My car is slower after mods

[supmet]

Originally Posted by PK198105

why not , if you have a good reliable receiver it can be as accurate if not better than the actual speedo - the lag time.

Well for one, if I keep a steady speed and go up a steep hill, the GPS drops a few mph even though I'm going the same speed.

[kmf123kmf]

Originally Posted by supmet

Well for one, if I keep a steady speed and go up a steep hill, the GPS drops a few mph even though I'm going the same speed.

I would expect this result if the GPS was not aware that its altitude was changing. Does anyone know if (or to what extent) GPS maps incorporate altitude data?