I have an '03 s3 and I want to show off the swing arm. I am currently running a TOR low mount exhaust and was wondering what the consequences would be if I simply took the can off. Actually, there is a piece of pipe that I will leave on (that connnects to the header-about 12inches in length) just beneath my foot, but I want to take off the entire carbon fiber bit. A good friend of mine who has/rebuilds old muscle cars says it shouldn't do anything to the bike or its performance. Another friend says he thinks it may be bad for the bike. Anyone know for sure?
what is back pressure?
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If you do that you will be running straight open pipes. Besides giving you a possible reduction in power, it will cause the hot exhaust gases to flow out too quickly and it is very likely that you will have exhaust valve failures. Starting the bike to hear what it sounds like is okay. But only for a short and brief period before everything is up to operating temp.
I would no do it, but the choice is yours.
I would no do it, but the choice is yours.
An open exhaust is for drag racing or otherwise running WFO all the time, apart from that it is not useful at all. You will lose bottom end torque for sure and possibly a lot of mid-range power, not to mention being hard on equipment. You'll need to retune and richen it up across the board.....lean mixtures create high temperatures, which will in turn harm valves, etc. Scavenging will also be affected, which plays a part in the fuel/air mixture swirl inside the combustion chamber, which will directly affect combustion.
Many HD owners run those horrible looking/performing 2" or 2 1/4" open pipes on bikes that simply don't need that big of an opening.........so they get pissy when my 30 year old shovelhead walks all over their 2001 bike (on the streets), because I use a quality exhaust system, coupled with a proper camshaft, and a carb tuned for the combo. (yeah I know it's a Speedy post....but I think it serves to make a point)
Now if I had a 145 cubic inch engine, I might be interested in a set of those monster pipes. But paying for the fuel would be a different story. :razz:
So that's the long way of saying that I think it would be a mistake unless you live on the drag strip and are prepared to tune properly. As far as proper tuning goes......I am new to Speedy and can't speak about them confidently yet, but all common, internal combustion, piston engines work on similar concepts.
Many HD owners run those horrible looking/performing 2" or 2 1/4" open pipes on bikes that simply don't need that big of an opening.........so they get pissy when my 30 year old shovelhead walks all over their 2001 bike (on the streets), because I use a quality exhaust system, coupled with a proper camshaft, and a carb tuned for the combo. (yeah I know it's a Speedy post....but I think it serves to make a point)
Now if I had a 145 cubic inch engine, I might be interested in a set of those monster pipes. But paying for the fuel would be a different story. :razz:
So that's the long way of saying that I think it would be a mistake unless you live on the drag strip and are prepared to tune properly. As far as proper tuning goes......I am new to Speedy and can't speak about them confidently yet, but all common, internal combustion, piston engines work on similar concepts.
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Actually, what Dragonrider said is somewhat misleading. If you do what you said you will indeed have a straight pipe exhaust system, but there's little reason to think you'd have exhaust valve problems. This is usually caused by back pressure pulling cold air in over hot valves. Your system is long enough that this wouldn't be an issue. (8" long individual pipes like you see on dragsters is where you start seeing this problem.)
The real problem is twofold: For one, your faster moving exhaust tends to scavenge the combustion chamber better. This leads to a lean condition which robs horsepower. Note that a lean condition can also burn valve seats. Another problem is the change in "signal" that is part of the back pressure scavenging process. This can change your mixture too, sometimes lean sometimes rich, depending on how the header is designed. Tuneboy and some dyno time could solve these problems.
Simply put, this is back pressure: Your exhaust system works kind of like an old style ratcheting bumper jack. On each exhaust pulse the gasses move out the header so far, then get drawn back inwards just slightly. Ideally, during this cycle this should cause a slight vacuum in the combustion chamber. This is due to fast moving exhaust having momentum. Properly tuned, the pulse of the exhaust gasses coming back in should happen just as the valve closes- maintaining the vacuum inside the combustion chamber to aid in the intake stroke.
When there is valve overlap (exhaust and intake valves open at the same time) this backwards pulse (called "signal") can be used to stop intake gasses from flowing out the exhaust port. This is a very good thing!
However, making changes to the exhaust system can cause the "signal" to arrive at the exhaust port at the wrong time. If this happens too soon, then you flow exhaust gasses back into the combustion chamber. If it happens too late, then you get unburned fuel/air in the exhaust. In either case performance is effected negatively.
