Hey guys...finally got around to installing the ZT-2 last night and was able to hook it up to the FC-Datalogit with the PFC and was able to make a few logs (although I couldn't save any of them because I was soon pulled over and cited for speeding, leading me to close the laptop quickly, and the computer eventually restarted...blech)

I decided to use the ZT-2 simply for wideband output (no RPM, boost, EGT logging), so all I needed to hook up from the ZT-2 were the power wire, the ground wire, and the signal wire going to th AN-1 input on the Datalogit. I was able to get an ECU diagram off the net, but the ground wire was actually wrong, and I thought it'd be nice to post in case somebody else runs into this. (Note: you should ALWAYS check the wires with a multimeter before doing any splicing.)

I've extracted the pages from the SAFC diagrams and placed them here.

THE GROUND WIRE WAS WRONG on my ECU. Our cars utilize the Z3-b diagram, and on my car, the ground wire was on the pin directly to the right of the pin indicated in the diagram. The IG Power pin was correct, and since I didn't hook up the throttle, pressure, or RPM signal, I can't verify those.

Also for reference, the polynomial variables for the ZT-2 should be:
A = 0.6270
B = 0.4574
C = 9.7758
According to the best fit line I had charted:



I wasn't able to setup the software yet to actually graph the a/f values in the P/N cells, but I found some helpful information at this thread:

https://www.rx7club.com/power-fc-forum-47/whos-using-diy-wideband-wth-datalogit-367949/

Hopefully this info will help somebody else planning on using this setup!

 

Oh wait...maybe this should be moved to the Power FC forum area. Moderator?

 

I actually re-plotted to eliminate the 15.60 voltage, which looked a little irregular, and we don't really care about AF ratios that high, and I arrived at a new set of polynomials:

 

Good stuff. I was thinking of going with the zeitronix in the future, but using it for EGT as well.

 

So it works with the Datalogit, I thought I read something that it doesn't.... hmmm...

 

Yes it definitely works. I went out for a trial run last night and came up with some readings in the mapwatch:



For some reason as I was doing some idle tuning, I realized that a HIGHER A/F ratio means a LEANER mixture. Air-to-fuel ratio...more air to fuel means leaner...duh! And vice versa, of course.

Can anybody tell me what the target values should be? What's considered conservative and aggressive and engine kaboom?

 

Man oh man if you didnt know that I recommend caution in your tuning......learning to tune when apex seals are involved can lead to a large repair bill .

On boost it looks like your a/f's are in the 10s and 11s, which is where you want them---I'd say 10.5 to 11.5. Everyone has their own opinion, but I feel it's better to tune very rich for safety's sake. Look's like you're running stock seq twins based on the boost dip at N12 (4800 rpms)....who tuned your pfc? You have to take into account your ignition timing when looking at all this as well, keep in mind.

 

Thanks for the feedback GoodFella! Steven Kan actually dyno tuned the car about two weeks ago. I have NO idea how to handle the timing, but Steve said that he tuned it with a really large retard (~25 degrees?) bc during tuning there seemed to be some problem with fuel delivery, so he adjusted it to be extra safe.

I noticed on both of the two runs that there was a pretty serious lean spot at N08/P09, so I'm planning on throwing in some additional fuel at that point, which will hopefully remedy that.

What AFR should I aim for in the idle area (N01/P06)?

 

Is there a non-permenent way to install the zt-2? I don't want to splice the ecu wiring harness. My understanding is that with innovative lm-1, you simply plug it into the cig lighter socket?

 

You could probably fabricate something to make it a non-permanent install w/o splicing into the ECU, but there is no ready-made application available that I'm aware of.

 

Read up on tuning with the datalogit a bit more before making changes. The one lean spot you mentioned is not in a boost area and it is likely ok, plus you may have had only one sample there meaning it may not be representative of an on throttle acceleration or cruise event, perhaps you were coasting down thru that cell. Go to the mapwatch screen and select number in the pulldown menu that has avg displayed in your posted screen shot.

Also look at knock in those cells with max selected in that same pulldown menu.

Last suggestion is to log a single run at a time to ensure the data in the cells is representative. Do several runs for comparison before making changes to ensure the logs are consistent. Inconsistency is an indication of many issues such as misfire.

 

Yeah since that last thread, I realized quite a few things about tuning. Still some really good information though, and I totally agree with what you're saying.