Nomad78SA

I was going through some web sites the other night and got reading about some formulas on making your own octane booster and whay quanities to mix it with your fuel depending on how many points you want to raise it. I would like to read some more on it or hear from some corvette owners on their brew.
Here is the post I was reading... with the cost of boosters for a pint and you can make a gallon of it for about 2-3 dollars seems like it deserves a look
http://www.vtr.org/maintain/gasoline-octane.html
Neil in Tenn


[Modified by Nomad78SA, 10:33 AM 11/24/2001]

Jon69L46

Well...i don't mix up my own brew, but I do buy 110 octane leaded and mix
1 1/2 gals into about 8 gals of 91 octane +/-. Works well, allows me to be a little more agressive on timing and such without ping at WOT. Have been doing this about a year and I am averaging about 15.00 a month.




[Modified by Jon69L46, 9:10 AM 11/24/2001]

Chuck Harmon

Neil,

I saw this site last year. Unfortunately, Toluene and Xylene now cost more than $4 per gallon. About the same as 110 race gas in bulk.

Chuck

nastee383

I make my own using that very formula except I use Xylene instead of toulene. I only use it when I'm squeezing at the track though. Been doing it for about a year with no apparent adverse effects.

Chuck Harmon

Nastee,

How do you pay for the stuff and in what quantity?

Chuck

nastee383

I buy the xylene (gal.) from Home Depot, mineral spirits (gal.) at Walmart and the trans fluid (qt.) anywhere. I make a gallon at a time and put it in 20oz. plastic water or soft drink bottles. Cost less than $10 a gallon (and there's still some ingredients left over) and it lasts me one racing season. I got tired of paying $6 for 16 oz of 104 Octane Boost.

Chuck Harmon

Nastee,

You are absolutely right that it is cheaper buying from Home Depot than 104+; but, race gas is about the same octane for ~$4 per gallon, not ~$10. This was my point on the published recipe showing Toluene at only $2.50 per gallon - if only this was true! Might as well talk about 100+ octane that was only 39.9 cents per gallon while I was growing up. (Yes, it is debatable if I ever will grow up)

Chuck

nastee383

Thats probably a valid point but a gallon (or two) of race gas ($5 here) will last me one trip to the track. Once its in there its in there. A gallon of homemade brew lasts 6 trips, one 20 oz. bottle per trip. Thus $30-$60 for race gas vs $6-$10 for my brew. I'm a BROKE racer on a budget!!! :D

Chuck Harmon

Nastee,

A pint of race gas added to your tank will increase your octane to about the same level as adding a pint of the more expensive Toluene or Xylene.

Chuck

Nomad78SA

Thanks Jon and Nastee for the comments. I figure the motor I built is on the verge of needing some extra kick to get the performance I really want

chuck,
what is buying race gas in bulk,ie what quanity are we talking about. Where does on purchase race gas at?
I will have to go out and see what the items cost here in Tenn
Neil in Tenn


[Modified by Nomad78SA, 10:49 PM 11/24/2001]

trw

Chuck

Are you saying, adding a pint of 104 race gas will increase the whole tank?

I thought we talking about raising the tank to 104 or there abouts.

Just my opinion

Terry

Chuck Harmon

When you mix fuels of different octanes such as Toluene, Xylene, and 110 race gas the new octane for the blend is the average of the ingredients. i.e. adding 1 gallon of 110 race gas to 10 gallons of 90 octane will make 92 octane. When you buy the middle grade gas at the pump, they are mixing the premium fuel with the base (regular) grade. If Xylene has an octane of about 116 and race gas about 109, it would take a little more race gas to equal the same blended octane rating as adding Xylene. But, additives other than race gas can bring about other problems that may make race gas a far better choice for a better mixture.

Chuck


[Modified by Chuck Harmon, 10:01 PM 11/24/2001]

BubbaJJ

Isn't av'gas only 2.50 a gallon? I'm not sure what the octane is though.

Chuck Harmon

It's been awhile since I've bought Av-Gas. The 100LL (low lead) is about 100 octane. A great deal of money is saved not having the road tax. I wouldn't be surprised if it is now around $2.50 per gallon in parts of the country.

Chuck

Hib Halverson

I recently researched and wrote a fairly lengthy magazine article on gasoline for street high-performance and racing engines. The story will be published in the near future by Hemmings Rods and Performance magazine. It's not possible to reproduce the story here, but several issues discussed in the magazine piece apply to this discussion.

Blending your own race gas using commercially available products such as xylene or toluene is expensive and questionable in its benefit. For those "DIY blending engineers" using xylene, know that there are three types (or "isomers") of xylene. Commercially-available xylene rarely will be identified as to its isomer because, since most commercially-available xylene is not used for octane boosting, there's no need to differentiate. Laboratory-grade xylene may be identified as to its isomer but, if you think commercial-grade xylene is expensive; go price the laboratory stuff. The problem comes when using xylene as an antidetonant. Only two of the three xylene types have an octane higher than pump gas. If you unknowingly use the third type you may lower the octane of the resulting brew rather than raise it.

