BMW 1 Series Coupe Forum / 1 Series Convertible Forum (1M / tii / 135i / 128i / Coupe / Cabrio / Hatchback) (BMW E82 E88 128i 130i 135i)
 





 

Post Reply
 
Thread Tools Search this Thread
      06-10-2021, 11:43 AM   #1
Phloozy
Second Lieutenant
219
Rep
210
Posts

Drives: BMW 128
Join Date: Oct 2019
Location: Pennsylvania

iTrader: (0)

Rev Matching Issue

I have been having issues on track where I cant seem to heel toe rev match under hard braking. I thought maybe it was a personal issue but then another friend with a 128 told me he was also having the same issues. On the street it heel toes fine but at the track its like the car kills the throttle under hard braking. I tried mashing the gas with my heel and still nothing.

I have done all the normal track coding but maybe there is something else I need to code out? Has anyone else experienced this and have input on what it can be?
Appreciate 0
      06-11-2021, 03:01 PM   #2
spidertri
Lieutenant
spidertri's Avatar
United_States
395
Rep
461
Posts

Drives: 11 128i 6MT Sport
Join Date: Sep 2010
Location: Rock Hill, SC

iTrader: (1)

Garage List
2011 BMW 128i  [0.00]
I have experienced that on track as well, my brakes have otherwise been fantastic since I coded off:

- C0F_FLR ("Engine Power Reduction to Prevent Brake Overheating") - changed from wert_01 to wert_00 and wert_02
- C0F_FBS ("Brake Fading Compensation") - changed from wert_01 to wert_00
- C0F_BB_RAB "(Ready Brake Alert") - changed from wert_01 to wert_00
- DSC: Added C0C_DBC_MIN_AUSLOESEDRUCK min_pressure 00 value

Before adding the last one I had a super weird brake pedal when hard on the brakes. It was distracting enough that I couldn't tell you if it was cutting throttle as well. Brakes are super consistent since then, using PFC08s and 200TW tires.

Are you turning the TC off by holding the button down for ~5sec before you go on track?
__________________
11 128i slicktop
13 WK2
19 Alltrack S

Last edited by spidertri; 08-02-2022 at 07:32 AM.. Reason: I have experienced this issue
Appreciate 3
tsk941516.00
chris82827.00
      06-11-2021, 06:04 PM   #3
Phloozy
Second Lieutenant
219
Rep
210
Posts

Drives: BMW 128
Join Date: Oct 2019
Location: Pennsylvania

iTrader: (0)

Quote:
Originally Posted by spidertri View Post
I haven't experienced that at the track in my car. It's actually been fantastic on the brakes since I coded off:

- C0F_FLR ("Engine Power Reduction to Prevent Brake Overheating") - changed from wert_01 to wert_00 and wert_02
- C0F_FBS ("Brake Fading Compensation") - changed from wert_01 to wert_00
- C0F_BB_RAB "(Ready Brake Alert") - changed from wert_01 to wert_00
- DSC: Added C0C_DBC_MIN_AUSLOESEDRUCK min_pressure 00 value

Before adding the last one I had a super weird brake pedal when hard on the brakes. It was distracting enough that I couldn't tell you if it was cutting throttle as well. Brakes are super consistent since then, using PFC08s and 200TW tires.

Are you turning the TC off by holding the button down for ~5sec before you go on track?
Quote:
Originally Posted by spidertri View Post
I haven't experienced that at the track in my car. It's actually been fantastic on the brakes since I coded off:

- C0F_FLR ("Engine Power Reduction to Prevent Brake Overheating") - changed from wert_01 to wert_00 and wert_02
- C0F_FBS ("Brake Fading Compensation") - changed from wert_01 to wert_00
- C0F_BB_RAB "(Ready Brake Alert") - changed from wert_01 to wert_00
- DSC: Added C0C_DBC_MIN_AUSLOESEDRUCK min_pressure 00 value

Before adding the last one I had a super weird brake pedal when hard on the brakes. It was distracting enough that I couldn't tell you if it was cutting throttle as well. Brakes are super consistent since then, using PFC08s and 200TW tires.

Are you turning the TC off by holding the button down for ~5sec before you go on track?
Yeah dct fully off. I don't think I did that last one and I definitely have some weird brake feel when I am hard on them. I'll check my coding to see what I have
Appreciate 0
      06-12-2021, 08:40 PM   #4
iminhell1
C2H5OH
iminhell1's Avatar
United_States
3907
Rep
2,141
Posts

Drives: 2010 SG 135i auto
Join Date: May 2015
Location: Darwin, MN

iTrader: (1)

It's not going to be a braking coding issue.
It will be a throttle safety coding/tuning problem. On the 135's we have an option we have to turn off to do good power braking burnouts. You'll be fine with a small brake press but once brake pressure passes some point, and I don't know what that point is, the computer kills the throttle. It's a safety measure, think Toyota and the 'unintended acceleration' debacle. Every electronic throttle vehicle has something similar now.

