Nistune and SELIN DUAL MAF Translator

[Kruse]

Which setting should i be using, and what should i alter in Nistune? ADD/AVG



Thanks in advance.

[Eric]

if you set the SELIN translator to ADD, you won't have to change the K-value

if you set it to AVG, you will need to double the K-val

[Kruse]

Thanks, that solved most of my idle issues

[Kruse]

Is 12.7 reading on my wideband ok for idle?

[Matt]

should be about 14.7:1 for idle thats what the fuel maps are usually tuned for from factory. Might need to lean out injection multiplier a bit

[Delox]

I had heard there was a power advantage to one setting over the other, I forget which. Most people just set it for whatever there generic tune chip is set for, but others with piggybacks/standalones have been able to try both and saw gains. I forget which one, but I will look for it and report back if I am able to find it.

I believe its AVG, and the document you posted seems to infer this also.

[kisaki]

I have the same problem. Same setup and same 12.7 AFR at idle (AVG). It was 14.7 with ADD. I just doubled the K-val, but i'm sure this is not the only parameter to modifiy. Suggestions?

Thanks

PS: i cant go with the ADD setup because my car is pushing more then 500rwhp.

[Torque]

I don't know if you are aware of this, but the ECU ignores the Lambda sensor when not in gear ...
(I always found this strange but possibly this improves idle stability, but is less economical)

[Matt]

There is Latency (which adds/minus injection time), K const (injection multiplier) which multiplies the fuel map, and obviously the fuel map values themselves which are the main ones to adjust

[Torque]

@Matt =>
Have you ever figures out which value actually dictates the A/F when not in gear?
Is it actually the fuel map value?

[Matt]

Fuel map is still used when in IDLE. However the same does not apply for timing which uses the idle/decel timing maps (or warmup timing maps when within warmup parameters)

[RobH]

Assume you've sorted this issue already but anyway, I'm using the Selin translator in ADD mode. K constant still needs to be adjusted if you're not using standard injectors. I found K needed to be a little lower than the default when resizing injectors, I think mine ended up at about 186 (default for 555 is 192 I think), further latency adjustment was still required to get it slightly leaner than stoich at idle.

I think if using AVG mode, a larger fuel map scale is possible but the map loses resolution, therefore becomes less accurate. ADD mode should be good up to the HP limit of the AFM, Z32 AFM should be good for well over 500HP, as I understand it..

Also, are you using a pair of widebands or a single exhaust outlet?? I've permanently installed 2 x LC-1 so that I can confirm both banks are running evenly, easy to spot if there's a problem on one side (providing you can calibrate the sensors regularly!). If using twin (independant) exhausts and a single sensor you'll have little indication of what is happening on bank 2.

[RomChip200]

I don't know if you are aware of this, but the ECU ignores the Lambda sensor when not in gear ...
(I always found this strange but possibly this improves idle stability, but is less economical)

You are wrong, this is just not the case on Z32. Lambdas are used to reach 14.7 in idle. Closed loop just starts to work after staying 30s in idle.

[RomChip200]

I've permanently installed 2 x LC-1 so that I can confirm both banks are running evenly, easy to spot if there's a problem on one side (providing you can calibrate the sensors regularly!). If using twin (independant) exhausts and a single sensor you'll have little indication of what is happening on bank 2.

I have the same setup than you (and XD16 gauges in front of me).
I always work in open loop, even when cruising (except in idle for which I use OEM NBs because I made Z32 is E85 flex)
Both Bosch WBO2 are fitted in the downpipes (before cat) at the same location/angle.
I can notice some discrepencies in the AFRs b/w both banks:
_when cruising, I got 17.5 (open loop !) on one and 16.5 on another (sometimes error is less, let's say 0.5). I have no air leak
_in full throttle, max boost (pull 3rd gear) I get this:

Code: Select all

11.34	11.77
11.26	11.78
11.26	11.78
10.53	10.9
10.74	10.99
11.05	11.15
10.92	11.39
11.34	11.52
11.56	11.77
11.58	11.98
11.52	11.95
11.84	12.28
12.03	12.28
11.87	12.27
11.96	12.36
11.98	12.53
11.81	12.12
11.71	11.92
11.59	12.02
11.59	12.08
11.48	11.87
11.84	11.99
11.74	12.28
12.25	12.68
12.11	12.3
11.64	12.21
11.81	12.28
11.62	11.83
11.49	11.71
11.9	11.99
11.93	11.87
11.83	11.81

Basically, I always have a bank that is slightly richer than the other .....

[RobH]

I guess the instrumentation and sensor isn't infallable. Mine is also richer on one side, you probably wouldn't notice if using analog gauges. I'd put my difference down to one sensor being a couple of years old with the other brand new and only having been free air calibrated once, apparently they need calibrating less frequently as they get older. I've also heard mention that one of the air control devices only operates on one side, which may make a difference (?)