AFR monitoring on carburated small block Chevy

[ian_uk1975]

Old school small block running Holley carb. Running side pipes with lambda bungs just after the collectors.

What do folks recommend for monitoring AFR to help fine tune carb jetting? I'm looking at the Innovate MT-L and LM-2. The MT-L is more for real-time monitoring, while the LM-2 does data logging, etc. The LM-2 requires an RPM signal, too.

Does anyone have experience of AFR monitoring on a carb motor running conventional ignition? Any alternatives to the Innovate stuff? Any advice welcome.

[Ive]

STACK wideband (UK relabel of US Autometer brand).
Very reliable, delayed start only after engine runs. Prevents sensor element cracking from condensed water.

[GreenV8S]

I've only used the Innovate wideband so I can't compare it to the others. I found the controllers a little unreliable (I think I'm on my third now) and keep telling myself I'll look for something better next time, but the other options seem so much more expensive that I keep coming back to Innovate. I think it's a reasonable choice for light use.

I've lost track of the MegaSquirt WB02 project but if that ever came to fruition I think it would make an interesting alternative.

[stevieturbo]

ian_uk1975 said:

Old school small block running Holley carb. Running side pipes with lambda bungs just after the collectors.

What do folks recommend for monitoring AFR to help fine tune carb jetting? I'm looking at the Innovate MT-L and LM-2. The MT-L is more for real-time monitoring, while the LM-2 does data logging, etc. The LM-2 requires an RPM signal, too.

Does anyone have experience of AFR monitoring on a carb motor running conventional ignition? Any alternatives to the Innovate stuff? Any advice welcome.

What type of manifold ? single plane or other ?

LM2 will be handy as you can record both banks ( with 2 sensors of course ) and it can log other channels on-board. Logging AFR's on their own is meaningless without some other reference....rpm at a minimum. If you also want to throw in TPS there too ( or maybe manifold presure which can be easier on a carb ) than that's even better.
At least you can then get a picture of when/where any fueling changes need made.

As much as I have a dislike for the reliability of Innovate widebands....here it would be a good choice simply because it can do everything you need with one box.

Daytona Sensors makes stuff too, but you'd have to buy it from the US, and it will be more expensive, probably quite a bit more.

[liner33]

Wideband o2 sensors wont live very long on a carbed engine ime so I would plumb for an lm-1 and fit it when you need to

[ian_uk1975]

stevieturbo said:

ian_uk1975 said:

Old school small block running Holley carb. Running side pipes with lambda bungs just after the collectors.

What do folks recommend for monitoring AFR to help fine tune carb jetting? I'm looking at the Innovate MT-L and LM-2. The MT-L is more for real-time monitoring, while the LM-2 does data logging, etc. The LM-2 requires an RPM signal, too.

Does anyone have experience of AFR monitoring on a carb motor running conventional ignition? Any alternatives to the Innovate stuff? Any advice welcome.

What type of manifold ? single plane or other ?

LM2 will be handy as you can record both banks ( with 2 sensors of course ) and it can log other channels on-board. Logging AFR's on their own is meaningless without some other reference....rpm at a minimum. If you also want to throw in TPS there too ( or maybe manifold presure which can be easier on a carb ) than that's even better.
At least you can then get a picture of when/where any fueling changes need made.

As much as I have a dislike for the reliability of Innovate widebands....here it would be a good choice simply because it can do everything you need with one box.

Daytona Sensors makes stuff too, but you'd have to buy it from the US, and it will be more expensive, probably quite a bit more.

Modified Performer RPM dual plane (notched plenum divider). Recently switched from a Victor Jr.

I'm kinda torn on whether to go for just a gauge and eye ball it whilst driving vs a data logger like the LM-2.

Saw the Daytona stuff... yes, a bit pricey. The Innovate products do seem quite good value.

[GreenV8S]

Definitely log it. Logging makes it much easier to deal with transient issues.

[stevieturbo]

ian_uk1975 said:

Modified Performer RPM dual plane (notched plenum divider). Recently switched from a Victor Jr.

I'm kinda torn on whether to go for just a gauge and eye ball it whilst driving vs a data logger like the LM-2.

Saw the Daytona stuff... yes, a bit pricey. The Innovate products do seem quite good value.

With it being a dual plane....and hence using 2 parts of the carb totally separately, I would definitely run one wideband per bank because you are essentially using 2 carburetors.

Yes it is unlikely you would jet either side of the carb differently....but you may need to and you would want to know how each side ( and the engine ) is performing.

And as Green says...dont underestimate the value of logging. Manually watching the display is certainly very good and useful, but with logging you can just get a much much better picture...without the distraction of having to look and then trying to remember.

Starting with an LM-2 here just seems like the best option for something that can cover pretty much all of what you need with a single box.

But you would probably need to add some sort of interface to give it an rpm signal, and likewise the addition of a map sensor or better for a n/a carb setup a TPS sensor would be very helpful.

[99hjhm]

Ive said:

STACK wideband (UK relabel of US Autometer brand).
Very reliable, delayed start only after engine runs. Prevents sensor element cracking from condensed water.

Agree with this, very easy to use, had one in an MGB for almost 10 years. I personally don't see the need of logging if your own car and on a carb engine. Also have an LM2, good bit of kit, never used it for logging either. Got one after seeing it used by a top professional mapper and still affordable.

[PeterBurgess]

We use a single and a dual LM2 for on road testing sometimes logging. They are not used much so the sensors have been ok with carbs.
The rolling road uses the NGK Powderdex which uses a good sensor. We have used three in 7 years losing them to wire damage none have failed due to crap from carb fuelling. The NGK version is nla but there is an alternative. The real time monitoring is good as is the logging.
https://www.bmotorsports.com/shop/product_info.php...

If logging and using a carb with a needle, testing with a notch or system of notches can help with working out needle position.

Peter

[stevieturbo]

I'll say it again, never underestimate the value of logging.

Buying a unit that cannot log, when you also have no other means of logging....is almost throwing money away in this instance.
Not a total waste of money because a wideband always has value, but close to it when there are also cheap options that can log.

If you really want a budget unit with no frills...in this instance there's one of the AEM's that offers some degree of logging built in and has a map sensor built in. Not sure whether it can receive a signal for rpm though. I think it's their failsafe unit.

Zeitronix is another system that you can add various sensors too to log. Maybe not quite as convenient as Innovate's but still a very valid option.

[Sardonicus]

I have had the LM-2 full kit for over 5 years now and apart from initial bugs which firmware revisions sorted its been trouble free inc the 02 sensor latching up the RPM input is easy and useful for logging which is all I use the LM-2 kit for nowadays, for full time use I just rate 14point7 products I use both gen 1&2 of the Spartan on different set-ups and they work great and most of all reliable comparing both Spartan and Innovate give or take a knats readings on both compare bob on pretty much

Edited by Sardonicus on Saturday 6th January 11:57

[GreenV8S]

stevieturbo said:

Zeitronix is another system that you can add various sensors too to log. Maybe not quite as convenient as Innovate's but still a very valid option.

I liked the ZT-2. It has lots of logging inputs and a decent display for a reasonable price. I was very sad when mine got slightly melted and stopped working.

[ian_uk1975]

Thanks for the input, think I'll go for the LM-2.