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Exhaust question

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Old Mar 22, 2012 | 02:21 PM
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Default Exhaust question

Question about my exhaust. I have a 2012 Ultra. I have removed my cats to lower the heat. The question I have is if I have the fiberglass removed from the slip ons would I need a download, or power commander? I'm wondering if there would be enough back pressure, or if it would turn the bike rich…

A friend of mine who works a Stealership told me I would need a dyno. I told him I wasn't changing the intake, only the exhaust. I was under the understanding I would only need a power commander if I changed the exhaust and the intake…

Has anyone removed the fiberglass and cats on their bagger?
 
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Old Mar 22, 2012 | 02:38 PM
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From: Phoenix '53, '88, '09 Big Twins
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according to Supertrapp's techs;

when the baffling is removed in a muffler, the gasses and pulse waves can loose direction and "eddy" inside the muffler, possibly resulting in reduced exhaust flow.
The gasses and waves go through the baffle into the outer chamber, then may return to the core travelling at a random speed in a random direction.

this will vary greatly depending on rpm, as gas velocity, volume and pulse wave frequency all vary greatly by rpm.

But you could certainly try it as it is doubtful that you would damage anything--tuning wise. Especially if you stay with the stock restrictive air cleaner.

- make sure the pipes are all the way clean, as pulse waves can suck up debris ( metal filings/ packing) and carry all the way into the cylinder


the results of this may not get you anywhere, but if you are doing this for enjoyment, rather than as "work" go ahead.

and report back


mike
 

Last edited by mkguitar; Mar 22, 2012 at 02:52 PM.
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Old Mar 22, 2012 | 02:49 PM
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Before I completed my stage 1 I removed the cat and added a slipon muffler. No AC change or tune. Bike popped and backfired like crazy.
Some say if you just change exhaust you wont need a tune. In my case I needed a tune and went full stage 1 upgrade.
I would suggest calling Fuel Moto and talking to Jamie. A PCV and SEAC might be cheaper and give you more bang for your buck than having a dealership dyno your bike with a download.
 
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