So you'll have to look through the Brake computer and the DME to get it working best for you IMO.
Appreciate 1
chris82827.00
      07-08-2021, 06:33 AM   #5
Phloozy
Second Lieutenant
219
Rep
210
Posts

Drives: BMW 128
Join Date: Oct 2019
Location: Pennsylvania

iTrader: (0)

I found a video to demonstrate. In the video at 38 seconds watch the downshit into T5 of thunderbolt at NJMP. You can see the RPMs basically dont move from 5k rpm during the downshift. It seems to cut throttle because i am 100% hitting it with my heel, but it also prevents the car from clutch kicking it seems by holding the car at 5k rpm.


Last edited by Phloozy; 07-08-2021 at 07:12 AM..
Appreciate 1
chris82827.00
      07-08-2021, 08:14 AM   #6
bbnks2
Colonel
1207
Rep
2,025
Posts

Drives: 135i N55
Join Date: Jan 2017
Location: NY

iTrader: (0)

Quote:
Originally Posted by Phloozy View Post
I found a video to demonstrate. In the video at 38 seconds watch the downshit into T5 of thunderbolt at NJMP. You can see the RPMs basically dont move from 5k rpm during the downshift. It seems to cut throttle because i am 100% hitting it with my heel, but it also prevents the car from clutch kicking it seems by holding the car at 5k rpm.

From what I have seen with my 135i logs, if you do any kind of shifting too fast in these cars you hit a torque limiter. If you upshift too fast there is a torque limiter as well... the next gear will bog for several hundred rpm.

N54 platform released a "shift bog" fix which addresses torque limiter 2048. The same has not been done for N55 yet. I am sure the DME logic is the same as N52 dme in regard to torque limiters around shifting. It's brutal... time for a standalone.

While I hate shifting slow... it is sometimes faster. Same with rev matching on the downshift. If you try to do it too fast it seems like nothing happens. Time your downshifts better so that you can roll into the gas over a slightly longer period of time for th rev match before slamming the next gear. Seems like the dme needs to see that split second of extra input to be happy.
Appreciate 0
      07-08-2021, 08:21 AM   #7
Phloozy
Second Lieutenant
219
Rep
210
Posts

Drives: BMW 128
Join Date: Oct 2019
Location: Pennsylvania

iTrader: (0)

Quote:
Originally Posted by bbnks2 View Post
From what I have seen with my 135i logs, if you do any kind of shifting too fast in these cars you hit a torque limiter. If you upshift too fast there is a torque limiter as well... the next gear will bog for several hundred rpm.

N54 platform released a "shift bog" fix which addresses torque limiter 2048. The same has not been done for N55 yet. I am sure the DME logic is the same as N52 dme in regard to torque limiters around shifting. It's brutal... time for a standalone.

While I hate shifting slow... it is sometimes faster. Same with rev matching on the downshift. If you try to do it too fast it seems like nothing happens. Time your downshifts better so that you can roll into the gas over a slightly longer period of time for th rev match before slamming the next gear. Seems like the dme needs to see that split second of extra input to be happy.
It is possible but it only seems to happen on downshifts and under hard braking. In this video at around 35s you can see it blipos just fine because I am not braking super hard in the rain.

Appreciate 0
      07-08-2021, 08:32 AM   #8
bbnks2
Colonel
1207
Rep
2,025
Posts

Drives: 135i N55
Join Date: Jan 2017
Location: NY

iTrader: (0)

Quote:
Originally Posted by Phloozy View Post
It is possible but it only seems to happen on downshifts and under hard braking. In this video at around 35s you can see it blipos just fine because I am not braking super hard in the rain.
Maybe because it's raining you clutched in a bit earlier there? There is definitely some shitty logic around the throttle and clutch for safety/economy and what not.

