Let me tell you what I have learned:

All straight flow through exhausts are the same. Some quiet a little more than others because they have a larger muffler. But in the end they will not quiet the car to how much I would like because we have a inline 4 cylinder car. The i4 is what really kills us and with the same setups the GNX's will always be quieter because of their motor design.

The absolute only way to bring it down to a stock like quiet setup is to create a restriction. Something like a wall, where the exhaust sound wave can bounce against and cancel itself out. The oem muffler is our friend for that, but it just kills the performance. So thats what the VT muffler does. The plate stays closed and most of the exhaust sound pulses bounce back and cancel out as the exhaust gas makes its way around the edges. And when there is enough pressure created, the exhaust gas pushes the valve open creating a 3" setup for the pressure to escape.

Also very important. Its the Bass that you want to muffle down. That is what creates the droning. All the straight through mufflers that you add will quiet it down, but there still will be that bass that eventually may bug you if anything louder than stock is an issue to you like it is to me.

Yes, an ebay cheapo exhaust can be used and will work the same as other exhausts. I prefer Buschurs slip fit because its so much easier to work with. All I did was remove the axle back and clamp on the vt muffler. I did not cut anything or weld anything.

The key is non straight flow through setup for quiet then automatically turning into a straight flow through as needed. Only 3 options: Vt muffler, boost activated cutout, varex remote control cutout. Remember if you put the boost activated cutout at the rear of the car and run a center muffler, it will not be that obnoxious loudness as you have experienced with those cutout dumps people run on their down pipes. This should probably be the same loudness as my car is now, because you still have that center muffler doing its job when the cutout opens during boost.

Also stop adding a high flow cat to every exhaust option. The cat does not quiet the car as much as you think. My buschur double magnaflow was a heck of a lot quieter compared to Buschur magnaflow rear and cat center. A day and night difference!

 

Here are the exhausts and combinations I have had, in order of quietness during normal driving: Scale 1-10 (10 quietest)

10. Complete stock turbo back.

9.5 Dynomax VT muffler exhaust

9.5 3" downpipe, testpipe and OEM catback

8.5 Tanabe Medallion catback with OEM cat and OEM downpipe!!

7.5 Buschur Double Magnaflow exhaust. (7" rear magnaflow and 6" center) catless

6.5 Cobb TBE exhaust (catless) (over time got a little louder, I guess packing burning up)

5.0 Buschur TBE with bullet center and vibrant widebody muffler in the rear

5.0 Buschur TBE with HFC and Magnaflow muffler

5.0 Tanabe medallion catback with 3" testpipe and downpipe

4.0 RRE stealth exhaust with 3" downpipe and testpipe.

2.0 Jun BL catback with 3" downpipe and testpipe

1.0 Buschur TBE with bullet center no muffler in the rear.

 

Ok, then the VT muffler obviously will not work for the "cutout after center muffler" plan, correct? because it is built into the muffler itself.

That leaves either a vacuum switch or manual switch, if that it was I am after. Is there a VT-style spring loaded cutout that can be added after the muffler, before the tip?

Thanks for the descending scale. It is very helpful. I'd say mine is probably between a 1.0 and a 2.0 as it is just a catted perrin tbe with a loud muffler. That probably drops to a .5 with my GT35R, which as you can imagine is pretty unacceptable for street use.

I may very well be looking into a used stock TBE, IX Turbo, etc. That kinda sucks.

 

I have greddy evo 2, pretty quiet. the drone noise you are hearing could be from the engine. who installed your cams? I had my cams installed by experienced installer and the oil pump sprocket was out phase, my car was loud!!! after install.

 

I'm not sure what your asking/plan was? Yes the flapper plate system is built into the muffler and due to the size of the muffler it would have to be installed at the rear of the car. I dont know if it will fit under the car in the center area if thats what you wanted to do. You could try cutting it open and possibly building a new round housing around it?....

Well its not vacuum switch but more like boost activated. Similar to how the wastegate actuator works. After around 11 psi it cracks open. So as long as your under 11 psi of boost, you should be oem quiet.

