Is using an A/F digital gauge worth the cost and is it beneficial in a drag car application? I would love to install a data logger but just not feasible for me at this time. Thank you

It is very beneficial to me. It shortens the time to tune my carb if I make any changes. I bought a used Gold Claw early on when I started racing and it allowed me to get that carb set up to be a really good piece.

When I get in the spring or fall it really helps to see the jet change so I'm not too lean. Once you have the data then they are just along for the ride other than if something starts causing a problem you have it to look at.

I am a big believer in O2. I have used EGT and had very poor results with them. The O2 has been a big help. With that said I do not think you can get a good consistent finish line reading on it with out some kind of recording device, GoPro camera on it or data logger etc.

I run 8 of the O2's and look at data right before finish line wide open. What I am looking for is one that is out of line with others and overall readings. For my motor it liked 12.9 to 13.1 on the gas scale on alcohol.

Question for Curtis Reed, Why do you have to change jets in your carb in Spring and Summer? A carb is self adjusting to weather as the thicker, denser the air is the more fuel it pulls into motor.
I run mechanical injection and so I do have to compensate for better air by adding more fuel but it is not much.

Bruce, it's self adjusting to a certain point. I've seen you make these comments before but jets will only flow so much fuel no matter how dense the air gets.

I was racing in -DA weather a couple weekends ago. +4700' in the heat of summer. I don't care to race real lean because it swings too much as the air changes.

If you use MSD 7730 Grid ignition, they offer a wide band O2 module that records. Several I’ve seen logging O2 data in Grid look very good.

Before investing in a data logger consider purchasing an ECU instead. It’ll data log and can run many functions in the car and more for close to the same price. Fully expandable in the future if desired.

My ECU controls afr to what is programmed. I’ve raced -700 to 4500 DA with an et swing of 0.18 for the afr I’ve used. Recently updated software in this ECU now allows for programming afr in 0.05 increments.

Have used a Inovate Motor Sports digital for years great tool to dial in new carb or combo with mine will program to many types of fuel all down loadable from Inovate just over 200 bucks

where are you guys installing the o2 sensor ? I have min in the collector but is is not reading properly at a idle seems to read correct down track at speed

quote:

Originally posted by camaro77:
where are you guys installing the o2 sensor ? I have min in the collector but is is not reading properly at a idle seems to read correct down track at speed

You need 12 - 16” of pipe past the O2 sensor for it to read properly at idle.

Mines in the collector and has 16” of pipe behind it. I believe it reads correct at idle on both methanol and pump gas.

quote:

Originally posted by camaro77:
where are you guys installing the o2 sensor ? I have min in the collector but is is not reading properly at a idle seems to read correct down track at speed

I have bungs in 1,2,7,8 and both collectors. Two sensors, one on each side. That way I can move them around to check different readings. I do have turnouts on my headers so I have a good length after the collector I have never even looked at the readings at idle.

Have a bung in #5 and #2 yes at idle it jumps some from4.9 to 5.1 but seems to stage best there its at 5.3 down track

Here’s a graph of RPM, AFR and Closed Loop compensation. The crosshair is at idle with the TB button just pressed prior to 2 step WOT. The AFR is varying from 4.7 to 4.9 at idle in this display. This is 90* , 4000+ DA weather.

I have a Virtual Switch programmed on my dash, that when activated will lean the idle AFR into the 6’s and raise the EGT to high 900’s with TPS of less than 5%. This is self-cancelling if left ON during WOT operation.

How long does an O2 sensor last using leaded race fuel, or is it even done?

quote:

Originally posted by camaro77:
where are you guys installing the o2 sensor ? I have min in the collector but is is not reading properly at a idle seems to read correct down track at speed

The exhaust pulses are to far apart at idle so outside air is drawn into the collector causing a lean reading than what is real! Logging idle AFR is not required, you can easily adjust the carb to get good idle without one.

Once rpm exceeds 4000 or so, it will read the correct AFR the motor is actually seeing.

quote:

Originally posted by Goob:
How long does an O2 sensor last using leaded race fuel, or is it even done?

I have had mine in for ten plus years. Still good.

I will say this, they aren't all the same! When tuning with AFR's, let the time slip tell you what the motor wants and not what joe pro engine guy says it should be 12.9 or 13.2 etc. The motor is smarter than all of us, so listen to it. And as is said O2 calibration from sensor to sensor is a factor.

quote:

Originally posted by TOP38:

quote:

Originally posted by Goob:
How long does an O2 sensor last using leaded race fuel, or is it even done?

I have had mine in for ten plus years. Still good.

I will say this, they aren't all the same! When tuning with AFR's, let the time slip tell you what the motor wants and not what joe pro engine guy says it should be 12.9 or 13.2 etc. The motor is smarter than all of us, so listen to it. And as is said O2 calibration from sensor to sensor is a factor.

ABSOLUTELY!!! Some people say "What should my O2 reading be?" Does not matter what scale you use or what the numbers are. Tune to best ET and MPH and then look at the O2 and those are numbers you want. It is not the same for all motors and sensors, loggers etc.

I do not know how long they will last with leaded gas. I know I run them with alcohol and never had any problems.

I do use the gas scale simply because it is easier for me.

I’ve never used or needed an afr gauge when on MFI. Tuned it for best mph and then most consistent et’s. Only recently did I install a complete ecu minus the injectors to see what the MFI tune up looked like. When I switched to EFI I programmed using the same target afr map as prior and performance was the exact same.

I agree with others, the type of afr sensor and gauge will vary your results. What you record in afr and another does with same set-up can be very different.

I have viewed several EFI configuration files that use same ecu, afr sensor ($300+ NTK), fuel type and n/a injection as I do. Their afr programming maps are very different from what I have programmed.

[QUOTE]Originally posted by Goob:
How long does an O2 sensor last using leaded race fuel, or is it even done?[/QUOTE
That would be my question. Was always taught leaded fuel would kill on O2 sensor.

quote:

Originally posted by Eman:
[QUOTE]Originally posted by Goob:
How long does an O2 sensor last using leaded race fuel, or is it even done?[/QUOTE
That would be my question. Was always taught leaded fuel would kill on O2 sensor.

Not long if you are stupid rich, I lost a couple of 4.2 O2 sensors running a 4 cylinder BMW rich. That was 10 years ago, haven't lost any since and I do a bunch of circle track engines running leaded 110
.

Next question…….. Why is the need to use leaded race fuel?? I looked at a VP product list and the majority is leaded. I’ve always used methanol, so don’t understand this.

The NTK O2 sensor is recommended in Holley ecu for methanol and leaded race fuel.

quote:

Originally posted by markemark:
Next question…….. Why is the need to use leaded race fuel?? I looked at a VP product list and the majority is leaded.

I'm a methanol guy too, but just look at the (R+M)/2 octane ratings for the unleaded fuels. There's no unleaded fuel that is going to allow 15:1, 16:1 engines to run healthy.