I'm in the process of getting my list together for my current upgrade (full stage II). Got the A/C, cams, pushrods all picked out (not to mention new shoes and driver backrest). I'm curious as if changing my Cobra Slash-Cut Slip-Ons is going to benefit me much. I've looked at all of the dyno charts I can and can't really get a good feel for how much increase you get out of the different mufflers. I have the '09 stock headers, so no cats to worry about and I don't like the look of the 2-1. Just curious as to what the professionals might have to say.

 

imo,no different pipes may change where the power band is,but overall not enough to make a huge difference,unless your doing a all out monster motor.a few more hp at wot,or a few more foot#"s at lower rpm not enough for me to bother with.

 

It does matter. You want your exhaust to complement your engine combination and what type of riding you do. Duals typically make more mid and upper power, while 2-1 makes better low and mid. More restrictive mufflers tend to make more torque, and free flowing mufflers tend to make more horsepower at higher rpm.

These are 'general' and not absolutes. But something to go on.....

 

I'm not a Coba fan but I really don't think there is much power difference between good slip-ons for most builds. If anyone could prove 5+ hp difference between aftermarket slip-ons, I haven't seen it??? But 5hp is 5% or so????

 

The slip ons would be your weekest link. If your going to spend that kind of money on your motor, then do a full exhaust

 

I don't have any dyno charts to back this up, just the seat of the pants on how my bike felt...... But when I put on my 2-1 Fat Cat, I felt more power..... Enough to notice. I picked Fat Cat, for the matching dummy pipe. Just my $.02

 

Does anyone know if Rinehart restricts flow to the left pipe to create more backpressure?

 

No, each slip on muffler is the same from one side to the other.

 

Same bike, 3 different slip ons. All tuned at wot.

 

So with the same exact set-up there was a 20ish difference in the best to worst performing slip-ons. That sounds a bit much to me. Were there other changes?