There is no way it has anything to do with any brake coding that you could do.
Appreciate 0
      07-13-2021, 07:17 AM   #9
Mach3M3
Private First Class
14
Rep
101
Posts

Drives: 2011 E82 128i
Join Date: Aug 2017
Location: Columbus, OH

iTrader: (0)

Quote:
Originally Posted by spidertri View Post
I haven't experienced that at the track in my car. It's actually been fantastic on the brakes since I coded off:

- C0F_FLR ("Engine Power Reduction to Prevent Brake Overheating") - changed from wert_01 to wert_00 and wert_02
- C0F_FBS ("Brake Fading Compensation") - changed from wert_01 to wert_00
- C0F_BB_RAB "(Ready Brake Alert") - changed from wert_01 to wert_00
- DSC: Added C0C_DBC_MIN_AUSLOESEDRUCK min_pressure 00 value

Before adding the last one I had a super weird brake pedal when hard on the brakes. It was distracting enough that I couldn't tell you if it was cutting throttle as well. Brakes are super consistent since then, using PFC08s and 200TW tires.

Are you turning the TC off by holding the button down for ~5sec before you go on track?
Where did you find PFC08s for the rear?

I have been having really bad brake feel problems running ST43s and I think it's because they grab too aggressively for the ABS computer. It's so bad that I noticed wheels locking up at an autox i did with them. So I am switching to PFC08s hoping their release characteristics play nicer with the ABS cal on this car.
Appreciate 0
      07-13-2021, 07:38 AM   #10
spidertri
Lieutenant
spidertri's Avatar
United_States
395
Rep
461
Posts

Drives: 11 128i 6MT Sport
Join Date: Sep 2010
Location: Rock Hill, SC

iTrader: (1)

Garage List
2011 BMW 128i  [0.00]
E36 M3 pads shapes fit the 128 calipers (front and rear). The clips on the rears don't fit snugly in the rear piston though.
__________________
11 128i slicktop
13 WK2
19 Alltrack S
Appreciate 0
      07-13-2021, 07:46 AM   #11
Mach3M3
Private First Class
14
Rep
101
Posts

Drives: 2011 E82 128i
Join Date: Aug 2017
Location: Columbus, OH

iTrader: (0)

Quote:
Originally Posted by spidertri View Post
E36 M3 pads shapes fit the 128 calipers (front and rear). The clips on the rears don't fit snugly in the rear piston though.
Sweet. I'll have to order some e36 M3 rears then. Unsure when my next track time will be but I am hoping the PFC08s will feel better.

I swapped back to stock pads for autox and did one wet event on them and the ABS engagement felt better, but it wasnt really the best testing conditions.
Appreciate 0
      07-13-2021, 01:06 PM   #12
amg6975
Captain
amg6975's Avatar
487
Rep
634
Posts

Drives: '12 M1.5, '05 ZHP, '98 M3/4/5
Join Date: May 2017
Location: Rochester NY

iTrader: (0)

I bet this is a throttle overlap issue (thanks Toyota.) It's because the car thinks the throttle is stuck and you're panic braking to try to overcome it. My car does this noticeably if I left foot brake with too much overlap, like putting some heat in the pads.

The way to see if this is the case is to lift on the brake, immediately reapply hard and see if you can blip. Once the computer realizes you're doing it on purpose it should let you overlap throttle and brake.
Appreciate 0
      07-13-2021, 04:48 PM   #13
Mach3M3
Private First Class
14
Rep
101
Posts

Drives: 2011 E82 128i
Join Date: Aug 2017
Location: Columbus, OH

iTrader: (0)

Quote:
Originally Posted by amg6975 View Post
I bet this is a throttle overlap issue (thanks Toyota.) It's because the car thinks the throttle is stuck and you're panic braking to try to overcome it. My car does this noticeably if I left foot brake with too much overlap, like putting some heat in the pads.

The way to see if this is the case is to lift on the brake, immediately reapply hard and see if you can blip. Once the computer realizes you're doing it on purpose it should let you overlap throttle and brake.
I am not sure this is the case. I have done lots of brake dragging to warm up brakes and the car couldnt care less.
Appreciate 0
      07-14-2021, 12:24 PM   #14
amg6975
Captain
amg6975's Avatar
487
Rep
634
Posts

Drives: '12 M1.5, '05 ZHP, '98 M3/4/5
Join Date: May 2017
Location: Rochester NY

iTrader: (0)

Quote:
Originally Posted by Mach3M3 View Post
I am not sure this is the case. I have done lots of brake dragging to warm up brakes and the car couldnt care less.
It'll let you do it to a certain point of brake pressure, that's why it only does it to OP under hard braking. Just dragging the brakes will work fine. Both my stock 135 and S65 swapped car will definitely pull back the throttle if you really get into the brakes when also on the gas.

