Stock exhaust vs. "racing exhausts".

[BangkokReady]

Hoping to get a slight expert (or at least experienced) opinion on this.

 

I was looking at racing exhausts, out of curiosity.  As I understand it, they may or may not improve performance much, but they can sound nice (as well as awful) and they can look pretty good as well.

 

I then noticed price lists for what appeared to be the stock exhaust that comes on the motorcycle, and it seems to be a lot more expensive than the "racing upgrade".

 

What's up with that?  Is it something to do with what goes on inside the stock exhaust vs. the racing exhaust?  Sound and emissions? 

 

I assumed the racing exhaust would be more expensive than the stock exhaust.

 

If the stock exhaust is expensive due to doing a lot more, doesn't it seem foolish to change the exhaust to a cheaper one, just because it looks/sounds nicer?

 

(I'm now wondering if they are even legal...)

[Dante99]

mods, please move to the teenage forum

[BangkokReady]

2 minutes ago, Dante99 said:

mods, please move to the teenage forum

 

What are you doing in the motorcycles forum if you don't know that considering buying a different exhaust is a perfectly adult thing to do?

[stubuzz]

52 minutes ago, BangkokReady said:

I was looking at racing exhausts, out of curiosity.  As I understand it, they may or may not improve performance much, but they can sound nice (as well as awful) and they can look pretty good as well.

For what bike?

[johng]

An exhaust pipe on its own will make very little diference to performance on a "normal" four stroke engine unless it has been deliberately restricted at the factory

(diameter of the hole restriction for legal /licence reasons)

In the case of a 2 stroke engine then the exhaust can make a big difference to performance.

 

A nice stainless steel exhaust is a good investment as is  should last the life of the vehicle/owner.

exhaust "header" and "muffler" are not the same  muffler is to keep the noise down and all Thai registered bikes should have a muffler with a T.I.S stamp on it.

[BangkokReady]

2 hours ago, stubuzz said:

For what bike?

 

I was more interested to know why the stock exhaust would be more expensive than the new exhaust.

[Kinnock]

1 hour ago, BangkokReady said:

 

I was more interested to know why the stock exhaust would be more expensive than the new exhaust.

Stock exhaust needs to be tested and certified for type approval and noise legislation in many countries ... that costs.

 

Plus original spare parts have a high mark-up compared to accessories.  Compare original equipment brake pads or shock absorbers with accessory pads and shocks ... the (possibly better) non-original parts will be cheaper.

 

Also, some original exhaust systems contain a catalytic converter - which is a costly item often containing platinum or palladium, which is not cheap.

 

But with the aftermarket exhaust silencer, that lack of certification will bite you at the annual inspection .... so you may need to refit the original one if the test center is serious.

 

Swapping for a louder 'silencer' will mean less back pressure, so unless you also tune the fuel injection (or re-jet the carburettor) you may lose some power.  With retuning you can get a little extra power, but there's often a cost in reduced fuel economy.

[BangkokReady]

9 hours ago, Kinnock said:

Stock exhaust needs to be tested and certified for type approval and noise legislation in many countries ... that costs.

 

Plus original spare parts have a high mark-up compared to accessories.  Compare original equipment brake pads or shock absorbers with accessory pads and shocks ... the (possibly better) non-original parts will be cheaper.

 

Also, some original exhaust systems contain a catalytic converter - which is a costly item often containing platinum or palladium, which is not cheap.

 

But with the aftermarket exhaust silencer, that lack of certification will bite you at the annual inspection .... so you may need to refit the original one if the test center is serious.

 

Swapping for a louder 'silencer' will mean less back pressure, so unless you also tune the fuel injection (or re-jet the carburettor) you may lose some power.  With retuning you can get a little extra power, but there's often a cost in reduced fuel economy.

 

This is a very thorough explanation.

 

Thank you.

[novacova]

11 hours ago, BangkokReady said:

 

I was more interested to know why the stock exhaust would be more expensive than the new exhaust.

 

10 hours ago, Kinnock said:

Swapping for a louder 'silencer' will mean less back pressure, so unless you also tune the fuel injection (or re-jet the carburettor) you may lose some power.  With retuning you can get a little extra power, but there's often a cost in reduced fuel economy.

Stock pipes are engineered not only to muffle but for proper back pressure, swapping out the correctly engineered muffler for a loud bonehead fart can is rather idiotic, just because it’s loud doesn’t mean it’s going faster, it’s just loud and buttholeish 

[JonnyF]

Depends what you mean by racing exhaust.

 

A proper aftermarket system like Yoshimura or Temignoni can increase performance if you adjust the ECU, air filter etc. as well. Power gains are minimal though, it's normally more about weight savings, looks and sound. 

 

But putting a locally made 1500 Baht can on a Honda Grom will likely make no difference. Maybe even make it run worse due to lack of back pressure.