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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > Oscillations on Cobb stage 1 + 4.02 based map massaged in ATR



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      11-08-2013, 05:44 PM   #1
mfish123
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Oscillations on Cobb stage 1 + 4.02 based map massaged in ATR

I've been battling oscillations for a while. Really the only thing I found that helped a little was to take the D factor multiplier values from stage 0 and utilize those but it only helps a little. I'm at loss as to how to modify the other PID tables.

Please note my car is hyper sensitive to timing drops when actual load gets close to or exceeds requested load so I made the load very high and use the boost limit multiplier to control boost which helps for this phenomenon. My map is based off 4.02 stage 1+ linear throttle. Details of my car are in signature. I can upload the map if anyone wants to see it but aside from D factor multiplier all the PID related tables are the same as stage 1+ OTS. Any suggestions on what to modify to control oscillations?

3rd gear: http://datazap.me/u/mfish123/3rd-gear-oscillations

4th gear: http://datazap.me/u/mfish123/4th-gear-oscillations
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      11-08-2013, 06:05 PM   #2
enrita
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get a protune by PTF ....
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      11-08-2013, 06:56 PM   #3
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mfish123

That looks more like WGDC base values are screwed up ie there is too much value reduction in the WOT path of the table.

The values in the path of the WOT, which can be found by following the log referencing the BSP and Maf Req, need to be ascending in value downwards. If this causes overshoots followed by TC then you need to back off of your adder, if it was modified, as the PID tables at your power level should remain stock

If you decide to throw in the towel which can get "expensive" due to getting no where testing, and perhaps a ticket, might as well hand it over to ProTuning Freaks (PTF) and they will get map that you will desire at the level your car is at. It will save you money in the end, well that's if you don't care about wasting it
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      11-12-2013, 11:24 AM   #4
mfish123
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Quote:
Originally Posted by BuraQ View Post
mfish123

That looks more like WGDC base values are screwed up ie there is too much value reduction in the WOT path of the table.

The values in the path of the WOT, which can be found by following the log referencing the BSP and Maf Req, need to be ascending in value downwards. If this causes overshoots followed by TC then you need to back off of your adder, if it was modified, as the PID tables at your power level should remain stock

If you decide to throw in the towel which can get "expensive" due to getting no where testing, and perhaps a ticket, might as well hand it over to ProTuning Freaks (PTF) and they will get map that you will desire at the level your car is at. It will save you money in the end, well that's if you don't care about wasting it
BuraQ

Thanks for the tip. It did work! I do like messing around in ATR. Part of the fun, at least for me, is the continual tweaking. And yes I do acknowledge frequent 3rd gear redline pulls can get me in trouble with the law. I have a pretty safe stretch of road to do them on.

I went back to the OTS 4.02 stage 1+ WGDC base values and low and behold the oscillations are gone! And all this time I thought I was a zen master in smoothing out the boost curve.

I do have some overboosts but they're at high MAF / setpoints. I took a little out of 2 of the bottom right cells of the WGDC base but left the values ascending downward. I think I can hopefully tame the rest by carefully lowering the WGDC ceiling and adder in the affected areas.

3rd gear: http://datazap.me/u/mfish123/3rd-gear-overboost
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      11-12-2013, 01:29 PM   #5
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WGDC Base should be used to control TC on an elementary level of learning. Boost curve and minor overshoots can be controlled in the P-Factor table. However you need to be extremely careful with this or else you be back to were you started again
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400+ launches, 3 Driveshafts, No DCT Slippage, Flash Only
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