# 170 MPH in 2001 M3 Covertible



## Bruce (Dec 24, 2001)

Tsb 62 02 96


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## Leo (Apr 23, 2003)

Do you have a link to the document?


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## Bruce (Dec 24, 2001)

Nope.


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## andy_thomas (Oct 7, 2002)

Bruce said:


> BMW considers acceptable speedo error to be 10% + 2.4 mph. IOW at 60 mph you speedo could read 60 + 6 + 2.4 or 68.4 mph and still be within acceptable limits.


They had a moment of clarity when they built my car. At 90 mph, the speedometer shows 92. At an indicated 61, I'm really doing 60.


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## andy_thomas (Oct 7, 2002)

Leo said:


> Do you have a link to the document?


I found this reference:

http://stevens-area.de/astra-site/technik/tachogen.php

ECE-R39 is the directive which governs speedometer accuracy for EU manufacturers. I don't know if it covers cars imported from outside the EU, but a very generous margin for error is allowed so it couldn't take that much effort.

As Bruce says, ECE-R39 says 10% + 4 km/h (2.48 mph) is "OK" according to this reg. The US, naturally, would follow its own standards for speedometer accuracy - not least because it uses imperial measurements, not metric.


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## Leo (Apr 23, 2003)

Thanks for the link Andy 

It confirms the 0-7% for German registered cars. 

And it also confirms Bruces statement 

I wasn't sure under what regulations the US cars fall under.


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## armstd (Jan 2, 2004)

ELinder said:


> Is the speedo error on the E46 M3s nonlinear? While cruising on the highway on straight sections a few days ago, I set the cruise in steps of 10mph from 50 to 90 and checked it against the NAV functions, and it always read 0.8mph over the needle. Problem is, I don't know if it was reading the GPS for that calculation, reading off the same sensor as the speedo, or calculating it some other way.
> 
> Erich


If by "NAV functions" you mean OBC, then I think that is not a GPS speed calc you're seeing, it's just the car's speedometer.

Try using a seperate Garmin or Magellan to get real GPS speed calculations when checking your speedometer. I have an eTrex Vista for my mountain bike I can prop up on my dash with a speedo/odo/alt layout. Pretty handy when changing tire sizes.

-Daver


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## Jim in Oregon (Dec 23, 2001)

vegasm3 said:


> On my way to LA from Vegas this last weekend, around 1 AM, on a long straight away, with no one in front of me for at least a mile, I floored my 2001 M3 to see how fast this bad boy could go, from 100 MPH it took me I would say 10 to 15 seconds to reach 170 MPH!!!! The limiter kicked in and I could go no faster. Never in my life have I gone this fast in a car! It handled great, no vibrations!


Just ask the Highway Patrol to clock you with their radar guns as to your true speed.....he he.


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## HUMMM 3 (May 10, 2003)

vegasm3 said:


> On my way to LA from Vegas this last weekend, around 1 AM, on a long straight away, with no one in front of me for at least a mile, I floored my 2001 M3 to see how fast this bad boy could go, from 100 MPH it took me I would say 10 to 15 seconds to reach 170 MPH!!!! The limiter kicked in and I could go no faster. Never in my life have I gone this fast in a car! It handled great, no vibrations!


You won't get any vibrations when you're airborne.


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