[Vwgrk1]

Here is a log of a 3-4 run. 50% ethanol. Cobb AP; otherwise stock.

Is it normal for timing to be pulled after a high speed shift across so many cylinders?


I have another run where it does the same thing. My 5 4th gear only runs were perfect with no corrections, at all.

[Ilma]

Originally Posted by Vwgrk1

Here is a log of a 3-4 run. 50% ethanol. Cobb AP; otherwise stock.

Is it normal for timing to be pulled after a high speed shift across so many cylinders?


I have another run where it does the same thing. My 5 4th gear only runs were perfect with no corrections, at all.

Timing flatline symptom.

Happens on the 3-4th shift....

Myst can tell you more about his Cobb experience, but I think he and Dzenno have been working on a solution.

[themyst]

Interesting, this is on a 6MT. I'd say contact Jake@PTF for a custom e-tune or Cobb for feedback. Do you have a log where it doesn't do this?

[Ilma]

I had a closer look at your data......and I am not a Cobb user.

BUT

If I am reading things correctly, during 3rd gear your timing on Cyl#1 is running 12 degrees thru the midrange up to 5700 rpm and your engine is happy with no corrections, then it drops down to 8 degrees until you shift at 6700 rpm.

That's weird.

Timing will usually rise as rpms do.

Then post-shift, there is a reading of 21 degrees for timing which then subsequently seems to set off timing corrections.

I would be looking at the timing request tables

These values don't seem right to me.

[johmei]

Interesting.. My car run perfect except that I have the same issue with timing correction at shifting and will look into the timing tables. Thanks for pointing at the excess timing after shift.

[Vwgrk1]

Originally Posted by Ilma

I had a closer look at your data......and I am not a Cobb user.

BUT

If I am reading things correctly, during 3rd gear your timing on Cyl#1 is running 12 degrees thru the midrange up to 5700 rpm and your engine is happy with no corrections, then it drops down to 8 degrees until you shift at 6700 rpm.

That's weird.

Timing will usually rise as rpms do.

Then post-shift, there is a reading of 21 degrees for timing which then subsequently seems to set off timing corrections.

I would be looking at the timing request tables

These values don't seem right to me.

What you point out is partially expected and partially the issue. You also raise some good questions. The reason timing drops before the shift is that IATs went from below 100 to over, triggering Cobb's IAT-based timing reductions. I expect that.

What I can't get around is why timing is so darn low after the shift. I thought that the Cyl 1 timing column was your map's timing less any IAT adjustments. Is it only 2-3 degrees because of the timing corrections? I thought those were independent and didn't affect this column. To give you an idea of the disparity, I am requesting 12-14 degrees (and its giving me 2 to 3).

To address the 21 degrees of timing and add to the mystery; that 21 is from the plain Jane 401 map. No changes were made. In fact, the columns after the 21 degrees were modified to be a higher number than the 401 map. So, the disparity between the columns is actually LESS than the regular 401 map. Also factor in that I am running higher effective octane (reducing knock risk) and it makes me think that this was pulling timing to an even worse degree on the 401 map (for which I have no logs).

I don't suspect that AFR is the problem, but I'd not rule out anything, I guess. Do you have any new ideas given this information?

[Vwgrk1]

Originally Posted by themyst

Interesting, this is on a 6MT. I'd say contact Jake@PTF for a custom e-tune or Cobb for feedback. Do you have a log where it doesn't do this?

No, this is the first time its been logged. There is another run with the same phenomenon. Once the tank is dry and can be filled with 93 octane, I'd like to see if it does this stock and with the regular 401 map.

Cobb was contacted today and a response is being hoped for. Why do you suggest I talk to Jake? Does he know something about this that you can share? With respect, and I'm sorry if I am misinterpreting you, but the goal is to tune myself and not pay someone else to do it, you know what I mean?

I'd wager many more people are having this and have not logged it since we tend to focus on single-gear runs.

[themyst]

I've been through this for over 2 years and only recently with the emphasis on logging are others coming forward with it. All I can say is pay PTF for the work. I've researched all these theories and such well before you guys. This is truly a case of ignorance being bliss.

It is fixed on my car and I don't even know how. If you ever figure it out, please let me know.

