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Hi all,

My r33gtst has had a drone problem at 100 k's since day 1. Originally it had a 3'' exhaust with hi flow cat and stupidly huge rear cannon with 7'' tip. Stupid, but that's what came with the car and I have spent money elsewhere.

I fitted a decent 3''in/out centre muffler and 4'' magic cat and it was great for awhile but then I fitted a bigger turbo and it was exactly the same as day one. Just like taking the centre muffler back off.

A real pain in the arse.

So now I'm looking at getting a new rear cannon of sensible proportions but want to get one which actually works - has anyone here swapped cannons and found one that significantly reduces that rotton drone at 3000rpm???

I've looked at a few websites and there's heaps to choose from - all not very cheap so I want to be sure that my new rear muffler takes some of the drone away at least and isn't the same as the existing one. I've run out of room under the car for other mufflers so this is my last chance otherwise it's earplugs.

Cheers

Edited by gtst25
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this is what works on my SR20:

http://www.flyn.com.au/pictures%20that%20m...20flame%20e.JPG

If you use the silencer then it is droney, but without (who uses silencers anyway) there is very little drone. However it is loud, although not unpleasantly so.

my mate has a jasma muffler that was on his car (so i don't know the exact brand since jasma doesn't seem to be one) and it splits into 2 sections in the rear muffler. flows well and is super quiet.

i have another mate with a straight through jasma muffler and it is quiet but not as quiet as the split one.

my mate has a jasma muffler that was on his car (so i don't know the exact brand since jasma doesn't seem to be one) and it splits into 2 sections in the rear muffler. flows well and is super quiet.

i have another mate with a straight through jasma muffler and it is quiet but not as quiet as the split one.

My understanding is that Jasma is a quality control / EPA organisation. Basically if you have Jasma on a muffler, it means that it complies with a certain standard.

My understanding is that Jasma is a quality control / EPA organisation. Basically if you have Jasma on a muffler, it means that it complies with a certain standard.

JASMA stands for "japanese approved silenced muffler association, so yea it basically means that if the muffler/exhaust you have has that tag on it then it has passed a certain standard and noise level (i think the limit in japan now is 93 or 95db)

My HKS Silent High Power is jasma approved and is quoted by hks to be 93db, it is only a catback so when i finish the rest of the exhaust i expect it to get bit louder.But it does sound very good at the moment, a little bit drony sometimes but it is very toned, at 100kph you cant tell it apart from standard really

In my opinion you cant go past a jap brand catback/muffler etc, spend the extra money and get somethin that you know will work.

JASMA stands for "japanese approved silenced muffler association, so yea it basically means that if the muffler/exhaust you have has that tag on it then it has passed a certain standard and noise level (i think the limit in japan now is 93 or 95db)

My HKS Silent High Power is jasma approved and is quoted by hks to be 93db, it is only a catback so when i finish the rest of the exhaust i expect it to get bit louder.But it does sound very good at the moment, a little bit drony sometimes but it is very toned, at 100kph you cant tell it apart from standard really

In my opinion you cant go past a jap brand catback/muffler etc, spend the extra money and get somethin that you know will work.

Thats pretty interesting, my hks super dragger has a jasma plate on the muffler aswell, i didnt know what it was for but i guess you learn something new everyday lol...

you thought about the in-car controlled silencing valve exhaust fitting?

t'is an electronic setup you add between ur cat and rear muffler/cannon that opens and closes (not all the way closes) a valve that quietens/amplifies the sound of your exhaust.

Might be cheaper for you if ur purchasing a new muffler with fitting fee's aswell.

Just a thought.

my apexi 3.5" drons at cruise speeds 80-100 i reakon its only due to punched out cat, which i will soon be rectifying.. p.s it has jasma plate with apexi stamped into it on the top of the cannon tip.

There is no such thing as 'drone'. The sound that you don't like is basically the loudness.

If you fit an oval muffler, why is there less 'drone'? because it's simply softer.

So there's nothing wrong with a cannon. They work. They do what they're supposed to do, and that is, not 'muffle' the sound as much, and thus allow more noise through.

If you want less 'drone', muffle the sound by fittign a more restrictive exhaust, such as an oval muffler, and/or a centre muffler.

an oval muffler doesn't really restrict the exhaust more. it just has a bigger body for the sound particles to dispense their energy. if you have 2 mufflers, both with a body 30cm long, and a 3" pipe through the centre, which ever has the biggest area outside of that centre tube will be quieter (however this also depends on the packing inside the muffler).

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