BMW M3 Forum (E90 E92)

BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   M3Post - BMW M3 Forum > E90/E92 M3 Technical Topics > Engine, Transmission, Exhaust, Drivetrain, ECU Software Modifications
 
Lux Angel Eyes
Post Reply
 
Thread Tools Search this Thread
      01-06-2013, 03:59 PM   #1
Munit
Banned
 
Drives: m3
Join Date: Oct 2012
Location: CA

Posts: 220
iTrader: (0)

recorded over-revs on stock engines?

I often come across in a variety of random threads the fact that several people and dealers have recorded some pretty insane overrevs from stock cars or even tuned cars with the regular 8400 redline. I am talking about DCt cars.

How is it that the car can record revs as high as 8900 in some cases with a DCt? I often drive mine right to redline and especially in 3rd often hit the fuel cuttoff just a bit and then I shift.

If a car randomly overrevved even if you did nothing wrong and had no tune to increase limited, what would bmw do in that case? I thought the nannies in both DCt and manual prevented from overrevving within each gear (minus money shifting on a manual)
Munit is offline  
0
Reply With Quote
      01-06-2013, 04:05 PM   #2
Vic311
Banned
 
Drives: 2011 e92 M3
Join Date: Dec 2012
Location: NY

Posts: 1,469
iTrader: (0)

Quote:
Originally Posted by Munit View Post
How is it that the car can record revs as high as 8900 in some cases with a DCt?
Simple, it can't

Quote:
Originally Posted by Munit View Post
I thought the nannies in both DCt and manual prevented from overrevving within each gear (minus money shifting on a manual)
Only mechanical over-revs are possible with a manual transmission..aka money shifting.
Vic311 is offline   United_States
0
Reply With Quote
      01-06-2013, 04:57 PM   #3
italyix
Lieutenant
 
italyix's Avatar
 
Drives: '08 E90 M3
Join Date: Dec 2011
Location: Bay Area

Posts: 494
iTrader: (1)

My dealer recorded an over rev of exactly 12,000 rpm from the previous owner. Even the SA was skeptical about it. Cars is running fine after having one of its valve springs replaced.

EDIT: I should add a PUMA case was opened and BMW remotely accessed the ECU and saw the over rev, NOT the dealer.

Last edited by italyix; 01-07-2013 at 12:05 PM.
italyix is offline   United_States
0
Reply With Quote
      01-06-2013, 05:17 PM   #4
averrec6262
Enlisted Member
 
Drives: 2008 BMW M3 e90
Join Date: Feb 2012
Location: philadelphia

Posts: 46
iTrader: (0)

Garage List
2008 e90 BMW M3  [0.00]
Don't our cars have rev limiters though?
averrec6262 is offline  
0
Reply With Quote
      01-06-2013, 07:00 PM   #5
Munit
Banned
 
Drives: m3
Join Date: Oct 2012
Location: CA

Posts: 220
iTrader: (0)

Guys that is my point. I am not asking about the theoretical chance, I am asking how it could happen given there are multiple documented accounts of revs that were 8600 plus on stock cars.

Mike Benvo I know has posted something on this or an example of some car in the past. Maybe he will chime
Munit is offline  
0
Reply With Quote
      01-06-2013, 07:33 PM   #6
pbonsalb
Major
 
Drives: 08 E90 M3, 99 E36 M3 Turbo
Join Date: Feb 2011
Location: Concord, NH

Posts: 1,497
iTrader: (3)

Rev limiter will not save you from a mechanical over rev such as accidentally downshifting into 3rd instead of upshifting into 5th while at 8300 rpm in 4th. But this should occur only with 6 speed manual due to the computer controlling the shifts on the 7 speed DCT. Rev limit will save you from staying in the gear past the rpm limit or from free-revving beyond the limit, but it cannot defy the laws of physics from a mis-shift. A few people have done this on E36M3s with old, tired shift linkages and worn out tranny and engine mounts -- it is called the "money shift" because it is expensive to fix. But not as expensive as on a newer M3 for which the parts are much costlier.
pbonsalb is online now  
0
Reply With Quote
      01-06-2013, 07:35 PM   #7
Mike Benvo
BimmerPost Supporting Vendor

 
Mike Benvo's Avatar
 
Drives: 08 E90 M3 / 400whp Turbo 7
Join Date: Apr 2008
Location: SoCal

Posts: 4,526
iTrader: (7)

Garage List
1990 BMW 735i Turbo  [5.00]
2004 BMW M3  [0.00]
2008 BMW M3  [5.00]
Send a message via Skype™ to Mike Benvo
DCT cars will hit almost 8,600 RPM in some cases in stock form.

6MT cars you can over-rev if you shift to the wrong gear. The highest one I've seen is 9,114 RPM and it's still running fine 20,000 miles later.

