8/23/2022 I FOUND THE SPREADSHEET!

ok, putting my assumptions up front.

methanol burns appropriately for FI at 5.5:1 (most scientifically backed figure found on google)
gasoline burns appropriately for FI at 11.5:1 (from experience on here)
the weight of gasoline is 6.25 lb/gal (most scientifically backed figure found on google)
my bsfc is .6 (from Kurt Urban)
my (future) flywheel horsepower will be 1200
I have calculated earlier that I move 22.2 gal/hr methanol
(375 ml/min nozzle + 625 ml/min nozzle at 220 psi pressure) (from Matt Snow)


the rest is math. here we go.. this took 6 post-it-notes to get right.

Total Fuel Flow = hp * bsfc = 1200 * .6 = 720 lb/hr
720 lb/hr * 6.25 #/gal = 115.2 gal/hr

11.5 parts air to 1 part gasoline = 12.5 parts total
total flow through the engine (air + fuel) = 12.5 * 115.2 gal/hr = 1440 gal/hr

% of total flow that is gasoline = 1 / 12.5 = .08 = 8%

now here is the addition of methanol to the flow

1440 gal/hr + 22.2 gal/hr = 1462.2 gal/hr (total flow of air + gas + methanol)

% of total flow that is methanol = 22.2 / 1462.2 = .01518 = 1.518%

the ratio of methanol % flow to fuel % flow = 1.518 / 8 = .18975

this .18975 is the methanol part of the 1 fuel part (in the X:1) a/f ratio
the gasoline part is what is left over (1 - .18975) = .81025

the new combined air/fuel rato is...
gasoline factor + methanol factor = new appropriate mixture a/f ratio
(11.5 * .81025) + (5.5 * .18975) = 10.3615

you can also calculate your new octane rating with the same factors
(93 * .81025) + (126 * .18975) = 99.26 (a close guess on the meth octane)

whew!

*remember you have to calculate your OWN methanol flow and use your own flywheel horsepower..
*this is only my effort at the calculation, I certainly cannot gauantee it is 100% correct.

questions / comments please!

Link to Calculator Spreadsheet

 

and good with math too.

i mean i understand whats goin on, but i dont know nuff about the meth factors and how they actually apply here. wow! good work!

 

Damn.... wheres my calculator...

 

Interesting post that I somewhat follow.
I definitely understand 1200 horsepower. Are you going to stay with the six-speed?

 

yes i am

 

I thought methanol was 99 RON+MON/2 ?

 

all I have to say is excel formulas here I come

 

too late, i did it for you.

intmd8, maybe so.. but i have definitely read otherwise... do you have any good links on it?

here is the easy way for you slackers you can change whatever you want such as the octane rating for the alcohol if you like.

Link to Calculator Spreadsheet

and i'm spent.

 

can you post the link to the downloadable .xls file. i dont have the windows service pack to get to it but have excel.

 

well it's nice to know all those figures, but really no need for all that math since the wideband does not care what fuel is used.The a-f number is just a programmed output.

If your using a wideband it outputs voltage/lambda. The display then shows an A-F number programmed to convert the voltage/lambda number into a a-f number for gasoline.
So if you were to convert your motor to pure methanol and ran it at a true 5-1 AF, your wideband would STILL show 11.5-1 unless you reprogrammed it for the new fuel.
5.5 is lean for methanol . Most racers using methanol run it near 4-1 but 5-1 is good.
5.5-1 methanol is the same lambda as 12.6-1 gasoline.
11.5-1 gasoline is the same lambda as 5-1 methanol.
11.5 is good and safe for either fuel.
So all you need to do is shoot for 11.5-1 on the wideband.

Methanol is no where near 126 octane. Just a tad over 100. But it has powerful detonation effects because of the shear volume of it used and the intense charge cooling it provides and is more detonation resistant than the best gasolines when run 100%.
But when you run it lean (5.5-1) it can be very prone to detonation.

Steve

 

awesome !

now all we have to do is convert the methanol flow rate to be able to figure out what size nozzles to run

Or in yoru spreadsheet case, work iterate backwards until you find how much methanol you want to add, and find appropriate nozzles.

 

i'll put the file up when i get home.

steve. i appreicate the input and would love to see where you get your data from.

where do i find what most methanol burning drasters put their a/f at? on gasoline scale & methanol scale?
where did you find that the methanol octane is 100?

i am just relaying from what i found from about 5 hours of searching on the internet..

i know that if you just were able to watch lambda it would not matter.. but most people are looking at gasoline programmed meters.

 

wouldnt it jus be easier to add the methanols effect on the octane rating for the equation instead of all that?

 

i dont know what you mean.. i dont think so.. show me it worked out.

link was updated a little Link to Calculator Spreadsheet

 

heres what i mean: instead of going through all that, use an average octane rating of the methanol and how many points it raises the gasoline and figure that in instead of getting A/F from both sides and dividing and wht not. because higher octane takes more heat to burn so find the octane rating first of the combined fuels then find the A/F that way. or would that not work? linky no work for me.. pos computer

 

i just re checked the links, they work for me.. you need microsoft excel to use them.. you need windows xp to view the first one or right click save as to get the second one.

i dont think an average octane would be as exact and i still cannot figure out what you are talking about without it worked out on here. its certainly possible the way i worked it out could be more complicated.. but its allready done for you

 

I just wonder if you can use ur idea and then make 1200 crank hp with just meth. I"m thinking no.

 

john, at that point you have to pay attention to your octane level and decide for yourself if it is possible..

can you make 1200hp on straight methanol.. i certainly do believe so.

sjh, i have been reading all afternoon.. i see your point about just shooting for say a .8 rich lambda for either fuel and that 5.0 afr of methanol will show up as 11.5 afr of gasoline (on a gasoline scale)

that would mean all my work was a waste of time.
what i cannot figure is how the best running/longest lasting alky/pump gas cars that i know of have air fuel ratios that dip into the low 10's.. (i thought my calculation was right based on that sotp measurement and comparison)

by the lambda rule the should be able to safely run the same afr with methanol as without it. and that just seems too easy for all the hard time and no answers i've seen on the net and on this board in the past..and then you just throw in a 1-liner here after i spent all last night trying to find it my own way.

my second comment is on the octane. if you are certain that meth is only 100octane or so then that would mean i am making over 830rwhp on 366ci with barely 95 octane?

 

Nobody ever said you made 830rwhp safely.

 

i was looking online and there are cars making over 3000hp with straight methanol.. its the btu's thats more important than the octane i guess...

gotta figure out what to do with btu's to estimate hp capability since octane wont help figure it out then

*john the car ran perfectly at that level for 4000 miles until i floored it after changing fuel injectors* safe to me.