[Advice Please] Argh! Exhaust Droooooone...

[Oosh]

Okay, just got a R32 GTST-type M 4-door, loving it to bits, sounds great when you put the hammer down but...

...on longer drives the exhaust drone drives me nuts!

The engine/turbo are stock (for the moment), the exhaust system is:

stock dump -> 3" front pipe -> 3" CAT -> smallish resonator -> 5" cannon (3" inlet with 4" tip)

I definately want something quieter, however in the medium-term i'll be going a 2530 turbo upgrade, so i'm willing to sacrifice some flow but not too much.

I'm basically after some advice on good resonators, should i replace the small one or just add another one, i believe there is room?

Also what about other mufflers, cannons' are a little showy (read "cop-bait") for me, i like twin outlets for some reason...

I'm looking to get away with less $500 all up, so please don't suggest anything Titanium, big-name-brand, etc.

Cheers!

[Busky2k]

I would replace the resonator with a proper muffler. Resonators usually dont do shit cos they're just not big enough!!

I have a Lukey 3" center muffler (offset but straight through) and it certianly is much quieter than ther SR's with no mufflers at all... My system is the same as yours otherwise (3" dump aswell tho) and I have zero resonating issues. Shouldnt cost you any more than 300 to get done.

[wilch]

I have an intermediate muffler too (small one before my muffler)... 0 drone, and nice rumble/roar @ WOT.

wil..

[discopotato03]

Please don't confuse noise with resonant vibration and remember a 3" exhaust is a great engine steady . I would start with a flex joint and use propper mufflers . My experience is hanging huge straight through mufflers at the very end the tail pipe achieves little . The sound pressure waves and gass flow take the least path of resistance which is out the back rather than into the packing . If you can find room I'd put the most effective mufflers in the middle . Lots of people will disagree but a 3" pipe is overkill on a two litre road motor particularly with that std turbo . 2.5" would have been fine with a reasonably std engine .

[Ska]

Well I went from 15.3 down the quarter with a stock zaust system to 14.7 just from a turbo back 3 inch system.

I only have 4 bends in the whole system, and a *cough* high flow cat and well the tip, hmmmm lets just say it looks like it was home made, BUT the whole system is 3 inch and I bought it for a steal, BEST thing is, (and I have no idea why but) there is very very very very little drone, which all but dissapears when the windows are up, which is great.

I have no resonators, just a 3 inch dump, high flow cat. other than that the whole system is basically straight with one bend at the top of the dump, one bend at the bottom of the front, one small 2 degree bend after the cat and one 2 degree bend where it passes over the diff.

Now here's where the story gets interesting, I did whack on a mates HKS super dragger cat back with the rest of the stock system, and it was LOUD, way louder than with the current full system, stiil another good thing about this current system, Very nice noises under load

I am not proffessing to know why, just the results.

Plus I have dyno's of before and after with JUST the HKS super dragger, added 15rwkw, and I did not do anything but add the HKS super dragger cat back on the same dyno.

I do not have dynos for before and after I have put this full system on though, yet

Anyway hope that helps, I dont know why it would and I think I have had way too much coffee today which is why I am still typing so I'll just go whore somewhere else..............

[QWAK]

turn the stereo up

[Bobjones]

I have a 5 ziggin large muffler, NOT a crap arse cannon...no centre muffler and stock front, dump and cat at the moment...noise in minimum and all mandrel bent from the cat back...

Just get a decent rear muffler mine is about 25cm wide and 30cm or so long, big fat thing, 3 inch inlet, 4 inch outlet. No drone and nice note and at highway speeds hardly a sound@!!!

[Anquetil]

Just get a decent rear muffler mine is about 25cm wide and 30cm or so long, big fat thing, 3 inch inlet, 4 inch outlet. No drone and nice note and at highway speeds hardly a sound@!!!

What he said, mines pretty much 3" all the way through, with high flow cat and a big blitz muffler with 3" in, 6" out.

