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judeisnotobscure
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« Reply #15 on: April 14, 2011, 02:41:03 PM »
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I would like to see those.
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I have a b5 s4
but i just want to dance.
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Phil R
Newbie
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Posts: 20
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« Reply #16 on: April 28, 2011, 10:01:16 AM »
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wow nice work, interesting stuff. I'm still very much in the just reading phase but it to see your work displayed graphically vs formulas I dont yet understand.
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Bische
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« Reply #17 on: February 22, 2013, 01:26:53 PM »
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Alright, im bumping this to verify my sanity regarding boost linearization. I understand what is described here is for making the boost linear to WGDC, and why that is desired.
What I have gotten hung up on is what is also really desirable, boost vs rpm linearity. Look at a fixed duty WOT log, the curve doesnt stay very level in most applications.
What we do here is to linearize within this characteristic to make DC weigh "equal" or linear, since the DC output pre LDRL must be linear.
I hope any of this makes any sense, what im asking for is: Is it not desirable to linearize the raw DC to output a more stable boost pressure vs. RPM?
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jibberjive
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« Reply #18 on: February 23, 2013, 03:45:53 AM »
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So you're looking for a more linear 'spool' (linear powerband), like one would desire on a road course? Just making sure I'm understanding you right. I think most people with big turbos want the max spool they can get at a given time, when going WOT, and don't car so much about spool linearity (until the point where it reaches desired boost, from then on, of course, you want it to be a linear cap).
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nyet
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« Reply #19 on: February 23, 2013, 11:16:25 AM »
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So you're looking for a more linear 'spool' (linear powerband), like one would desire on a road course? Just making sure I'm understanding you right. I think most people with big turbos want the max spool they can get at a given time, when going WOT, and don't car so much about spool linearity (until the point where it reaches desired boost, from then on, of course, you want it to be a linear cap).
I think you misunderstand the goal. The linearity you are looking for has nothing to do with linear powerband; it has to do with the PID controller acting better if the control response is linearized. |
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ME7.1 tuning guideECUx PlotME7Sum checksumTrim heatmap toolPlease do not ask me for tunes. I'm here to help people make their own. Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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jibberjive
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« Reply #20 on: February 24, 2013, 03:36:34 AM »
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I think you misunderstand the goal.
The linearity you are looking for has nothing to do with linear powerband; it has to do with the PID controller acting better if the control response is linearized.
I understand PID controllers and the need to linearize it to match the wastegate response (independent of boost level/boost profile), but I thought Bische was saying something else. I thought he was referring to utilizing the boost control to slow down the boost profile to a more 'linear' slope with regard to RPM (rather than just having the turbo spool asap and just using the boost controller to cap off the boost at a peak level, like most of us do). After looking again at his post, I see he's just talking about using a different reference to linearize the PID (linearize the PID with respect to RPM rather than N75 DC), and not necessarily linearizing the actual boost profile with RPM. |
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« Last Edit: February 24, 2013, 04:18:44 AM by jibberjive »
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Bische
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« Reply #21 on: February 24, 2013, 08:19:47 PM »
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Look at the graph I attached. What would be desirable is for the pressure to stay level once the WG cracks at a fixed DC, like the line I painted on there.
If we linearize with the top DC boost curve as reference, there will still be some of this behaviour as the that curve is not "flat" either.
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julex
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« Reply #22 on: February 25, 2013, 01:10:14 PM »
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I am about to go through all this to calibrate Tial 770 KFLDRL. I am on virgin waters here since there is no file in existence that actually has working PID control for GT turbos on this engine... due to obvious as we just pioneered the mechanism to use boost sensor above 22.5psi. So... Any chance (elRay) to post that excel formula in copy/paste format? [  ] |
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julex
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« Reply #23 on: February 25, 2013, 01:12:41 PM »
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Look at the graph I attached. What would be desirable is for the pressure to stay level once the WG cracks at a fixed DC, like the line I painted on there.
If we linearize with the top DC boost curve as reference, there will still be some of this behaviour as the that curve is not "flat" either.
That's why PID controller is implemented, to adhere as much as possible to that flat line (or whatever load/pressure limit limit you throw at it). MEechanically there is no way to come up with soem linearization and have flat boost curve... It might be possible to come close but would go out of the window as soon as temps for example change etc. |
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s5fourdoor
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« Reply #24 on: February 25, 2013, 01:48:12 PM »
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ElRey - Can you please clarify for me, is this what your KFLDRAPP looked like when you did 10%? I just want to make sure this is exactly what you did, to verify your procedure. My reading of your method was a bit ambiguous, perhaps I'm an idiot idk... anyways, this should clarify.
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julex
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« Reply #25 on: February 25, 2013, 01:55:37 PM »
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ElRey - Can you please clarify for me, is this what your KFLDRAPP looked like when you did 10%? I just want to make sure this is exactly what you did, to verify your procedure. My reading of your method was a bit ambiguous, perhaps I'm an idiot idk... anyways, this should clarify.
I understood it this way too. You want to have 0% DC under 40% of gas pedal position to not kill yourself when driving casually but otherwise at max duty the table allows. It is really not important what values you use but the one you'll have your pedal at during the pull, which probably means 100% when you floor it. |
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elRey
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« Reply #26 on: February 25, 2013, 02:14:23 PM »
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ElRey - Can you please clarify for me, is this what your KFLDRAPP looked like when you did 10%? I just want to make sure this is exactly what you did, to verify your procedure. My reading of your method was a bit ambiguous, perhaps I'm an idiot idk... anyways, this should clarify.
Correct. I didn't want the ECU holding the N75 open @ 10% when it wasn't needed. So, I left the lower PED rows set to 0. If I were to do it again on another car I would consider this -> Exposing some VS_VERST vars to TKMWL (unisettings) func ?Unless you have an emulator. Must be nice. |
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« Last Edit: February 25, 2013, 02:19:47 PM by elRey »
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elRey
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« Reply #27 on: February 25, 2013, 02:40:31 PM »
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I am about to go through all this to calibrate Tial 770 KFLDRL. I am on virgin waters here since there is no file in existence that actually has working PID control for GT turbos on this engine... due to obvious as we just pioneered the mechanism to use boost sensor above 22.5psi. So... Any chance (elRay) to post that excel formula in copy/paste format? [ ] How about I attach my excelsheet? |
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julex
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« Reply #28 on: February 25, 2013, 06:42:17 PM »
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Snatched I will have to modify it if I can only run DC up to 60 though, right? |
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elRey
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« Reply #29 on: February 25, 2013, 09:03:36 PM »
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Snatched I will have to modify it if I can only run DC up to 60 though, right? If you are only calibrating up to 60%, then I would make KFLDRL linear from your newly adjusted 60% row to the 95%=95% row. But I'm just guessing. Experience/testing may prove different. |
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« Last Edit: February 25, 2013, 09:20:55 PM by elRey »
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