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AP Logs, which map is better?

Posted: Wed Aug 31, 2011 9:14
by movovr
Trying to figure out which of these two maps are better based on the logs. Mods are only Cobb SRI/TIP, & 1 step colder plugs

Stage 1+SF 91 v108 or Stage 1+SF+TIH 91 BTv102?

In both logs my fuel pressure is holding fine so that's reassuring. What I don't like are my AFR's with the v108 map. I'm hitting 15-16lbs of boost for a few seconds with AFR's of 12-13 before settling in to the upper 11's.

With the boost based map it appears that as soon as I go into boost my AFR's react quicker to the 11's although overall boost is lower.

Any thoughts? How much should I worry about that brief moment where I'm in "high" boost and lean? Although the BT map feels "slower" it also looks safer.

I highlighted the areas of the log I'm referring to. You can see in the BT map my AFR's get to the 11's much quicker (despite being rich overall).

Appreciate any help....Wafer?

Posted: Wed Aug 31, 2011 9:14
by erod550
You still had virtually no knock and DI engines can safely run leaner than port injection engines. I think you're fine with the boost target map.

And the other map feels slower because it is. I'd run the BT map and keep an eye on knock. As long as you still aren't seeing any, you should be fine. Also, it's not like it's holding 13s at redline. I know it's a different car, but my friend's 2011 STi held leaner than 13.5 until almost 4500 rpms on the stock map. By 4000 rpms you're in the mid 12s and dropping so I think you're good. I wouldn't go more aggressive than that on the AFRs, but I don't think you're endangering your engine.

Posted: Wed Aug 31, 2011 9:14
by movovr
Thanks. I read in Abilor's tuning guide that you can change in ATR the speed at which you transition from CL to OL in order to command an AFR faster at a particular load. Would that help the ECU bring my AFR's down faster in an OTS map? Keep in mind I know NOTHING about tuning. I don't want to screw anything by playing with these maps in ATR.

I've also yet to go through the MAF calibration either. How important is it for an OTS map? MY LTFT are within the -8/8 that COBB recommends but some like to see -4/4 or less. Would calibrating improve the overall performance of the map?

Posted: Wed Aug 31, 2011 9:14
by erod550
Yes, changing your tip-in to transition faster to OL should get it to your target AFR faster so you don't have that full second of 13s before it gets into the 11s. I know that lean AFRs at tip-in are one of the biggest concerns people have when making their own tunes in ATR. I unfortunately don't have any experience actually making those changes so I don't know how you tweak it.

Calibrating the MAF might bring your fuel trims closer to zero but I'm not 100% sure on that as I have not done any of my own MAF tweaking. I know that Nick at MAC spent a good hour just calibrating my MAF when I got a protune.

Posted: Wed Aug 31, 2011 9:14
by chickenwafer
Calibrating the MAF will always improve the maps performance, but it does take quite a bit of time.

Posted: Thu Sep 01, 2011 9:14
by movovr
Thanks guys. I'm pretty sure I can follow Abilor's MAF calibration how to. Might work on that this weekend when I have more time to drive around.

Posted: Thu Sep 29, 2011 9:14
by RichB
Yea, the MAF cal is a pain. I have been working on mine for a few weeks. Right now I have it within the +/- 2 range. I plan on adjusting AFR targets to see how well they hold.

Posted: Thu Sep 29, 2011 9:14
by dsm_luck
Just make sure when you guys do a MAF cal you let the new map settle for 100 miles or you will likely be chasing bad LTFT and A/F readings all over the place. It really does take that much time to settle.

Posted: Thu Sep 29, 2011 9:14
by RichB
Yup, which is why it has taken me weeks to get my trims to their current state.