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Its Only a 600?
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319 Posts
Discussion Starter #1
Hey guys, I just got my GYTR Slip on and PCIII. I'm still waiting on my Mid Pipe. I got a few questions. When I install these three, how much low end will i lose because of the removal of the exup? Is there a way to gain back some low end with the removal of this? thanks for the help.
 

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Go Heels! #1
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126 Posts
the removal of the exup wont be your issue, its the removal of backpresssure. im running gutted headers midpipe and a graves slip on. before with just the slip on i didnt loose alot but now there is a noticeable loss, i just rev higher and slip the clutch more from a light to make up for the loss, but since you look all stock then it will be a big diff. i dont have a pcIII so that may help you, i dunno, but you gain high end power, wheel comes up at end of first and second.
 

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Phi Phi K A
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823 Posts
the removal of the exup wont be your issue, its the removal of backpresssure. im running gutted headers midpipe and a graves slip on. before with just the slip on i didnt loose alot but now there is a noticeable loss, i just rev higher and slip the clutch more from a light to make up for the loss, but since you look all stock then it will be a big diff. i dont have a pcIII so that may help you, i dunno, but you gain high end power, wheel comes up at end of first and second.
I don't mean to sound rude, but this is not a correct statment.

Mufflers often (if only slightly) reduce power. When using a any typical freeflowing (aftermarket) exhaust "backpressure" is nonexistent. The term "backpressure' is very often misused or misunderstood. Exhaust theory is a bit too involved to fully explain here. But no matter how much genius engineering goes into an exhaust design, it always comes down to testing (on a dyno).

The only why to compansate for the reduced, for lack of a better word, "backpressure" is change the the valve timing(or overlap). For example, if an engine were running a camshaft of 106 degrees lobe separation before a backpressure reduction, select a cam of 112 degrees.

In other words, don't worry about it. Also, a PCIII will not help anything that you are concerned about and you probably wasted money buying one. Sorry. To be honest, you would probably be better off without the PCIII. I have done many dyno runs with and without it.
 

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Go Heels! #1
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126 Posts
yeah, by removing the cat and honeycomb you lose backpressure cause its free flowing. im sorry though, i have no idea what im talking about cause i have pretty much the exact setup he will have. and the term dont worry about it is stupid because the bike loses alot of low end once this setup is installed but gains high end.
 

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Phi Phi K A
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823 Posts
yeah, by removing the cat and honeycomb you lose backpressure cause its free flowing. im sorry though, i have no idea what im talking about cause i have pretty much the exact setup he will have. and the term dont worry about it is stupid because the bike loses alot of low end once this setup is installed but gains high end.
Listen bro. You do not have to get PO'd about it. Just admit you have no idea what you're talking about. You probably heard the term "backpressure" from someone and are now using it incorrectly. I have done many tests with many different set ups, including not running any headers, only headers(striaght pipe), factory set up, aftermarket with and without PCIII's, ect, ect, ect.....

Trust me, you are misusing the term "backpressure" as it pertains to his question and this thread. If you can explain it to me, in your own words, how back pressure works, what causes and doesn't cause it, and what it actually effects, than I will eat my above statement.
 

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Go Heels! #1
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126 Posts
backpressure is resistance of exhaust flow, by running straight pipes there is no resistance to exhaust flow. you want exhaust to exit as fast as possible with as little restriction as possible. no backpressure will cause you to run lean i know this too cause my bike runs really hot now. im just speaking off experience of actually riding the bike with the system that he will be using
 

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Registered
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I don't mean to sound rude, but this is not a correct statment.

Mufflers often (if only slightly) reduce power. When using a any typical freeflowing (aftermarket) exhaust "backpressure" is nonexistent. The term "backpressure' is very often misused or misunderstood. Exhaust theory is a bit too involved to fully explain here. But no matter how much genius engineering goes into an exhaust design, it always comes down to testing (on a dyno).

The only why to compansate for the reduced, for lack of a better word, "backpressure" is change the the valve timing(or overlap). For example, if an engine were running a camshaft of 106 degrees lobe separation before a backpressure reduction, select a cam of 112 degrees.

In other words, don't worry about it. Also, a PCIII will not help anything that you are concerned about and you probably wasted money buying one. Sorry. To be honest, you would probably be better off without the PCIII. I have done many dyno runs with and without it.
I have to completely agree about the PCIII. Hate um.
 

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Phi Phi K A
Joined
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823 Posts
backpressure is resistance of exhaust flow, by running straight pipes there is no resistance to exhaust flow. you want exhaust to exit as fast as possible with as little restriction as possible. no backpressure will cause you to run lean i know this too cause my bike runs really hot now. im just speaking off experience of actually riding the bike with the system that he will be using

Backpressure MAY cause the motor to run lean, but it dose not always mean it WILL run lean. Running hot is def a sign that you are running lean. Remember that the more air that flows into the motor the hotter the motor will run. However, no backpressure can cause the opposite effect. It is all about the valve overlap. Let me also say that I am by no means an expert. I have been fortunate to have a friend who is an expert and who owns a dyno in his shop. I have done a lot of research on this subject and have learned a lot from my buddy.

I have to completely agree about the PCIII. Hate um.
+1. I think they are the biggest scam ever pushed onto the sportbike community.
 

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pop wheelies
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1,615 Posts
I have a midpipe with a gutted header, and I think if anything I got more power all around. I don't think I lost any? Also its not like our bikes are 2 strokes and need an expansion chamber, so I wouldn't be to worried about back pressure. Let me as you this, on drag cars, do you EVER see any sort of mufflers, or mainly open headers?
 
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