Idle AFR and throttle enrichment on rb26

[MrStabby]

Idle AFR and throttle enrichment on rb26

Setup: Nistuned R32 GTR, stock cams, 1000cc xspurt, Nismo MAFs.

My idle is 12:1 hot (injector latency is set higher than spec), but i also have some leaning out just as the throttle is first opened. I was hoping to be able to reduce the latency to lean up idle, and fix the throttle leaning out by tweaking the throttle enrichment. However, I cant see any throttle enrichment tables in Nistune, and the Nistune doc says they are "Only available for some (RB series) vehicles".

So, it it normal not to have throttle enrichment tables on early R32 GTR ECUs?

And if it is normal, is there any point in trying to bring the idle closer to 14.7 and then using the fuel map to try to offset the leaning out?

[Dose Pipe Sutututu]

You can enable Alpha-N flag which will squirt extra fuel based on the TPS voltage change, I've never used this feature on any Nissan I've tuned on Nistune but I suspect with the GTR and 6 ITBs you get air into the cylinders before the AFM(s) are able to register a change. I think this "may" only be available on the Feature Pack version of Nistune as I've only recently noticed it.

Try setting the idle cells to 0 and also change the possible minimum TP Load. Also disable the o2 correction on those cells (usually bottom 4) by highlighting them and pressing O (for octopus).

[MrStabby]

5 hours ago, Dose Pipe Sutututu said:

You can enable Alpha-N flag which will squirt extra fuel based on the TPS voltage change, I've never used this feature on any Nissan I've tuned on Nistune but I suspect with the GTR and 6 ITBs you get air into the cylinders before the AFM(s) are able to register a change. I think this "may" only be available on the Feature Pack version of Nistune as I've only recently noticed it.

Try setting the idle cells to 0 and also change the possible minimum TP Load. Also disable the o2 correction on those cells (usually bottom 4) by highlighting them and pressing O (for octopus).

Thanks man. I dont have either Feature pack, but I also notice in V2 the "Injection Latency table" sounds interesting, as;

"With the larger injector sizes offered by companies like Bosch (Injector Dynamics) and sometimes to resolve issues
with other injector brands, the custom adjustment of latency is required at various voltage levels."

I'll have a look for Alpha-N - sounds like it should help.

The idle fuel cells are already at 0 (is that weird?), and IIRC I dont need to turn off o2 correction as its not used in the bottom left hand quarter of the map, right? (eg the filtered /unfiltered difference)

[Dose Pipe Sutututu]

o2 correction will be still applied, they are the cells highlighted in that teal/green-ish colour, the best way to see if they are doing anything is by looking at the Short-term & Long-term Fuel trim graphs.

If they're on '0' and your AFRs are stupid rich, try dropping the latency a little bit - however if the injections don't like low pulsewidths then you're going to massive issues with light load / moderate RPM cruise.. it will buckle and splutter.

[MrStabby]

Ok, I wasnt in "expert" mode so the throttle enrichment tables were hidden.

The Xspurts are Bosch, and they're supposed to still work well at low pulsewidths. I'll try dropping the latency and putting on more throttle enrichment as a first stop. Then later look at Feature pack if its still not right.