? On exhaust
- Thread starter kybusa05
- Start date
If ur saying someone replaced the cans and mid pipe with exhaust tips u really wouldn't need to do anything. IMO not an expert just a knucklehead
Blrry
Registered
From another forum:
"It will not hurt your bike to remove the stock muffler/tail pipe/silencer.
2-strokes do need a slight bit of back pressure to run correctly, but most of the back pressure is created by the exhaust pipe and not the muffler/silencer. The back pressure for the 2-stroke is created in the expansion chamber/conical baffles in the exhaust pipe.
There is an on going debate that removing the muffler on 2-strokes and 4 stroke that it will reduce there horsepower.
Back pressure in a 4 stroke robs horsepower. When most people talk about back pressure they are talking about restricting the spent exhaust flow. Restriction in a race engine lowers horsepower, but if you had no exhaust (no restriction), you would lose horsepower. Why is that?
If you look at drag racing cars and bikes, they do not use any mufflers, they use what is called "tuned exhaust". They set up the length of their headers so that the pulse of the last exhaust pulse pulls (due to vacuum caused as the pulse exits the end of the pipe) the exhaust that is entering the exhaust port as the exhaust valve is opening. Now because timing the exiting pulses increases horsepower, people think it is due to back pressure. Is that back pressure? Some say yes and some say no. The point is you have to have and exhaust pipe at a certain length to make the most horsepower. You technically could do that with a straight pipe but you would have to work with the length to get it perfect."
The guy answering is a motorcycle mechanic, drag racer etc. Take it for what it's worth, I guess (I certainly don't know the answer!)
I've heard it could shorten the life of your exhaust valves though.
From Revzilla's Motorcycle Exhaust Systems 101:
"Should I run drag pipes/open exhaust?
Maybe. If you’re at the drag strip or track, probably. If you’re anywhere else... probably not! Realistically, ‘open’, or unmuffled pipes make horsepower high in the rev range, where the engine is expelling the highest amount of exhaust. However, because they do not promote good velocity in lower portions of the rev range, they tend to be a poor choice for street use. Tuning the bike is very difficult with drag pipes, and almost all open exhausts leave weird ‘flat spots’ where power is delivered erratically, or can even decrease!
If you’re honest with yourself, you’ll probably find that wide-open throttle most of the time is not really how you ride on the street.
There are a great many federal, state, and local laws in America, and typically they mention unmuffled pipes as being problematic - again, every place is different, but by and large, having at least a muffler is usually the minimum exhaust requirement you’ll need to meet for most vehicle inspections.
The fact is that the exhaust manufacturers spend quite a lot of time and money developing an exhaust product that will lend you the most horsepower and torque for your particular motorcycle without being overly obnoxious. Loads of dyno-tuning and testing back up their product. It is pretty rare to achieve a better all-around exhaust for street use than the ones the big players in the exhaust game have developed. Keep in mind that most of them do significant exhaust acoustics testing - they know you want your bike to sound nasty, and the time-tested exhaust manufacturers have had many satisfied customers over the years. Unless your bike is way different than a stock engine, a bolt-on exhaust is probably just what you need for a little more oomph!"
"It will not hurt your bike to remove the stock muffler/tail pipe/silencer.
2-strokes do need a slight bit of back pressure to run correctly, but most of the back pressure is created by the exhaust pipe and not the muffler/silencer. The back pressure for the 2-stroke is created in the expansion chamber/conical baffles in the exhaust pipe.
There is an on going debate that removing the muffler on 2-strokes and 4 stroke that it will reduce there horsepower.
Back pressure in a 4 stroke robs horsepower. When most people talk about back pressure they are talking about restricting the spent exhaust flow. Restriction in a race engine lowers horsepower, but if you had no exhaust (no restriction), you would lose horsepower. Why is that?
If you look at drag racing cars and bikes, they do not use any mufflers, they use what is called "tuned exhaust". They set up the length of their headers so that the pulse of the last exhaust pulse pulls (due to vacuum caused as the pulse exits the end of the pipe) the exhaust that is entering the exhaust port as the exhaust valve is opening. Now because timing the exiting pulses increases horsepower, people think it is due to back pressure. Is that back pressure? Some say yes and some say no. The point is you have to have and exhaust pipe at a certain length to make the most horsepower. You technically could do that with a straight pipe but you would have to work with the length to get it perfect."
The guy answering is a motorcycle mechanic, drag racer etc. Take it for what it's worth, I guess (I certainly don't know the answer!)
I've heard it could shorten the life of your exhaust valves though.
From Revzilla's Motorcycle Exhaust Systems 101:
"Should I run drag pipes/open exhaust?
Maybe. If you’re at the drag strip or track, probably. If you’re anywhere else... probably not! Realistically, ‘open’, or unmuffled pipes make horsepower high in the rev range, where the engine is expelling the highest amount of exhaust. However, because they do not promote good velocity in lower portions of the rev range, they tend to be a poor choice for street use. Tuning the bike is very difficult with drag pipes, and almost all open exhausts leave weird ‘flat spots’ where power is delivered erratically, or can even decrease!
If you’re honest with yourself, you’ll probably find that wide-open throttle most of the time is not really how you ride on the street.
There are a great many federal, state, and local laws in America, and typically they mention unmuffled pipes as being problematic - again, every place is different, but by and large, having at least a muffler is usually the minimum exhaust requirement you’ll need to meet for most vehicle inspections.
The fact is that the exhaust manufacturers spend quite a lot of time and money developing an exhaust product that will lend you the most horsepower and torque for your particular motorcycle without being overly obnoxious. Loads of dyno-tuning and testing back up their product. It is pretty rare to achieve a better all-around exhaust for street use than the ones the big players in the exhaust game have developed. Keep in mind that most of them do significant exhaust acoustics testing - they know you want your bike to sound nasty, and the time-tested exhaust manufacturers have had many satisfied customers over the years. Unless your bike is way different than a stock engine, a bolt-on exhaust is probably just what you need for a little more oomph!"
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IRight or wrong its been stated thatthe biggest rrestriction in the flow through the Busa engine is the factory header and that dropping the cans does little to nothing. Race engines are probably a completely different animal. Lots of folks running exhaust tips without issue reported. I went with a system designed by Brock.
Blrry
Registered
Most aftermarket exhaust manufacturers recommend you tune your engine after replacing the exhaust. I imagine this would affect the power of the bike in some way (going to just tips) for good or for bad (flat spots in the power delivery probably?), but yah, for what it's worth, sounds like its safe to do (as far as engine life goes).
StrtRac3r
Registered
I know a while back I was bored and ran just the yosh header and single side mid pipe to be obnoxious. I achieved that. But on the freeway at mid to higher rpm it felt to pull harder. May be a lean mixture giving me a little more power, or the free flow. Probably a bit of both. But now that it's out of my system I won't do it again.
cosmic_ocean
Registered
Exhausts are designed specifically, for every engine, keeping in mind the best mix of regulations (sound levels), power, waste gas expulsion, weight, prevention of back pressure, engine heat dissipation, ability to not interfere with the valve working and a host of other features. Randomly bypassing the OEM specs with just something that will 'fit the hole' is never a good idea on the whole. You may achieve the sound you want but will compromise on a host of other things, whose repercussions will only be known in the long run.
Best stick to the stock one or an after-market from a reputed maker.
Best stick to the stock one or an after-market from a reputed maker.
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