O2's with Alky?

[tazgn]

I posted this in the alky section too, but I figured I would try here too as there may be more people in this section that know the answer.

I just got back from my first real track time with the alky kit and have a question. I have a FAST DFI and my target A/F was set for around 11.6 at WOT (street program, playing it safe). But with the alky turning on around 13 psi boost and pump set at 7, my A/F is going down to 9.81 (I think the bottom of the range of the O2 sensor). How does the alky affect O2 readings? I'm trying to figure out if my WAY rich condition is due to the alky or due to my FAST setup. My EGT at the finsih line was only 950* so the O2 readings are right.

Thanks,
Derrick

 

[Craig Smith]

Mixing methanol and gasoline will have an effect on the O2 reading, but the effect depends on the proportion of methanol to gasoline. The O2 sensor will always display a/f ratio readings under the assumption that gasoline is being burned, since that is what the sensor is designed for. However, with straight methanol, a displayed a/f reading of 13:1 is really about 6:1.

Wish I could tell you a little more. Among the trillions of geeks on this board, one of them must be familiar enough with the math involved to inform you of what effect a certain fuel proportion will have on your O2 reading. If so it will be a learning experience for me as well.

Hope this helps.