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Discussion Starter #1
Ive installed a stg 4 turbo cam from zzp, with 136 springs, bigger valves, PnP heads. Im trying to tune in Open Loop with hp tuners. And I cant seem to get my commanded Afr to stay at 14.7, ive set the open loop Afr to 14 7 at all temps, zeroed out the adders, and subtractors, and my commanded afr still climbs up to 16.80 while loggin the drive. Ive even tried the Open Loop Maf Tuning how to from Russ K on the Hp tuners forum and still the same effects. So i started adjusting the maf airflow frequency curve by hand. If afr is showing a 15 in the Afr vs Maf Chart then i add .05 G/s. Once it starts getting closer to 14.7 i start using 0.01 or .002 till its close to 14 7. Since i been doing this. The car seems to be getting more knock in the lower rpms on top of where it was before. It will also show knock on start up but then go away after a few mins or if i blip the throttle. So i removed 5 degrees of timing from the entire table of both the hi and lo octane tables and the problem still exist.All spark adders and subtractors have been zeroed since the start. What i did notice it the closer to the commanded afr i am the less knock i have. So is the commanded afr what the car wants ? Everything ive read says OL is suppose to be at 14.7
I have researched so much and watched so many vids i feel i have more knowledge on how to tune an ls engine, then the 3800 lol.
 

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Discussion Starter #2
TTT...... anybody???
 

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Un-F*** your tune, put things back to normal, and tune it regular. LS cars are more into open loop, but ours work great using the MAF and skewing IFR table as needed.

Your setup is close to what mine was the past decade. I can dig up my MAF and IFR tables to give you a starting point, and crawl-walk-run (idle-cruise-boost) your scanning/tuning from there.
 

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Discussion Starter #4
So tune in closed loop?
That would be awesome. I would greatly appreciate it.
 

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Ya, I've dabbled in O/L tuning years ago, and usually just unplug the MAF sensor to force it to happen. Not really necessary, since you'll dial in everything based on the MAF table and setting up your A/F tables.

Edit: I'll be tuning my ST5 setup once I decide on where to get some LS7-ish lifters, and re-assemble the car (decided not to chase adjusting OE-R's). That will remind me of the joys I've avoided for the last couple years while leaving it alone.
 

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Discussion Starter #6
Thanks. Ill get to tuning in CL Loop. I didnt mess with the IFR table cause it was already set for the 42.5 injectors from cartuning.
Thanks.
 

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Discussion Starter #7
Do i need to get my fuel trims inline before reducing some timing for kr ?
 

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Correct, for idle/normal driving, you want to use the average LTFT at each MAF value to adjust that number in the table. There are some spreadsheets you can use to drop in your table and scan data to make it easier. (I really need to get my old laptop going to extract these files instead of chasing them down elsewhere.)

Example charts (also, be sure to manually smooth the values, usually watching the %difference between each final value:

Fine tuning the regular driving section, but maxxing out up top before changing some settings...



After using AFC and IFR skewing to get it in order up top (based on %diff from WB O2 readings & Cmd AFR), also some tweaks down low...

 

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Discussion Starter #9
Thanks. Ive been working, in it. I was going to post my tune and log. But i guess you cant on here.
 

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Feel free to email me... Just add @gmail
 
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Discussion Starter #11
Cool thanks. Ill send it tomorrow. In the process of moving, bo wifi till tomorrow
 
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