Questions about adding air/fuel ratio meter

I've got a fresh engine running, have ordered an exhaust system, and this would seem a good time to add an O2 sensor provision. For a carburetor, is it a worthwhile tuning aid? I don't think I want a permanent gauge, just something temporary to get the carb set up. I don't have any experience with these, so what's a good source of information?

For a street car, a wide band O2 is indispensable IMHO. BUT! The tuner has to understand the carb, it's circuits, and have the tools and parts to make the necessary changes. Seeing a problem is one thing, knowing where to go in the carb to address it is another.

As to the O2, things happen very fast so I think logging is a necessity. Trends such as the fuel curve through the RPM range can be hard to note without it. Besides, trying to drive and closely watch the gauge at the same time can get dicey.

Definitely add one if you have the means. You can always remove it and plug the bung if you want to run one temporarily.

I had my trusty exhaust shop weld in an O2 bung right after the collectors (that way I didn't touch the headers which already had ceramic coating applied to them). This has always worked for me very well.

Like others have pointed out, to really make good use of this feature you'd want the ability to LOG. So from that perspective I do not actually have a fulltime connection/display in the dash, instead I hook up my O2 wide-band sensor, toss all of my Innovate stuff on (couple of boxes and extra sensors), fire-up the laptop and go for a tuning ride.

I go through a repeated process (so basically a Step1, Step2...StepN kind of a thing), do my data capture, come back home, park the car, crack open a cold one and replay it all back on my laptop as I jot a few notes down in my paper log-book.

It's actually kind of fun...I love doing the carb work and the only thing missing in my log today is a TPS setup for my Carter TQ and the second O2 sensor for the other cylinder bank. There are a few modules floating around out there, so once my new engine is up and running that'll probably be the next add-on.

and then use it to tune the other cars and trucks in the fleet

I’m tuning with an Autometer AF right now on a 427 Cobra. Without it it’s quesswork. Turned out it was leaning out under heavy throttle and I never would have guessed that. Also discovering that fuel bowl management with a Holley DP is harder than we think! Really glad I did this. Mine will be a permanent gauge. Stoich!

i bought and started using a Innovate LM1 years ago, later added the kit to convert it to dual readings and storing the readings on the control unit, I could start and stop recording the readings and transfer it to my lap top later for reading it at home
I used that on my old pump gas Duster with a low deck six pack set up stroker motor
That was one of the bust buys I have ever made

I added a innovate lm-2 with dual sensors to my bee a few years ago, I also added a tach input, throttle position sensor and a map sensor. I was able to log all of the inputs lm-2 and display on my laptop. It worked pretty well snd was really not that hard to setup.

Kevin

Kevin,



Which TPS did you use? ...and which carb is it attached to?

I have LM-1, the RPM Kit and the AuxBox. I can do MAP with the AuxBox, the RPM converter captures a steady RPM signal, but the TPS really has to connect to the AuxBox.

I think I bought it from innovate motorsports

TPS-TH36

Kevin

This is a picture of it installed

Great tool to have but you will need to learn the dark magic of carbs to really dial one in good. I learned so much after a successful carb build on a 500HP 360 that got good MPG and had good manners that I abandoned ship quickly and went EFI! I have a toolbox full of blank air bleeds and feed restrictors and all these tiny drill bits and that was the stepping off point for me haha.

In my opinion the TPS sensor on a carb doesn't have much value from a data logging standpoint.

During my current Holley 4150 tuning I learned that he carb is extremely sensitive to float height. In fact it wants very low bowl levels or the carb floods out during cornering or heavy braking, and this is with whistles in both bowls, extensions in the secondary, and a connection tube on the bowl vents! Now I’m buying the ridiculously overpriced secondary linkage in order to bring the secondary’s in sooner.

Doesn’t the proximity of the harness to the secondary shaft concern you?

Excellent thread, thank you gents.

I'm leaning towards this, I'm leaning so much I've almost tipped over.

I'd recommend it to anyone. The difference adjusting idle fuel and transfer slot restriction on mine has been pretty dramatic, cleaned it right up.

Funny, once I knew how far off certain things were, I didn't hesitate to drill and tap a basically brand new carb for the tiny jets to make an adjustment where before I wouldn't want to do something like that to a new part.

I started off with a f.a.s.t. (comp) display, it worked fine during the day but the brightness of the display was too much for me at night + wasn't adjustable I wanted to tear the car down for a bunch of work anyway so I sold it to a buddy. My next one will probably be either an innovate or possibly daytona sensor.

Thanks for the replies. I'll for sure weld in a bung, so will have options.

I have both Racepak N2O's and all 8 Racepak EGT sensors on my Challenger. Always good tuning info to have and being able to data logging everything is nice, but costly as well.

Hmm...interesting comment.

My goal in deploying a TPS on the TQ is to be able to correlate the metering rod position w/ respect to the jet, to the actual throttle openning itself.

Combine that with a VAC sensor reading and you've got yourself a fully featured "see through" Carter TQ model.

Heck...if that seems crazy, I do actually have a sectioned TQ body here that (umm...you know, COVID came to town, it was winter time...and I got bored LOL), that I've studied a little and have done my fair share of air-bleed adjustments and tuning already.