Methenol Injection question
Methenol Injection question
(OP)
I am in the racing industry and i have learned to use this site for advice. The use of methenol an/or water injection into a turbocharged gasoline engine to both cool the combustion chambers and raise the octane of the fuel has been around for quite some time. in my experince i have been able to use 100% methenol injected as a fine mist into the air intake after the turbo has worked the best. i have been able to use timing and boost pressures for c-16 (116) octane fuels on 100 octane and methenol injection. somone however brought up an intreaging question to me. what is one were to use the same setup but inject RC car fuel which is chemicly 80% methenol and 20% nitromethane. assuming we are taling about an engine that is machanicly able to hadle extream power. would i see any benifits from adding nitromethane to the mixture? tuning WOULD be done and figure a 500ML delivery rate as an average.





RE: Methenol Injection question
Nitromethane is also very difficuilt to atomize. The Nitro will add more oxygen as it burns, leading to a lean mixture, meaning you will need more fuel to couteract this.
Experiement at your own risk!
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RE: Methenol Injection question
RE: Methenol Injection question
As 100% nitro methane likes a fuel to air ratio of about (from memory) 1.8:1, if you use a lot of it in a high compression engine, the evaporated fuel in the cylinder can approach or even exceed the compressed volume of the cylinder, leading to extremely high compression ratio or even hydraulic lock which causes extreme engine damage.
Nitro methane is also quite toxic and it's products of combustion are quite corrosive to many metals typically used in engines.
For boost enrichment of a petrol engine, I would recommend 100% methanol as a safe and most effective fuel.
Additives to make the flame visible would considerably improve safety in case of a methanol leak or spill and a fire. There is a greatly increased burn risk from the fact that methanol fires are invisible.
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RE: Methenol Injection question
RE: Methenol Injection question
Nitro methane also has a very slow burn rate, so it changes ignition timing requirements.
Nitro methane also has a different co-efficient of expansion to methanol, so the percentage changes with temperature changes. Also as a lot more is required, a much larger tank is required. Unless this is a very short course race car, the extra fuel load will outweigh any power gains.
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RE: Methenol Injection question
RE: Methenol Injection question
It will still decrease the octane of the methanol.
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RE: Methenol Injection question
RE: Methenol Injection question
RE: Methenol Injection question
RE: Methenol Injection question
If you'll reread pat's post. It lays out the benefit vs cost pretty clearly. You'll need more fuel, less dynamic compression and the nitro might eat parts in your engine. 3oz a pass tells me that you've got room for improvement in that meth setup. Since there's no parameters for your "race car"; it's hard to say what it's going to do but since you're in the race industry and your going to tune it the answers are there if you roll it up on the dyno. You might be able to "tune" an advantage over just straight meth but just dumping it into the tank probably won't yield any gains.
RE: Methenol Injection question
RE: Methenol Injection question
RE: Methenol Injection question
Are you saying that with a puny little nitro methane fuel enrichment system over a petrol main fuel system you cannot get hydraulic lock, or are you saying that a high percentage nitro methane main fuel system cannot hydraulic lock.
What is your source of the a:f ratio for nitro methane.
My source is the "Harvey Racing Engines Fuel Injection Basics" 3rd Edition.
Re optimum a:f ratio for various fuel it states:-
Gasoline 13:1
Methanol 5.9:1
100% Nitro 1.6:1
90% Nitro 1.8:1
Top fuel cars run mechanical injection because electronic injection cannot supply anywhere near enough fuel for the reasons you state.
A blown alcohol V8 can run as many as 32 high flow special racing methanol injectors. So far as I know, no one has tried to fit and fire the 80 to 100 injectors that a blown 100% nitro V8 would require.
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Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Methenol Injection question