BMW M3 Forum (E90 E92)

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


Go Back   M3Post - BMW M3 Forum > M3 (E90 / E92 / E93) > General M3 Forum (E90 + E92 + E93)
 
Evolve Automotive
Post Reply
 
Thread Tools Search this Thread
      01-27-2013, 09:36 PM   #1
besiktas
Ultimate Driver for the Ultimate Driving Machine
United_States
31
Rep
1,016
Posts

 
Drives: BMW M3 E92
Join Date: Oct 2009
Location: Houston, TX

iTrader: (0)

Why BMW speedo overshoots but the other speedos don't

I was driving the glk and i was surprised how the speedo was showing the exact speed of a gps speed monitor tool. Unfortunately, in my car, the speedo is off a bit. Then gps shows 77, the car shows 80. Today, I was watching the c&d video of x1 and the video mentioned how this is an issue for BMW and not for other cars. Anyone knows why?

Link to c&d review:
http://youtu.be/eoqinOfudzY
__________________

BMW M3 E92 - Silverstone II
BPM Sport Stage II Tune + Test Pipes, GTS DCT Tune
Appreciate 0
      01-27-2013, 10:04 PM   #2
MMME30W
Riff Raff Refugee
MMME30W's Avatar
Germany
10
Rep
625
Posts

 
Drives: Civic
Join Date: Mar 2012
Location: Tampa

iTrader: (1)

First BMW?

http://en.wikipedia.org/wiki/Speedometer

"The indicated speed must never be less than the actual speed, i.e. it should not be possible to inadvertently speed because of an incorrect speedometer reading.

The indicated speed must not be more than 110 percent of the true speed plus 4 km/h at specified test speeds. For example, at 80 km/h, the indicated speed must be no more than 92 km/h."
__________________


Character does count. For too long we have gotten by in a society that says the only thing right is to get by and the only thing wrong is to get caught. Character is doing what's right when nobody is looking... " --J. C. Watts
Appreciate 0
      01-27-2013, 10:07 PM   #3
Parkanzky
Private First Class
1
Rep
156
Posts

 
Drives: '10 SGM M3
Join Date: Aug 2012
Location: Grand Rapids, MI

iTrader: (0)

Volkswagen have historically had very optimistic speedometers, although our most recent '09 and '10 TDIs actually read about 1 MPH slow.
Appreciate 0
      01-27-2013, 10:23 PM   #4
Rshane
M-Flight Member
Rshane's Avatar
United_States
13
Rep
1,087
Posts

 
Drives: 2011 E92 M3
Join Date: Jul 2010
Location: San Antonio, Texas

iTrader: (0)

My Audi's do the same thing...3km less than what's indicated on the speedo.
__________________
2011 Le Mans Blue M3// Black extended Novillo w/ Blue Grey Aluminum trim/DCT/ZTP/ZCW/ZPP/ZCP Premium Sound ///Akrapovic Evolution Exhaust

2012 Le Mans Blue 135i M Pkg DCT
2013 Ford F150 FX4 Supercrew
Appreciate 0
      01-27-2013, 10:29 PM   #5
bdaddylo
Major
bdaddylo's Avatar
United_States
17
Rep
1,134
Posts

 
Drives: 2011 E90 M3 ZCP
Join Date: Dec 2010
Location: Houston, TX

iTrader: (2)

Garage List
BMW programmed a factor to display speed higher than actual due to Euro laws what requires speedometers to never read below actual speed. This factor can be coded out.
__________________
_______________________
2011 E90 M3 ZCP/AW/Ohlins R&T
Appreciate 0
      01-27-2013, 10:34 PM   #6
1MOREMOD
2014 Track Days - 11|Ridge 1:52:24|Pacific 1:35:72
1MOREMOD's Avatar
United_States
172
Rep
12,929
Posts

 
Drives: Race car->
Join Date: Mar 2009
Location: check your mirrors

iTrader: (5)

know issue. quite a shock at the track once i started getting gps data that showed i was slower in the straight than i had thought.
__________________

02 Tiag e46 M3|6MT|GC plates|MCS c.o.|GC bars|GC race control arms|GC bushings|BW eng. & tran. mounts|subframe kit|BW race shifter|BW Jaffster|Euro header|BW exhaust|K&N c.a.i.|Epic race tune|Rouge pulleys|Seibon CF hood|CSL bumper|ST-40|XR-2|SS lines|half cage|Recaro profi|Profi 2 harness|BMWpedals|BW studs|
Appreciate 0
      01-28-2013, 01:26 PM   #7
besiktas
Ultimate Driver for the Ultimate Driving Machine
United_States
31
Rep
1,016
Posts

 
Drives: BMW M3 E92
Join Date: Oct 2009
Location: Houston, TX

iTrader: (0)

Speedometer Scandal! C&D

Interesting article from C&D - Speedometer Scandal!

http://www.caranddriver.com/features...ometer-scandal
__________________

BMW M3 E92 - Silverstone II
BPM Sport Stage II Tune + Test Pipes, GTS DCT Tune
Appreciate 0
      01-28-2013, 02:06 PM   #8
jphughan
Brigadier General
jphughan's Avatar
United_States
39
Rep
3,474
Posts

 
Drives: 2011.75 M3 E92 6MT
Join Date: Mar 2011
Location: Austin, TX

iTrader: (0)

