Air / Fuel Meter Recommendations

[Captain Obvious]

I want an A/F ratio meter like many of you other guys have so I can make a run with the car while logging the fuel ratio details.

My short list is "I want to do data logging, and I prefer an analog display over digital."

If I pulled the trigger today, it would be for Innovate's MTX-AL (analog). Why? Because I know nothing about such devices and Innovate is a big player in the market, and hopefully produces quality stuff.

Any input about Innovate's logging and analysis software? If I don't like it, are there other third party offerings that I could use instead?

Any other recommendations about brand or style?

 

* I thought I had asked some of these questions in the past, but I just can't remember or find it if I did. So apologies if I'm rehashing something I've already done.

[Dave WM]

since I know you have done the research can you explain a few things?

diff in "narrow band and wide band"

where to mount O2 sensor.

How to mount sensor.

Before or after cat (if you have one, like I do on my 75 cali Z).

[SteveJ]

Differences: https://www.haltech.com/oxygen-sensors-and-wideband-controllers-explained/ If you're doing the O2 sensor for tuning, it's wideband all of the way. If you have a simple EFI system with an O2 sensor input and don't intend to do data analysis, narrow band will work.

Mount it after all of the exhaust tubes come together and ALWAYS before the cat. You want to see what's happening inside the engine.

How? Drill a hole into the exhaust and weld the proper curvature bung to the exhaust. About any decent muffler shop can do this.

[Dave WM]

would be an interesting mod if you could adapt the wide band readings into the AFM as a way of making the early systems into a closed loop. A small plus or minus voltage added to the wiper of the afm arm.

Edited November 5, 2020 by Dave WM

[SteveJ]

I have been working on a 280Z recently whose owner had someone install a rising rate (normally aspirated version) adjustable fuel pressure regulator. The person who installed the FPR did not connect it to a vacuum source. The owner connected the FPR to a vacuum port but reported no improvement in performance. He brought the car to me, and I researched the FPR. It actually called for a stock FPR to be in the circuit with the adjustable FPR. 

After looking over the car and tweaking some things, I took it for a drive. There was a stumble at throttle tip-in, but eventually it came to life. The wideband AFR meter matched my butt dyno. I could see the car getting really lean on the AFR meter at tip-in. I actually talked with the engineer who designed the adjustable FPR (Corky Bell), and he confirmed that my research was correct. The owner needed a stock FPR added in.

So even with the stock ECU, the AFR meter can give you some good data with regard to something like an adjustable FPR. Frankly, I'd like to see a fuel pressure gauge and AFR meter side-by-side.

[Captain Obvious]

11 hours ago, Dave WM said:

would be an interesting mod if you could adapt the wide band readings into the AFM as a way of making the early systems into a closed loop. A small plus or minus voltage added to the wiper of the afm arm.

Yeeesh. Too much black magic and voodoo in that ECU for me to ever consider doing something like that.       If you ever succeed with this, I will drive my Z to your house and loudly proclaim in public that your kung fu is the best.

[Captain Obvious]

How about a couple pokes for input (in no particular order)?   

@Chickenman, @duffymahoney, @jonbill @blodi, @JSM, @conedodger

Edited November 6, 2020 by Captain Obvious

[jonbill]

I have a Prosport controller and gauge that I ran for a couple of years stand alone with carbs and distributor. it was very useful to see what the gauge was saying as I drove and it helped me identify problems with fuelling. when I switched to Speeduino EFI, I connected the Prosport controller in  and started logging from that, which makes tuning it really easy. 

I would think logging would have little value if you can only log AFR - only useful if you have the AFR data against load (tps or map) and RPM. 

so there's the answer, fit a standalone modern ems and log everything 🙂

[Captain Obvious]

Thanks Jon. Hmmm... I see your point.

For my logs, I guess I was looking for mixture vs RPM. As far as engine load goes, I was going to have to do that by memory, as in "This was a full throttle third gear pull." and then interpret the results knowing those conditions.

So I guess the question is do the stand-alone gauges (like the Innovate MTX series) even know what the RPM is and output the RPM data on their log stream? Does the MTX even have an RPM input pin?

Or do I need something like the LM-2 to do that like blodi:

[240260280]

I have an old Innovate LM-1 that works fine. Remember Toronto 🙂  

I simply stick it up the exhaust pipe when needed.  It logs but has an old rs232 i/o. It also has an aux input for logging another input (such as rpm).

You will have more precision if you measure at the manifold or collector however measuring at the exhaust output gives the same steady state values (cruise, acceleration, idle) but the instantaneous changes are smoothed. (See lovely graph below) 🙂

Ideally an exhaust gas temp sensor and O2 sensor on each runner would be the best but for street, using IR thermometer on plug or exhaust runner and measuring RPM drop when pulling one p[lg at a time are adequate checks for cylinder-to cylinder performance variance.

 

Edited November 6, 2020 by 240260280

[jonbill]

looking at this: https://thumpertalk.com/forums/topic/1273912-wideband-with-data-log-how-does-it-work/

It looks like you need a bunch of kit.

you could get a 14point7 SLC free and a speeduino for a lot less, just to log. 

You'd hook it up to the coil for an rpm signal and you could even put a potentiometer on the throttle. 

Edited November 6, 2020 by jonbill

[AK260]

I use the innovate you mentioned in your original post. My initial plan was to take it to bits and build it into the clock face so as to keep the car “looking” original but at the flick of a switch, the minute hand on the clock would turn into an AFR display. (My clock is dead anyway!) Actually, that is a terrible idea as I find having it in my field of view far more useful than having to take my eyes off the road to read it.

 

I looked at options to add rev and MAP sensors as well as the data logging unit. It does get costly though. This would be the ideal way forward and I will go that way at some point when I can justify it.

 

What I have found though, is that even using it standalone temporarily stuck to the windscreen - doing 2nd or 3rd gear pulls on my local dual carriageway from 2k rpm, it has been invaluable for my WOT tuning efforts.

 

It also helped me instantly know my fuel pump had failed when the engine intermittently lost power - the AFR needle went Far East quickly. Watching the needle dancing based on throttle conditions does become addictive.