air fuel ratios and meth
LOL yeah I made some grammar mistakes, who's all married in here?
you know how it is when your wife wants you to get off the internet, I rushed a tad bit
you know how it is when your wife wants you to get off the internet, I rushed a tad bit
Last edited by bnice01; Jan 14, 2008 at 07:57 PM.
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NO NO NO thats for a car running only methanol, like that is primary and only fuel
60% gas 40% meth your new stoich would be 12.72, your still shooting for .82-.85 if its gas or meth/gas mixed. New stoich means a new lambda scale. ex 14.7 stoich with a .82 , will have different afr than .82 with 12.7 stoich. Now look @ the formula:
AFR in lambda:
Lambda = actual AFR / stoich AFR
which means:
actual AFR = Lambda * stoich AFR
when stoich change so does everything else
everything revolves around it
this will affect guy running quite of bit of meth
60% gas 40% meth your new stoich would be 12.72, your still shooting for .82-.85 if its gas or meth/gas mixed. New stoich means a new lambda scale. ex 14.7 stoich with a .82 , will have different afr than .82 with 12.7 stoich. Now look @ the formula:
AFR in lambda:
Lambda = actual AFR / stoich AFR
which means:
actual AFR = Lambda * stoich AFR
when stoich change so does everything else
everything revolves around it
this will affect guy running quite of bit of meth
oh and going from 11:1 to 12:1 afr makes a huge difference in power.50/50 mix in the right volume will lower A/F 1/2 point. 100% meth will lower a little over 1point. A 50/50 mix is about 113 effective octane when used with a 91 octane base fuel.
With a normal A/F of 11.5, you enable the meth and should see the A/F drop. Now you can do one of the following: remove fueling, add timing or increase boost. Any of the three will then lean out the A/F. A good target A/F with meth on an Evo is 12.2-12.4, if you are running a fail safe like our IFS-10, or other. If you don't have a fail safe, do not lean it out more then 12.0 with 50/50 or 11.5 with 100%.
Best regards,
Dan
With a normal A/F of 11.5, you enable the meth and should see the A/F drop. Now you can do one of the following: remove fueling, add timing or increase boost. Any of the three will then lean out the A/F. A good target A/F with meth on an Evo is 12.2-12.4, if you are running a fail safe like our IFS-10, or other. If you don't have a fail safe, do not lean it out more then 12.0 with 50/50 or 11.5 with 100%.
Best regards,
Dan
crcain, as i've mentioned before, even in high quantities of methanol/gas ratio, keeping it around the .82 lambda is ideal. from the cars i've dynoed with meth, when running a bunch of meth running lower then .80 lambda power drops off, misfiring, and poor fuel economy.
i wouldn't go over 12 afr. just treat it like you were running 100 octane. Personally i like it at 11.8 but then again most of my customers road race their cars. .82 lamda is about 12:1AFR. .75 lambda is 11AFR:1
Last edited by vboy425; Jan 15, 2008 at 04:01 PM.
lamba = actual AFR/ideal AFR.
For instance, an 12.5 actual AFR/14.7 ideal AFR = a lamba of .85.
slowcar, yes meth is less viscous and has a lower surface tension than water. Good lord I didn't calculate it! I just looked it up in a reference book
. I haven't had to do a calculation in quite some time! But the point is, meth flows BETTER than water. We all know how hard it is to get a meth leak to stop, the stuff flows that well!
For instance, an 12.5 actual AFR/14.7 ideal AFR = a lamba of .85.
slowcar, yes meth is less viscous and has a lower surface tension than water. Good lord I didn't calculate it! I just looked it up in a reference book
. I haven't had to do a calculation in quite some time! But the point is, meth flows BETTER than water. We all know how hard it is to get a meth leak to stop, the stuff flows that well!