Designing a quiet (ish) yet free-flowing exhaust

[smitty]

I have a 3" oval chambered muffler I took off because I found it to quiet, can have that for $20+ postage if you want, can take photos if your interested. Surprised its still loud with varex.

Hey Fieldy, send me some pics of this muffler dude!

 

[fieldy107]

Sorry mate got the message just haven't had a chance to go dig through the shed looking for it, I'll make an effort tommorow morning

 

[Dice]

I have a weird system which I like. 3" exhaust after the iida front pipes with a couple of resonators, hollow TRUST muffler, 4.5" tip and an Apexi spring loaded silencer. Relatively quiet on idle and roars when given some boot. Without the silencer it's way too loud on any speed - idle and on highway driving.

 

[Poita]

Where can you get the Fujitsubo mufflers from? I want an oval, not a canon shape if possible. More so because I like the oval look, don't know if it sounds better/quieter.
I know you can get the Fujitsubo Legalis Super R from RHD Japan, but it's fairly costly once you include shipping and it is a canon.

As with the OP I want the performance gain, but not the noise, it's going to have kids in the back seat eventually! So if I can buy a JASMA muffler and get someone in Adelaide (AM Performance?) to do the piping + cat + 2 resonators I am hoping this will get the desired result.

 

[Hotwire]

My exhaust has 2 resonators and 1 large oval muffler, and everyone knows how loud my car is :lol: Thus why i have the silencer for daily duties, and take it out for club meets, dyno days etc.
its all in the final muffler design. Resonators will only affect drone, hardly effects the final db.

 

[Poita]

Well I HATE drone, especially in a wagon, so will be going with the 2 resonators.

 

[Guest]

Where can you get the Fujitsubo mufflers from? I want an oval, not a canon shape if possible. More so because I like the oval look, don't know if it sounds better/quieter.
I know you can get the Fujitsubo Legalis Super R from RHD Japan, but it's fairly costly once you include shipping and it is a canon.

As with the OP I want the performance gain, but not the noise, it's going to have kids in the back seat eventually! So if I can buy a JASMA muffler and get someone in Adelaide (AM Performance?) to do the piping + cat + 2 resonators I am hoping this will get the desired result.

You want the Legalis R typeEVOLUTION. Get them off Yahoo Auctions Japan, good used ones do come along.

 

[Poita]

Sounds good! Can I get them new? Just the muffler that is, the rest of the piping/resonators could easily be done here by an exhaust shop (correct?)

 

[fieldy107]

I have 2 resonators and it still drones pretty hard, if you have no muffler on the end I think it will drone regardless of resonators

 

[Interloper]

go two 3" mufflers

 

[Poita]

Ummmm who said anything about no muffler??? That is what the last few posts have been about

 

[Kenneth]

An exhaust being quiet or loud (from the outside of the car anyway) is not directly related to exhaust drone.

Drone is caused by the exhaust reaching its resonant frequency. Regardless of what mufflers and resonators you have, if your exhaust reaches resonance at a frequency the corresponds to an RPM which you use a lot, it is going to drive you mad.

For a quiet exhaust, you just need plenty of muffling or noise cancellation. If you want quiet AND high flow you either need a very large muffler or to be able to achieve noise cancellation over a wide RPM. To do the latter you will most likely need to fit a number of resonators (not those straight through mufflers which are usually called resonators). In the end, lots of muffling is probably easier/cheaper and will actually fit under the car.

 

[Macca]

Well I HATE drone, especially in a wagon, so will be going with the 2 resonators.

Like Kenneth said its more about the design and size of the resonator/s not how many you have on your car

 

[Xoxide]

Correct me if I'm wrong, but wont the material have a significant impact on how the car sounds? Mild steel is going to have a different resonance frequency than stainless, even in an identical setup. An exhaust will always drone at some frequency, the goal isn't to try and move the resonance frequency up the range using "resonators " but to reduce the overall amount of resonating by breaking up the standing waves and nodes. As mentioned, the only real way to do that is decent mufflers to diffuse that energy. From there resonators can help, but blindly adding them might work against you too. Acoustics are a bitch... with some time and a lot of patience you could custom tune an exhaust to whatever pitch and intensity you wanted, within reason... but why bother.

What do the Fuji systems sound like?