Brewing your own race gas with additives can be dangerous. Handle the chemicals carefully. It goes without saying to avoid working with them near open flames or in confined areas lacking ventilation. Also, watch out for sources of static discharge. I recommend rubber gloves and even a respirator if you're not sure of ventilation.

Know that while toluene and some varieties of xylene will increase the octane of a pump gas to which they are added, when those products are mixed in proportions high enough to be effective, burn time of the fuel is always lengthened. This means a fair amount of the fuel is burning in the exhaust after the exhaust valve closes. With home-brewed "race gas" made from pump gas spiked with xylene or toluene you may see an octane increase but you will probably also see a power loss and a decrease in throttle response when compared to a "conventional" mix of pump gas and racing gasoline of the same octane.

The economics of homebrew race gas vs. mixes of pump gas and racing gasoline are never favorable. For a given octane, mixes of pump gas and racing gasoline are always less expensive. In addition mixes of pump and racing gase will increase power output as well as increasing octane.

This is also true of mixes of pump gas and canned "octane booster" products vs. mixes of pump gas and racing gasoline.

On canned octane boosters: the only ones that show a *practical* improvement in octane of the gasoline to which they are added are those that use the chemical "MMT" as the active ingredient. The problems with MMT boosters are 1) the poor economics 2) the reddish deposits left by MMT itself and 3) MMT, in long-term use, damages catalytic converters.

Lastly, if you still want to use a canned octane booster rather than mixing pump and racing gas, avoid using MMT boosters at concentrations higher than recommended by their manufacturers. High concentrations of MMT will cause hard-metallic deposits to form in the combustion chambers and cylinder walls. These metallic deposits will cause rapid engine wear. Generally, if you insist on using an MMT booster, I wouldn't expect more than about 94.5 oct when the best MMT boosters are mixed according to mfg. instructions with 91 oct pump gas. This is because virtually all canned octane boosters are more effective with low octane gas than with high octane, "premium" unleaded.

MikeC

Yeah what he said!

But seriously aren't toluene and xylene very toxic substances?

Jon69L46

LMAO.......that's why I buy the bulk 110 and mix a gallon or two. It's a little bit of a pain. But with 11:0-1 and 36 degrees timing, I live with it for now.

Hib Halverson

Well, "toxic" is sometimes a relative term but, yes, both are toxic with toluene perhaps the more toxic of the two, however, both can be safely handled using precautions everyone should use when working with highly flammable solvents.


[Modified by Hib Halverson, 12:52 PM 11/25/2001]

Nomad78SA

I went down today to the local auto parts store and asked where to but Race gas at. They tols me at Scoggin's a race supplier for $4.00 a gallon and another local shop. They said I could get AV fuel here at the air strip for about 2.50 a gallon and thought it was 120 octane.
Now in a 20 gallon tank how much race or AV fuel would I mix? What would be a good octane level to try to obtain and not do damage to the motor
I have a 68 GTO 400 4 speed and a modified 388CI in my vette to use it in.
Neil in Tenn



[Modified by Nomad78SA, 4:20 PM 11/25/2001]

Hib Halverson

There are two aviation gasolines (AVGAS) 100 and 100LL that can be used in an automotive engine. For the purpose of automotive use, the octane of both is about 100. AVGAS100, has 4 grams per gallon of tetraethyl lead and AVGAS100LL has 2 grams. AVGAS 100LL has a higher percentage of aromatic hydrocarbons than does AVGAS 100 and that's why it has the same high octane but half the TEL.

At most airports, all you will find is AVGAS 100LL.

It is against Federal law to dispense aviation gasoline into anything but an airplane fuel tank, however, some airport FBOs that sell fuel are willing to circumvent that law by dispensing it into fuel cans that the seller believes the buyer will then use to fill an airplane fuel tank.

It is also against Federal law to use gasoline with more than .05 g/gal. TEL in any road vehicle built later than the 1974 model year---but, enforcement of that law is rare. Of course, .05g/gal. TEL is effectively "unleaded" gas so, in practice, that law makes any leaded fuel use in 1975 or newer road vehicles illegal.

You will find that for best performance on AVGAS or mixes of pump gas and AVGAS you'll need to rejet a carb or recalibrate a fuel injection system. In addition, AVGAS is formulated for use in low rpm aircraft engines rather than high rpm automotive engines and there are some drivability issues that can come from that along with a slight problem with burn speed.

Nevertheless, in cases where getting the utmost in performance from a given engine and a gasoline of a given octane rating is *not* important, use of mixes of pump gas and AVGAS can be a practical way of increasing octane and those mixes are less expensive than those that use racing gasoline.

The usual cautions about use of leaded gas apply: you'll notice a build up of lead deposits in the combustion chambers and on spark plugs.

Lastly, you cannot use AVGAS in any engine that is equipped with a catalytic converter as tetraethyl lead quickly destroys the cat's ability to convert exhaust gases and may eventually plug the converter. Same is true of oxygen sensors.