Zackary,

I know what Bonehead meant and he is wrong. Read the JimH and TonyfromOZ explanations of how a Jake Brake works. The more air you get into the engine, the more braking power it has. Even non Jake Brake engines have some braking because of friction in the air some of the heat of compression is lost to the cooling system before the compressed air pushes the pistons back down. And with a Jake brake you get a compression stroke every turn of the crankshaft instead of every other stroke in the normal 4-cycle operation.

If someone here knows how the valves are controlled by the Jake break system, I would be interested how the system works.

P E H