OP do you have 18" or 19" wheels? I'm guessing 19 by the pic in your sig, but in addition to the fact that BMW does indeed calibrate their speedos to display slightly faster than reality (though this can be disabled for the digital speedo via coding), wheel size makes a difference too. I don't know whether the factory adjusts the speedo calibration based on the wheel diameter you ordered, but if they only calibrate for one size, it would be for 19" to avoid risk of the speedo displaying too low when the car has 18s -- and if that's true then people who have 18" wheels would have their speedos showing faster by an even greater margin than those with 19". Of course even if the factory does calibrate differently for the different wheel sizes, if you switch sizes aftermarket all bets are off. Relative to the stock calibration setup, larger wheels will make you go faster than indicated, smaller wheels (like people who switch to 18s on the track) will make you go slower than indicated.
__________________
11 M3 E92 Le Mans | Black Nov w/ Alum | 6MT | Premium 2 | Convenience | 19" | EDC | Prem Audio | Moonroof | BMW Apps | Yoko AD08 R | Vorshlag Adjustable Camber Plates | StopTech ST-60 380mm BBK | Castrol SRF Fluid | ModMyNav.com rear camera | OEM Euro Sunglasses Holder
Appreciate 0
      01-28-2013, 10:45 PM   #9
1MOREMOD
2014 Track Days - 11|Ridge 1:52:24|Pacific 1:35:72
1MOREMOD's Avatar
United_States
172
Rep
12,929
Posts

 
Drives: Race car->
Join Date: Mar 2009
Location: check your mirrors

iTrader: (5)

Quote:
Originally Posted by jphughan View Post
OP do you have 18" or 19" wheels? I'm guessing 19 by the pic in your sig, but in addition to the fact that BMW does indeed calibrate their speedos to display slightly faster than reality (though this can be disabled for the digital speedo via coding), wheel size makes a difference too. I don't know whether the factory adjusts the speedo calibration based on the wheel diameter you ordered, but if they only calibrate for one size, it would be for 19" to avoid risk of the speedo displaying too low when the car has 18s -- and if that's true then people who have 18" wheels would have their speedos showing faster by an even greater margin than those with 19". Of course even if the factory does calibrate differently for the different wheel sizes, if you switch sizes aftermarket all bets are off. Relative to the stock calibration setup, larger wheels will make you go faster than indicated, smaller wheels (like people who switch to 18s on the track) will make you go slower than indicated.
most people are sticking to similar outside diameter tires when switching. my 18 set up is .1 inch different than my 19 inch set.
__________________

02 Tiag e46 M3|6MT|GC plates|MCS c.o.|GC bars|GC race control arms|GC bushings|BW eng. & tran. mounts|subframe kit|BW race shifter|BW Jaffster|Euro header|BW exhaust|K&N c.a.i.|Epic race tune|Rouge pulleys|Seibon CF hood|CSL bumper|ST-40|XR-2|SS lines|half cage|Recaro profi|Profi 2 harness|BMWpedals|BW studs|
Appreciate 0
      01-29-2013, 02:28 PM   #10
mdosu
Banned
No_Country
117
Rep
8,517
Posts

 
Drives: Double Vanos'd Civic-M3
Join Date: Oct 2009
Location: San Francisco

iTrader: (6)

Quote:
Originally Posted by besiktas View Post
Interesting article from C&D - Speedometer Scandal!

http://www.caranddriver.com/features...ometer-scandal

rofl, did you see the comment written on this article? lol

"My BMW 335 is off by 5 mph at 80. That is almost 6%. So when the vehicle gets to 50,000 miles, the odometer, and the NADA value, will think the vehicle has 3,000 more miles on it than I actually drove. When speedo error is so far off that it effects your resale value, that seems a bit excessive."
Appreciate 0
      01-29-2013, 02:30 PM   #11
1MOREMOD
2014 Track Days - 11|Ridge 1:52:24|Pacific 1:35:72
1MOREMOD's Avatar
United_States
172
Rep
12,929
Posts

 
Drives: Race car->
Join Date: Mar 2009
Location: check your mirrors

iTrader: (5)

Quote:
Originally Posted by mdosu View Post
rofl, did you see the comment written on this article? lol

"My BMW 335 is off by 5 mph at 80. That is almost 6%. So when the vehicle gets to 50,000 miles, the odometer, and the NADA value, will think the vehicle has 3,000 more miles on it than I actually drove. When speedo error is so far off that it effects your resale value, that seems a bit excessive."
i had this the opposite way with my last truck. had 35s on it and so registered lower miles than i drove by a big amount.
__________________

02 Tiag e46 M3|6MT|GC plates|MCS c.o.|GC bars|GC race control arms|GC bushings|BW eng. & tran. mounts|subframe kit|BW race shifter|BW Jaffster|Euro header|BW exhaust|K&N c.a.i.|Epic race tune|Rouge pulleys|Seibon CF hood|CSL bumper|ST-40|XR-2|SS lines|half cage|Recaro profi|Profi 2 harness|BMWpedals|BW studs|
Appreciate 0
      01-29-2013, 02:34 PM   #12
Car54
Captain
10
Rep
899
Posts

 
Drives: 1999 Z3 Mcoupe | 2008 M3/4
Join Date: Sep 2007
Location: Lutz, FL

iTrader: (1)

That's the craziness...BMW knows exactly how fast you're going and all the computer's know it as well. With coding you can have it be actual.

They just choose to change the speedometer for the safety reasons. Mostly all motorcycles are like this too.
__________________
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
Forum Jump


All times are GMT -5. The time now is 04:18 AM.




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