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Removed Silencer
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Knee Draggin!
 
Posts: 533
Join Date: June 10, 2009
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Removed Silencer - June 5, 2010, 09:13 AM

I recently removed the silencer insert to my devil slip-on with idea of putting in a slightly larger one to make it a tad louder.

Only reason I'm messing with this stuff is for exhaust note, which isn't terribly important to me but enough to try out some things when I have some spare time.

Anyways, I've left the silencer out entirely for now to see how I like it. I've read various things about doing this: I will actually lose power, I might get too lean in a/f ratio, etc.

I know I could put it on a dyno to see, but could anyone set the issue straight? Is it typically bad for the bike in terms of power and/or A/F ratio?

-Quentin


-Quentin
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June 5, 2010, 09:37 AM

Bad? Like damaging... no.
Bad like... screwing up A/F ratio and limiting power or chenging power band... yes.


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June 5, 2010, 11:54 AM

Mess up the AFR too much and it can be damaging. Lean condition can do all sorts of fun stuff.
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June 5, 2010, 03:01 PM

I'm sure some of the motorheads on the site will set it straight, but as I understand it; you will lose out on some low end power because there will be less back pressure, but at speed it will increase because of better flow.
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June 5, 2010, 03:17 PM

Quote:
Originally Posted by Madduc2k
I'm sure some of the motorheads on the site will set it straight, but as I understand it; you will lose out on some low end power because there will be less back pressure, but at speed it will increase because of better flow.
Backpressure only reduces power, it doesn't increase low end power. When a higher backpressure exhaust is installed and low end increases, it's due to more optimum flow velocity at low speeds, if you measured the backpressure at that rpm, you'd find it had decreased. Ideally, you want zero (or negative) backpressure at all rpm. See my previous posts on the topic.


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Knee Draggin!
 
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June 5, 2010, 04:01 PM

Quote:
Originally Posted by birdman View Post
Backpressure only reduces power, it doesn't increase low end power. When a higher backpressure exhaust is installed and low end increases, it's due to more optimum flow velocity at low speeds, if you measured the backpressure at that rpm, you'd find it had decreased. Ideally, you want zero (or negative) backpressure at all rpm. See my previous posts on the topic.
Thanks for the posts from all and in particular this one.
I'll do a bit more searching for the relevant posts on this topic.

Don't have baseline dyno but will need to put it on one or just put the bigger silencer back in.


-Quentin
-Aprilia rsv4, street
-Yamaha R6, track project
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