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MG MGB Technical - Methanol?

I've just finished a long trek through the Archives for fuel octane boosters/additives. I have this memory of someone, somewhere,sometime, publishing a home brew recipe, but can't find it. I believe it featured methanol( MEK?) and denatured alcohol with some eye of newt, but just cannot find it. Does anyone out there know of any expedite way to kick up Calif gas from the low nineties octane rating. If you read the "Booster's Blurb", their 4-6 points gains are 1/10ths, not full points. Vic
vem myers

Vem;

Methanol is not MEK. MEK is Methyl Ethyl Ketone and is not something you should be fooling around with. It is a known cancer causing agent and should be handled very carefully. This also goes for toluene, xylene, and any of the other aromatic chemicals which are used to provide octane kick.

Your best bet is to use the same method that a friend of mine uses to bump the octane for his Lambo Muira. Buy a 5 gallon fuel jug at your local jet-ski or motorcycle shop. Find a motorcycle or jet-ski shop in your area that sells off-road high octane gasoline (this can be as high as 114 octane) and fill up your new fuel jug (make sure you tell the shop you are only using the gasoline for off-road use if they ask you). You will probably pay about $4 - $5 per gallon for this.

Go home, pour the high octane gas into your fairly empty gas tank and then head to the gas station and top off with premium gas. This mix should produce an octane mix in excess of 100 average octane [(RON + MON)/2].

Unless you have a highly modified engine in your MG, this is all a waste of time as your stock engine will not see any appreciable power gains. Higher octane only provides real benefit to high compression engines since it allows the timing to be adjusted for max power without pre-ignition.

And if you read your MGB owner's manual and it says to use 97 octane, remember that this is based on RON octane only which is 5 points higher than the average octane number you see on your local gas pump. Therefore, the 91 or 92 octane premium that you can buy is what the stock MGB engine was designed for.
Ron Kluwe

Vem,

I considered the "home brew" method, too, but for all the reasons Ron gives, it is not worth the effort. If I recall correctly, the "method" was to go to the paint store, buy some solvents and add them to your fuel, hoping all the while that all your fuel system gaskets don't turn to mush. Alternatively, any parts store product with "MMT" listed is indeed a proper booster, but it is awfully hard to figure how much you're actually getting. It took about 20 bucks worth of MMT to eliminate ping in my hc engine (10:1) at the desired advance. I found it more reliable to simply purchase "purple" 114 octane race fuel from the speed shop and use it at about 50/50. I intend to try to get it down to 25% "purple" and see if that doesn't work just as well to eliminate pre-ignition.

Now for the rant, not directed at anyone in particular:

Don't let the TV adds of decades past sway you in this millinium - octane does not equal power at all. It only inhibits pre-ignition. Any claim to the contrary is either an outright lie, or coming from an individual so influenced by the halo effect that they have convinced themselves of the existance of a physical anomaly. The modern exception is an engine that is capable of sensing knock and actually advancing the timing to take advantage of higher octane fuel. Even then the engine is basically tuned for high octane in the first place, but has the ability to retard timing to make do with lower octane fuel. I get tickled when the old guy who sells me race fuel says, 'over the counter octane boosters don't really have extra octane, they only help reduce pre-ignition'. He means well.

Dean
Dean Lake

vem
On top of health hazards, MEK has a really low flash point and a heavy vapour so is a big fire risk from static. We use it in pint quantities under very controlled conditions as a solvent for printing inks. After seeing the results of a fire with a column of vapour blazing 20' in the air I'd never be tempted to use the amounts needed as car fuel.

Vic
V Todman

MEK is also a paint remover and very aggressive solvent. Would probably turn any seals in your fuel system to goo. This stuff is not something to be used casually.
R. L Carleen

Dean,
When the old guy says "over the counter octane boosters don't really have extra octane, they only help reduce pre-ignition", he's right. Octane is a hydrocarbon that used to be a significant part of the gasoline formula used to reduce preignition. Today's gasoline uses other compounds such as alcohols in place of octane. "Octane booster" typically contains these compounds. Thats why gasoline has an octane "rating" and not an octane "level"
Bill
Bill Boorse

Bill,

Thanks for the clarification, but it is largely a semantic issue. "Octane" the way I used it in my post (and as it is used in virtually all parlance today) is meant to describe the rating. In the future, I will be more careful to add "rating" in the interest of accuracy and clarity. Your point is totally valid.

Being that octane proper is not used anymore in our regular fuels, it is probably not used in the racing fuels either (I don't have any particular knowledge, it's just a guess). I doubt the old guy means that the special fuel actually has a given level octane, as opposed to a particular octane rating. I did not describe for you in detail the entire conversation, but suffice it to say: he is under the common misconception that octane rating is synonymous with power potential, and also is ignorant of what the octane rating actually means. In fairness, the next time I see him, I'll ask him just to be sure I haven't slandered him ;-)

Dean
Dean Lake

Just for what it's worth:

Personally, I would not fool around with any "home brew" fuel. There are many reasons but the stand out one is the possible harm to seals, oil etc in the simple engine itself.

