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One thing I'd love to see in modern manual transmission sports cars is a lockout to prevent mechanical over-revs. It would be extremely cheap and simple to eng

One thing I'd love to see in modern manual transmission sports cars is a lockout to prevent mechanical over-revs. It would be extremely cheap and simple to engineer—knowing the current RPM and gear ratios, it would just be a matter of a servo motor actuating a bar, physically blocking the shifter from engaging gears that would cause a mechanical overrev. If done right, the driver wouldn't even notice it was there, until they were going around a sweeping right-hander on the track, up-shifting from third to fourth, and find the car prevents them from accidentally pulling it into second instead... Of course, most drivers don't track their cars, and it's pretty hard to mis-shift when you're not on the track if you know what you're doing. (Or even on the track, if you're careful.) But sometimes it only takes one, and given how simple it would be to implement something like this, it seems like a no-brainer for companies like Porsche, especially given we're already seeing things like auto-blip for manuals (which I'm far less keen on, fwiw, but fine with as long as it can be turned off!)

manfredo 8y ago
If that servo fails to unlock, though, now you can't shift into certain gears. I thought that a centrifugal clutch disengage mechanism would solve this. Centrifugal clutches are already common in scooters - the clutch engages gradually as you rev above idle rpms. My theoretical feature is basically the opposite: a centrifuge that disengages at a given RPM. You _can_ shift into 1st at 100mph but your clutch will quickly disengage as your revs approach redline. You may burn out your clutch but those are cheaper to replace than engines. Of course I have zero mechanical engineering background so who knows the feasibility of this approach.
- tempestn 8y ago
  Re-engineering the clutch sounds like a lot more work than adding a little servo. (Or two: one for 1/3/5 and one for 2/4.) And yeah, like anything in the car I guess it could fail, but something so simple could be made very robust—and if it did fail, it wouldn't be catastrophic. Would also be simple enough to add a mechanical override screw accessible under the shifter boot or something like that.

manfredo 8y ago

If that servo fails to unlock, though, now you can't shift into certain gears. I thought that a centrifugal clutch disengage mechanism would solve this. Centrifugal clutches are already common in scooters - the clutch engages gradually as you rev above idle rpms. My theoretical feature is basically the opposite: a centrifuge that disengages at a given RPM. You _can_ shift into 1st at 100mph but your clutch will quickly disengage as your revs approach redline. You may burn out your clutch but those are cheaper to replace than engines. Of course I have zero mechanical engineering background so who knows the feasibility of this approach.

tempestn 8y ago
Re-engineering the clutch sounds like a lot more work than adding a little servo. (Or two: one for 1/3/5 and one for 2/4.) And yeah, like anything in the car I guess it could fail, but something so simple could be made very robust—and if it did fail, it wouldn't be catastrophic. Would also be simple enough to add a mechanical override screw accessible under the shifter boot or something like that.