I am not sure why we should make this so difficult. Just put an electronic lock on any gate that can not be selected at a given time. All you need then is the speed sensor. For example:

Car is moving at 90mph
Gears 1, 2, and 3 (the shift gates) are locked and you can not even select them.

Car is moving at 70mph
Gears 1 and 2 are locked out

The electronics already exist to do this. Look at the Acura cars, specificly the TSX. Reverse has a speed triggered lockout. If the car is moving forward, Reverse is electronicly blocked (with the 6 speed). No matter how hard you try, you will not be able to select 6th until you stop.

 

i dont know what disengaging clutch do when engine is reving at 9300 rpm.
disengaging clutch wont stop from over-reving, since throttle is connect to engine, not the tranny. On top of that engine in neutral will rev much faster than in any gear (you are aware of this, right?).

 

reverse is locked out by mechanical not electrical.

 

electronicly-actuated, mechanical lock if you like.

 

There is a rev limiter that prevents the throttle from causing over-rev - the problem that is being discussed is a MECHANICAL over-rev where the speed of the car at a lower/incorrectly selected gear forces the engine to go past the redline.

 

You ever considered reading the posts before commenting?

 

Will a soft-touch rev limiter work? These rev-limiters do not operate like the factory fuel cutoff and instead cut spark to cylinders. Something like the MSD soft-touch rev limiter is what I had in mind.

I had one on my 2.3L turbo Prelude with JG race ported cylinder head that I used to spin to 8000 RPM.

 

I am amazed at how hard this concept is to understand. We are not talking about revs induced by air/fuel/spark. We are talking about over-rev induced by the momentum of the vehicle coming up through the wheels and drive train, through the gear box with too low a gear selected (by accident) forcing the engine to spin much faster than it is capable of spinning.

Suppose you're in 5th traveling fast and wish to change back to 4th. But you accidentally select 2nd. It will be the momentum of the car forcing the engine to spin, not combustion.

 

The discussion is about a mechanical overrev, I don't think cutting the spark would be any help as if it's overrevved high enough, the piston can hit the valves, and cutting the spark wouldn't do anything about that. I think the only way to do this is either disengage the clutch , or have some sort of mechanical lock preventing downshifting into that gear.

 

i guess i didnt read it throughly....