I've considereed, but not yet followed through on aviation gas for a higher octane AND a little dose of lead.

It is above 100 octane with a low level lead. It's also about 50% higher in cost than at a typical "filling station".

I have heard there are rules, regulations regarding aviation fuel in passenger cars, but in chatting with a local flier who runs a flight service, he'll fill me up, I guess, just to make the sale.

One of the things I cherish with my '64 is going back to a simplier time -- just like a time machine. Fooling around with the petrol it uses is a farcical endevor.
glg

Dean,
You're right. Most people assume that premium fuels and octane boosters will give some sort of magic performance boost, and that's probably what the old guy is saying. I didn't mean to nitpick, I just wanted to clear that up for anyone who was interested. And sometimes those "old guys" know more than we give them credit for.
Bill
Bill Boorse

vem,
Have you seen any *need* for better fuel? Personally, I've run my '69 on everthing from 91 down to 87 with no additives and no problems (other than the need to tweak the timing a bit). I've also seen no valve recession in the 30k or so since I had the valves ground... Of course, someone people's experiences may be different from mine, but I think people worry too much...
Rob Edwards

I was just about to post a similar question, but directed towards tetraethyl lead. A few years back, a friend was buying it by the jug for his turbo B. He has since moved away and has lost touch with the supplier. Does anyone know of a source? I vaguely remember an ad in Hemmings. I'd like to try some in my '66 and play with the timing a bit. I'm running 10.5:1 and it may be beneficial.
David
David

I don't think you can buy Tetraethyl Lead over the counter anywhere in the U.S. This is now pretty much a banned substance except for certain industrial uses and is sold under very controlled circumstances.

Tetraethyl lead is an octane booster in that it inhibits pre-ignition (which is why no-lead gas is 4 to 5 octane points below leaded gas). It will not add power. There is no inherent benefit to using it instead of the higher octane off-road fuel and mixing. Tetraethyl lead was used by the refining industry because it was way way way cheaper than the other options.

I run a very highly tuned 1940CC motor with 11.5:1 compression on pump premium gas and I have no problems with pre-ignition. I also keep the motor constantly tuned and there was a lot of attention payed to the motor build to ensure adequate cooling, etc. Tune your engine once a month, including valve clearances, and 91 or 92 octane should be just fine.
Ron Kluwe

Octane makes a huge difference under hi load conditions. Modern cars have knock sensors that retard the spark to prevent damage to the engine from poor fuel. They also retard the spark as the engine gets hotter and the fuel tends to knock under lighter and lighter loads.
My 01 Olds coupe with a 3.4 v6 is a fun car to drive over "Hopland grade" a winding road about 6 miles up one side and 5 miles down the other with a 8 to 9 % grade and very twisty narrow road. I usually haul over it at 25 mph in the tight spots and up to 50 in a few short spaces. The other day I came over with my wife who believes I'm speeding at anything over 25 on the grade. We headed up the hill slowly with the air conditioning on high. It was a hot day and the heat guage moved up towards the red area. I was at about 20% throttle at 15 to 30 mph. Toward the top I floored it just to see how much I had left. -- Nothing! -- . Apparently the engine was so hot that as I gave it gas it would have knocked and the knock sensor just pushed the spark timing way back as needed to prevent knocking. If I'd had higher octane gas that sensor wouldn't have been triggered and I would have had more power.
I remember in the "old days" pushing a flat head 6 cylinder Henry J over the hills with the heat guage way up there. It not only knocked, it started to detonate. It sounded like uncontrolled explosions. The car lost virtually all power and the only thing to do was to pull over and let the car cool off. Better gas would push those limits higher.
Hi compression or high temperatures both contribute to knock. An alloy head will dissipate heat better and can run a higher compression using the same fuel and consequently produce more power and get better fuel mileage, all other things being equal.
Barry
Barry Parkinson

Barry:
Did that Henry J have "Supersonic" cast into the cylinder head? We have one in our '50 Jeepster and it seems misnamed. No detonation problems but we are on flat ground, barely above sea level.
Marvin Deupree

I think the key to understanding the octane issue in fuel is to avoid the qualitative judgement that higher octane is equivalent to "better" (which is the dubious claim historically made by the marketing department). The octane rating (the arbitrary frame of reference for anti-knock qualities) simply describes how resistant the fuel is to detonating under compression. This resistance to detonation is a variable requirement of IC engines in operating conditions. An engine which does not require slower detonating fuel will not see any benefit from it at all. If an engine is suffering pre-ignition AND is properly tuned AND in proper running order (e.g. cooling system is functioning), then it truely requires higher octane fuel. Barry, you are absolutely correct in your analysis of your experiences that preignition harms performance. But just to clarify, that is not the same thing as saying that higher octane fuel provides performance gains. The situation you describe is one where the engine was apparently not up to the task of charging up a steep grade on a hot day with the AC on. Alternatively, this may have been due to a cooling system problem. I do not dispute your observation that higher octane would have reduced the preignition in that circumstance. However, I submit it would be advisable in such a circumstance to either solve the cooling issue or resign oneself to that particular limitation of the engine. Using higher octane would at best be a bandaid to a problem, at worst it would have allowed you to fully drive that temperature needle into the red! ;-). I am preaching too much, I know, but there is sooo much money wasted on high octane gas in this country for all the worst reasons. It all goes back to my college days when we would split the gas bill on road trips and the driver would insist on wasting our beer money on premium gas; I have issues, I know. I'll stop now. ;-) Dean
Dean Lake

Tetra-ethyl-lead is more than an octane booster, although it does do that.

