I'm looking for some feedback for tuning with 02 sensors and methanol. I bought a dragster that has the o2 sensors and I'm unfamiliar with the technology. I've had EGT and understand how use that, but this is my first rodeo with 02.

I understand that like EGT, the numeric values are merely a reference when it comes to tuning and what each individual engine likes or doesn't like. Having said that..What is a normal range most of you guys are seeing with methanol at idle, mid range, and top end? Thanks in advance.

What system and is it set to read Lambda or air fuel ratio and what scale?

Daytona Sensors Wego III. Reads AFR. Not sure about the scaling.

Looks like the scaling for methanol is 4.5-8.6 according to the WEGO site.

I use the gas scale and run alcohol. My car on the dyno and at the track runs best at 12.9 to 13.1. Your mileage may vary, things like calibration may make yours somewhat different than mine. Tune to best eat then note the o2 and that will be your target.

I first got 2 O2 and had 4 EGT I now have thrown away all of the EGT and have 8 O2. Now the reason I did that is because I have mechanical injection and I can tune each cylinder. With a carb you do not need that many. On my car the EGT was totally useless for tuning.

Most sensors/software can be programmed to display the data in different forms. The sensor has no clue what fuel is being used so it doesn't matter what scale you program it to. All the program does is take the same data and display it differently. Here are some very general guidelines for each...

Lamda - 0.85
Gas Scale - 12.5
Methanol scale - 5.4

Scott

quote:

Originally posted by 358T:
Most sensors/software can be programmed to display the data in different forms. The sensor has no clue what fuel is being used so it doesn't matter what scale you program it to. All the program does is take the same data and display it differently. Here are some very general guidelines for each...

Lamda - 0.85
Gas Scale - 12.5
Methanol scale - 5.4

Scott

This^^^^

I have the grid with two O2 sensors, one in each collector.

Never looked at idle. Only records on the 2 step and up.

Left side reads 4.9 and goes up to 5.1 on an 1/8 mile pass.

Right side reads 5.4-5.6 on the same run.

SBC with an alcohol carb.

Everybody's will vary slightly depending on where the sensor is, the scale and the calibration to begin with. I have a Wego111 that is tied into my data recorder. You can see my average is roughly 5.6 with this in the #7 pipe about 8" before the merge. Mine won't be as smooth as one that is in the collector.



Curtis

I like the Ballenger Motorsports setup, it's a very wide band controller (6.0-20 gas, 2.61-8.7 alk). They also use higher-grade NTK sensors...the lab quality ones aren't cheap though. It's only single channel though.

The big issue with O2 sensors and alcohol is that the alcohol fuel will mix with the zinc from the oil that isn't removed by the piston rings...the chemistry of alcohol + zinc = a substance which is known to very quickly kill the actual sensing junction in the O2 sensor itself.

Not sure what you call quickly. I’ve had the same sensor in since 2012 only on alcohol.

Here's a tuning chart I created many years ago.
Use and share if you want.

http://www.hardtail.com/download/lambda-tuning.xls

Thanks for the replies everyone! AlkyIroc, thanks for the share. Very useful!