Cobb or GIAC, can you do something about this ?

tscdennab · 11-13-2011, 06:07 PM

It's about the shift bog on manual transmission cars. Again. Since this problem has not really been solved until now, I want to keep some interest on it with (perhaps) some new information. I am sick of ruining 50-60% of my drag strip runs because of the shift bog.

I don't expect any piggyback manufacturer to be able to do something about it, because I think it's a mechanism from the ECU software. This could only be solved by altering the software.

The picture below is a magnification of a 3-4 bog event. As you can see, the ECU demands that the boost to rise slowly after the shift (look at the target boost mild slope !). The throttle blade only acts to control boost until the actual boost drops under the boost target, after which it opens fully, but the boost continues to climb slowly on a mild slope set by the ECU.

Since I have been able to induce bog when my car was stock, I believe that it is a protection mechanism.

I wonder if any flash tuner is able to alter this piece of software from the ECU ?

vasillalov · 11-13-2011, 06:27 PM

I would not be surprised if BMW purposefully did this to limit the amount of shock various drive train components are exposed to from the all-mighty N54. This is the reason why they put the notorious clutch delay valve.

I agree though, the shift bog would be nice to be coded out or at least, its effects reduced.

Jeff@TopGearSolutions · 11-13-2011, 06:29 PM

I dont experience shift bog on the Cobb or PROcede. You can "tune" it out so to speak.

boom · 11-13-2011, 07:55 PM

It looks to me like the rev limiter is at play here. What happens if you shift a couple hundred rpm earlier?

nitehawk · 11-13-2011, 08:08 PM

I cant say that I've ever felt the shift bog w/ Cobb...I mean is it actually noticeable without looking at the data? I think the no lift shift feature would help maintain higher boost levels between shifts

dicostal · 11-13-2011, 11:09 PM

Quote:

Originally Posted by tscdennab

It's about the shift bog on manual transmission cars. Again. Since this problem has not really been solved until now, I want to keep some interest on it with (perhaps) some new information. I am sick of ruining 50-60% of my drag strip runs because of the shift bog.

I don't expect any piggyback manufacturer to be able to do something about it, because I think it's a mechanism from the ECU software. This could only be solved by altering the software.

The picture below is a magnification of a 3-4 bog event. As you can see, the ECU demands that the boost to rise slowly after the shift (look at the target boost mild slope !). The throttle blade only acts to control boost until the actual boost drops under the boost target, after which it opens fully, but the boost continues to climb slowly on a mild slope set by the ECU.

Since I have been able to induce bog when my car was stock, I believe that it is a protection mechanism.

I wonder if any flash tuner is able to alter this piece of software from the ECU ?

yes please solve it if possible, it is so annoying. shifting a bit earlier does help a bit, but i still feel the bog. I have GIAC I, i believe this issue only applies to Manual cars.

Alpina_B3_Lux · 11-14-2011, 03:27 AM

I can also feel that on a regular basis. GIAC stage 2 with MT here.

Alpina_B3_Lux

vasillalov · 11-14-2011, 10:14 AM

Yes, it is there with and without Cobb. I've felt it with GIAC as well.

Brey335i · 11-14-2011, 01:53 PM

Quote:

Originally Posted by vasillalov

Yes, it is there with and without Cobb. I've felt it with GIAC as well.

Must be your car. My buddy has the CDV in place and no bog on shifts...

vasillalov · 11-14-2011, 02:56 PM

Quote:

Originally Posted by Brey335i

Must be your car. My buddy has the CDV in place and no bog on shifts...

Could very well be.

What ISTA version does he have?

tscdennab · 11-14-2011, 03:42 PM

Quote:

Originally Posted by vasillalov

Could very well be.

What ISTA version does he have?

I know multiple people with GIAC/JB4/Procede who have the shift bog. It's not your car...

I have sent detailed logs to Austin @ GIAC and he said they will take a look to see what's happening. Hopefully they can find a solution. If there is someone who has the means to solve it, I think GIAC is the one. I think they are the most advanced with N54 software reverse engineering right now.

I will post here if I receive interesting information.

dicostal · 11-14-2011, 04:11 PM

CDV does not resolve this issue. I think the car just kills the boost on shift

the higher the rpm the more boost lag is felt.

SennaZ · 11-14-2011, 04:28 PM

Just a simple matter of opening the throttle valve sooner

Beemw335 · 11-14-2011, 06:22 PM

I heard the procede does a greag job with bog, but I wouldnt know since Im auto

Zeph · 11-14-2011, 10:10 PM

It is definitely there. I have it on my car... stock, SSTT, and even with different versions/stages of COBB now. It is really bad from 3rd to 4th for some reason. I know I lose some eta/mph on a drag run because of it, but there doesn't seem to be any way to solve the problem.

Zeph

tscdennab · 11-14-2011, 10:52 PM

I received a very encouraging answer from Austin@GIAC !

