under body exhaust

KRS1 said:

secondary pipe is actually longer than that because it goes back and forth an additional 2 times. But good call, your one of the people that actually get it

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The reflection / pressure wave that forms the tuned length is cause by a pipe end or change in section. The primary length from exhaust valve to mid pipe joint is 19 inches (pipe section change caused by the carbon gasket and slip on), the 'tail length' is to just past the foot rest hanger mounting bolt, (18 inches to the end of the pipe in the silencer box), the 2-3 passes in the silencer box are not helping in the tuned length.

exhaust pipes

BBDC 40°, 8500rpm, 249cc

The majority of slip-on's have a longer mid-pipe and silencer tube causing the secondary tuned length to increase the low end torque at the expense of high rpm power.

Nearly everyone who fits a slip-on comments on the slight increase of the bottom end but indicates you need a power commander to get the top end back as it feels lacking.

In my opinion the slip-on's need resigning to be more compact as not to alter the secondary tuned length.

I once thought of modding that underbelly exhaust can from LeoVince than I imagined the amount of work put on it to make it perform well as stock:
-New pipe (if you want to keep the stock thing): 130$ (in my place probably cheaper but I will give the US price for better calculation)
-Custom-made chamber (it's the big box-like mid-pipe on big bikes like the CBR1000RR or CB1000R). Reason for having this thing is to keep a little back-pressure up AND the noise down. Trust me with the sound part, you don't want to hear it scream at 7-8k rpm everyday after work. Price will varies, if you have access to a CBR150R mid-chamber, go for it, it's small and compact and really does the job well on the 150cc machine.
Here it is, the black box before the exhaust can

-The LeoVince can: 500$. may have to add 50$ for labor retrofitting stuff to "hang" it under the bike.
-The fuel control unit: why, you may ask. It's because you've just changed the exhaust into a full system: 300$. You can calibrate the thing yourself but it's best to leave that to a professional. NOTE: this does not include dyno fee or labor time.
-This is optional (I think): new airfilter for the added thirst for air of the new system ~ 10-20$

The total is almost 1000$ solely for the look good effect on a 5000$ machine. I'm not trying to talk you out of this, I simply state my opinions. I welcome modders because they can do what I am too afraid to do. Hope you find this informative.