Engine protection device??? electrical "box", lockout to prevent wrong gear choice?? Options

[Mueller]

We don't read about people shifting into the wrong gear too often which ends in costly repairs, but when we do hear about it, it gives everyone a sick feeling knowing that big money is about to be spent.

Now it seems it wouldn't be too difficult to have a "box" that monitors engine RPM as well as what gear the driver is in and MPH. Of course the "box" is going to have to have some logic control with user inputs for different variables.

Basicly what we want to do is have the "box" tied to an electrical/mechanical device that will not allow you to put the car into a gear which the "box" has deemed unsafe.

So if you are in 4th @ 6500 and want to go to 3rd which will raise the rpms to 7000 (borderline redline)
the "box" will "okay" the gear choice and not interfer....well, due to some odd reason, the driver picks 2nd gear instead, the "box" knows that 7500 rpm is way too high and it gives a signal to the electrical/mechanical device and "blocks" the gear selection.

Now the only way the driver can put the car into a gear is: Stay in 4th or, shift into 5th or slow the car down enough so that the road speed will match the RPM/gear/MPH safety combination which is the "box" will be programmed for.

This is nothing new, Porsche used this logic on thier PDK transmission and RUF had this for his clutchpedal-less manual shifting cars.AFAIK, no one has this as an "add-on" device or to be used with a clutch pedal

[lapuwali]

That just sounds like a run-of-the-mill automatic transmission, just made more complex by trying to package it with normal gears rather than planetary gear sets.

The devil is in the details. You still have a conventional clutch, so no power-sapping torque convertor. It's really just a different way to lock each gear to its shaft rather than using dog rings or dog gears. The good bit about his design is that it will fit comfortably inside any existing manual gearbox after you remove all of the existing synchro/dog assemblies and the shift forks. The hydraulic system actually ends up being simpler than an automatic transmission.


Converting an existing H-pattern gearbox to sequential is an expensive proposition. It also violates the rules for a number of racing organizations (as does the multi-clutch setup I've discussed). What might be simpler would be an H-pattern shift gate (ala Ferrari), with a set of lock-out plates that move based on wheel speed and the current gear position. Move into neutral, and the lockouts only provide the safe gear slots, the others being blocked until the wheel speed is low enough. Indeed, for the 914, you'd really only need a lockout for 2nd and 3rd. First is rarely selected by accident, and it's hard to blow up the engine by downshifting into 4th too early.

Another option along those lines might be a "lock in" plate, which doesn't allow the shift lever to be moved out of the 4/5 gate above a certain wheel speed. This could be accomplished with a single solenoid, positioned to the left of the R/1 gate, which extends so the shifter can't be moved to the left when activated. Even simpler, a slotted plate with a tongue and pin that, when the pin is extended, doesn't allow the slotted plate to move to the left. You could even use the existing lockout plate and modify it. The tongue points to the right, presenting a hole for a solenoid-actuated pin in the 4/5 slot. The pin is extended above wheel speed X, and retracted below that speed.

Wish I could draw some pictures of this...