2009 LSA MAF tuning questions

[bljalbert]

Hello everyone,
So I will start off by saying I am new to tuning. I have read a lot and I have had a few people help me, but I still have questions. I have a 2009 LSA supercharged stock from GM Gen 4. I have a pretty good base tune as the car runs pretty good as is. I did just do a muffler delete and I feel like I have lost a little bit of power, so I thought it would be good time to try and clean it up some before I do anything else. Is it possible to lose some back pressure with the muffler delete and make it not pull as hard now? Just curious! I have added my most recent tune along with my last scan. I think I am getting pretty close with my MAF at this point. I have also added at the bottom of this post a list of things I have turned off to do closed loop tuning and force it to run only on the MAF. Please let me know if I missed anything, or if I made changes I should not have. These settings are what I have read or had someone help me with.

So here are a couple of questions I have:
1. When tuning the MAF what is the correct way to drive to get an accurate scan. I have seen where one person says to sweep across the Hz and try to fill as much data as you can with smooth transitions. Then I read where someone says to try and hold the throttle in each cell until the values level out. I sort of feel like holding the throttle in each cell until they level out would be best, but I am uncertain.

2. When tuning the MAF when does PE come on? Can I tun the entire MAF just by trying to hold the throttle in each cell all the way to WOT? Not really realistic as I would be going way to fast to do that. I have read that after roughly 5700Hz PE starts to come on and really anything under that would be where I want to target my MAF tuning. Then do another scan trying to start above this Hz and do a single gear run to WOT. Then tune the second half of the MAF this way. I am a little confused about what is correct. How do I know when PE will come on for certain?

3. I have been copying the entire MAF error and multiplying by % half to the calibration. But this tends to change the parts of the scanned Hz that are good (I am shooting for +-1 or 2 max across the board). If I have enough hits in the cell to give me good data, can I just add in or pull out fuel per cell to make it fall in my target? Or maybe highlight a few cells and extrapolate to smooth it out? I am not sure the best procedure to dial this in. Using the entire table gets me REALLY rich to the point I have a really bad flat spot off idle. So I have started over a couple of times now.

Well that is all I have for now. Please don't beat me up to awful bad for the newbie questions.
Thanks

scan8.hpl
MAF_Step5.hpt

Closed Loop Settings

Engine, Fuel, Cutoff
Disable DFCO by setting "Deceleration fuel cutoff"
Set Enable RPM = 8100
Set Disable RPM = 8099

Engine, Fuel, Temp Control
Set COT to disable

Engine, Fuel, Oxy Sensors
Set "O2 Readiness ECT" to 400*

Engine, Airflow, dynamic
Disable Dynamic Air by
Set High RPM Disable to 100
Set High RPM Re-enable to 99

Spark, Advance,
Subtract -5% across spark table

[5FDP]

PE happens when you tell it too. Just look at your power enrichment settings, whatever your delays are, that is what it will wait for to enter power enrichment.

If you are open loop tuning without fuel trims using a wideband error against the commanded AFR, it does not matter when PE happens. As the error graph is always going to report the error against the commanded.

You may drive yourself crazy trying to get everything within 1-2% of zero everywhere. If I can see 3-4% of zero throughout the MAF curve I would be more than happy with that. The fuel trims when back to closed loop can make on the fly adjustments with ease. WOT fueling is a tad easier to fine tune once the rest is done because it only takes small changes to make it really close.

Just drive normally to gather data. I don't try to hold the throttle or the load when street tuning. The longer the data logs the better to prevent spikes or dips in the curve. Aim for 20-25min logs if you need too.

[bljalbert]

Thanks 5FDP! Will do!