Inaccurate Tachometer?

[infernosg]

Originally Posted by Mobius

Here's a question, what did you use to measure your speed?

Good question. I'm using the stock speedometer of course, and I suppose that can also be off, but that is purely mechanical correct? I suppose I can always go back and use my wife's GPS unit for another speed reading. I guess what I'm really saying is I really need a digital tachometer to know what the engine is REALLY doing. To bad no one around me actually carries something like that, let alone allows rental...