I tried out my new LM-1 wide band O2 sensor and datalogger this morning. Shown below is the afr for a short burst in third gear up to about 6000 rpm. The afr starts out at 13.2:1 when I first punch it, rises to 16.8:1 (even though I was WOT) and then lowers and settles in to about 11.5:1 at about t=39.5

Why the momentary rise in afr to 16.8? I'm not sure, but I've seen that behavior every time I've done a WOT run. Maybe due to the initial in-rush of air before the ecu has time to compensate. Also, right at the end of the run the afr dips to 10.5, due probably to suddenly cutting off air to the engine while it's still injecting.

The LM-1 has provisions for 5 more inputs, so eventually I'll be able to correlate afr with rpm, throttle position, maf voltage, boost pressure and intake air temperature.

 

Time to try that with the stock ECU.

 

Yep. I'll swap out the ecu tonight and see what afr I get on the way to work tomorrow.

 

Also, when you *USED* to get detonation with the JWT ECU, was it in the begining of the run where 33.3-34.5s lean area is?

Add some fuel until whatever rpm is ~39.0s and take some out after that with the JWT before you swap too.

Cool tool.

 

How many "runs" will this hold before download them to the computer?

Very cool indeed. I may need one this spring.

 

It will store up to 44 minutes of data.

 

Yes it was, now that you mention it.

 

Either your JWT ECU isn't programmed properly or your 370s/FPR can't keep up jumping from 34psi-->43psi for the amount of air your getting.

 

Can you designate the start and end of a pull? IE - at a test and tune at the drag strip, If I run 10 times, I'd want to record them all, and be able to tell them apart, and so on.

Where did you mount the sensor in the y-pipe?

 

There is a button you press to start recording data, hit it a second time to stop, and so on. Each set of data points is downloaded to the computer as an individual session.

I have the sensor mounted in my test pipe. It would be better to mount it right after the collector portion of the y-pipe and in front of the flex section. Where I have it now, it is susceptible to fresh air contamination if there is a leak at the test pipe joint.

 

Perfect. Thanks.

 

so where are you mounting this device?


Are you using this to actively monitor as you go as well as looking at the data later?

ie, would it be worth to not get a EGT and to just get one of these?

 

Right now I just set it on the passenger seat, but that is not very practical. I'm eventually going to get the analog gauge, but I don't know where to put it. I'm kinda gauged out at the moment. I suppose an egt gauge would be redundant, so maybe I'll replace the egt with the afr guage.

 

Is the wideband strictly for tuning or does it measure the exhaust gas better? I am not sure exactly what the O2 sensor measures.

 

It's for tuning. It measures the oxygen content in the exhaust gas, and from that it can determine your air/fuel ratio directly, rather than indirectly like the egt gauge does.

 

Any runs with some A/F tweaks?

Also, what do you need to measure RPM?

 

I've done a few, but not with the A32 ecu yet. I'm waiting on the rpm converter needed for datalogging the rpm, and I've ordered a 2 bar MAP sensor so I can record boost pressure as well.

 

So with the wideband 02 meter and RPM and MAP sensors, you can pretty much tune the car yourself with an AFC?

 

Yep, that's the idea. And you can do it out on the road in real world conditions instead of in the somewhat artificial environment of a dyno shed.

 

I got the lm-1 about a month ago myself. I'm running it on an 88 300zx that I put TT injectors in. I get the same jump to lean that you speak of. I'm assuming its normal and because the ecu doesnt have time to catch up. I'm still working on reprogramming the stock ecu to work well with my TT injectors. It runs pretty good right now but I think it goes real rich when I nail the gas. I've got the lm-1 logging afm voltage, rpm, chts voltage, vac/boost, and AFR. If you get the boost sensor out of a z31 you can feed a 12v source to it and get a good lower volt signal out of it to log. The only thing you need to do is figure out the scale.

 

how much are tehse things? does anyone have a website?

 

$349 for the O2 sensor and controller/data logger from Innovate

I found it for $20 cheaper by doing a google search.

 

I wonder if theres anyway to incorporate the Lm-1, or some kind of Wideband O2 sensor with AUTOENGINUITY's product. They have a "speedtracer" dyno program which seems pretty through, and takes into account weight, gear ratio, drag soe, frontal area, tire circum, extra weight, gear ratio, temp, elevation, humidity, and baro pressure... I think this could even be MORE accurate than the stationary dynos because you include drag into the equation.

Now if you could hookup an Wideband O2 to this program, I think that would be perfect. Unless LM-1 has all these functions already... The obd2 logger should be easy, with no splicing involved because it just plugs into your DLC, and then you get all the standard OB2 sensors, rpm, map, o2, timing, etc etc.

 

Also... i have a question... does anyone know what frequency the ECU transmits data at? I heard for ISO specs its between 2-8 Hz. What is it for our maximas? Just to see how accurate it is... Also if you want to read about speedtracer more.. heres a link.
http://www.autoenginuity.com/products-speedtracer1.html

 

Incidentally, here's what a WOT run in second and third gears looks like, with throttle position, rpm, manifold absolute pressure and maf voltage looks like:

 

You can get a pretty good estimate of engine power by looking at maf voltage. For instance, in the run I show above, I hit a maximum maf voltage of 4.22 volts when I was at 6670 rpm, at about 10.5 psi boost. Assuming the Z32 maf maxes out at 420 hp at 5.1 volts (according to JWT), (4.22/5.1) x 420 = 347 bhp, or about 288 whp if you apply a 17% drivetrain loss through the manual transmission. This is almost exactly what I dynoed at a couple of months ago, and I haven't changed anything since then.

 

True... the MAF voltage could be an estimate.. but like you said, its an estimate, and doesnt really account for what happens inbetween the MAF reading and when that power gets applied to the wheels. Actually, with all your data, you could plug it into an excel sheet and find out the same data that the "speedtracer" program provides. You just have to find out all the different variables weights in the HP equations. The program just gives you a more user friendly method. i am trying to find out from the engineers there if they support a Wideband O2 sensor input. That way, everything would be integrated into one complete package. But i do not think they support that.. hmmm..