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 Post subject: Fuel
PostPosted: Mon Jul 13, 2015 10:31 pm 
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Joined: Mon Jul 13, 2015 12:17 pm
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Recently I ran my GP on methanol. I was flabbergasted about the increase in performance.
A lot has to be sorted our. Pickup was bad. Consumption outragious. Mixture too lean.
Finding old blends as used in the 1920's proves to be difficult. As far as I understand lots of them had bezol in high percentages. Because the carcinogenic properties I do not want to go that way.

I am interested to hear experiences with methanol/acetone/regular gas mixtures.


Regards Miko


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 Post subject: Re: Fuel
PostPosted: Tue Jul 14, 2015 8:39 am 
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Joined: Wed May 12, 2004 4:26 pm
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Location: Reeuwijk, The Netherlands
You really should talk to Bart Rosman (bugwrench on this forum) on this subject. He is very experienced on these matters.

As for fuel consumption: Expect a 1:1 ratio (km/liter). This effectively means your carb should be able to handle some 3,8 liter per minute. Think about that... I suggest sourcing a spare carb and rebuild that one.

Also keep in mind methanol kills most rubber seals, is highly flamable and burns without visible flames. So keep an eye on safety. (not to discourage you, just take some safety measures).

Additives like acetone and toluene are readily available, although I believe these were used in ethanol fuel.

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 Post subject: Re: Fuel
PostPosted: Tue Jul 14, 2015 11:59 am 
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Joined: Mon Oct 19, 2009 6:28 pm
Posts: 180
All racers have there own systems and mixes but without giving anything away:

Methanol permits the use of very high compression ratios when unsupercharged or high boost pressures when supercharged. The large cooling effect increases volumetric efficiency and is of particular use in the supercharged engine reducing charge temperature after compression. A tendency to pre-ignition is most noticeable at weak mixture levels. A car set up well on methanol is brutal on the street

Acetone works as an additive to lots of fuels, but with methanol its there to reduce pre-ignition sensitivity and promote easier starting(though I start with petrol via kigas tank), up to 10 percent acetone in methanol to reduce pre-ignition sensitivity.

For a 35B you need a carb that can handle a flow rate of a gallon a minute so an SU or a Zenith 48 is best with no rubber in the fuel system.

Everyone who regularly runs methanol should run a top lube or methanol additive( I use Alky).This additive is designed to increase lubrication of valve trains for methanol and ethanol powered cars. It will also reduce the corrosiveness of methanol and ethanol. In addition it will reduce bore wash. An notable and useful additional feature is that if methanol or ethanol catches fire the ALKY will change the colour of the tip of the flame from invisible to yellow and from the exhaust you do get smoke(pure methanol you don’t).

According to the guys in the US who are advanced in this tec 1 Bottle of Alky (215ml) will treat a 205L drum of methanol.

When racing against other methanol cars remember its extremely hydroscopic a car in the UK I race against runs very wet as a result if I’m following it for any time all the polished steel on my car will rust on the leading edges if not properly cleaned within 12 hours.

Who knows what its doing to our lungs?? No Don’t answer that…….


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 Post subject: Re: Fuel
PostPosted: Mon Jul 20, 2015 9:12 am 
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Joined: Thu Mar 01, 2007 4:21 pm
Posts: 434
Location: Bergen NH (NL)
Fully agree so far with 37quest.
Fuels for ignition-actuated combustion engines have certain physical and chemical properties which should be considered. Most important ones are
- octane number
- calorific value
- boiling point / range
- chemical structure (oxygenates)

