wkdivr

iTrader: (8)

Let's get a good discussion going. We all know the best AFR with forced induction at wot is in the neighborhood of 11.9-12.00. Now....when spraying 100% meth, would you still shoot for the same target afr, or should you shoot for something in the range of 10.5-10.8? Remember that the stoich of methanol is 6.45 to1 vs 14.68 to 1

trever1t

iTrader: (14)

We have gotten the best results (on the dyno) with keeping the A/F in the high 11's

kbracing96

iTrader: (26)

Quantity of meth your spraying to gas that's going in is usually much less. Being its higher octane, anyway I usually shoot for the same target AFR, around 11.5-11.7 for my setup.

Holty

iTrader: (6)

way to double post Billy! you should check your email more often!

https://www.performancetrucks.net/fo...d.php?t=391897

gmforlife

iTrader: (2)

I know that the stoichiometric ratio for methanol is 6.47, but since you are not running on that you can't use it, but i would imagine something a lil bit lower that 13:1 at least, like the other guys said, like 11-12:1

wkdivr

iTrader: (8)

Here's a quote from the Turbo Buick site


If your wondering what stoich is when mixing fuels, it will depend on how your O2 sensor is setup. If your sensor is setup to read out stoich as 14.7, then stoich will always be 14.7 no matter what fuels you are burning. I run 100% methanol and my sensor read out has always been setup for gasoline A/F reference numbers. I just read it as if I'm burning gasoline. Idle A/F is 13.4 to one, WOT lean best torque is 13.3 (very dangerous for blown alcohol), WOT rich best torque seems to be around 12.4 to one, although I run mid to high 11s to one at WOT to be safe. You must remember that the O2 sensor is reading left over oxygen after combustion. That is all. It doesn't care what the fuel is, it is only reading oxygen. When the least amount of oxygen is present, the more complete the combustion process. I believe that is stoich.

dewmanshu

iTrader: (4)

This is amost a confusing statement. Ofcourse if the setup is "supposed" to be reading 14.7 as stoich then 14.7 is stoich. LOL combustion of gasoline and air's ratio to be a PERFECT burn IS 14.7 lbs of air to 1lb of gas. Methanol is 6.4x lbs of air to 1 lb of meth. We have already established this. By mixing the 2 I find it hard to believe that if your setup is designed around 14.7 then your still looking for 14.7. ????

Now take into consideration we all understand under load this won't work due to the extreme heat caused from this "perfect" combustion and let's face it, what's good for whatever setup in WOT is almost strictly opinion, not fact based. But we have appropiate windows eg; 11.7 to 12.3 under boost and so on. So more fuel or meth is added to richen the mixture up. But with that said, I'd imagine there is an equation of sorts that would show us by introducing meth into the gasoline we would need to take that into consideration. Just cause we would run straight meth on a system that is "setup" for 14.7 doesn't mean we still shoot for it. If that was the case, you'd burn the exact same amount of meth as gas, and if it that was true...oil business would pratically die over night.

Only people like Wilde Racing would see HUGE differences in AFR's when they use meth. His IDC goes from 115% to 70% when his THREE nozzles come on. And I mean huge differences like he would need to take into consideration that 12:1 just isn't gonna work for him.

I ran meth last year and had my setup running with no kr at 11.8 w/gasoline. Same setup, shot meth...tuned it to 11.7ish:1 and coudn't get rid of the kr. Brought it down to 11.5 and it ran like a champ. So with whatever my equation of added meth it "seemed" to me that knocking .3ish off the afr helped emmensly.

dc_justin

iTrader: (13)

Personally, I would richen it up a tad more with the meth mixture, and here is the reasoning. When running pure gasoline, once you've burned one part fuel to every 14.7 parts air in the cylinder, no more will burn. All remaining fuel in the chamber has but one purpose. Thermal management. You richen up from 14.7 down to 11.5ish to use that excess fuel to remove heat from the combustion chamber to keep detonation from heat from occuring. When running meth, you're substituting a portion of that heat buffer with a liquid that will theoretically be completely burned at that AFR, leaving you with less remaining fuel to remove heat from the chamber. If you're running a safe AFR to begin with, you will be fine, but if you're at the edge of safety to begin with, I'd definitely target a slightly richer AFR.

Edit: Didn't see dewey's post when I posted. This is exactly the condition I was talking about.

wkdivr

iTrader: (8)

All Very interesting thoughts! Please remember guys, we're not trying to start any kind of bashing, or anything, just wanting to hear all the different opinions people have. Dewey, what were you running for wot timing when you ran the meth? I'm thinking I can kick it up quite a bit. The whole reason this discussion came about is the last time I ran at the track (also the first time using meth), my afr thru the traps was in the mid tens. I was thinking that was WAY too rich, but in talking to Julio, he mentioned that was a good, safe starting point, definately safe. Then add timing till you get knock, and pull it back some. Lastly, after the timing is in the ballpark, pull fuel till the best mph is reached, using afr as point of reference.

dewmanshu

iTrader: (4)

I didn't mean to sound bashing...just that quote sounds funny to me, stating the obvious. LOL

In my setup I was getting 22* with the meth at 11.5:1. I currently run 19* with no meth on the street. I kinda like not to run meth on the street, it's not THAT much of a gain to warrant filling that meth tank (window washer tank ) up every tank of gas. However, I didn't experiment enough with the meth on my setup. I took a stab at 24* and had some kr, but as in my theories above, I bet dropping that AFR to 11.0 would definitely solve that. I just didn't experiment enough. And to be honest, I was having some other issues (trans), but I didn't get any faster going from 22* to 24*, granted the kr pulled some of it away.

Julio would know I guess, but 10.x:1 just sounds crazy rich for anything under 10#'s of boost. Just test it out at the track, raise the spark a degree at a time and see if you get more power out of it (time slip comparison I guess). The back off frm the kr. Theeeeen, start leaning it out a little and see if you gain some power from that or kr comes on. blah blah blah...LOL, I am rambling, it's all in my head, just can't get it on the screen.

So the big question, super rich and maxed timing is better or leaner mixture with moderate timing is more power. parish has pretty much paved the way for answers on this right? He preaches more meth more meth more meth!