[Vwgrk1]

Originally Posted by themyst

I've been through this for over 2 years and only recently with the emphasis on logging are others coming forward with it. All I can say is pay PTF for the work. I've researched all these theories and such well before you guys. This is truly a case of ignorance being bliss.

It is fixed on my car and I don't even know how. If you ever figure it out, please let me know.

I see what you are saying. Were there any noticeable tade offs such as reduced midrange power?

[JamesM3M5]

Originally Posted by themyst

I've been through this for over 2 years and only recently with the emphasis on logging are others coming forward with it. All I can say is pay PTF for the work. I've researched all these theories and such well before you guys. This is truly a case of ignorance being bliss.

It is fixed on my car and I don't even know how. If you ever figure it out, please let me know.

When I get some time, I'm going to have to dig deeper into my car, as well. I get a significant lag in acceleration after shifting fast. It's kind of annoying, and seems to be slightly worse than several months ago. I'm sure it's a combo of factors.

[dfv2]

I've always had this shift bog issue, figured if nothing else it's saving my clutch

[Jeff@TopGearSolutions]

Originally Posted by JamesM3M5

When I get some time, I'm going to have to dig deeper into my car, as well. I get a significant lag in acceleration after shifting fast. It's kind of annoying, and seems to be slightly worse than several months ago. I'm sure it's a combo of factors.

That sounds like shift bog. That is different then post shift timing flat lining. However, some people can experience both!

I wish I had a definitive answer for either. I suggest contacting your tuners as they have more experience with problems.

[flexinator]

I am having the same thing. Between shifts actual load drops significantly so the dme is asking for timing in the 20s. As you push back on the gas it takes a moment for load to build thus timing too high, corrections start...

At least that's my 2cents

[Boosted-M]

Originally Posted by themyst

I've been through this for over 2 years and only recently with the emphasis on logging are others coming forward with it. All I can say is pay PTF for the work. I've researched all these theories and such well before you guys. This is truly a case of ignorance being bliss.

It is fixed on my car and I don't even know how. If you ever figure it out, please let me know.

Since your car is Pro Tuned you cannot open the map and make addt'l changes down the road right?

[Carl Morris]

I've been working in this area lately and have noticed a few things. One is that the 3-4 shift is usually worse than the earlier shifts. The air charge temps are getting kinda hot at this point and there are spots in the Timing Total Cor. (Charge Air Temp) map such as 4000rpm and 75 load where it's not pulling nearly as much timing as it was at higher load. I think that contributes to the problem. Sometimes you also need to pull a little more timing in the main timing map in the 4500-5500rpm range at lower loads where you end up at on the shift.

Those changes can help, but I think there might be something else going on that makes it more susceptible to this but I'm not sure if anything can be done. I notice you have the same thing going on as I do where the rpm actually oscillates for a moment. Notice that your rpm goes from 5666 to 4900 to 5142 to 5064 to 5042 before it starts climbing steadily again. I don't know where our angle sensor is at but it would seem that the timing chain or something is slapping around on a hard shift and maybe making some noise and causing weird rpm readings at the same time...maybe even causing the ignition to fire at a slightly different time than it should relative to the crank? Just a thought...

[Joshboody]

Hey good discussion guys. I think bog can be either ignition or boost. (EDIT:my bad you can just use boost mean Abs channel, so deleted my earlier comment)

Timing is reactive to load, so yes you’ll have higher timing with less boost… but boost is rising of course. Maybe try experimenting with the spool table by altering the y axis (rpm) and reducing timing here instead of your main map. I wonder how spool is defined in the DME.

Carl, I think the varying rpms is just when the clutch catches… this should be reduced with a fresh, high force pressure plate. Log a fast part throttle (low load) shift and it should be a sharper rpm rise point in relation to throttle… assuming a proper shift.

James, I almost think there could have been a slight change in either procede firmware at some point. Or potentially some difference in BMW, or for me Cobb throttle plate reaction mapping… not sure if there is such a thing, but seems like.it. Or the throttle motor could wear a little over time. It use to be easier to keep the throttle more open during a shift it seems.
EDIT: As in another thread, a thought is that WG solenoids have some lag, or bleeding vac... ie, WGDC in the logs may not be actual output.