The higher the octane rating the higher could be the compression and/or the charging pressure, and therefore the power output. Would go too far to define here the difference between MON and RON, so all ON figures I show here are RON, and quoted from memory without checking my literature.
The calorific value is the "energy content" of a substance, the higher it is the less fuel as such is needed, and also the air (oxygen) part of the combustion mixture is lower in order to reach ideal lambda value.
The boiling point - or range - of a fuel should be low in order to perform good cold running properties, but on the other side high to avoid problems with hot engines. Gasoline is a hydrocarbon mix with a boiling range between 30 and 200°C, so offering a good performance at all conditions.
Although also hydrocarbons (formula containing only C and H atoms) may have different structures which result in different combustion behaviours, the main topic here are the so-called oxygenates, which contain also O (oxygen) atoms, like alcohols (methanol, ethanol) and ketones (acetone). Oxygenates normally have a rather low calorific value, and the oxygen in them results in an even lower air requirement to form an ideal lambda combustion mixture. A positive effect is their internal engine cooling behaviour.

Standard gasoline/petrol (in Europe) until the early 50's had abt. 70-80 octane which was the main reason that engine compression in that time was rather low. Once the physics behind "engine knocking" had been unveiled in the 20's there was a R&D run on potential anti-knock additives and alternative "non-knocking" fuels. Noteworthy in this respect is the MOTALIN additive (ferro-carbonyl) developed by BASF (IG Farben) and tested extensively in different race cars, including a Bugatti T35C raced by the head of their automotive testing department, Georg Kimpel. The breakthrough was the invention of TEL (tetra ethyl lead), which even in very small dosages performed an enormous increase of octane rating to figures of 100 plus. However, although in use in the US since the 20's the large scale automotive use in Europe started only in the 50's.
Alternative fuels in that time had been had been restricted by their availability. The petrochemical industry was in their very early beginnings then, and mainly based on coal instead of petroleum. Benzene (aka benzol, benzole) was a by-product from coal gasification for town gas, but only very little of it could be processed in chemical industry. So in order to get rid of it it was blended into liquid fuels, and when is was discovered that it had an octane rating of abt. 100 is was an ideal gasoline component. A typical automotive fuel until the 50's was 50:50 gasoline:benzene.
Very high octane ratings are performed by alcohols, especially by methanol (abt. 130), with ethanol somewhat behind (abt. 115). Ethanol (liquor spirit) was available in large quantities, but methanol was scarce as it could only be processed from wood. Also acetone which then was made from sugar molasses had a certain importance.

The calorific value of methanol is abt. 50 % of that for standard gasoline, and ethanol is abt. 65 %, so fuel consumption is considerably higher when running on alcohol. Consumption increases also by the fact that engines are revving much higher, and supercharged ones can be operated with a higher boost. Part of this calculation is also the reduction of air (by percent) due to oxygen content of the alcohols. This is not only simply mathematics, but also requires extensive testing, especially if alcohols are used not pure but in a blend with other fuels.

As already said a standard gasoline - today but also in the old times - has a boiling range of 30-200°C, which allows an unproblematic performance at all conditions. Running an engine on single compounds like e.g. Methanol means a rather static boiling point instead of a full range. Most products mentioned here have a b.p. between 60 and 100°C, so especially the lower end for cold running performance is missing. Additions of acetone or ethers are helpful, nut normal butane will do also (although blending requires industrial equipment due to the gaseous nature of butane).

Period racing fuels in the 20's first of all had been limited by commercial availabilities, so alcohols (biological) and aromatics (from coal) had been main options. Most of it was "trial and error", and even prospective solutions like Motalin disappeared rather soon due to problematic side effects. In the 30's R&D activities had been intensified, especially in Germany in order to reduce the dependance on imported petroleum, but also with the target to find the perfect racing fuel. Mercedes-Benz and Auto Union teamed up with some of the large petroleum companies, and they constantly improved their blending formulations.

