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S bend mid pipes and slip ons

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15K views 13 replies 12 participants last post by  Bevo  
#1 ·
Hey guys, first of all i would like to apologize for the 10,000th slip on question thread, but i havent found any concerning the mid-pipe (poor search skills) which is partly what this question is based on, so im taking the chance of starting a new thread.

But, i have an 08 cbr 1000, and i really like the yoshimura r-77 slip on, and the akrapovic, they are both possibilities.

My question to you guys is,

Why are some midpipes like an s, they curve and look like a snake, im sure you know what im talking about, and some are straight through? I really favor the look of the s pipe, can someone aware me on that?

also, when just going with a slip on, like the akra or the yoshi, would i need to take my bike in and get it re-mapped?

when i bought the bike it had a 2 bros slip on, and it sounded seriously amazing, but for some reason i put the stock exhaust back on and sold the 2 bros.


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is the s pipe bad for horsepower? and where do you get it? as most come with the straight mid pipe.


thanks for any advice you can give me, i know i addressed multiple things in this post.

and thanks again for reading the (probably) 10,000th slip on post.
 
#2 ·
resonance tuning, google it... Exhaust comes out in extreame pressure, low pressure pulses, the only way to even those pulses out is to either run a longer muffler, or snake pipe under the bike... or install a baffle like oem. Im sorry but two brothers is a noise making can that sucks balls, on HP and sound... With exhaust that is short and not snaked the exhaust has to push the gas out, not let it flow... with snaked exhaust the flow is smooth and even... You are better off with stock exhaust then 2 hoes... get a exhaust with an s bend or a longer muffler...

Learned that from "Rebillet, and Mr dude 1"

And back pressure is a myth... "sal"
 
B
#4 ·
It's nothing to do with evening out pulses, and it's not a replacement for baffles. It isn't really about resonance either but harmonics. Back pressure is not a myth but is often missunderstood. The goal is to create low pressure at the exhaust valve when it opens. The exiting gas has its own mass and therefore momentum which can be used to suck out the next cylinder. There are different designs because engine speed is variable and the performance gain is targeted. A race system is short because the target is max power at high revs. The slip on is longer to boost mid range. The Akrapovic slipon gives great midrange and in terms of quality & finish is streets ahead of the Yoshi. The only downside of the Akrapovic is that it can't be covered with a filler pannel like the Yoshi.
 
T
#5 ·
There are way too many people misinformed and I don't get why. But yes this "back pressure" thing doesn't exist. Do you think they put Little blockages in the pipe to force the exhaust back into the motor? No, its all about bernoulli's principle getting the optimal size pipe to induce maximum flow. I hope many people see this and stop asking about "back pressure".
 
#6 · (Edited)
backpressure is created as soon as a bend or kink is added into any pipe. it doesnt matter what you are trying to do, certain things (such as backpressure) happen as a result.


edit to add...


the exhausts with s-bends in them tend to offer a bit more performance because they are in a sense already tuned compared to the pipes that run straight.
 
#10 ·
Username said:
also, when just going with a slip on, like the akra or the yoshi, would i need to take my bike in and get it re-mapped?
Click to expand...
need?? no.
its not a bad idea to get any bike tuned to be ideal for the engine, instead of being setup to meet the factory balance of emissions, warranty claims and power.
because your bike is not setup "ideally" from the factory, you will see gains anytime you tune it.. regardless if you change your exhaust or not.

that said, it will not harm your bike to change nothing except the exhaust.


Username said:
Why are some midpipes like an s, they curve and look like a snake, im sure you know what im talking about, and some are straight through?
Click to expand...
packaging.
there is an ideal length (or atleast, length range) for your exhaust.
because it is so close to the bike, the exhaust designers have two choices... snake the pipe around the free space to get the length... or run it directly.

cheap exhausts run it directly. it is not best for power, but its easy to make.
better exhausts snake it, but they often cost more.. if you look at the welded S pipe, you can easily see why.



Username said:
I really favor the look of the s pipe, can someone aware me on that?
Click to expand...
huh?

Username said:
is the s pipe bad for horsepower? and where do you get it? as most come with the straight mid pipe.
Click to expand...
its good for HP.
it comes with the exhaust kit.

most come with the mid pipe for the kit. if you want a different midpipe, buy a different kit.
 
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