"Hi Catalin,

From the logs that you have sent over, it seems like you are triggering the clutch/transmission protection safeties in the DME. This is something that can be removed, however, it is likely to shorten the life of your clutch significantly." Austin asked for some more logging, however.

This leads me to believe that with a slipping clutch (subtle slipping and not knowing it), this can happen more often.

If I can remove this, I will. GIAC would gain a lot of customers if they could remove this

Glowin · 11-15-2011, 12:29 AM

Quote:

Originally Posted by tscdennab

GIAC would gain a lot of customers if they could remove this

Good news if they figure it out, but that's a bit of a stretch IMO... Not all the MT's seem to have it nor has it been such a huge deal, or you'd read about it every day on the forums...

OpenFlash · 11-15-2011, 01:05 AM

Quote:

Originally Posted by Beemw335

I heard the procede does a greag job with bog, but I wouldnt know since Im auto

Yes, it was an easy fix. Next week, we should also have a fix for bogs caused by accidentally bumping against the rev limiter. And then hopefully something for the high powered 6at guys who are running into transmission slipping/shifting issues. The nice thing about winter is things slow down enough to get a lot of developement/testing time in

Shiv

tscdennab · 11-15-2011, 04:27 AM

Quote:

Originally Posted by Glowin

Good news if they figure it out, but that's a bit of a stretch IMO... Not all the MT's seem to have it nor has it been such a huge deal, or you'd read about it every day on the forums...

It doesn't happen if you shift "normally". Try it at the drag strip or at a circuit when you want to shift fast...it will happen.

It MAY happen more often with a slipping clutch. This is just my supposition. And it really is a huge deal, just search the forums for "bog".

tscdennab · 11-15-2011, 06:04 AM

Quote:

Originally Posted by shiv@vishnu

Yes, it was an easy fix. Next week, we should also have a fix for bogs caused by accidentally bumping against the rev limiter. And then hopefully something for the high powered 6at guys who are running into transmission slipping/shifting issues. The nice thing about winter is things slow down enough to get a lot of developement/testing time in

Shiv

Here is a bog posted just yesterday with your latest maps:

http://www.e90post.com/forums/showpo...13&postcount=6

piele_bps · 11-15-2011, 07:04 AM

^ +1

Zeph · 11-15-2011, 10:09 AM

I like the idea that the clutch is seeing slippage and that is why the bog occurs. I was planning to upgrade my clutch soon anyway and I was hoping/wishing this would fix the issue in case it was related to slip. Maybe it happens more on the 3-4 shift since by then things are heated up much more as this is the last shift during a drag race. I know HPF concluded that it was possibly a slippage issue in another thread... of course that was a thread where they were trying to sell their new clutch so you have to take that information with a grain of salt.

On the other hand, I didn't realize DME's/ECU's even had that type of ability to detect MT clutch slippage and lower power to compensate... but definitely possible!