It is my understanding that the lead cools the edges of the exhaust valves and lubricates them a little. Valve seat recession occurs when unleaded (unlubricated) fuel is used in an engine designed for leaded fuel.

The sharp edges of the valve get hot and, when the valve closes, it spot welds itself to the cylinder head. When the camshaft pushes the valve open again, the weld is broken, pulling a tiny bit of metal with it. This also creates a rough surface, which only accelerates the wear.

To get around this, engines designed for unleaded fuel use hardened steel in the exhaust valves and hardened steel seats that are press-fitted into the cylinder head.

This is why hardened seats are only needed on the exhaust valves. The intake valves are already cooled by the incoming fuel/air mixture.
Paul Noble

Vem, try this link.

http://www.gnttype.org/techarea/misc/octanebooster.html

Fred H

Here's another link

http://www.vtr.org/maintain/gasoline-octane.html
Fred H

Fred,

Good site. The fact that toulene is readily available and is historically a component of fuel anyway makes it tempting. I may have to play around with this some day, afterall.

Vem,

The best over the counter option I have found lately is Pennzoil "'The Outlaw' Maximum Performance Octane Booster". This particular product comes in four little cans to a pack. However, it took 20 bucks worth (two four-packs) to get a full tank adequate to stop pinking on a 10:1 engine in race conditions and at an agressive advance. There is another similarly named product by Pennzoil that comes in a single bottle but makes no mention of MMT (a known effective octane booster), so it may not work. The best over the counter product I ever found was bardahl's octane booster. It was listed for "off road use only", contained MMT, and did the trick for about eight bucks a tank (two bottles). Last I knew, it was not available any more in the retail market, but the manufacturer would send out a case directly. They are on the web. I would suggest that at some point you try mixing in one or two gallons of 114 race fuel (available at speed shops for about 4-5 bucks a gallon) and see if that isn't just as esy and more economical in the long run. Good Luck. Dean
Dean Lake

Many of the octane boosters are mostly toluene. The bottle might say "raises octane by 4 points", but what they don't tell you is that a "point" is a tenth of a point as rated on the pump. So if it says it increases octane by 4 points and you have 93 octane gas, that's only 93.4
Fred H

I recently read, "While the Weslake-designed kidney-shaped combustion chamber renders its best performance when the ignition timing at full advance is set at 34 to 35 degrees BTDC", and "the ignition should reach full total advance no later than at approximately 3,500 to 3,700 RPM"

So this is how I understand the relationship of octane to power:

1. Reaching the optimum advance setting for a particular engine setup is limited by knocking.

2. Higher compression means more power.

3. The higher the compression the more you need to retard the timing.

4. Therefore - if you can reach optimum timing with 94 octane, then there is no advantage to using higher octane fuel.

5. Higher octane allows you to run a higher compression ratio.

Is this right?????



Fred H

Fred;

Yep, you pretty much hit the nail on the head. The only reason to go to a higher octane fuel, on a carburated engine with distributor type ignition, is if you have significantly raised the compression ratio.

The reason why Barry saw an apparent power increase on his electronic ignition car is that the computer controlling the engine can detect the imminent "knock" condition and automatically advance or retard the ignition, something a distributor cannot do.

Back when I had my twin turbo RX-7 (prior to my sons turning 16 and watching my insurance premium quadruple), I would run 104 octane Union 76 NASCAR racing fuel through it occasionally (a local gas station sold the stuff legally through the pump) and could feel a significant increase in power. This was solely due to the engine computer being able to detect that there was no pre-ignition occuring, therefore both advancing the ignition and allowing more turbo boost at full throttle.

Unless you have made serious modifications to your stock MG engine (and by serious I mean thousands of dollars of internal engine mods), you are not buying anything by trying to bump the octane. And playing with toluene and xylene is not worth the damage that both those chemicals can cause to your body, both short and long term.

Just to let you all know what you are dealing with, I just checked my "Dangerous Properties of Industrial Materials" (I am a chemical engineer by profession) and the OSHA exposure limit for toluene and xylene is 10 minutes at 100 ppm, which also coincides with the lowest published toxic concentration. Both of these chemicals are also known carcinogens. To put it bluntly, this is nasty stuff.
Ron Kluwe

This thread was discussed between 01/10/2003 and 08/10/2003

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