I have a AFX air/fuel gauge that reads from 9.0-16.0 AFR. The gauge is setup to read gasoline outputs but is also compatible with methanol. I put on an methanol carb and the gauge is reading 9.0-9.3 AFR at idle. Does anyone know the conversation OR the calculation to show the methanol AFR? I know the AFR at idle on methanol should be between 5-6 AFR. Any help would be greatly appreciated! Thanks

Easiest way is to just tune any fuel to the gasoline air fuel ratios you are used to, if the gauge is on a gasoline scale.

You could re-adjust gauge to alcohol stoich or tune in lambda but you'll probably end up calculating back to gasoline scale anyway.

Don't hurt your engine by trying to use AFR on E85, you need to read it in the Lamda scale for alcohol

Cab
is there conversion to lamba

If the gauge will read in lambda do so . Mine has a switch and different face that you swap.

More importantly learn how to read methanol plugs for timing and mixture. Far more valuable than any gauge and nothing like Gas

I did the converting over on my racepac when I switched from pump fast to alcohol. I got the tune close by doing that but if I may suggest something buy and egt reader and weld a fitting in one or two tubes. I welded two in but have only used one and I have mine set were it runs very consistent. I finally added it to my racepac but if I remember right the other system I bought was around 300.00 to read one cylinder

Doesn't matter as long as you know what you're trying to accomplish.

Stoich gasoline is 14.68 Stoich Meth is 6.45 Lambda 1.0

So if you're naturally aspirated and wanted to run for example .88 lambda WOT that would be gasoline 14.68 x .88 = 12.91 or meth 6.45 x .88 = 5.67

Yes you could convert gauge output to lambda or change it to meth stoich as a base point but doesn't matter if you don't have that option.

The gage I have has no adjustments, it was reading around 9 at idle any idea what that would be on methanol ?

all AFX and ask them what to do with their gauge on E85
Do they have a tech info help page on their web site?

the math
14.68 x.62 = 9.10
6.45 x.62 = 3.99

so to answer your question, it's waaaaay fat.

here's a chart for the math challenged



Joe

Again, if your gauge is on gasoline scale, tune it to known gasoline air fuel ratios.

If gauge is set to 14.68 or gasoline stoich and it shows 9-1 at idle, as mentioned, pig rich. Not even sure how you could have accomplished this.