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    Cobb - Timing Drops / WGDC Base almost at 0 / ATR / Boost Over Shoots / Logs and WGDC base Attached

    I've been wrestling with timing drops Cobb Stage 1 4.01 Aggressive OTS map. I've even tried the sport map and drive map too and get the drops to a slightly lesser extent. I've even tried all 3 levels of the maps on version 3.01 and get the same result. I don't believe its hardware. I never get codes, have 45K on the odometer, changed the spark plugs at 37K and the HPFP was replaced in 2010 with the revised version.

    Timing drops always coincide with actual boost exceeding requested boost. I've pulled a ton out of WGDC base and still have not been able to eliminate it. Things are better. Whereas before I would see lots of negative timing now I see more low positive numbers. Wide open throttle and the above 4K RPM's are actually very good. Its mostly at the onset of boost that these happen. I get the drops on part throttle too. My DME seems to like to pull timing aggressively and only closes throttle on rare occasions. When it closes throttle its already too late.

    What's especially frustrating is that when I give a light stab of throttle on the highway in 5th or 6th gear (only requesting around 2 psi) Ialways over boost as you'll see in the attached. My WGDC values in this range are already at 0.05 - 0.5. I'll pull them down to 0 but where do I go from here? Any suggestions using PID?

    Interestingly on the stage 0 (mimics stock map) I don't get any timing drops even in low boost part throttle situations. Is there something fundamentally different in the underlying logic in this map?

    I'm under a CPO warranty and I really am hesitant to stack with a JB4 for this reason although I know doing that seems to be the current workaround. Any suggestions of what I can do ATR with just the Cobb are much appreciated.
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    I forgot to mention I have a manaul transmission.
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    bump @Josh@Cobb

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    Shoot me an email with a copy of the map you're using, your rom version, and some logs with MAF Req (WGDC) and Boost Setpoint Factor logged.

    The timing drops are an ongoing battle that I'm working on.

    josh.dankel@cobbtuning.com
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    Can we have a detailed update on torque intervention progress? I know of 1 cause that can be reduced through ATR, but a little reluctant to share at this time.

    Boost control and torque targeting is separate subjects... what is the focus/direction to control the sensitivities?

    OP, haven't reviewed your logs but if you are concentrating on lower boost in 6th you may want to consider reducing WGDC before >1 setpoint factor. Do you have an aftermarket BOV? There's another set of tables that control WG based on temps and they control WG values that i don't think ATR has access to... but theoretically WG could be globally reduced here. Or you could change the factors, but i've never done this.

    Also in tuning WG base you probably want to focus on areas after spool, so start a run at low rpms. I wonder if there's a factor for gear... Cobb this a potential table in the future?

    It seems many peeps gave up on figuring the details and tune WOT in a way that works, but not optimal IMO.

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    Click here to enlarge Originally Posted by Josh@Cobb Click here to enlarge
    Shoot me an email with a copy of the map you're using, your rom version, and some logs with MAF Req (WGDC) and Boost Setpoint Factor logged.

    The timing drops are an ongoing battle that I'm working on.

    josh.dankel@cobbtuning.com
    Josh, thanks for reaching out. I emailed you the logs and map directly.
    Last edited by mfish; 02-19-2013 at 10:25 AM.
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    Click here to enlarge Originally Posted by JoshBoody Click here to enlarge
    Can we have a detailed update on torque intervention progress? I know of 1 cause that can be reduced through ATR, but a little reluctant to share at this time.

    Boost control and torque targeting is separate subjects... what is the focus/direction to control the sensitivities?

    OP, haven't reviewed your logs but if you are concentrating on lower boost in 6th you may want to consider reducing WGDC before >1 setpoint factor. Do you have an aftermarket BOV? There's another set of tables that control WG based on temps and they control WG values that i don't think ATR has access to... but theoretically WG could be globally reduced here. Or you could change the factors, but i've never done this.

    Also in tuning WG base you probably want to focus on areas after spool, so start a run at low rpms. I wonder if there's a factor for gear... Cobb this a potential table in the future?

    It seems many peeps gave up on figuring the details and tune WOT in a way that works, but not optimal IMO.
    Joshbody - Thanks for your input. I do not have an aftermarket BOV. I'm literally in bone stock hardware form, currently. I had been running BMS DCI's a few months ago and had the same symptoms. I went back to the stock airbox to see if that made a difference, which it did not.

    I'm with you in that I don't just want a strong tune at WOT. I also want smooth and powerful performance in part throttle situations.

