new exhaust giving me headaches!

[_turtle_]

hey guys i just bought a 2nd hand catback exhaust with a canon style muffler and it extremely loud! it already has a resonator in it, a hotdog style one and it is still loud. so loud that it drones wen i'm driving on the freeway. the exhaust is 2.5" and my car is NA. i just went to performance exhaust and put on a 2nd resonator, however this resonator looks just like the normal pipe only a tiny bit bigger and it doesn't seem to have helped much.

besides changing the muffler, what can i do?

[Warpspeed]

Sell it to someone else that has a turbo.

Seriously, otherwise it is going to drone and drive you mad no matter what you do. Go down to a smaller pipe size and get a decent rear muffler for it.

[GTR-80Y]

There are different sized resonators availiable, sounds like u got one of the smaller style hot dog types which is only slightly bigger than the actual exhaust piping. Some resonators are as big as the rear muffler, so effectively u have 2 mufflers. Another option is a reverse type muffler as opposed to the cannon straight thru type u have (these are the loudest).

[_turtle_]

thanks guys.

i already wasted $88 putting in the really small resonator which is like the size of the pipe. i regret doing that now, i should've removed the hotdog like resonator which was already on it and put in a big oval shape one instead which is similar in shape to the standard exhaust. the exhaust place wasn't very helpful.

but damn, im outta cash so i have to wait till i've paid my bills then do that.

so do u guys think that if i put in an oval shape muffler in it should take out the drone? its very annoying driving on freeway and going up hills and stuff. i just wanted a grrrrr noise. not a wooooowoooowooooo noise. although the grrrr noise does sound quite nice until the other one comes in.

anyone turbo guys out there with a smaller muffler and stuff wanna swap with me?

[_turtle_]

ok, this is what i plan to do, any feedback would be appreciated.

i plan to replace the 2nd resonator (hotdog shape) with a 2.5" oval shape muffler (the exhaust is 2.5"). should i get a 2.5" straight thru oval shape or just a normal 2.5"? would it be just as loud with the straight thru? bear in mind i don't really care about flow anymore, i just want to take the drone noise out with minimal costs!

would a straight thru muffler just be the same as a resonator? whats the difference?

bc, from what i fink, at the moment i've got no mufflers! just a small resonator followed by a 2nd hotdog shape resonator, followed by a apexi styled straight thru muffler (which isnt really a muffler bc its straight thru?)

shiat, sorry for the long posts.

also, would a 2 & 1/4" muffler after the resonator make less noise?

[Warpspeed]

Get yourself a conventional oval type muffler, not a straight through type. This will have internal baffles, and chambers, and you will not be able to see straight through it.

Fit this as far forward as you can find a place it will fit. This will reduce the noise. The pipe after the muffler will the give you a nice "note". This is really the same as a drone, but nowhere near as loud.

[MegaGTS4]

turtle,

This might help!(might not too!)

http://www.autospeed.com/A_0383/P_1/article.html

It is a comparison between a few mufflers and resonators on a few N/A cars!(not skyline though!)

I know the sound that you are chasing and it can only be aquired with chambered mufflers and resonators! These have a chamber in the middle of the muffler/resonator that allows the gas to act upon itself (cause turbulence) thus creating less sound out the back! These mufflers have a big barrel/oval!

MEGA

P.s chambered muffler pic attached (not worth downloading is for demonstation only).

[_turtle_]

alrighty, i've decided to go with the conventional chambered type muffler. but, will that mean more work because the inlet is on one side and the outlet is on the other so they have to change the piping from the outlet back? sorry to sound tite, it just that i've got exams and shiat coming up so i haven't been working for a few months already

hey warpspeed, ur in melb as well right? any places u recommend me to goto that won't rip me off? i mite ring around a few places on monday seeing as nothing is open on a sunday.

[Warpspeed]

Yes turtle, I am in the south eastern suburbs. I do all my own exhaust fabrication at home, so cannot realy advise on where to take it. Mufflers and mandrel bends generally have a recommended price, so it does not make a huge difference where you order these from. Fitting the damned things can be expensive though, price and workmanship can vary a lot.