Dealer can't see this information but BMW can.
__________________

-----| Like us on Facebook | Instagram || Tuning Information | Remote Coding |-----
----Visit us at www.BPMSport.com - Emotion. Driven. | Toll Free: (888) 557-5133----
Mike Benvo is offline   United_States
0
Reply With Quote
      01-06-2013, 10:58 PM   #8
gatorfast
Colonel
 
gatorfast's Avatar
 
Drives: MR E90 M3
Join Date: Jan 2008
Location: SoFla

Posts: 2,454
iTrader: (3)

Quote:
Originally Posted by Mike Benvo View Post
.
Dealer can't see this information but BMW can.
Can you explain this further?
gatorfast is offline  
0
Reply With Quote
      01-07-2013, 01:42 AM   #9
Munit
Banned
 
Drives: m3
Join Date: Oct 2012
Location: CA

Posts: 220
iTrader: (0)

Quote:
Originally Posted by Mike Benvo View Post
DCT cars will hit almost 8,600 RPM in some cases in stock form.

6MT cars you can over-rev if you shift to the wrong gear. The highest one I've seen is 9,114 RPM and it's still running fine 20,000 miles later.

Dealer can't see this information but BMW can.
This is what I mean-how often or when does the DCT hit 8600? Just randomly in a random car or if you redline the car constantly and you hit the limter a few times a week is this happening?
Munit is offline  
0
Reply With Quote
      01-07-2013, 02:20 AM   #10
Mike Benvo
BimmerPost Supporting Vendor

 
Mike Benvo's Avatar
 
Drives: 08 E90 M3 / 400whp Turbo 7
Join Date: Apr 2008
Location: SoCal

Posts: 4,526
iTrader: (7)

Garage List
1990 BMW 735i Turbo  [5.00]
2004 BMW M3  [0.00]
2008 BMW M3  [5.00]
Send a message via Skype™ to Mike Benvo
Quote:
Originally Posted by Munit View Post
This is what I mean-how often or when does the DCT hit 8600? Just randomly in a random car or if you redline the car constantly and you hit the limter a few times a week is this happening?
Usually DCT causes shifts around 8,500 ish, but in same cases will go higher. It depends on the situation. If you bounce off the limiter with DSC off you're more likely to hit higher RPM, but in some gears more than others.

Don't worry about it. Enjoy the car
__________________

-----| Like us on Facebook | Instagram || Tuning Information | Remote Coding |-----
----Visit us at www.BPMSport.com - Emotion. Driven. | Toll Free: (888) 557-5133----
Mike Benvo is offline   United_States
0
Reply With Quote
      01-07-2013, 02:21 AM   #11
Mike Benvo
BimmerPost Supporting Vendor

 
Mike Benvo's Avatar
 
Drives: 08 E90 M3 / 400whp Turbo 7
Join Date: Apr 2008
Location: SoCal

Posts: 4,526
iTrader: (7)

Garage List
1990 BMW 735i Turbo  [5.00]
2004 BMW M3  [0.00]
2008 BMW M3  [5.00]
Send a message via Skype™ to Mike Benvo
Quote:
Originally Posted by gatorfast View Post
Can you explain this further?
The dealer doesn't have tools to be able to read freezeframe data. They use ISTA/P and ISTA/D exclusively (both of which I have), and they are 'dummed down' dealer systems and not expert tools.
__________________

-----| Like us on Facebook | Instagram || Tuning Information | Remote Coding |-----
----Visit us at www.BPMSport.com - Emotion. Driven. | Toll Free: (888) 557-5133----
Mike Benvo is offline   United_States
0
Reply With Quote
      01-07-2013, 08:32 AM   #12
gatorfast
Colonel
 
gatorfast's Avatar
 
Drives: MR E90 M3
Join Date: Jan 2008
Location: SoFla

Posts: 2,454
iTrader: (3)

Quote:
Originally Posted by Mike Benvo View Post
The dealer doesn't have tools to be able to read freezeframe data. They use ISTA/P and ISTA/D exclusively (both of which I have), and they are 'dummed down' dealer systems and not expert tools.
Ok that makes sense. But what do you mean by "but BMW can"? Are you talking about BMW corporate? I dont get it.
gatorfast is offline  
0
Reply With Quote
      01-07-2013, 11:40 AM   #13
Mike Benvo
BimmerPost Supporting Vendor

 
Mike Benvo's Avatar
 
Drives: 08 E90 M3 / 400whp Turbo 7
Join Date: Apr 2008
Location: SoCal

Posts: 4,526
iTrader: (7)

Garage List
1990 BMW 735i Turbo  [5.00]
2004 BMW M3  [0.00]
2008 BMW M3  [5.00]
Send a message via Skype™ to Mike Benvo
Quote:
Originally Posted by gatorfast
Quote:
Originally Posted by Mike Benvo View Post
The dealer doesn't have tools to be able to read freezeframe data. They use ISTA/P and ISTA/D exclusively (both of which I have), and they are 'dummed down' dealer systems and not expert tools.
Ok that makes sense. But what do you mean by "but BMW can"? Are you talking about BMW corporate? I dont get it.
BMW NA, BMW AG, and field service technicians. Basically anything above the dealer level.
__________________