    How do I adjust the WGDC before the 1 setpoint? The WGDC base table has a minimum setpoint of 1.1. Thanks
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    Click here to enlarge Originally Posted by mfish Click here to enlarge
    Joshbody - Thanks for your input. I do not have an aftermarket BOV. I'm literally in bone stock hardware form, currently. I had been running BMS DCI's a few months ago and had the same symptoms. I went back to the stock airbox to see if that made a difference, which it did not.

    I'm with you in that I don't just want a strong tune at WOT. I also want smooth and powerful performance in part throttle situations.

    How do I adjust the WGDC before the 1 setpoint? The WGDC base table has a minimum setpoint of 1.1. Thanks
    I played with WGDC off boost and was able to reduce it drastically, but the direct effect from each table is not clear. Pre-control A is pretty straight forward, but only has a limited effect. The others would be the last 2 tables under WGDC section. I'm sure we don't have all the tables available that's needed though.

    The BOV could potentially have an effect. Stock DVs are designed to blow off with a differential of maybe 3psi pre/post throttle... not sure about the aftermarket options.

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    Bump

    I'm the op on this thread and am still having this timing drop problem in a big way. Has anyone discovered any new methods to try in ATR to help fix this problem? I'm very frustrated.
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    Click here to enlarge Originally Posted by mfish Click here to enlarge
    Bump

    I'm the op on this thread and am still having this timing drop problem in a big way. Has anyone discovered any new methods to try in ATR to help fix this problem? I'm very frustrated.
    Hi @mfish , we've managed to fix the timing drops at the onset of WOT on a number of our customer cars in the last while. Shoot me an email if you'd like to discuss. dzenno at protuningfreaks dot com

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    Click here to enlarge Originally Posted by dzenno@ProTUNING Freaks Click here to enlarge
    Hi @mfish , we've managed to fix the timing drops at the onset of WOT on a number of our customer cars in the last while. Shoot me an email if you'd like to discuss. dzenno at protuningfreaks dot com
    @dzenno - I just emailed you directly. Thanks in advance!
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    Dme/ecu version?
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    Click here to enlarge Originally Posted by enrita Click here to enlarge
    Dme/ecu version?
    IJE0S and I'm 6MT
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    I thought I had a miss when the motor was cold but I managed to capture it on the logger and it was this. I'm tightening up the P-factor so that it will kick in and reduce WGDC immediately as soon as I go over boost target rather than waiting until I'm 2+psi over boost before interfering. It seemed to help this morning but we'll see...

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    Click here to enlarge Originally Posted by Carl Morris Click here to enlarge
    I thought I had a miss when the motor was cold but I managed to capture it on the logger and it was this. I'm tightening up the P-factor so that it will kick in and reduce WGDC immediately as soon as I go over boost target rather than waiting until I'm 2+psi over boost before interfering. It seemed to help this morning but we'll see...
    Do about 70% on it see if it improves

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    It has definitely improved but I took a pretty big hammer to it. When you say 70% what do you mean? I just added on the negative (left) side of the table all the way up to the -0.0 column below about 4500 rpm. I have not seen any oscillations or other boost control problems since I started fooling with this but I never know if that's because of my elevation and if my changes will work correctly for someone at sea level.

    I think what I'm seeing is that I've completely gotten rid of throttle closures, but I am still seeing occasional timing pulls (with no knock) even when I am not exceeding the boost target. It's weird, I assume it's what Josh@Cobb said that he's been fighting with.

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    Click here to enlarge Originally Posted by Carl Morris Click here to enlarge
    It has definitely improved but I took a pretty big hammer to it. When you say 70% what do you mean? I just added on the negative (left) side of the table all the way up to the -0.0 column below about 4500 rpm. I have not seen any oscillations or other boost control problems since I started fooling with this but I never know if that's because of my elevation and if my changes will work correctly for someone at sea level.

    I think what I'm seeing is that I've completely gotten rid of throttle closures, but I am still seeing occasional timing pulls (with no knock) even when I am not exceeding the boost target. It's weird, I assume it's what Josh@Cobb said that he's been fighting with.
    Can you please post your P factor table? I know every car is different but being that we have the same problem if I can see what changes you made as compared to the OTS table I think a picture is worth a thousand words and then I'll understand how the table works and how to tweak it in ATR. It will also give me a good starting point.