Anyway, these are some of the points I’ve thought about.

[JamesM3M5]

Good points all around. I'm shifting out of 3rd at around 6000-6200 RPM (stock everything except Procede + meth).

The crank sensor is right around the #6 cylinder inside the engine. Not sure whether that would cause timing shifts due to torsional vibration, but BMW read the crank sensor off the vibration damper up until 1996 when OBD2 came out. I'd imagine it was worse on that older setup.

I think my boost is getting a little slow to respond - just a tiny bit. I'll test my solenoids for leakage, and probably have to replace some vac hoses.

What exactly causes "bog"?

I'll of course have to log, but I just don't have a great place to do 3rd/4th gear pulls - way too many state and county cops in my area.

[themyst]

Originally Posted by JamesM3M5

Good points all around. I'm shifting out of 3rd at around 6000-6200 RPM (stock everything except Procede + meth).

The crank sensor is right around the #6 cylinder inside the engine. Not sure whether that would cause timing shifts due to torsional vibration, but BMW read the crank sensor off the vibration damper up until 1996 when OBD2 came out. I'd imagine it was worse on that older setup.

I think my boost is getting a little slow to respond - just a tiny bit. I'll test my solenoids for leakage, and probably have to replace some vac hoses.

What exactly causes "bog"?

I'll of course have to log, but I just don't have a great place to do 3rd/4th gear pulls - way too many state and county cops in my area.

The 6MT shift bog has been going on with high boost since forever. It's frustrating and far worse than a 6AT timing drop after the shift since the 6AT issue can be corrected with a little blip of the throttle.

Try doing a wot shift on high boost at around 5500-6000 RPM, it won't bog. Do it north of 6000 it will bog, especially in the higher revs.

Have you considered the NLS/2-step? I heard this fixes the bog.

[themyst]

Originally Posted by Boosted-M

Since your car is Pro Tuned you cannot open the map and make addt'l changes down the road right?

No, but the pro tuner can make small changes to an existing map if needed. I have a E85-only map, an E85+meth high boost map, and a pump gas map.

Unfortunately, NYC pump gas must be crap because I can't get much power out of pump gas only safely.

[themyst]

Originally Posted by JamesM3M5

Good points all around. I'm shifting out of 3rd at around 6000-6200 RPM (stock everything except Procede + meth).

The crank sensor is right around the #6 cylinder inside the engine. Not sure whether that would cause timing shifts due to torsional vibration, but BMW read the crank sensor off the vibration damper up until 1996 when OBD2 came out. I'd imagine it was worse on that older setup.

I think my boost is getting a little slow to respond - just a tiny bit. I'll test my solenoids for leakage, and probably have to replace some vac hoses.

What exactly causes "bog"?

I'll of course have to log, but I just don't have a great place to do 3rd/4th gear pulls - way too many state and county cops in my area.

Also, 6500 RPMs in 3rd gear on a 6MT is like what, 94-95 mph? You don't need to wind out 4th.

[Carl Morris]

Originally Posted by themyst

The 6MT shift bog has been going on with high boost since forever. It's frustrating and far worse than a 6AT timing drop after the shift since the 6AT issue can be corrected with a little blip of the throttle.

Try doing a wot shift on high boost at around 5500-6000 RPM, it won't bog. Do it north of 6000 it will bog, especially in the higher revs.

Have you considered the NLS/2-step? I heard this fixes the bog.

It sounds like you're describing what happens if you hit the rev limit while the clutch is in. In this case I think the OP is talking about knock retard on the 3-4 shift. At least that's what I see in his log.

[themyst]

Originally Posted by Carl Morris

It sounds like you're describing what happens if you hit the rev limit while the clutch is in. In this case I think the OP is talking about knock retard on the 3-4 shift. At least that's what I see in his log.

Yeah, two different subjects here. The OP is talking about a post-shift timing drop, which is much more common on the 6AT, and James is talking about a shift bog. I was replying to James. The OP needs some TLC to have that tuned out.

I also have the same issue with the massive timing drops post-shift on my 6AT, but PTF has fixed it. I don't know how or where he fixed it as there is nothing evident in my logs that show anything changed.