Using racing fuels today in historic cars in some respect is easier, because we know much more then the pioneers of the 20's or even 30's. But on the other side it's more difficult because we also know more about the hazard properties, and the limited access to such chemicals. Benzene is a total "no go", because it is carcenogenic, and also only sold in large commercial quantities within the chemical industry. A suitable alternative may be toluene or xylene, which are chemically similar, and even have higher octane number (abt. 118). However, since hydrocarbon solvents are banned in paints and lacquers I do not know the B2C availability nowadays. Same for Acetone. Methanol seems to be still the most used solution, for details see 37quest's posting. However, methanol is very flammable and poisonous! Another important point is the compatibility of these components not only to polymers (hoses, sealings, gaskets) but also to certain metals. It is a wellknown fact that the Mercedes-Benz heritage dept. drains and flushes the fuel system of the GP cars immediately after a demonstration run.

I am lacking own physical experiences, but by theory I would go for a blend of mainly (50-60 %) methanol, some aromatics (let's say 15-25 % Toluene or Xylene), 15-25 % premium gasoline (for the higher boiling end), 5 % Butane (if workable blending equipment available, otherwise use dimethyl ether).


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 Post subject: Re: Fuel
PostPosted: Mon Jul 20, 2015 2:58 pm 
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Joined: Sun Mar 12, 2006 8:17 pm
Posts: 6
For me this is a very interesting topic.

I have been experimenting with methanol myself.
I started out with pure methanol, a main jet 4.0 mm. Slow running jet 2.4 mm.
Getting my carb to the point it will handle big fuel flows proves not to be easy.
To give the engine enough fuel I tried a mixes of 10-20% gasoline, 3-5% acetone, 1% castor oil and the remainder methanol.
Solex carb main jet 3.5 mm. slow running jet 2.1 mm. .
Fuel line with a 4.0 mm float valve is capable of 1,3 liter/min.
Above 4500 rev./min. in 4th gear it did not work out. Lambda went over 1.
Should I go back to pure methanol and a bigger jet and float valve?


Last edited by prototypet64 on Mon Jul 20, 2015 10:38 pm, edited 1 time in total.

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 Post subject: Re: Fuel
PostPosted: Mon Jul 20, 2015 7:48 pm 
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Joined: Thu Mar 01, 2007 4:21 pm
Posts: 434
Location: Bergen NH (NL)
prototypet64 wrote:
1% castor oil

Oh yes, I forgot this one! Lubricity of Methanol is rather low....


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 Post subject: Re: Fuel
PostPosted: Tue Jul 21, 2015 4:49 pm 
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Joined: Mon Oct 19, 2009 6:28 pm
Posts: 180
As I said Methanol technology is relatively straight forward.

Its easy to use, clean and gives big power increases in blown engines, all the development was done over the last 30 years by the UK VSCC racers and a lot of that came from bike racing(speedway& Grass track ).

Acetone is very easy to buy, all additives are available at least in the UK or you can buy ready mixed race fuel from Sunoco/ Anglo American with there own mix of top lube.

The mix you run is dependent on the setup of your engine(compression ratio is key) so not something to test at the track. additionally Big flow rate is what my engine builder says is most important carb aspect hence so many modified 48mm carbs racing, a good idle/ low end is not something to dial in.


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 Post subject: Re: Fuel
PostPosted: Tue Jul 21, 2015 4:59 pm 
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Joined: Mon Oct 19, 2009 6:28 pm
Posts: 180
prototypet64 wrote:
For me this is a very interesting topic.

I have been experimenting with methanol myself.
I started out with pure methanol, a main jet 4.0 mm. Slow running jet 2.4 mm.
Getting my carb to the point it will handle big fuel flows proves not to be easy.
To give the engine enough fuel I tried a mixes of 10-20% gasoline, 3-5% acetone, 1% castor oil and the remainder methanol.
Solex carb main jet 3.5 mm. slow running jet 2.1 mm. .
Fuel line with a 4.0 mm float valve is capable of 1,3 liter/min.
Above 4500 rev./min. in 4th gear it did not work out. Lambda went over 1.
Should I go back to pure methanol and a bigger jet and float valve?


Your flow rate is killing you. You need big fuel lines to a carb that can handle 1 gallon per minute that's 4.6 litres per minute so a big SU or a Zenith 48K or 48UST.


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