speedometer accuracy?
Thread Starter
Drifting
Joined: May 2016
Posts: 2,627
Likes: 1,487
speedometer accuracy?
It is well known that BMW speedos are purposely calibrated to report ~4% higher than actual speed.
Is it the same with Porsches?
I did a quick search and didn't turn up anything.
Is it the same with Porsches?
I did a quick search and didn't turn up anything.
Burning Brakes
Joined: Feb 2017
Posts: 1,219
Likes: 138
From: Golden, CO
Compared with the GPS speed displayed by my radar detector, my 991.2 speedometer reads two mph higher at all speeds from 30 to 85 mph.
BMWs have the worst speedometers in the industry. The most out of tolerance speedometer in the cheapest Chevy is more accurate than any BMW speedometer.
BMWs have the worst speedometers in the industry. The most out of tolerance speedometer in the cheapest Chevy is more accurate than any BMW speedometer.
Racer
Joined: Oct 2013
Posts: 322
Likes: 2
From: Minneapolis
Compared with the GPS speed displayed by my radar detector, my 991.2 speedometer reads two mph higher at all speeds from 30 to 85 mph.
BMWs have the worst speedometers in the industry. The most out of tolerance speedometer in the cheapest Chevy is more accurate than any BMW speedometer.
BMWs have the worst speedometers in the industry. The most out of tolerance speedometer in the cheapest Chevy is more accurate than any BMW speedometer.
Drifting
Joined: Feb 2011
Posts: 3,465
Likes: 312
From: Midtown Atlanta
Wow, interesting! My 991.1 GTS was dead-nuts accurate with both my GPS and the various "Your Speed Is:" signs around town. I assumed they've started using some sort of self-calibrating speedo that checks against GPS when available.
I had a 996TT that was like the two of yours -- 4mph high consistently, across the range, from 20mph to 150 mph and presumably beyond. It wasn't a percent off -- just exactly 4mph all the time. But no such error with the 991.1. Ditto the 981 I have now.
I had a 996TT that was like the two of yours -- 4mph high consistently, across the range, from 20mph to 150 mph and presumably beyond. It wasn't a percent off -- just exactly 4mph all the time. But no such error with the 991.1. Ditto the 981 I have now.
Three Wheelin'
Joined: Dec 2016
Posts: 1,881
Likes: 141
From: Toronto
Compared with the GPS speed displayed by my radar detector, my 991.2 speedometer reads two mph higher at all speeds from 30 to 85 mph.
BMWs have the worst speedometers in the industry. The most out of tolerance speedometer in the cheapest Chevy is more accurate than any BMW speedometer.
BMWs have the worst speedometers in the industry. The most out of tolerance speedometer in the cheapest Chevy is more accurate than any BMW speedometer.
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Rennlist Member
Joined: Apr 2017
Posts: 215
Likes: 41
Not breaking any laws if the speedometer is reading high... but in **** loads of trouble if they're reading below actual speed...
If you read the manual of my Ducati, they purposely state that the speedometer reads 5% higher than actual speed.
If you read the manual of my Ducati, they purposely state that the speedometer reads 5% higher than actual speed.
Drifting
Joined: Feb 2011
Posts: 3,465
Likes: 312
From: Midtown Atlanta
Wow, so am I the only one with two Porsches that both read perfectly accurate? In fact, I also have an ML350 and a Wrangler that are dead on as well. All four cars are 2014 or newer.
Maybe its my GPS receivers and local radar signs that are off!
Maybe its my GPS receivers and local radar signs that are off!
Drifting
Joined: Feb 2011
Posts: 3,465
Likes: 312
From: Midtown Atlanta
I don't have a fancy GPS, but my iphone 6, my old Garmin standalone unit, and my various in-car NAV systems all agree with each other to the exact mph. Don't know if they're all equally off, but it seems unlikely.
