It could effect the transition. If you have a canister that needs to be tuned--it could be so far out of adjustment that it's causing the rich condition you are describing.

I think it depends on the canister, but I do know that some canisters must be tuned. You have to cut the header off and adjust the canister closer. Just like a tuned pipe.

It's just like a tuned pipe. Eventually, you'll hit the sweet spot on the header and you should see an RPM gain.

This isn't true of all canisters. I admit--I don't know a whole lot about how they work or WHY some of them create a power boost and WHY some of them actually rob a little power, but make it quieter.

Dick Hanson is the guy you need to talk too. Maybe he will chime in.

The guy at Macs Pipes told me that a canister can sometimes be called a Folded Wave tuned pipe. But it depends on the design of the can. Some cans are purely made to get the engine quiet. Others will get it quiet AND increase the power output. But you have to tune those kind by cutting the header off and reading RPMs.