I would think you would want a portion of the methanol available for dissociation during the combustion process to do a good job of controlling combustion temps and hence detonation of the gasoline.
This is a fine line for an engine that is being pushed to the limits where cylinder and combustion temps are concerned. Any methanol that dissociates during the combustion process will most likely quench some of the combustion process. That would most likely be noted as a power loss. If combustion temps are at the limit and all the available methanol has already dissociated during the compression process and none is available to help cool the combustion process, you could be in trouble.
Generally, when a racer feels a loss in power, what does he do? He takes steps to raise combustion temps. Lean the mixture or increase timing, right?
Racing with methanol is all about controlling cylinder and combustion temps. As power levels increase, all temperatures increase and more methanol must be used. A/F ratios will generally increase as power levels increase. Much of the extra methanol that is used at higher power levels is not even burned and is used for one thing only. To cool the temperatures down below the autoignition temp of the methanol so that controlled combustion can be maintained. The mixture strength is a fine line that every methanol racer knows very well. There may be more power available if it's leaned just a little more, but would it blow the engine?
A safe power mixture with methanol always involves a small loss in power.
A true methanol engine may be run so rich at some power levels, that much of the methanol will not even dissociate until it hits the exhaust system. Some of it may even still be in droplet form by the exhaust system. I would expect that if a gas/meth mix engine was run at such a rich mixture, the power level would drop way off.
In fact, this is how my nitrous/meth anti lag system works. The nitrous/meth combination is so cold, and quenches combustion temps so much, that a very noticeable drop in the nitrous system hp rating occurs. Only a small percentage of the nitrous hit actually burns in the cylinder. It still nets a small increase in power over not using the nitrous system, but, depending on the size of the nitrous hit, there is a 50 to 85% loss in the system rating in the cylinder. The nitrous and meth that makes it out of the cylinder finishes dissociating in the exhaust system, and because the exhaust temps are above the autoignition point, with a little help from a retarded spark timing, the mix ignites in the exhaust system. The sacrifice of having so much of the nitrous hit light off in the exhaust system and help quickly spool the turbo is the lower power level that is extracted and transferred directly to the piston in the cylinder.
Methanol engines will always run safer if there is a reserve of methanol available to quench combustion temps below detonation limits. The trade off is a small loss in power. If you can't deal with that, you have no business playing with methanol, or your wallet is thick enough to deal with the consequences.
. I m going to be throwing even more methanol at it soon enough so we will see. It should be interesting if i run it on 93 pump gas and run in TAI. I plan on using 30gph of nozzles and switching to a 3 bar MAP for the alky.
