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Thread: Looking for some feedback on this tune

  1. #1
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    Looking for some feedback on this tune

    Looking for some feed back on this tune in a lnf Cobalt. GM 3 bar map sensors, maf relocate, intake, catless downpipe, intercooler and pipes with external bov and S20g. Datalog from a dyno pull and street driving. Dyno pull stopped at 5000rpm.
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    Last edited by umbrae; 04-15-2014 at 09:14 AM.

  2. #2
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    I will pull it up when I get out of work. I have another tune I have to go over anyways.

  3. #3
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    Thanks, much appreciated.

  4. #4
    Senior Tuner cobaltssoverbooster's Avatar
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    well i see you haven't touched the afr table. most of the stock table runs around lambda 14.7 to 1 and power is made smoothing it in to the higher rpm and load range.
    second traction control is still active which causes false events to be allowed correction. say traction kicks in and trims change...you tune for it then you tuned for an ecu correction rather than a forced correction.
    the more you lock the ecu into forced commands rather than letting it do work for you the better. this ecu is very self oriented and because of that it causes a lot of inconsistencies. the more you force it into user commanded mode the more you can control the output.

    hope that helps...if not im sorry
    2000 Ford Mustang - Top Sportsman

  5. #5
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    Sorry I didn't respond quicker. Since CSSOB commented on the tune I will take a look at that last. Only looking at the log I will say this, YOU ARE NOT LOGGING EVERYTHING YOU SHOULD. Sorry to caps lock that I just want you to know that it is very important to log more variables. Looking at your log I will also say your fuel trims are way off, your boost ramp is not desirable especially starting at such a low rpm, your boost drops load drops lambda shoots to 1 even though your foot is still WOT. Looking at the tune I think you should start over. I mean this in the nicest way. Your MAF tables need to be fixed. I don't understand why you changed the RPM axis table in the MALT table. My flash tune could be different then yours. I believe 1 of the year flash tunes was different so if I said anything that was due to that then I apologize. Start from a fresh file and work on getting your fuel trimmed correctly. Lower your timing at WOT. Everyone reads on how it makes magical power but people don't realize that there is a point you can hit where you will stop making power, prior to knock, and you will just cause extra heat. Not a good thing. I would worry less about timing at WOT and worry about the rest of the tune. Also your turbo will hold power a lot longer then the stock so I would change your DAL table. I would start from the stock file and modify and not modify the gm flash tune file. CSSOB made very good points so I would follow that as well.

  6. #6
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    I appreciate the feedback, always looking to improve my tuning. I had a SS LNF car 4 years ago, and havent done much with them since. This tune was from last year, I know things have come a long way since then in regards to tuning information and progress. I should have been logging fuel pressure. What else should I be logging? Maybe I shouldnt have posted that one data log, I did get fuel trims dialed in a bit closer before the dyno. I had a hard time tuning the MAF relocation. After dialing in the fuel trims, and flashing the changes, the car would slowly shift to positive LTFT again. I found this much more difficult then tuning any of the E40, E38 or LS1B ECMS. I must be missing something here. The MALT table RPM axis is the same as the stock calibration. When you talk about the DAL table, do you mean increasing it in the upper RPM range? The way it is configured in the tune now resulted in 22psi without any boost spikes. Without increasing the boost level, am I limiting myself by having these values set the way they are? Also, I understand the timing principle. I was hesitant to increase timing, and increasing the timing 1 deg on the last pull resulted in about 6whp gain.
    Can you explain what you mean about the boost ramp and how lambda shoots to 1.0 at WOT? And final question.... when tuning a LS car/truck and the fuel trims are off, they will lock at WOT and throw the WOT AFR out by that percentage. If my trims are so far out on this LNF tune, why/how am I hitting my desired lambda values at WOT?
    BTW, I just double checked and I did use his stock cal to build the tune, and not the GM stage 1 file. My mistake, I should have confirmed that last night.
    Last edited by umbrae; 04-15-2014 at 09:19 AM.

  7. #7
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    New Bitmap Image.jpg

    I completely missed the MAF relocation part. I attached a picture and you'll see where I have it at you'll notice you still have pedal position as 100% and commanded lambda of .88 but your lambda is 1, and boost drops off. If you have the pedal to the floor this should not be the case. The reason I said to raise your DAL's is because you'll notice that it slowly tapers off as the RPM's rise. Everyone has different ways they adjust the tables but with a turbo that holds power above 7000rpm I would not expect you to need to taper your DAL's like that. I understand your timing gained you horsepower it was just a suggestion to hold off on that. The picture is not the greatest but you'll notice your STFT's at one point in the upper right hand shows 14.1 and as it moved across the cells on the picture below that it was holding in the 12's for some of them including the ones that don't show as high of a number. If the car doesn't sit in those cells for a while it will cause those numbers to be off due to not having time to raise or lower the cell correctly. As for what to log, I log as much information as I can and I use the different screens available (Gauges, Charts, and Histograms) to monitor as much as I can while I'm logging. I have cam angles on mine right now but I wouldn't be too worried about that since you haven't made any changes there. I would be more focused elsewhere.