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Old 06-17-2011, 06:01 PM   #2
blue2000s
Porscheectomy
 
Join Date: Mar 2006
Location: Seattle Area
Posts: 3,011
Quote:
Originally Posted by schnellman
I know the topic has been talked about at great length here. And, I know there have been several solutions offered to find out your true speed versus what a Boxster speedometer will tell you. Don't forget about the HVAC diagnostics. Anyway, yesterday I saw a Sheriff's Deputy taking a snooze beside a local baseball diamond, so I decided to see if he believed in the "Protect and Serve" logo on the side of his cruiser. I asked him to clock me coming down a straight stretch of road. After a little grumbling he agreed. I held the Box (986) dead on 60 mph. When I circled back he said, "Looks accurate to me, I had you at 55 the whole time."
Just as I thought.
GPS is really accurate too. I'm about 5-8% off too. I'm also 5% off with both of my Subarus.

Every instrument of measurement has an amoint of inaccuracy, say +/- 5%. Automakers don't want their cars to ever read slow. Unintended speeding and all. So they set the meter to read low "nominally" so that one that reads really high will read no higher than true speed.
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