That said, I'm also not sure this is OPs issue, but it sounds like it.
Appreciate 1
2tonik28.50
      07-15-2021, 10:19 AM   #15
bbnks2
Colonel
1207
Rep
2,025
Posts

Drives: 135i N55
Join Date: Jan 2017
Location: NY

iTrader: (0)

Quote:
Originally Posted by Mach3M3 View Post
I am not sure this is the case. I have done lots of brake dragging to warm up brakes and the car couldnt care less.
How would you feel power reduction/torque limiter if you're riding the brakes?
Appreciate 0
      07-15-2021, 10:57 AM   #16
Dru128m
Private
70
Rep
85
Posts

Drives: 08 128i E82 & 09 328i E93
Join Date: Jan 2021
Location: Chesterton, IN

iTrader: (0)

Garage List
2008 BMW 128I  [0.00]
2009 BMW 328I E93  [0.00]
I've noticed this too, when really pushing the car hard. On my 3 to 2 downshift, sometimes I have to wait till I let off some brake pressure before I get a good throttle blip. Figured it was some kind of safety delay or whatever, never knew I could code that out. Interesting...
Appreciate 0
      07-15-2021, 06:55 PM   #17
bbnks2
Colonel
1207
Rep
2,025
Posts

Drives: 135i N55
Join Date: Jan 2017
Location: NY

iTrader: (0)

Quote:
Originally Posted by Dru128m View Post
I've noticed this too, when really pushing the car hard. On my 3 to 2 downshift, sometimes I have to wait till I let off some brake pressure before I get a good throttle blip. Figured it was some kind of safety delay or whatever, never knew I could code that out. Interesting...
i don't know of any brake related parameter that can change that behavior. Which one are you referring to that we can code?
Appreciate 0
      07-15-2021, 09:34 PM   #18
Dru128m
Private
70
Rep
85
Posts

Drives: 08 128i E82 & 09 328i E93
Join Date: Jan 2021
Location: Chesterton, IN

iTrader: (0)

Garage List
2008 BMW 128I  [0.00]
2009 BMW 328I E93  [0.00]
Quote:
Originally Posted by bbnks2 View Post
i don't know of any brake related parameter that can change that behavior. Which one are you referring to that we can code?
I don't know of anything specific. I hadn't thought of the possibility of some kind brake/throttle overlap limit. More than likely it's my shoddy footwork, but if there is some intervention occurring, I'm interested in removing it. That's all. I'll probably do some testing and find out it's a talent issue.
Appreciate 0
      07-16-2021, 07:30 AM   #19
Mach3M3
Private First Class
14
Rep
101
Posts

Drives: 2011 E82 128i
Join Date: Aug 2017
Location: Columbus, OH

iTrader: (0)

Quote:
Originally Posted by bbnks2 View Post
How would you feel power reduction/torque limiter if you're riding the brakes?
Because the car would suddenly lurch when it reduces the amount of power i am requesting from the throttle pedal.
Appreciate 0
      07-16-2021, 08:09 AM   #20
spidertri
Lieutenant
spidertri's Avatar
United_States
395
Rep
461
Posts

Drives: 11 128i 6MT Sport
Join Date: Sep 2010
Location: Rock Hill, SC

iTrader: (1)

Garage List
2011 BMW 128i  [0.00]
Yeah, sorry I probably confused the thread with the brake settings above. Definitely a different issue and one having to do with unintended acceleration.

Searching around it seems like a lot of different car makes are running into this at the track.

I'll pay attention when I'm at the track in a few weeks and see if I can get it to happen. AutoX tomorrow but I doubt it'll happen there, hah.
__________________
11 128i slicktop
13 WK2
19 Alltrack S

Last edited by spidertri; 07-16-2021 at 01:34 PM..
Appreciate 0
      07-16-2021, 10:46 AM   #21
amg6975
Captain
amg6975's Avatar
487
Rep
634
Posts

Drives: '12 M1.5, '05 ZHP, '98 M3/4/5
Join Date: May 2017
Location: Rochester NY

iTrader: (0)

Quote:
Originally Posted by bbnks2 View Post
i don't know of any brake related parameter that can change that behavior. Which one are you referring to that we can code?
Definitely can not code it off, unfortunately.
Appreciate 0
      07-25-2021, 09:48 PM   #22
mindspin311
Second Lieutenant
145
Rep
210
Posts

Drives: BMW
Join Date: Oct 2018
Location: Atlanta

iTrader: (0)

Quote:
Originally Posted by Mach3M3 View Post
Where did you find PFC08s for the rear?

I have been having really bad brake feel problems running ST43s and I think it's because they grab too aggressively for the ABS computer. It's so bad that I noticed wheels locking up at an autox i did with them. So I am switching to PFC08s hoping their release characteristics play nicer with the ABS cal on this car.
There are other ST compounds. 41 I have been told plays better with ABS.
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 05:10 AM.




1addicts
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST