Dog Box

[mjannusch]

A dogbox (also known as "crashbox") is a transmission like what is used in motorcycles. There aren't synchronizers between the gears, and the engagement of gears happens via interlocking "dog" plates. The dogs are kind of like squared teeth that are back-cut so they lock together when pressure is applied. Dogbox trannies typically use straight-cut gears instead of helical-cut gears like typical road cars use. The straight-cut gears have a tendency to whine during use.

When shifting a dogbox, you have to do it with authority or the dogs will grind against each other. The really nice thing about this sort of setup is that you can hold the gas to the floor, and just pull on the shifter and when the motor hits redline and the power is cut for a split second the gears should automatically slide into 2nd gear and then relock.

That's how I shift my bike - just get going in 1st gear, then apply pressure upwards on the shifter with my foot, and when it hits the revlimiter it just flicks up into the next gear. If it isn't setup sequential though then the 2-3 shift might need a bit of clutch to go with it since the shift will take longer than a 1-2 or 3-4 shift.

The drawback (other than the noise) is that you can't granny shift them - every shift has to be done quick so as to not round off the edges of the dogs.

If you want to see one in action, watch just about any rally race in-car footage from any of the pros.

[TwinTurboKid]

If you want to see one in action, watch just about any rally race in-car footage from any of the pros.

I think i have a vid on my old comp from rally in Portugal. I watch every year when i go on vacation.

When shifting a dogbox, you have to do it with authority or the dogs will grind against each other. The really nice thing about this sort of setup is that you can hold the gas to the floor, and just pull on the shifter and when the motor hits redline and the power is cut for a split second the gears should automatically slide into 2nd gear and then relock.

Sequential is just clutch for first gear and you dont have to shift, just tap shifter forward to gear up and tap it back to gear down. Makes a big difference in a rally race.

[UTRacerX9]

A dogbox for a car is a LOT different than for a typical motorcycle.

Motorcycles usually have two friction plates in between gears, and the gears and plates themselves are thin, allowing for slow shifting, while still being able to hold the power for quick downshifts and heavy throttle.

I'd be curious to see how this would perform in our cars... I can't imagine it would be very streetable at all. Those rally cars running dogboxes are pretty brutal.

However, I know the DSM dogbox does allow for some streetability, but the DSM's are much lighter so you don't have to be as precise with them to avoid stalling/jerking.

[mjannusch]

Yup, a motorcycle gearbox is different than what you'd put on a car, but most of the principles are similar and how they react for shifting is somewhat similar.

The big thing is the lack of synchros as far as shift feel goes. If you want to downshift in a dogbox you should double-clutch, etc.

[LeMoN1438]

5 pages with no updates.....ur killin me

[spewing oil]

shifting a dog box ....... not the right way.

http://toprpm.com/videos/HKS_R32_GTR.wmv

[Highboosted]

Originally Posted by GTO NEMESIS

Is this a finished, tried and tested fee?
If so I am interested.

Whats the score if I take one and break into lots of pieces?

Mark

Nope, pre-development cycle for production. Actual cost would include amorized development costs, and continued support. If you want a one-off, prepare to pay out over $120K, and little support.

As for breaking it, welcome to the big leagues. ProDrive supplies (or more correctly: the team buys) 4 complete transmissions to every race for their IMSA 550. If you're not breaking shit, you're not getting faster.

[Import Power]

Originally Posted by Highboosted

Nope, pre-development cycle for production. Actual cost would include amorized development costs, and continued support. If you want a one-off, prepare to pay out over $120K, and little support.

As for breaking it, welcome to the big leagues. ProDrive supplies (or more correctly: the team buys) 4 complete transmissions to every race for their IMSA 550. If you're not breaking shit, you're not getting faster.

if you aren't breaking shit, you aren't trying hard enough

[TypicalStateGuy]

Originally Posted by Import Power

if you aren't breaking shit, you aren't trying hard enough

you're such a bad ass.

[[3L]]

Hype monger