Now, that said I don't think simply removing you muffler will cause any back pressure signal problems. Most of the tuning involved with this is done in the collector. I still wouldn't do it. There's enough obnoxiously loud bikes on the road as it is. It gives us all a bad name. If you must show off your swing arm you could put a little supertrapp muffler down there, or better yet buy one of the under tail kits available.
If you want a faster bike and a quiet exhaust there's only one answer:
Turbo
(If I got any of that wrong, somebody correct me. I'm snowed in and bored out of my skull.)
The real problem is twofold: For one, your faster moving exhaust tends to scavenge the combustion chamber better. This leads to a lean condition which robs horsepower. Note that a lean condition can also burn valve seats. Another problem is the change in "signal" that is part of the back pressure scavenging process. This can change your mixture too, sometimes lean sometimes rich, depending on how the header is designed. Tuneboy and some dyno time could solve these problems.
Simply put, this is back pressure: Your exhaust system works kind of like an old style ratcheting bumper jack. On each exhaust pulse the gasses move out the header so far, then get drawn back inwards just slightly. Ideally, during this cycle this should cause a slight vacuum in the combustion chamber. This is due to fast moving exhaust having momentum. Properly tuned, the pulse of the exhaust gasses coming back in should happen just as the valve closes- maintaining the vacuum inside the combustion chamber to aid in the intake stroke.
When there is valve overlap (exhaust and intake valves open at the same time) this backwards pulse (called "signal") can be used to stop intake gasses from flowing out the exhaust port. This is a very good thing!
However, making changes to the exhaust system can cause the "signal" to arrive at the exhaust port at the wrong time. If this happens too soon, then you flow exhaust gasses back into the combustion chamber. If it happens too late, then you get unburned fuel/air in the exhaust. In either case performance is effected negatively.
Now, that said I don't think simply removing you muffler will cause any back pressure signal problems. Most of the tuning involved with this is done in the collector. I still wouldn't do it. There's enough obnoxiously loud bikes on the road as it is. It gives us all a bad name. If you must show off your swing arm you could put a little supertrapp muffler down there, or better yet buy one of the under tail kits available.
If you want a faster bike and a quiet exhaust there's only one answer:
Turbo
(If I got any of that wrong, somebody correct me. I'm snowed in and bored out of my skull.)
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I have been running a strait pipe for over 2K miles and I hope it didn't damage anythings. You will lose tq but not hp. It was cool at the biggining but now it's getting old. Going back to a stubby as soon as I decide which one to go with.
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:gpst: 
pcn:
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G
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Loud Pipes Saves Lives. This video I came across says it all. If you want a loud bike I say go for it. With some tuning your bike will run like a scolded dog and you'll get looks good and bad. Everyone has their own taste and style and you and I have the same. Why grow up? If you want to look back at your youth when your retired and regret that you never took any risks, never pissed someone else off, or never had a chick like you, then I'd recommend leaving that baffle on: otherwise rip it off and piss off all your neighbors and hook it up with some narly biker chicks.
Sail on- loud or not.
-CoonDogWheelieKing
Loud Pipes Saves Lives. This video I came across says it all. If you want a loud bike I say go for it. With some tuning your bike will run like a scolded dog and you'll get looks good and bad. Everyone has their own taste and style and you and I have the same. Why grow up? If you want to look back at your youth when your retired and regret that you never took any risks, never pissed someone else off, or never had a chick like you, then I'd recommend leaving that baffle on: otherwise rip it off and piss off all your neighbors and hook it up with some narly biker chicks.
Sail on- loud or not.
-CoonDogWheelieKing
As someone who is around the loud pipes saves lives crowd a lot, let me say this.
Pulease.
Loud pipes only do one thing- they make it harder and harder for ALL motorcyclists to go where we want, when we want.
Ever pull up to a hotel and they tell you "no bikes allowed".
It surely wasn't a finely tuned machine that caused the problem, it was a bike with some Straight Shots on it. No baffles. All loud pipes do is piss off the local resident who can't do a thing about the bike sitting next to him but he can make life miserable for the next 10,000 riders to come along.
Pulease.
Loud pipes only do one thing- they make it harder and harder for ALL motorcyclists to go where we want, when we want.
Ever pull up to a hotel and they tell you "no bikes allowed".
