exhaust question

[turbodaily]

alrite guys, this is regarding my starlet but im sure someone will be able to advise me,

ive got a blitz nurspec back section on my ep82, its the new style one that sits at an angle. me mates got the earlier one and his is a fair bit bassyier than mine.

had a look inside his rear box today and his has a baffle all the way through (the bit with holes in it) mine only has a baffle 3" long in the rear box, the rest is just solid pipe with no holes in it. guessing this is whats making it quiter?

am i right in thinking the length of the baffle, or the bit with the holes in it, determines how bassy it is?

cheers lads - dan

 

[youngsyp]

Mmmh, I guess it could do....

First of all, a silencer in a sports exhaust, does not usually have baffles. Baffles are used in OE exhausts and reduce exhaust volume by means of reflection. These make the silencers very restrictive
In a sports exhaust silencer, the usual method of volume reduction, is absorption, due to the straight through design. Inside the silencer will be a straight through perforated tube, that the exhaust gas passes through. Around this tube (between the outer wall of the tube and inner wall of the silencer case), will be sound absorbing material, like steel wool or fibreglass wool. This is one of the least effective silencer designs, in terms of sound level control but, they will be the best for power gain and are very un-restrictive.

The reasons why your exhaust is less bassy, would normally be down to a resonator in the pipe run. This is a length of pipe, that will be fatter than the rest of the pipe, and normally torwards the rear of the system. These are use to drop the frequency range of the exhaust note.

If your mate has one of these and you dont or, if his is larger than yours, his exhaust will be bassier.

Other things that could affect it, are length of time the exhaust has been on the car. As carbon deposits would fill the pipe perforations in the silencer over time. This would tend to make the exhaust louder more than bassier though.

If the pipe work is larger bore, would lower the frequency range of the exhaust note, as would the inside diameter of the tail pipe. Again, this would also increase the volume of the exhaust. With the larger I/D tailpipe being louder.

 

[turbodaily]

mine doesnt have a resonator.

its straight through from turbo to bakbox.

mates rear box has a longer perfuated tube inside, where as mine only has one half the size. the rest is solid pipe.

i have been given a resonator but not sure if it will make it quiter or what?

my mates has a resonator on his aswell.

 

[turblio]

ello dan raced any R,s lately (he hee)

 

[turbodaily]

ello frank, got chased by a 1.3 recently?

 

[saddler]

ello frank, got chased by a 1.3 recently?

been told these starlets are great little cars..??

 

[youngsyp]

my mates has a resonator on his aswell.

There's the answer to your question ! ;-)

Adding a resonator, may make the exhaust quieter, it all depends how large it is !

 

[turbodaily]

but his has the perfuated pipe for the entire length of the backbox, mines only half the length. also mine is jasma stamped, where as his isnt..

resonator is about 4" that ive been given. have looked on the web and most says they silence the exhaust. but a couple i see for sale on ebay say makes it bassier... **** knows

 

[youngsyp]

but his has the perfuated pipe for the entire length of the backbox, mines only half the length. also mine is jasma stamped, where as his isnt..

resonator is about 4" that ive been given. have looked on the web and most says they silence the exhaust. but a couple i see for sale on ebay say makes it bassier... **** knows

It is the resonator that changes the exhaust sound characteristics. If you fit one to your exhaust, it will become 'bassier'.
Also, due to the inherent design of a resonator, depending on the size, it could reduce the sound output level of your exhaust too. Although, this would be negligable either way.

At only 4 inches long, I wouldn't expect it to effect noise levels at all.
In my custom exhaust, the resonator is around 13" long and that was still loud before I added a centre silencer !

The silencers only purpose is to silence, nothing else. The reason your silencer design is slightly different is because yours is JASMA approved. Therefore, it will be quieter than your mates non JASMA approved set up.
From what you write, it sounds like your silencer design is a lot more efficient than your mates. So, to keep sound levels reasonable, Blitz only needed to use half the silencer volume, to attain this.