Originally Posted by speed_racer
Good old fashioned stop clock to 100km/h. So 60mph should be only really .2 of a second difference at best.
We are talking about the Jeep grand Cherokee WK2 3125kg 5.7 hemi right? hehe
Well, about 2300 or 2400kg according to the spec sheet - still pretty heavy though...
If you are timing with a stop watch manually that could explain the poor time, as the reaction time could add about a half a second at start and stop, so maybe 1 second or so total. Best way to measure is with a tuner connected to the OBD interface. As for smart phone app's to measure times I've heard mixed reports, but would doubt their accuracy within half a second or so.