how fast can I go if I have an open highway?


The Grumpy Grease Monkey mechanical engineer.
Staff member
I think my 700r4 trans is slipping,
That's what the tachometer says anyway. In third gear I floor it and the tach jumps up to 7000rpm and stays there as the car accelerates.
It will accelerate up to 150 doing it this way. Any thoughts at all are welcome. What other information would be helpful from me.

Id have to point out , most tachs and speedometers are not exceedingly accurate,
most valve trains have control issues at 7000 rpm,
and valve train failure is a distinct possibility if the engine run at that speed for very long,
especially under full load,
your risk of detonation damage is vastly higher at that rpm level,
that most tires are not rated to run at 150 mph, most police tend to get overly concerned with your lack of regard for posted speed limits
and most cars are not stable nor do they have the brakes to stop rapidly in a controlled manor from speeds exceeding 120 mph,
keep in mind at some point the air flow resistance which increases rapidly as speed increased will have a huge effect on the potential max speed you can reach
the air resistance to a car increases with the square of speed, so at 200km/h you need 4x as much power as at 100km/h - obviously some body designs produce much higher drag and frontal area than others,
thus your car will eventually reach a speed where it can no longer accelerate, due to drag, etc.
your concern about the trans internals or converter slipping may be valid,
but you are likely to have other problems if you run the car at that speed,
anyplace but a race track or closed airport run way.
ID also point out that if the trans was slipping you would never get close to 150 mph
Last edited: