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That's what I read too. (see below) I'm curious though. What method would they use? What method could they use to keep the odometer separate from the speedometer?
Speedometer Miscalibrated
Diagnostic: Speedometer reading shows higher than your actual speed.
Cause: Engineering problem in design of Boxster.
Details: Porsche claims that the tolerance range for the speedometer is 10% over your actual speed to 1% slower than your actual speed. There are several ways to have this checked:
•Radar gun
•Dyno
•Mile or kilometer markers on a freeway
•GPS (Global Positioning System)
To use the mile or kilometer markers on the freeway, they must be accurately spaced. You will need a stopwatch. Measure your time driving past several markers at a constant speed (use the cruise control if you have it), then use this formula: (3600 � number of markers) � number of seconds = actual speed.
One owner ran his June 1997 Stuttgart built Boxster on a dyno. It showed the speedometer to be within one mph of accuracy at 60 mph, so not all cars have this deficiency. This is important to know because you cannot presume to have five mph slack without checking your speedometer.
Time in Shop: None
Repair Instructions: None
Notes: Even if the speedometer were calibrated correctly at the factory, there are a number of factors which can contribute to the speedometer reporting inaccurate speed:
•Tire tread
•Tire pressure
•Tire size
The odometer uses a separate technique to measure distance, so it does not have this problem.
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