Thinking of going from 4.5" slip-ons to 4".

Anyone ever do this? Did you have to retune and did you see an increase in performance? Was your bike louder and not as deep? Think thats what I read some where.

Thanks

 

What if any is the difference in baffle size? That is going to be the determining factor more so than the 1/2" decrease in OD. You should not have to re-tune for the muffler swap unless they are dramatically different...

 

The 4.5 has a "unique baffle design transitions from a 2.5 inch louvered core into a ceramic wrapped 3 inch perforated baffle" where the 4" is a "precision tuned 2.5 inch louvered core baffle".

 

2.5 baffle is too big,2” would be better for low and mid power.

 

A lot of people would be surprised by that, but it's true. I'd say for your "typical" bike, 2" is about the sweet spot. Even 1.75" is good unless someone just has a monster motor and actually needs more. I had Vance and Hines High Outputs (should be called low outputs) and hated the torque loss right in the prime riding RPM range.