I dont know of any spring loaded cutout that can be added after the muffler. But if your pretty crafty or know anyone that can fab things, you could try modifying the VT muffler completely. Cutting out the valve system and constructing a round muffler around it. Also maybe change the spring to a slightly stiffer spring that will stay closed with cam setups but still open completely during WOT. Actually come to think of it, this is not a bad idea at all. And some one with a weld could easily make it work.

 

Thanks for all the answers you have given. You have truly devoted a lot of time into quiet exhausts, and I'd have to say you are certainly a SME at this point.

I just posted a request for a parts list to go back to a stock turbo. I don't want to waste thousands of dollars attempting to make my car quiet when I can just go back to a stock turbo and cams and be a whole lot closer to my goal. I'd rather have a quiet 350whp than a loud 500whp for my street car.

I'm not maxing out the boost on my GT35R on the street anyway, so I'd likely lose turbo efficiency and that's it. I'd expect the benefits to be better fuel mileage, quicker spool, better street manners, and peace and frickin quiet at some point. If I can achieve those goals, I'll be happy. As a sidenote, my car gets calculated 5MPG when driven hard. You can very literally watch the needle go down.

 

The Tanabe exhaust compared in the magazine is the Medallion Concept G Blue. I believe the one BluEvoIX was referring to was the Medallion Touring. I think this system uses a pouch instead of a canister like the Medallion Concept G Blue.

 

I'll go with poster om page 1. I have the greedy evo2, very quiet. Good size muffler and resonator. I run catless and can have a normal volume conversation with passenger at 70. Tone opens up at 4k rpm.

 

Check my thread: https://www.evolutionm.net/forums/ev...w-exhaust.html

Basically my exhaust is so quiet I'm actually sorta disappointed how quiet it is, lol. I'd say its about as load as a stock corvette ZO6's exhaust. Except its a 3inch straight through turboback, no cat. Hard to go wrong with that.


^ I apologize. I didn't intend to be rhyming in that last part.

 

Thats a huge change you'll be going through. Also since you have an aftermarket turbo kit, most likely your setup with a o2 dump . That would explain why its obnoxiously loud during WOT.


Correct, I was referring to the Medallion Touring.

 

I have this one: http://www.youtube.com/watch?v=g9YDN...eature=related

My setup, 3inch dp, stock cat, but soon to be with perrin hfc. I already did some search and the hfc won't make a big difference on the sound. I have almost full bolt on setup except cams and o2 housing and hfc with stock 8 turbo. Let me tell you, there was no droning on freeway cruising at all. I really like the setup. You can trust me on this one because I hate booming sound in the cabin.

 

I had a B&B turbo back and it is by far the quietest EVO exhaust i ever have heard.

 

That makes more sense. Thanks for clarifying.

Wait, the Evo 2? not the SP 2? I heard the Evo 2 is middle of the road, by no means one of the quietest out there.

This is what I want, to be so quiet I am disappointed. Unfortunately I think your system might sound worlds different with a GT35R, cams, and supporting mods. Nevertheless, I will check your thread, thanks!

Yeah, but I think it is worth it. I'd think I'd be able to pocket some cash while quieting my car down and maintaining respectable power levels for street use. Don't you think?

Can't see the vid at work, but I will come back to it, thanks!

Hmm... It hasn't been mentioned in most of the quiet exhaust threads. Have you heard the B&B compared to other "quiet" exhaust-equipped Evos? The B&B's I've heard on other cars, mostly V8's were pretty loud.

 

I will second (or is it 3rd @ this point) that this exh is bone stock quiet.
I can easily hear the tranny whine @ full throttle over the exh.

I have a 9 turbo (on an 8), ported exh and turb housing, 3" DP, and 100 cel cat (upper/lower pipes and intake). This exh might be holding me back a bit, but I'm @ 318 on stock cams/IC. Some mild S1's, an IC, maybe a couple other mods would probably get you to the 350 your looking for.

 

The more I think about the impact of ID on performance, the less I want a step down muffler. I've heard so many things about the sound level on this one that I will certainly investigate it, I'm just hoping that the 2.65" ID won't cost me 30whp over the 3". Maybe I can find a back to back comparo. It seems like stock frame comparisons are more readily available.