AC idle tuning
#4
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I think i changed my stit, ltit, and ac airflow adder limits all to 3.0 g/s (i'm going from memory here since my laptop crashed). Also you may want to enable stall saver because that will disengage the ac clutch if your rpm drops below a certain point. Oh yeah, I also made my ac idle speed 850 with my normal idle speed at 800. Besides that, i think if you make sure all the normal stuff is good you should be set.
#5
Get your ltit right with a/c off. Then when you turn on your a/c see what the a/c airflow is and what the stit's jump to. You will probably need more a/c airflow. With moderate to big cams you usually will see about 2-4 on a/c air flow, but the stits will rise high trying to add enough airflow. If this is the case you need to add more a/c airflow.
#6
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Would someone be willing to look at a log of mine? I can do fresh log tomorrow. I will start car, log, and let sit there until it gets to operating temp.
From what I have noticed for some reason, is I log my idle while driving is that bad?
I notice my Ltit, to be -.08 all the way through, then after car warms up and gets hot it jumps to -.32 or something crazy. Doesn't make sense to me. That is with AC off.
With ac on, my Ltit/Stit goes to zero, and there is something in hp tuners called a/c airflow or something like that. If someone could get me on track would be very much appreciated.
From what I have noticed for some reason, is I log my idle while driving is that bad?
I notice my Ltit, to be -.08 all the way through, then after car warms up and gets hot it jumps to -.32 or something crazy. Doesn't make sense to me. That is with AC off.
With ac on, my Ltit/Stit goes to zero, and there is something in hp tuners called a/c airflow or something like that. If someone could get me on track would be very much appreciated.
#7
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So basicly, the ECU keeps track on how much air to add when the a/c compressor engages? This is limited to .5 in the stock tune? In reality cammed cars may see a much bigger spread between a/c-off and a/c-on airflow. If you have perfect idle trims and you turn on the a/c and lets say it requires .75 additional air, once the a/c trim reaches it's max difference ( .5 ) it starts to adjust the stit to the remaining.25. Then when you turn the a/c off, your stit is still at .25? So the a/c additional airflow limit ( .5 ) needs to be upped?
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#8
Originally Posted by GuitsBoy
So basicly, the ECU keeps track on how much air to add when the a/c compressor engages? This is limited to .5 in the stock tune? In reality cammed cars may see a much bigger spread between a/c-off and a/c-on airflow. If you have perfect idle trims and you turn on the a/c and lets say it requires .75 additional air, once the a/c trim reaches it's max difference ( .5 ) it starts to adjust the stit to the remaining.25. Then when you turn the a/c off, your stit is still at .25? So the a/c additional airflow limit ( .5 ) needs to be upped?
You have a pid for a/c airflow. You need to get your LTIT in check with the a/c off. Then turn on the a/c. You will see an a/c airflow amount on the a/c airflow pid. It is somewere around 2-3 stock. When you put in a moderate to big cam, this is not enough airflow. You need to tune it like you do the LTIT's. With the a/c on look at what the stit's do. If they go way positve, then you don't have enough a/c airflow.. This is just like stit's and ltit's. you add airflow until the ltit's and stit's get around 0. I actually like them a little negative (better to more airflow then not enough). Except with the a/c airflow you only use the stit's to see what adjustment you need to make to the a/c airflow.
#9
Originally Posted by Michael Ozorowsky
Would someone be willing to look at a log of mine? I can do fresh log tomorrow. I will start car, log, and let sit there until it gets to operating temp.
From what I have noticed for some reason, is I log my idle while driving is that bad?
I notice my Ltit, to be -.08 all the way through, then after car warms up and gets hot it jumps to -.32 or something crazy. Doesn't make sense to me. That is with AC off.
With ac on, my Ltit/Stit goes to zero, and there is something in hp tuners called a/c airflow or something like that. If someone could get me on track would be very much appreciated.
From what I have noticed for some reason, is I log my idle while driving is that bad?
I notice my Ltit, to be -.08 all the way through, then after car warms up and gets hot it jumps to -.32 or something crazy. Doesn't make sense to me. That is with AC off.
With ac on, my Ltit/Stit goes to zero, and there is something in hp tuners called a/c airflow or something like that. If someone could get me on track would be very much appreciated.
#10
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let me see if I got this straight: What I do is start scanning STIT/LTIT. Look at LTIT, let's say is -.08, then (with hp tuners) I go to my base running air flow, and -.08 from whatever temps necessary. Then, I turn a/c on, and look at my STIT, what table do I modify? Could someone please explain this as easily as possible?
#11
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take a look at my writeup on RAF (and many other idle related things) at http://redhardsupra.blogspot.com/200...le-tuning.html
just a quick advice: for Idle tuning, set your scans to g/sec, as the numbers come out much more precise than in lb/min so you get 20g/sec as compared to some 0.07lb/sec or something. same thing, better display.
just a quick advice: for Idle tuning, set your scans to g/sec, as the numbers come out much more precise than in lb/min so you get 20g/sec as compared to some 0.07lb/sec or something. same thing, better display.
#13
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I cant see any specific RAF value for AC on. However, I can see PID airflow decay rates for AC ariflow. Try doubling the Proportional and Derivative decay rates if your AC increases airflow ridiculously high and see if that helps.
#14
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AC airflow is torque based. You can try increasing the AC torque numbers under Engine -> Torque Mgt, Engine Torque if your STITs are moving too far positve when the AC is on.
Chris...
Chris...