Air Fuel Ratio data

[ischmitz]

I had a chance to play with an LM-1 Digital Air/Fuel Ratio meter. It loggs data while driving around and you can download it to a PC afterwards for analysis.

When running with the NBD chip the steeper RPM curve proves that I have more power on tap. Pretty cool

[89turbocabmike]

Nice Ingo! The LM1 is a great unit that will keep getting better as Klaus has a real passion for this project. As the LM1 can output two NB signals with modified switch points, can you use this to adjust your AFR where it drops below 12.8(going to do this on my CIS turbo in the next week or so) or is this something that needs to be modified in the chip? Looks like there's even more power to be had there....too cool

[RoninLB]

Originally posted by 89turbocabmike
Nice Ingo!

....too cool

I want one.

[pwd72s]

Could somebody explain how this differs from an exhaust gas analyzer, how it would aid in tuning?

[MotoSook]

You'd need a rolling road to use a gas analyzer to record data such as Ingo did with the LM-1, or the analyzer has to go with you, and you'd need to tie the analyzer to a PC or a datalogger to log the data on the fly.

Ingo, was the test performed on the same stretch of road and in the same direction? I'm not doubting the increase in power. The AF ratio change would indicate a change, but I wonder if the slope change was all due to the AFR change. Also, how far a part the were runs (minutes?)?

[Lorenfb]

The LM-1 just measures the AFR (ideally 12.6 for max torque). An exhaust gas
analyzer can provide AFRs and; CO, HC, CO2, NOx, & O2. Check out this web
site (www.systemsc.com) on the Graphs page for more info.

The optimum way to tune an engine is to place it on a dyno while monitoring the
torque & AFR and tweaking the fuel and ignition maps (AFR & timing) to achieve
the max torque at each RPM. This effectively maximizes the area under the torque
curve to produce the maximum overall (over complete RPM range) horsepower.

[Lorenfb]

More info should be provided:

stock motor? - cams, exhaust, intake system

Since it's WOT, an increase in the fuel pressure would yield the same results.

[makaio]

How much $ ?

[irnwill]

I'm running my LM-1 in place of the heated narrowband sensor on tbitz's cis to efi conversion. The only drawback so far is that it outputs a narrowband sensor signal to the megasquirt box. I have been able to get a pretty good ve table with it and it's nice to see realtime air fuel ratios.

[ischmitz]

Originally posted by Lorenfb
More info should be provided:

stock motor? - cams, exhaust, intake system

Since it's WOT, an increase in the fuel pressure would yield the same results.

Have you noticed the text in the graph: Stock with Super C2 cams, 993 HE's into a Magnaflow dual-in dual-out with resonators on the outputs.

Ingo

[tbitz]

Originally posted by irnwill
I'm running my LM-1 in place of the heated narrowband sensor on tbitz's cis to efi conversion. The only drawback so far is that it outputs a narrowband sensor signal to the megasquirt box. I have been able to get a pretty good ve table with it and it's nice to see realtime air fuel ratios.

Will,

MegaSquirt can accept a wideband signal (0-5v). No need to run your wideband in "narrow band" mode just to feed the MegaSquirt unit. Unless ofcoarse this unit doesn't have a wideband output?

Tony

[irnwill]

Tony, I'll try wideband output with it tomorrow. The LM-1 uses a stereo headphone cable to output two configurable 0 to 5v signals. The LM-1 software looks pretty easy to navigate.

[Wayne 962]

This thing is an excellent tool - I'm featuring it in my new book:

http://www.pelicanparts.com/catalog/shopcart/MISC/POR_MISC_INNOVT_pg1.htm

While good for what Ingo is using it for, it really shines in being able to help you tune Weber carbs and MFI systems without a dyno...

-Wayne

[RoninLB]

Originally posted by Wayne at Pelican Parts


it really shines in being able to help you tune Weber carbs and MFI systems without a dyno...

perfect.

so my unused SSI o2 bung will have a real function.. and not just tuning but a carb check-up and prob diagnosis.. am I thinking correctly ?

[ssetek]

[/B]

got a little rich in the 5k range for a na car...

other than that looks good

[ischmitz]

Originally posted by Wayne at Pelican Parts
This thing is an excellent tool - I'm featuring it in my new book:

http://www.pelicanparts.com/catalog/shopcart/MISC/POR_MISC_INNOVT_pg1.htm

While good for what Ingo is using it for, it really shines in being able to help you tune Weber carbs and MFI systems without a dyno...

-Wayne

Wayne, I agree. But the basic kit isn't very useful other than for adjusting idle. To get meaningful data in the absense of a dyno you'll need the inducive RPM clamp, the Aux input adapter, and the venturi clamp for the O2 sensor. Once you get the RPM vs. AFR data under various loads it's easy to figure where to richen up or lean out your tuning, might these be Webers or a chip. Unfortunately, the accesories set you back another 200$ on top of the base kit. Have you thought about offering a complete kit?

Ingo

[Wayne 962]

Not yet - in fact they don't even have enough of the aux pieces to sell to us right now.

The aux components do help, however, they are not super-necessary for tuning. For instance, you can accomplish the same thing with an assistant and a clipboard who is taking measurements as you drive (that's how I've been doing it).

I've been using it to measure the adjustment of the carbs on the 308 under load. I have found that it is running super-lean at higher RPM (17-18:1 AFR). For carbs or MFI, there isn't enough fine adjustment in system to warrant requiring the precise measurement of AFR with respect to RPM.

I will agree that the O2 sensor bracket is very useful, although you can use a $1 hose clamp instead of the $80 bracket...

-Wayne

[klatinn]

Hi,

New LM-1 software/firmware is now released. Download it here:

New LM-1 Software

With the new LogWorks software you can (among many other things) analyze the logs to get an AFR over RPM and MAP table, sorted into user definable bins that you can match to your EFI's main fuel table. It can also calculate for each bin by what factor to change your table entry to get the desired AFR.
Also logs and displays realtime on laptop and can play back logs to the on-screen gauges realtime + many other funtions.

Regards,
Klaus

[ischmitz]

Klaus,

I downloaded it and was pretty impressed. A couple of comments from my side for further enhancements:

I would like to see a surface plot function implemented. The 3D surface plot function in Excel is borderline since it doesn't handle empty bins that well. Have you thought about packages like IDL or MatLab to implement those?

It would be nice to be able to define the bins individually since most PT fuel tables are not evenly spaced with regard to load.

On the analyzer it would be nice to have a way of telling if all bins have at least one value when you try to generate RPM/Load vs. AFR maps by driving around. Any idea how to acomplish something like that?

Other than that I stand by my comment that this a really nice product. The RPM converter is mandatory to really make full use of it. My "assistant" wouln't have been able to write the first RPM number down before we hit red line. But then his is not the "fastest" assitant around

ingo

[klatinn]

Hi Ingo,

The surface plot is already scheduled for the next release.
You can simulate the uneven spacing by just changing the spacing and start point. Then look only in those you are interrested in.
Bins that don't have at least one value are blank.
When driving around while realtime logging, the bin you are currently running in is highlighted, so you can adjust your driving to fill in the blanks.
Yes, the RPM converter is very helpful and required for the full functionality. We are building the product line out to add other built-in sensors as well (EGT/CHT, dwell/duty cycle, MAP, acceleration sensors and so on).
The next release of LogWorks will be able to handle up to 32 channels, incl. up to 8 AFR channels.
We are also adding the capability to calculate traces where you can add your own formulas (like hp/torque from acceleration and weight, or from the RPM differential, tire dia., gearing and weight)

Regards.
Klaus