LM-1 Sensor Position

[NevenM]

Hi

If you putting the LM-1 in an MFI setup, I can't see any great advantage in 2 online sensors, You can balance left to right by other methods (syncrometer) or if you wanted log dual MAP sensors in the intakes, There would be an argument for dual bungs in the muffler (I haven't bothered tho as the LM-1 only shipped with 1 bung) so that you could check the
LR balance. If they are out for any particular reason (cam timing, intake leak, faulty injector) then you are stuffed until you fix the problem. as youb can't correct the side individually

Neven

[michel richard]

I was under the impression that the MFI systems that use vacuum advance use two runners (#1 and #4 IIRC) symply to get strong enough a vacuum. I run an MFI on a 2.2, without the vacuum, so I could be wrong, but I believe the vaccum is not drawn from both "banks" as such, only from two cylinders that happen to be one on each bank. Staggering the intake events may also have been a factor in choosing the cylinders to use, I'm sure.

FWIW, I've got the LM-1 and I installed the bungs at the very end of the headers, just ahead of the muffler flange. One bung per side. Initiallly, the plan is to use the LM-1 only as a diagnostic and tuning tool, one bank at a time. Later there is a plan to couple the LM-1 to an electronic box and a servo motor that would adjust the position of the main rack on the MFI pump. Neven is doing the heavy lifting in that regard.

Michel Richard
914 2.2E MFI

[klatinn]

Hi Grady,

Let’s do a little simple engineering here and design a switch for left-right. The sensors are relatively inexpensive. How is an O2 sensor powered in Factory configuration? The only issue I see is the LM-1 calibration cycle.

That's not possible. The WB sensors are not simply 'powered', but have a heater that needs to be controlled. The operating temp of the sensor MUST be regulated to 800 degC. The controller (LM-1) regulates the temperature to that. Otherwise the sensor will live only a very short time.
We (Innovate) are coming out shortly with what we call a 'Lambda cable' or LC-1 (prototype was shown at SEMA last week). This product has the WB controller of the LM-1 molded waterproof into the sensor connector itself. It has the same programmable analog outs as the LM-1 and also has 2 serial ports for logging. With the serial ports it can be daisy-chained with the LM-1 (serial out of LM-1 to serial in of LC-1, serial out of LC-1 to laptop or digital display(s) ). Up to 12 LC-1's can be daisy-chained.

Regards,
Klaus

[Mike Bonkalski]

Forgive my inexperience on this topic, but if your carbs/throttle bodies are balanced and your fuel supply is accurately accounted for (proper psi, having fuel injectors test for flow) and your timing is accurate, what benefit will you gain from measuring each bank?

If you have aftermarket engine management aren't the changes you can make with fuel supply and possibley timing is usually limited to the whole system and not each bank? With batch injection you can't control fuel to each indvidual cylinder.

It seems if the muffler location can give an accurate reading, as Wayne stated, it looks as if it is the way to go.

[Grady Clay]

Klaus,

Cool. Is this up on your site yet?

Yes, I understand the issue of controlling the temperature. I should have used the word “controlled” rather than “powered.”

As I understand what you posted, you can now have up to 12 sensors (each controled by a LC-1) and the data and control daisy-chained back through the LM-1. I assume you go through the calibration process (heater & free air) for each sensor via the LM-1.

Good for you guys! Take a great product and make it better.

Is there a reasonable method of having an additional calibration point in addition to “free air”? Are there suitable calibration test gasses available? What would be the procedure?

Best,
Grady

[klatinn]

Hi Grady,

It's not on the web-site yet. We just introduced it, but it will take a month or two before we ship.

As I understand what you posted, you can now have up to 12 sensors (each controled by a LC-1) and the data and control daisy-chained back through the LM-1. I assume you go through the calibration process (heater & free air) for each sensor via the LM-1.

No, each LC-1 is stand-alone. It can run completely independent. Calibration can be performed individually on each. In it's simplest form you can just use a LC-1 and an analog gauge. Or 2 LC-1's and a double gauge like Westach makes with 2 needles. You can still real-time log with LogWorks then. The LC-1 has a special interface wire for calibration. Just ground that wire through a pushbutton switch to initiate free air cal.

Is there a reasonable method of having an additional calibration point in addition to “free air”? Are there suitable calibration test gasses available? What would be the procedure?

The LM-1 (and LC-1) have 2 calibration points already. Free air is one. The other is stochiometric. As the pump current is zero for all sensors at stoich, independent of sensor tolerances, there is no need for a separate cal point. Different to other widebands, the LM-1's measurement principle yields inherently a linear output. For that only 2 points are needed.
Calibr. gases are of course available. We are using lab quality cal. gases to verify and test LM-1's. A simple way to test Lambda 1.0 is to use MIG welding gas (Argon/CO2 mix).

Regards,
Klaus

[304065]

Forgive my inexperience on this topic, but if your carbs/throttle bodies are balanced and your fuel supply is accurately accounted for (proper psi, having fuel injectors test for flow) and your timing is accurate, what benefit will you gain from measuring each bank?

Good question, I guess my answer is that's a lotta ifs.

Since you can't practically install a bung in each cylinder, if you measure each bank it allows you to verify your "Check Measure Adjust." One element of that regimen is to adjust the throttle rods side-to-side, and you are supposed to set them the same. But no measurement of the rods is perfect, and if you came up with an obvious lean-running bank it would allow you to isolate the problem, either to that bank or to an individual cylinder within the bank.

Beats guessing. With the sensor in the tailpipe you could have a rich bank and a lean bank and not know it.

[Mike Bonkalski]

Would I be correct in assuming the process of setting up two sensors would be more applicable for MFI, due to the complexity of the system as opposed to carbs or throttle bodies (efi), or it would apply to all because they all have throttle rods that need to be in proper adjustment?

[304065]

Mike,

For MFI you have the issue that each throttle body has a throttle plate adjustment. The injection quantity, if your MFI pump is calibrated correctly, is the same for all cylinders. So the issue becomes one of adjusting the throttle stop and the air bleed screw to match the injection quantity on each cylinder.

EFI would have this issue, insofar as multiple throttle bodies also need to be synchronized, and then you have the issue of injector pulse width for your fuel quantity. So there are two variables.

Carbs still have the left-to-right issue, because of the cross link.

[Grady Clay]

To add to John’s comments about carburetors, the “just off idle” movement of carb butterflies not only adds more air&fuel but uncovers various air-fuel transfer ports. This is the critical transfer progression from running on the idle circuit to eventually on the main circuit. Being able to isolate one bank (carburetor) or even a single cylinder is the “art” of carb tuning.

Best,
Grady

[Mike Bonkalski]

I appreciate all the info guys. I am starting my webers to throttle bodies project this weekend and now I have a little more to digest. I will be following this thread with interest.