANE BOOST How to make your own octane booster (this is the basic formula of one of the popular octane booster products). To make eight 16 ounce bottles (128 oz = 1 gal):
100 oz of toulene for octane boost
25 oz of mineral spirits (cleaning agent)
3 oz of transmission fluid (lubricating agent)

This product is advertised as "octane booster with cleaning agent *and* lubricating agent!". Diesel fuel or kerosene can be substituted for mineral spirits and light turbine oil can be substituted for transmission fluid. Color can be added with petroleum dyes.

[Grey Vw]

Thanks. I was going to ask about this in a few months. So is the "How to Make" tried and true?

[Pu241]

Wonder how old that info is, would love to find toluene for $2.50/gal and Xylene for $2.75/gallon.
Looking at the prices again this info must pretty old!
I doubt you can get hold of MTBE other than through a chemical distributor, given the problems it has caused when it leaked from gasoline into ground water.
Pretty sure the info is correct, if not the pricing.

[festivaWES]

How about one moth ball in a tank of gas..

[Pu241]

Naphthalene (mothballs) has an octane rating of about 90.
So to raise the octane of regular 87 to even 88 octane will require 33% of the fuel to be composed of naphthalene.
Because naphthalene is a crystalline solid at room temp with a melting/sublimation point of 80 degrees C it's going to be hard to stuff that much into a tank. However, it is soluble in gasoline, to what extent I don't know.
I'm sure though that at anywhere near 33% that it will substantially change the A/F ratio, maybe to the point of being outside the ability of an EFI engine to compensate.
And a handful of mothballs in your tank is unlikely to do squat for octane or MPG.

I think this came from the days when gasoline had octane between 40 and 70, so a small amount of naphthalene could actually make a difference.
Where as now, even crappy gas should have octane rating of 87.
Except at high altitudes were you can get away with 85 or so.

[bakerga1969]

i just use marvel mystery oil and 92 octane you can feel and notice the difference.

[Pu241]

i just use marvel mystery oil and 92 octane you can feel and notice the difference.

If you do it isn't because MMO increases your octane!
Maybe keeps your injectors clean and keeps their spray pattern where they should be, chlorinated solvents will do that!

[blkfordsedan]

Naphthalene (mothballs) has an octane rating of about 90.
So to raise the octane of regular 87 to even 88 octane will require 33% of the fuel to be composed of naphthalene.

So, how does the Octane mathematics work? Is it just a simple average based on the percentage of each component?

In other words, If you had a 1/2 tank of 87 and a 1/2 tank of 91, would you end up with a full tank of 89?
What I want to know is this; The highest octane around here is 91. If my Stang has a 12Gal tank, how much E10 would I have to add to 91 Premium to get to 93? Could I even get there using E10, or would I have to use E85? I want to order a custom 4-chip tune and would like to have one of the tunes be the 93 race tune.

[blkfordsedan]

i just use marvel mystery oil and 92 octane you can feel and notice the difference.

In theory, increasing the octane rating should have no effect on performance without advancing the timing. All you need is a high enough octane to resist pre-ignition, which is determined by mechanical factors such as compression ratio & ignition advance. That being said, the other attributes of a quality Premium fuel can have some positive effects on engine performance.

[bakerga1969]

got to be better than moth balls ;to many and your car will rev real fast and then boom.

[Pu241]

So, how does the Octane mathematics work? Is it just a simple average based on the percentage of each component?

In other words, If you had a 1/2 tank of 87 and a 1/2 tank of 91, would you end up with a full tank of 89?
What I want to know is this; The highest octane around here is 91. If my Stang has a 12Gal tank, how much E10 would I have to add to 91 Premium to get to 93? Could I even get there using E10, or would I have to use E85? I want to order a custom 4-chip tune and would like to have one of the tunes be the 93 race tune.

For materials like Ethanol, toluene, isopropanol, t-butyl alcohol, Xylene it a straight out average.
For material like TEL = Tetra Ethyl Lead, and some others, only grams per gallon were required to boost octane level into the 90's or even low 100's.
Subsequently you could blend 1/2 tank of 96 and 1/2 tank of 87 and get a full tank of say 94. because TEL gave the biggest boost in octane with the addition of the first gram or so more gave you more octane but at a diminishing return.

[getnpsi]

If you have e85 in your area might as well go to summit.com and build an e85 system. youll never come out ahead mixing things.


another thing....e-10 91 octane is the same octane as 91 octane with no ethanol. Marginally less BTU but the same anti-knock index rating. They use more inferior gas when they blend them to get the same 91 rating. you dont think an oil company is going to give a drop of anything away free do you?

[CharlieZ]

got to be better than moth balls ;to many and your car will rev real fast and then boom.

Maybe the moth is the wrong choice.
According to National Geographic dot com, "The new title for world's biggest testicles (relative to body weight) goes to the tuberous bushcricket, a type of katydid, according to a new study.