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Discussion Starter #1
Can someone explain what a dog box is? I searched for it, but only found people mentioning it and not explaining it. Thanks. Also, how much does it cost, and how much would it increase performace?
 

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Discussion Starter #3
I see. But I thought I saw someone saying with a dogbox, you have to match the revs before shifting (double clutching?)
 

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Thinking Man's Engine
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I'm not sure about that...the matching revs part....it's because you're missing the synchronizers.
 

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Long post straight from Ravensblade:

Q: What is a dogbox?
A: The "dog" in dogbox does not refer to the gears at all, but the the shifting mechanism. You can have a dogbox without straight cut gears. And you you can have a straight cut gearbox with synchronizers. Production car gearboxes have helical cut gears to keep them quiet. Straight cut teeth are ususally bigger but there is backlash and the teeth knocking together produce the distinctive gear whine. Production gearboxes also use synchronizers to provide smooth, quiet shifting. The synchro's job is to "grab" the gear when you are shifting and match it to the same speed as the driven shaft to provide a smooth silent shift with no grinding. This happens as you move the lever into the gate for that particular gear. The trouble with synchros is they slow down the shifting process and they have little teeth which aren't so strong compared to the mysterious "dogs". The engaging teeth on the gears are equally small so you could potentially strip all the synchro engaging teeth off the gear and have no more drive in that gear even though all the gear teeth are in perfect condition! A dogshift box does without the synchronizers. Instead you have 6 or 8 big dog "teeth" on the gear. On the shift slider you may have a corresponding number of "slots" that the dogs fit into. The are other designs as well. When you shift since there is no synchro to make the gear speeds match you have to match revs with a blip of the throttle for a smooth shift. But that's not necessarily accurate, really, because you can crash it right in. That's why they are also known as "crashboxes". The clutch is not required when shifting. When accelerating a quick, partial lift of the throttle will do. When downshifting a blip of the throttle to match revs will ensure a smooth shift. A dogbox will shift as fast as you can move the gear lever! No waiting for synchros. Also, the dog mechanisms don't take up as much room as synchros so a wider gear can be fitted.
 
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