How do you know it is 140mph? Can't rely on gps to measure your speed accurately. Unless your speedo is broke or you got way oversized tires/rims and/or an undersized gear set which would make no sence to have (and I doubt).
A vehicle's top speed will be limited either by engine RPM or drag, but in our age of concern over liability it can also be limited by a governor. That's the case with the Mustang. The 99+ Mustangs are electronically limited to 120 MPH due to the speed rating of the tires that came on the car from the factory. The speedo goes up to 140 simply due to the car's performance image.
Ive got a 04 v-6, speedometer only reads 120. Everything on the car was stock when i topped it out including the wheels and tires and it topped out all the way to 120. All this was done in an isolated desert highway (highway 62 in 29 Palms California), dont be a dumb ass and do it on a crowded freeway? What i dont get from reading the replies is this, if they are governed at 120 MPH, why would my buddys 03 GT pass me at a much higher speed than me and still accelerating while I was doing 120 in my v6? everything except the exhaust and CAI is stock on his car?
My 2000 3.8 pegs the speedometer. I have added 17 inch rims 245/45zr17s, K&N cold air, throttle body spacer and a jet chip. The chip modifies the rev limiter.