It surely wasn't a finely tuned machine that caused the problem, it was a bike with some Straight Shots on it. No baffles. All loud pipes do is piss off the local resident who can't do a thing about the bike sitting next to him but he can make life miserable for the next 10,000 riders to come along.
Unfortunately I just watched that whole video. I am really pissed at my self for wasting 2 minutes of my life that I will never get back, and the 2 it took to type this.
I think I am going to go stab myself in the eye w/ a spoon, it would be more fun than watching that again! :knkknk:
By the way, that is the video they play in Hell, over and over. :lgh:
I think I am going to go stab myself in the eye w/ a spoon, it would be more fun than watching that again! :knkknk:
By the way, that is the video they play in Hell, over and over. :lgh:
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:roflmoa2: well womcat, guess you just saved me from watch'n it. :-D I agree with the "don't piss everyone off" crowd(this coming from the man that just bought a Zard :hammer: ). I've never heard a good sounding modified stock exhaust. I guess it can be done, but I've never heard it. Loud?... yes, sound good?... hell no! I'd find sumt'n I like in the aftermarket line, but then again, it's not my bike. :hammer: :-D
I took the twin cans off of my old Trophy and it back fired quite a bit on deceleration. Wouldn't that happen here too? I don't know if I would go for an under tail kit due to the price (I'm cheap), but I would look at the Triumph high rise can (Fraction of the price) and it shows of the swing arm more.
Btw, the best sounding motorcycle EVER is without doubt a 1978 Kawasaki Z1r with a 4:1 Kerker header. Any one who does not agree obviously has never heard one, and any one who has never seen one/heard of one doesn't know much about motorcycles. I mean WOW!
Btw, the best sounding motorcycle EVER is without doubt a 1978 Kawasaki Z1r with a 4:1 Kerker header. Any one who does not agree obviously has never heard one, and any one who has never seen one/heard of one doesn't know much about motorcycles. I mean WOW!
Oh man that video was BAD! I'm so glad i dont live in flordia anymore! :razz: sorry to those of you who do, no offense but you know what I'm talking about. I was the manger of an auto parts store on the west side of jacksonville and delt with people just like that all day. that video was HELL Dont watch it.
As far as the exhaust is concerned: the zard system seems just as short and stubby as the modification I am proposing. Maybe mine won't sound as 'good' and maybe it will be louder than the zard but, really... by how much? I am not sure that it will differ in too significant a manner. I have seen the zard and w/o the db killer it looked like the equivalent of a straight pipe with a little baffle in it, not unlike the one I am proposing. At the same time, by doing it this way I can save myself the $1200 that it would cost me to get a full Zard system (02-03's don't have slip ons). Seems that, like Crashmasterd said, if I get it tuned it should run just fine. If this set up lets cold air into the valves then so will the Zard. Again, like Crashmasterd said, this shouldn't be an issue: with the header pipes and the connector and the stubby baffle it seems that there will be enough pipe to stop this from happening. Additionally, although my set up may be loud I am sure it isn't any much worse than the busses, construction trucks, other bikes, cars with loud music, screaming kids, dogs, etc. I have in my neighboorhood now. And as long as i am not effin around on city streets I am sure I will be fine.
BTW Dr_Gallup, it is ironic that you would give a grown man advice on this topic in such a negative fashion. Telling another man to grow up is itself childish. I respect that you have a different opinion than me but I don't appreciate you telling me, or anybody for that matter, to "grow up." You don't know me and you have no right to judge me. I am sure you wouldn't agree with a lot of the things I do, BUT, that is what makes this country so great... it doesn't matter to me and I will continue to do them. Furthermore, I didn't ask for your personal opinion on my maturity... all I wanted to know is if my bike would run the way I want it to after some modifications. To make the situation personal and to attack me instead of the topic is what I consider immature.
BTW Dr_Gallup, it is ironic that you would give a grown man advice on this topic in such a negative fashion. Telling another man to grow up is itself childish. I respect that you have a different opinion than me but I don't appreciate you telling me, or anybody for that matter, to "grow up." You don't know me and you have no right to judge me. I am sure you wouldn't agree with a lot of the things I do, BUT, that is what makes this country so great... it doesn't matter to me and I will continue to do them. Furthermore, I didn't ask for your personal opinion on my maturity... all I wanted to know is if my bike would run the way I want it to after some modifications. To make the situation personal and to attack me instead of the topic is what I consider immature.
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