what is a inmo gas?have you guys factored in the 10%ethanol in the gasoline afr targets?inmo gas target should be closer to 11.0's
I would look at the methanol as a percentage of the total fuel. The total fuel would be 196 from meth + 378 from gas = 574 lb/hr. So the meth % would be 196/574 = 34%. That would be the meth% to use for a/f calcs if all the meth injected were burned in the combustion process. But as you alluded to this still seems like too high a %. The corresponding safe a/f ratios would be much lower than what we know works.
I did some quick calcs for the amount of fuel I'm injecting and what I know some of my friends are injecting for low 10sec cars. Using some calculators to guess what fuel the engine needs for those Hp levels I come out with about 22% more fuel needed than what we are injecting. So if we use 22% meth for a dual nozzle setup the equivalent a/f ratios correspond pretty well to what a/f ratios we know works at those power levels (10.3-10.4 or so).
So we are injecting 34% meth but only burning 22% in this case it seems. So what happens to the unaccounted for meth? Maybe even though that extra meth doesn't get burned its still needed to run the higher boost/power levels on pump gas as it cools down the cylinders and prevents detonation.
(Here's where I got my numbers from:
For my low 10sec car, I run around 274lb/hr of total fuel injector when on alky (~55% duty cycle on 83lb injectors). Now, if I use the handy TRX Performance calculator, it says I should be using a total of 350 lb/hr of injector to support my horsepower. I'm missing 76lb/hr, about 22%. If that 76 lb/hr is coming from meth, that number seems more along the lines of the % of meth we are burning to use in the a/f calculations. The corresponding a/f ratios for the 22% meth seem to follow what people have run/recommended for low 10 sec alky cars (say 10.3 for a 11.76 gas a/f ratio). For a high 9 sec car you might want to run closer to an 11.5 gas a/f ratio which would give you an corrected 10.1 a/f ratio for 22% meth.)
Now we need an equation for alky users with 93 octane fuel. Murphster help us out!
Am I missing something here? The a/f ratio showing on the wideband in the gas scale will always have stoich at 14.7 regardless of fuel.
For an example....e85. If you still use a gas scale....which I do...you still consider 14.7 stoich and tune for your normal 11.0 or whatever your target af is. Why would a gas/meth mixture be any different? I'm lost here.
I've seen data logs and a tune from a well known tuner and he used the gas scale normally when spraying a good deal of meth in a 9 sec car. Also helped tune a few cars myself on meth (these were only low 11 sec cars though) and I used my normal 11.2 or or so af for that power level and had good success.
Are you all saying that the WB should be reading low 10's and stoich should be considered in the 12's or so? I have to disagree if so. I don't see it any different then tuning with e85.
Were not looking for 100% vaporization which would happen when it boils. Thats impossible under the condituons. But we are looking for as much vaporization as possible. Its easy to see what happens when you don't have vaporized methanol in a dry flow intake and you are over injecting. It isn't pretty.