Having the outlet to one side is not really a problem, you can sometimes just move the pipe over a bit without things getting too far out of line. Or else a couple of gentle additional bends will get the pipe centre line back to where it was. Another way, is two similar mufflers back to back.

Where you put it is also important. The inevitable additional pressure drop is going to be the same wherever it goes, but the noise drop is going to be greater if there is a signifant length of pipe after the muffler. Ground clearance may be a problem though.

[blind_elk]

Have someone look into the length of the piping. Its possible its setting up some sort of harmonic at normal road speeds. It may need shortening a bit to shift the frequency of the harmonic.

[_turtle_]

hey blind_elk, wouldn't the piping have to remain a certain length, just enough to reach the rear muffler? how can it be shortened?

with the 2nd resonator in, its actually quite good wen the car is cold, not very noisy at all. wen i accelerate it also sounds ok, its only when i remain at a constant speed eg 100 on the freeway that it starts to drone.

thanks for the replys.

[blind_elk]

It doesn't have to be 'feet' being removed, it could be a matter of centimetres.

It could be that the mounts aren't isolating the exhaust from the chassis. Maybe a join isn't tight and is allowing the vibration to propagate.

I'm only suggesting this because a mate with a GT-R had a similar problem and it turned out to be the overall length of the exhaust that was causing the problem. Had it shortened a bee's dick, and the drone went away.

[_turtle_]

damn, i'll mention that wen i goto the exhaust place on friday. im pretty sure they can shorten it a bit, because i notice that the muffler is sticking out a lil too much for my liking.

thanks for that.

[_turtle_]

also forgot to ask, what is a baffled resonator?

[meggala]

b4 my car was turboed I put my turbo exhast on I know the pain you are in I made them take it off.

yuk

meggala

[rev210]

Originally posted by _turtle_

also forgot to ask, what is a baffled resonator?

The 'baffles' are plates inside the muffler that sepparate it into chambers. It slows down the exhaust a little (bad) and helps reduce noise over a non-baffled open chamber muffler.

If you are desparate to reduce noise baffled is best (it does add a 'tinny' note to the exhaust tho).

[MegaGTS4]

hey turtle,

A baffled resonator(a proper baffled resonator has a reverse flow action) or a reverse flow muffler will restrict power too much!!(though it would be quiet!)

You need a chambered muffler/resonator to reduce the noise just enough to remove the drone, Just make sure you get one that is glass packed as well as chambered. Lukey(walker) make heaps of configurations of this type. (preferably offset as this will help the sound reduction more!) These are some times referred to as a sports muffler! But this would not reduce the power too much, well not as much as a baffled resonator or a reverse flow muffler.

Thats just my opinion anyway(have worked in the exhaust industry for seven years now, geting too old :freak: )

MEGA

[Guest Boxhead]

turtle - dont worry im in the same boat as you, my muffler is very loud, i have twin hotdog style muffler, its soo anoying, i like the sound, its just too bloody loud, so yeah, i will get a silencer chucked in when i find some money.. and i should prolly get a new cat convertor too

[Guest SPOOLIN]

I have just replaced my exhaust tail section, I took off the big straight thru *muffler* and now i have a lukey offset/center sports on there also i reduced the diameter from 3.5in to 3in.

The car is much quieter now but i think i will redo the middle section after the cat and put another muffler in there aswell, as for power losses i dyoned my car on the wknd with that exhaust and it got 219RWKW then we took off the cat and put the big tail section back on and got 281RWKW.

Conclusion: Restrictive exhaust robs bucket loads of power:uh-huh:

Lee

[Pva_Glue]

is it possible same exhust on NA car will be louder then on Turbo?

what I am saying, if there is same exhust one is on Turbo sky and other one is on NA sky...

would it be louder on NA skyline cuz distance will be shorter bcuz the length the exust have to ttravel on turbo skys?

cheers

Joe