    As shown in the first post, I've already tried pulling our a ridiculous amount of WGDC by logging MAF Req and boost setpoint. That only got me so far to the point of the car getting slower and feeling unresponsive. Its all relative to requested boost so I think I too need to make the DME react quickly and strongly to even the slightest of overboosts to get rid of these super annoying timing pulls. Maybe I have tight waste gates and a cranky DME....who knows...I just want it fixed! Thanks
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    Sure. It's a work in progress, but this is what it looks like at the moment. Not sure if what works for me at high elevation will work for everybody. Notice that at high rpm I'm leaning hard on the wastegates to try to keep the boost up. There are a few cells where 0.0 is actually 0.05...you can tell the places where it says -0.0 when it's actually -0.05. But no big deal.

    Click here to enlarge

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    Click here to enlarge Originally Posted by Carl Morris Click here to enlarge
    Sure. It's a work in progress, but this is what it looks like at the moment. Not sure if what works for me at high elevation will work for everybody. Notice that at high rpm I'm leaning hard on the wastegates to try to keep the boost up. There are a few cells where 0.0 is actually 0.05...you can tell the places where it says -0.0 when it's actually -0.05. But no big deal.

    Click here to enlarge

    Thanks for posting that up. I'm much closer to sea level than you so I don't really need any of the tweaks that help maintain boost in the upper RPM's. My car holds boost very well. However I do need help knocking overboosts down much more quickly in the low to mid RPMS.

    Can you please point me in the right direction as to which cell ranges you edited to help mitigate overboosts? I really appreciate it.
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    In PID theory, positive error means the process variable is less that the setpoint, i.e. absolute boost is less than requested absolute boost. If you are overshooting, you want to adjust the P factors for the negative boost error cells.
    Eppur si muove.

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    Click here to enlarge Originally Posted by ajm8127 Click here to enlarge
    In PID theory, positive error means the process variable is less that the setpoint, i.e. absolute boost is less than requested absolute boost. If you are overshooting, you want to adjust the P factors for the negative boost error cells.
    Thanks for the concise answer - that was very helpful. So basically I'll be working in the upper left hand corner to mitigate over boosts in the low to mid RPM range. So in order to make the system react more quickly would I make those numbers lower (e.g. more negative if that makes sense) or would I make those numbers higher (e.g. closer to 0)? I'm thinking make the number lower (more negative) but just want to be certain.
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    You want to increase the magnitude of the proportional term to make the PID algorithm react more drastically to a difference between the set point and process variable. The negative sign is just a direction. If the proportional term was "-2", '2' tells the algorithm how dramatically to react and the negative sign indicates in which direction to adjust the process variable. A 2 (+2) tells the algorithm to react just as dramatically but in the opposite direction.

    A magnitude less that 2 (-0.5 or 1) tells the algorithm to react less drastically, in the direction dictated by the sign of the number.
    Eppur si muove.

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    Raising P will get you to target boost faster (rate of rise/drop correction will be higher) but the higher you go the higher the overshoot/undershoot will be. What you want is to reduce P essentially so that you get minimal to no overshoot essentially slowing down your spool. You'll end up losing a bit on the spool but with stock turbos I don't suspect much will be lost. I and D are used to stabilize the system in the case of overshoot (i.e. boost error in Cobb table terms) where the PID tries to stabilize the system when it overshoots/undershoots and starts to oscillate. You have to play with it and see how it works out on your car. If you start from scratch it can be time very consuming.

    Take a look here, some of those illustrations should be quite helpful:

    http://en.wikipedia.org/wiki/PID_controller

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    Click here to enlarge Originally Posted by mfish Click here to enlarge
    Can you please point me in the right direction as to which cell ranges you edited to help mitigate overboosts? I really appreciate it.
    Just look at any of the Cobb OTS maps to compare what I did to what they did. But in regard to your later questions yes, if you want to open the wastegate sooner as you go above target boost, make the negative numbers on the left side of 0 error bigger for that rpm. But the OTS code waits until the error is pretty large before getting involved...I'm mostly just adjusting the wastegate sooner as I overboost. They way they do it reduces the chance of oscillation, but allows enough overshoot to result in the weird timing pulls and such that we see.

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    Thanks for everyone's help. I actually did a lot of logging with setponint / MAF Req. So I combined a lowered WGDC table with the P factor table from carl morris. Then I lowered the numbers (made them "more negative") in the upper left offending regions. And I'm seeing big improvements!!! Overboosts are almost eliminated and timing is way better. Logs attached are WOT in 2nd and 3rd gear which are the hardest ones to tame. Charge air temps were around 105 degrees or else I'd probably be seeing a little more timing advance.

    I'm going to multiply the P factor from 3000 - 4000 RPMS in boost error -0.10 to -0.00 by 1.3 to see if it completely eliminates overboosts and in turn eliminates the timing drops. I still had a couple of bouts of negative timing (not captured on attached logs)
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