Methanol's affect on AFR readings
 

Thought I read somewhere on here that when running methanol injection it can make your AFR's appear leaner than they really are. For example: Your gauge is reading 11.8-12.2 when in reality it is around 11.2-11.5. Is there any truth to this or just misinformation that I was reading?

Misinfo.

A few points

Various widebands have different calibrations for different fuels

Also various fuels burn at different "ideal" ratios with air

When we are spraying alcohol in gas it is a hybrid fuel

The amount of alcohol used governs how rich the mixture should be

Generally you should run alcohol much richer than gas

I think you are talking about my thread Creamo, my AEM UEGO reads 11.2-11.6 on 100% VP methanol at WOT. anyone know what this means? too lean? Just right? any info would help alot of us out.

Is 11.2- 11.6 too lean when running Meth with Pump?

I will give you a Starbucks gift card, if you can translate that into 3rd grade english!:lol: Wasn't Lamda-Lamda-Lamda a frat house in a movie? I can't get past chuckling at that when I try to read thru it. What does it mean? is 11.2-11.5 with 100% Meth and 93 pump too lean? (readings on AEM UEGO wideband?)if spraying 100%? is that LEAN? Or Lamdaliscious?:lol:

I too would like a translation on that info althought it does seem to be useful :D I am just trying to figure out if the meth throws off the Wideband readings or not. And to answer above I don't believe that 11.2-11.5 is too lean. On the top of a 3rd or 4th gear pull I am seeing around 11.8 afr on a AEM UEGO.

smoked/creamo:what is your fuel to alcohol ratio? doesnt matter if its in volume or mass as they both have ~same density.

Now we are talking "ratios"?:lol: It's late, I suffer from adult onset Hydrocephalus, have shunts and metal plates in my head...........there is no more room for any information!! Just an OK, yes or no is what I am looking for!:lol: I have no idea my ratio, can I tell you my body-fat-index instead?:crap: :lol: I will have to look at this later, my head hurts.

I have found consistantly 93/ alky runs fastest at 12.5-13.5 . Same as non-turbo cars. Straight 93 octane needs to be rich to keep cylinder temps at bay. Alky does such a good job at absorbing heat that rich mixtures are not necessary. However fantasic power can be made at very rich mixtures (10.5-11.0)and is the safe way to tune. if the alky fails the airfuel ratios stay in a safer zone.

As far as the wideband reading goes. If the wideband is calibrated for gas and displays 14.7/1 for stoich.When that wideband is used for alky which is 6.5/1 stoich. The display does not change. It will read 14.7 when the air fuel is at 6.5/1 on alky. If you want the wideband to display 6.5 on alky you would have to recalibrate the meter to do so. So if you display reads 14.7 and you are running one part fuel to one part alky. Your actual mixture would be half way between 14.7 and 6.5. So the original question should be a yes. But it is deceiving because the mixture is richer because the content of alky/air needs to be richer.

Bingo! 94awdcoupe hits the nail on the head.

I also want to point out I have tuned for both ends of the scale. 10.5/1 and 13.5/1. Here is what I have found. When you are tuned for 10.5 and the alky fails it is hardly noticable power wise so it is easy to stay in the throttle and hurt the engine. Now when you are tuned for 12.5/13.5 and the alky fails it becomes immediately apparent because there is a very large power loss and usually results in lean misfire. Engine stays safe because its easy to notice the power failure and a quick lift of the throttle keeps the engine safe.

Thanks AWD coupe, great info (as usual)

I'm running a M10 nozzle w/ 100%methanol
FIC 650 CC injectors

94AWDcouple-Thanks for the clarification seems to make better sense now. I don't really mind when I see the wideband go from 11.8-12.2 because I know how much of a buffer the methanol puts on the overall mixture while still keeping things relatively safe.