Thread: Need clarity on a few things...

I've decided to start with a fresh tune and see if I can iron out some of the spiking AFR issues that I've been having. Could someone (multiple people is better, of course), clear up a few things...

1) When I setup the new tune file, I started from the B13 SR20DE base. I set the MAF to the N62, my current injector size to 400 (where it is on my current tune), and allowed the system to auto adjust the K value. I noticed that in the tune file my current injector size was still 259, but the K value was much lower than the one I've been running. Also, the fuel maps appear to have changed since the last time (I imagine this is due to a recent update). So, is the adjusted K value is acting as a place holder for the additional fuel that changing the injector size would have otherwise?

With the fresh tune, the car seemed to be running a little more rich while driving, but just on at idle after tweaking the injector size a bit... that's not to say that I had it setup incorrectly in the first place.

2) On the tune I've been running, I've noticed that even with a slight change in throttle, my AFR would dip down into the 10's. I'm hesitant to adjust the latency as my idle AFR is spot on at the moment, and as I understand it, this value would affect both idle and light throttle. Should I be looking at the fuel trims for acceleration?

3) According to the documentation, the voltage adjustment value is used when the voltage drops below 14. My car seldom shows a battery level of 14 or better. How exactly does this value affect the tune when the voltage drops? I've tried adjusting it in small increments, but I can't really see much of a difference in the AFR.

Thanks!

The fuel maps should NOT have changed with the new update.. nothing was touched in regards to that.

The adjusted kvalue does have a global adjustment on the maf load (which indirectly affects all fueling).



Look at the accel TAB and for the acceleration tables.. there are a few factors in there that should help you to get that sorted out without touching the latency.



The voltage scalar applies the offset when the voltage drops or deviates from 14 volts.. so you multiply the difference by your voltage scalar to get the deviated msec value.

The latency values end up being a linear line because of it just having an offset and scalar (think of it like y = mx+b).

Thanks for the info, John! Now that I think of it, I started my first tune from a file you sent me. Probably why the fuel maps looked so different.

All good stuff to know for when the SA version gets released.