The whole system is much quieter than other 33's, I put it down to the muffler.

[Oosh]

...3" pipe is overkill on a two litre road motor particularly with that std turbo . 2.5" would have been fine with a reasonably std engine .

Look that might be teh case, but the car came with 3" system, so i'll stick with it.

Hmm so we have a couple of schools of thought:

1. Use a high-quality rear muffler...

2. Replace resonator with a centre muffler...

Note to whoever was talking about gas following least resitance, while that may be the case, sound propogation is a different beast. They ARE linked, but note same, also gas doesn't all shoot thru the centre it will some will make it thru the perferations and it to the surrounding cavity.

Maybe i'll try number 2 first, then try a better rear muffler...

[Oosh]

As an interim i put the spare muffler, which came with the car, on and the difference is amazing. But, with how small the tip is there's no question it's robbing power, it's kind of made me lean towards a better rear muffler first up.

So now to find a decent second hand muffler, off to the trading forums...

[Zombie]

Why not find a new muffler?

Adam

[Oosh]

Why not find a new muffler?

Adam

Because I'm a tight-arse, but if i can't find what i'm looking for 2nd hand then, i guess i'll loosen my sphincter

[WazR32GTSt]

i tjhink your problem is your rear muffler

my setup is a 3" dump/front in one and 3" cat-back mandrel bent with cannon muffler and resonator. custom made and brand new...

NO DRONE AT ALL

so i say leave the resonator in...

if i were a betting man, i would have my money on your canon being old and stuffed and not muffling anything at all! (if its a jap exhaust, chances are it is 10 years old...)

[someonestolecc]

Hmm I have a sr20 with standard exi-mani, tomei style dump pipe, 3" to a crappy looking cat then 3" all the way to a xforce 3" with (guessing) 5" tip.

Sounds ok but too loud.

I've been told put in a centre muffler but with all you guys with RBs saying you don't have a centre muffler/resonator and have a good rear muffler and still have no drone/quiet I might try to steal my flatemate's kakimoto muffler frmo his r32 and try a little test.

If it works ok then I'll ditch the xforce cannon for a kakimoto (if it sounds/looks ok) or maybe another j-brand cannon (keep the drift look).

Thanks for the informative posts guys this is good for me cos it'll be cheaper than welding in a middle muffler if just changing my rear muffler will do the job!

[WazR32GTSt]

doesn't have to be a 'good' or 'expensive' muffler... just make sure its new!

cheers,

Warren.

[Busky2k]

someonestolecc, rear cannons dont muffle for shit compared to other designs, no matter what brand. Get a center muffler, that'll make worlds of a difference. I tend to find that the SR20s are far more drone prone than the RB series.

[drunkenmaster]

Yep, straight through cannons dont do much at all.

A straight through centre-offset muffler will be worlds quieter than any "cannon" and flow almost the same.

As for the broom sticked cat comment :thumbdwn:

[silver gts-t]

i have a 3" all the way until it hits the mufler and turns into 5" through it and a tip

if you get headaches u dont want to be in my car,

but sounds mean though!!!

you get used to it after a while.

(after 20% hearling loss) jk

[Lozza150]

HKS Super Dragger

Nice and Quiet... Flows great, cheaper than you think to....

[someonestolecc]

Thanks guys - sounds no middle muffler and a good quality rear muffler will flow better then a cannon with a middle muffler yeah?

If so I'll look at a HKS super dragger because I've heard their quiet yet they still have the cannon look (which will fit my car's rear skirt.. I'm worried a normal muffler won't sit out far enough.)

The other alternative is a really good centre muffler and a straight through from there.

My question is (newb question) why do cars have a centre muffler and a rear muffler? If one can do the job wouldn't it be cheaper to produce one that would do the job? - I don't understand why people have 2 when I assume it would cause more restriction (or is it negligible?)

Finally if cannons don't flow better why the hell do people use them? (to be loud?)