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Old 03-12-2017, 08:54 AM
Richard L Richard L is offline
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Join Date: Oct 2003
Location: England
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Default Re: E46 M3 WMI Design

As seen on the charts below, it is not practical to inject high percentage. Excessive cooling will rob power. Also putting undue stress on the stock ignition system (high % of water).
You can inject high percent of w/m but make sure you have a good flow monitoring setup to reduce power to a safe level should the wmi system fails.




10Kg of air, Gasoline's latent heat capacityof 350KJ/Kg

Water's latent heat capacity of 2256KJ/Kg

Methanol's latent heat capacity of 1109KJ/Kg



Injection water at different ratio to fuel at 100% water and 75% Water/25% Methanol. You can see the at 100% water injection, only 3% of w/f fuel ratio is enough to replace 2.5 point of a/f ratio (dotted line). As soon as 25% of Methanol is added, the a/f ratio is dropprd to 12.0 - loosing some cooling capacity









Each of the following chart show a 25% percent increase in Methanol concentration of the mix.







lastly, just methanol is added and no water. The chart on the right is 100% water









The two charts show (first and last) that you will require to inject twice the amount of methanol to equal the latent heat of water alone. Methanol is relatively low cost and very effective as a coolant so what is the problem?



When higher concertration of methanol is injected, you need to lean your engines a/f ratio to accomendate the extra fuel or your engine will bog down and loose power. Consequentially - one runs the risk of putting the engine into heat stress if the supply of methanol is suddenly interrupted. Injecting water does not affect the a/f ratio. It appears that 50/50 mix has the best of both worlds.


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