Zeph

11-13-2011, 06:07 PM	#1
tscdennab Banned 153 Rep 1,809 Posts Drives: BMW 335i Join Date: Oct 2010 Location: Europe iTrader: (0) Garage List 2008 BMW [6.24]	Cobb or GIAC, can you do something about this ? It's about the shift bog on manual transmission cars. Again. Since this problem has not really been solved until now, I want to keep some interest on it with (perhaps) some new information. I am sick of ruining 50-60% of my drag strip runs because of the shift bog. I don't expect any piggyback manufacturer to be able to do something about it, because I think it's a mechanism from the ECU software. This could only be solved by altering the software. The picture below is a magnification of a 3-4 bog event. As you can see, the ECU demands that the boost to rise slowly after the shift (look at the target boost mild slope !). The throttle blade only acts to control boost until the actual boost drops under the boost target, after which it opens fully, but the boost continues to climb slowly on a mild slope set by the ECU. Since I have been able to induce bog when my car was stock, I believe that it is a protection mechanism. I wonder if any flash tuner is able to alter this piece of software from the ECU ? Attached Images
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11-13-2011, 06:27 PM	#2
vasillalov Mad Linux Guru On The Loose 1130 Rep 5,404 Posts Drives: 2008 335i Sedan, 2023 M3 Join Date: Aug 2009 Location: Chicago, IL iTrader: (5) Garage List 2023 BMW M3 [0.00] 2008 335i E90 [8.00]	I would not be surprised if BMW purposefully did this to limit the amount of shock various drive train components are exposed to from the all-mighty N54. This is the reason why they put the notorious clutch delay valve. I agree though, the shift bog would be nice to be coded out or at least, its effects reduced. __________________
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11-13-2011, 06:29 PM	#3
Jeff@TopGearSolutions 3442 Rep 79,211 Posts Drives: C6 Z06, 09 335i, 10 335xi Join Date: Dec 2008 Location: www.TopGearSolutions.com iTrader: (37)	I dont experience shift bog on the Cobb or PROcede. You can "tune" it out so to speak.
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11-13-2011, 07:55 PM	#4
boom My X5d tows my spec miata to the track. 74 Rep 1,254 Posts Drives: 2010 X5 35d Join Date: Sep 2009 Location: USA iTrader: (0)	It looks to me like the rev limiter is at play here. What happens if you shift a couple hundred rpm earlier?
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11-13-2011, 08:08 PM	#5
nitehawk Lieutenant Colonel 102 Rep 1,903 Posts Drives: e92 335i 6MT Join Date: May 2011 Location: Toronto iTrader: (15) Garage List E92 BMW 335i [9.00] E92 BMW 335i \| Retired [10.00]	I cant say that I've ever felt the shift bog w/ Cobb...I mean is it actually noticeable without looking at the data? I think the no lift shift feature would help maintain higher boost levels between shifts
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11-14-2011, 03:27 AM	#7
Alpina_B3_Lux Colonel 263 Rep 2,563 Posts Drives: Audi R8 LMX, BMW M550i xDrive Join Date: Feb 2008 Location: Germany iTrader: (0) Garage List 2009 335i [8.90]	I can also feel that on a regular basis. GIAC stage 2 with MT here. Alpina_B3_Lux __________________ Audi R8 LMX, BMW M550i xDrive (G30 LCI); gone: Alpina B3 3,3 (E46), BMW 335i, Audi R8 V10 manual, Audi R8 V10, BMW M235i, BMW 550i F10
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11-14-2011, 10:14 AM	#8
vasillalov Mad Linux Guru On The Loose 1130 Rep 5,404 Posts Drives: 2008 335i Sedan, 2023 M3 Join Date: Aug 2009 Location: Chicago, IL iTrader: (5) Garage List 2023 BMW M3 [0.00] 2008 335i E90 [8.00]	Yes, it is there with and without Cobb. I've felt it with GIAC as well. __________________
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11-14-2011, 04:11 PM	#12
dicostal Lieutenant 55 Rep 495 Posts Drives: 2007 335i Join Date: Jun 2010 Location: Italian in CT - USA iTrader: (0)	CDV does not resolve this issue. I think the car just kills the boost on shift the higher the rpm the more boost lag is felt. __________________ GIAC stage II\|AA DP\|AA Charge pipe and BOV\|AFE S2 Intake\|HELIX FMIC
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11-14-2011, 04:28 PM	#13
SennaZ been there... done that 4 Rep 277 Posts Drives: 2008 335i Join Date: Aug 2008 Location: Phoenix iTrader: (1)	Just a simple matter of opening the throttle valve sooner
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11-14-2011, 06:22 PM	#14
Beemw335 Colonel 62 Rep 2,013 Posts Drives: 335i Join Date: Mar 2011 Location: My car is my home iTrader: (2)	I heard the procede does a greag job with bog, but I wouldnt know since Im auto
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11-14-2011, 10:10 PM	#15
Zeph Major 27 Rep 1,410 Posts Drives: 2008 E92 335i 6MT SGM CR/BD Join Date: Jul 2008 Location: Southeast USA iTrader: (0)	It is definitely there. I have it on my car... stock, SSTT, and even with different versions/stages of COBB now. It is really bad from 3rd to 4th for some reason. I know I lose some eta/mph on a drag run because of it, but there doesn't seem to be any way to solve the problem. Zeph
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11-14-2011, 10:52 PM	#16
tscdennab Banned 153 Rep 1,809 Posts Drives: BMW 335i Join Date: Oct 2010 Location: Europe iTrader: (0) Garage List 2008 BMW [6.24]	I received a very encouraging answer from Austin@GIAC ! "Hi Catalin, From the logs that you have sent over, it seems like you are triggering the clutch/transmission protection safeties in the DME. This is something that can be removed, however, it is likely to shorten the life of your clutch significantly." Austin asked for some more logging, however. This leads me to believe that with a slipping clutch (subtle slipping and not knowing it), this can happen more often. If I can remove this, I will. GIAC would gain a lot of customers if they could remove this
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11-15-2011, 07:04 AM	#21
piele_bps Enlisted Member 1 Rep 48 Posts Drives: E90 335i '07 Join Date: Sep 2009 Location: Romania iTrader: (0)	^ +1
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11-15-2011, 10:09 AM	#22
Zeph Major 27 Rep 1,410 Posts Drives: 2008 E92 335i 6MT SGM CR/BD Join Date: Jul 2008 Location: Southeast USA iTrader: (0)	I like the idea that the clutch is seeing slippage and that is why the bog occurs. I was planning to upgrade my clutch soon anyway and I was hoping/wishing this would fix the issue in case it was related to slip. Maybe it happens more on the 3-4 shift since by then things are heated up much more as this is the last shift during a drag race. I know HPF concluded that it was possibly a slippage issue in another thread... of course that was a thread where they were trying to sell their new clutch so you have to take that information with a grain of salt. On the other hand, I didn't realize DME's/ECU's even had that type of ability to detect MT clutch slippage and lower power to compensate... but definitely possible! Zeph
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