-----| Like us on Facebook | Instagram || Tuning Information | Remote Coding |-----
----Visit us at www.BPMSport.com - Emotion. Driven. | Toll Free: (888) 557-5133----
Mike Benvo is offline   United_States
0
Reply With Quote
      01-07-2013, 12:31 PM   #14
FogCityM3
Major
 
FogCityM3's Avatar
 
Drives: M3 (E90)
Join Date: Feb 2012
Location: San Francisco

Posts: 1,365
iTrader: (0)

Benvo during coding gave me the freeze frame info on my 6MT, had one mechanical overrev about 6 months prior to 8,800+rpm (likely due to wrong downshift)... 2 months later, differential nearly fell out of car due to bolt snap. BMWNA did come out and look at it, concluded that the diff bolt failure shouldn't have happened and approved the full diff and subframe replacement under warranty. Point is you're probably allowed a couple of "mulligans" with MT as long as it's not overly excessive (absolute amount and # of times), and with DCT probably a lot less to worry about.
FogCityM3 is online now  
0
Reply With Quote
      01-07-2013, 12:41 PM   #15
Mike Benvo
BimmerPost Supporting Vendor

 
Mike Benvo's Avatar
 
Drives: 08 E90 M3 / 400whp Turbo 7
Join Date: Apr 2008
Location: SoCal

Posts: 4,526
iTrader: (7)

Garage List
1990 BMW 735i Turbo  [5.00]
2004 BMW M3  [0.00]
2008 BMW M3  [5.00]
Send a message via Skype™ to Mike Benvo
Quote:
Originally Posted by mhabs View Post
Benvo during coding gave me the freeze frame info on my 6MT, had one mechanical overrev about 6 months prior to 8,800+rpm (likely due to wrong downshift)... 2 months later, differential nearly fell out of car due to bolt snap. BMWNA did come out and look at it, concluded that the diff bolt failure shouldn't have happened and approved the full diff and subframe replacement under warranty. Point is you're probably allowed a couple of "mulligans" with MT as long as it's not overly excessive (absolute amount and # of times), and with DCT probably a lot less to worry about.


I wonder if there is preventative maintenance for this diff bolt issue. I'm going to get 295/30/19's because I think it will reduce wheel hop that I get with my 265/35/19's on an 11" wheel. I'm terrified of this happening to me. 47K on the clock now and so far so good (even with 500+ times to 8,800 RPM)...

But then again I rarely launch the car.. Reminds me of the E46 subframe issues.. ridiculous to have fear to drive the car the way it's meant to be driven! I just love this car more than any other car I've had in my life and don't want to hurt it..
__________________

-----| Like us on Facebook | Instagram || Tuning Information | Remote Coding |-----
----Visit us at www.BPMSport.com - Emotion. Driven. | Toll Free: (888) 557-5133----
Mike Benvo is offline   United_States
0
Reply With Quote
      01-07-2013, 01:00 PM   #16
FogCityM3
Major
 
FogCityM3's Avatar
 
Drives: M3 (E90)
Join Date: Feb 2012
Location: San Francisco

Posts: 1,365
iTrader: (0)

Hi Mike, I did quite a bit of digging on this, it appears that using solid differential bolts (like GTS) would be a good preventative measure...they're available at some vendors (eg Turner Motorsports or maybe even the BMW dealers that sell Motorsport parts). What I was not able to conslusively ascertain was how it would affect NVH. If you find out about anyone who has done this and how it affected NVH, let me know, as once get out of warranty period, I would consider getting these installed.


Quote:
Originally Posted by Mike Benvo View Post


I wonder if there is preventative maintenance for this diff bolt issue. I'm going to get 295/30/19's because I think it will reduce wheel hop that I get with my 265/35/19's on an 11" wheel. I'm terrified of this happening to me. 47K on the clock now and so far so good (even with 500+ times to 8,800 RPM)...

But then again I rarely launch the car.. Reminds me of the E46 subframe issues.. ridiculous to have fear to drive the car the way it's meant to be driven! I just love this car more than any other car I've had in my life and don't want to hurt it..
FogCityM3 is online now  
0
Reply With Quote
      01-10-2013, 10:58 AM   #17
Bubbles
Green Bastard
 
Bubbles's Avatar
 
Drives: ZCP-Powered
Join Date: Jun 2007
Location: Bishop Bend

Posts: 3,545
iTrader: (3)

I haven't had any issues at 30k miles. I am considering swapping out the bolts for new ones, just in case, but why mess with something and create a problem? Decisions...decisions.
__________________
Bubbles is offline   Cayman Islands
0
Reply With Quote
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
Forum Jump


All times are GMT -5. The time now is 11:55 PM.




m3post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
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