GPS mph accuracy

[particlewave]

Yes, but the OP is having the opposite problem, unless he mistyped.
His speedo is reading slow, so he is speeding! Never heard of this one, so may be a typo.

Speedo = 71 mph
Actual (GPS) = 75 mph

[SJEFFB986]

Now I have to double check.... I could of sworn my GPS shows a faster speed than my speedometer. I will check on my way to work tomorrow and confirm.

Either way it's no big deal. It was just a general observation and question for other owners. Thanks for all the input.

[Westwood]

I'm on my eighth Porsche through the years, and they all showed me going 3 mph faster than the actual speed measured by roadside radar signs, and also on GPS in later years.

[brjak]

Originally Posted by particlewave

Yes, but the OP is having the opposite problem, unless he mistyped.
His speedo is reading slow, so he is speeding! Never heard of this one, so may be a typo.

Speedo = 71 mph
Actual (GPS) = 75 mph

My 97 is same. it shows me doing 114KMH when GPS shows 120KMH.

When going slower like 60KMH my gps may read 63KPH

[kk2002s]

Most of the time I look at GPS for Speed and trying to read Analog while driving is like texting
Porsche should have used that dial space for Oil Pressure and temp and just used a Digital display (Sure there is some regulation that a dial be there)

[SJEFFB986]

Originally Posted by brjak

My 97 is same. it shows me doing 114KMH when GPS shows 120KMH.

When going slower like 60KMH my gps may read 63KPH

Yep! I confirmed....My 99 boxster shows slower than my GPS. Guess some Boxsters are more special than others..ha ha..

BTW - This morning was frosty and chilly (21 degrees) here in Chester County, Pa. Boxster ran smooth as ice in the cold. I will be driving it in much colder weather in the coming months. Will see how she performs.. The only time I won't be driving her is in rain and snow.

[kk2002s]

Originally Posted by SJEFFB986

BTW - This morning was frosty and chilly (21 degrees) here in Chester County, Pa. Boxster ran smooth as ice in the cold. I will be driving it in much colder weather in the coming months. Will see how she performs.. The only time I won't be driving her is in rain and snow.

I'm basically across the river from you and when I drove my Box during the winter cold weather was never an issue, even single digits. If you have decent tires even snow is not really any worse than any other RWD car

[Joe B]

Originally Posted by SJEFFB986

BTW - This morning was frosty and chilly (21 degrees) here in Chester County, Pa. Boxster ran smooth as ice in the cold. I will be driving it in much colder weather in the coming months. Will see how she performs.. The only time I won't be driving her is in rain and snow.

My 2003 S speedo also reads 3MPH faster than my true speed.

21° F isn't very cold . I've driven mine at well below 0°, no issues. Why should there be; it gets cold in Germany (and Finland), no?