No, and I don't have a stock cat back. I'm quite sure that will rob power in a major way. I was kidding about welding stock mufflers together. I don't mind losing 10hp peak for near-stock sound levels.

93db... I can't remember what the stock db rating was, but db means very little to me without a car and a db meter in front of me. Basically, I don't know how quiet or loud 93 db is vs. 95 db vs 80 db, or how loud stock is (though I think I can probably look that up).

I think the Evo 2 is discontinued? [edit: nah that is the sp2, and I just read the Evo 2 is huge can and tip, and way louder, so not interested] But yeah. I'd love to hear an exhaust with my exact same setup and multiple cat backs. I don't think there are enough Evo's around to make that happen.

I think at this point I'm hoping BluEVOIX can tell me what is bar none the quietest aftermartet cat-back that doesn't involve flapper valves. Other input is certainly welcome, as I am very tempted to try the Tanabe and looking for the SP 2

 

well to quiet my exhaust down im running 2 18" preforated style resonators in line on my catback exhaust, restricts noise without flow....my car is a lot quieter especially cruising at highway speeds not boosting, not stock quiet, but quiet enough i can hear my radio over it without my system in the trunk anymore haha... good luck

 

Thanks.

I don't think I can use the radio as an indicator. I could hear the lyrics on the radio (volume 40! is that loud?) with my earplugs in, with my exhaust bugging the crap outta me.

I'm definitely considering the resonator option... part in due to igo4bmx's clips in the thread and on youtube. I'm hoping he can chime in on this too.

In his clips, he has a 10.5 hotside + hks 264s I believe. Maybe someone who can testify how much louder my GT35R and 272's will be than that. Honestly, at this point, I'm considering milder cams and a stock IX turbo or FP stock frame.

If I can't quiet this car down imma lose it.

 

now I have a problem.

Found turbolarry's posting of the Turbo Magazine cat-back comparo.

It lists stock at 92db idle, 92db at 3,000rpm.
Tanabe Medallion is at 96db / 101db! WTF. This does not seem quiet? The Greddy Ti Race listed here is at 102.

This is, however, what I am looking for in the gains department. I want something that is the quietest and would be ok giving up 2hp to the loudest, while making 30 more than stock.

Edit 2: Looks like this comparo is old as dirt. Like maybe from 2003? Anyone have any newer data?

 

GL.....

a larger turbo will be louder @ any speed, just due to the fact that turbine is not as restrictive....just think of a turbo as a rotary muffler!

even so with cams.....hks 272's are middle of the road...stock is quieter & s2's are louder.....

i have always wanted to try various i.d. plugs that could fit into the tip to reduce the noise vs power loss.... i am pretty confident having a 2.75" exit diameter is far worse than having a 2.75" section in the exhaust close to the turbo.

i forget the make / model of the db meter used, but the outside measurements were taken ~3' away from the muffler @ a 45* angle.

in-cabin measurements, i held the device ear level between both front seats...



I am in the same boat as you for searching / making a quiet exhaust...
this has been my exhaust for ~4 years


i bought the dynomax vt muffler......but i am hesitant for putting it on....

 

I do not have cams on my car. And yes the clip you heard of my car is actually very close to stock quiet. Here is an example of what happened when I met with a local evo owner. They shut off their evo and came out to check my exhaust. Then as I was approaching my car he said "ok start the car so I can hear it" . I turned around and said "its been on the whole time !!!"

The problem with having a cam'd car is the exhaust pulses hit too strong and erratic. The pulse hits the valve inside and bursts it open, then before the next pulse strikes, the valve slams shut and the process is repeated.

This creates a loud metal clanking sound as the valve opens and slams shut with each wave. Also since the valve bursts open it allows the exhaust sound to escape and its not quiet any more either.

Some people with cams are still quiet but experience some clanking here and there. It depends on the tune and aggressiveness of the cam. Also if your a VIII or IX since on the IX I heard the lopey idle can be smoothed out a little better.


Although I agree with you that running a cutout sucks. You could always add a center muffler and have the boost actuated cutout set up at the rear of the car. This would make WOT noises very tolerable and also its not opening under the car. This is what I originally would have liked to make but I came across the vt muffler sooner and also couldnt find a boost actuated cutout that was not on back order.

 

https://www.evolutionm.net/forums/ev...-beyond-7.html

 

Get the RRE stealth. It's close to stock sounding.

 

+1 I'm rockin' the same exhaust with a resonated testpipe and DP. No drone and very stock-like, even at WOT.

 

Those numbers are disheartening. 5db going to 10db louder on coast down, and twice as loud at 3k rpm than at the other ranges... right in highway range.

Yeah. I'm just not going to run a cutout. I would honestly go back to an IX turbo and 264 cams before I'd do that. I plan on having this car for 20 years so I can't live with something that just isn't street quiet.

Your project was centered around a 3" catless setup. If you weren't constrained by catless, do you think a HFC with the Buschur double bullet cat-back would have been quiet enough?

I'm going to go look up db meter prices now. If my current setup is anywhere near 93db I'm going to shove bananas in my tailpipe.

 

I cant believe none of you have heard of side branch resonators!--google it

I did some research when I had my Denali truck when I was about to put an exhaust on it but absolutely would not deal with the drone. I sold the truck before
installing so I didnt have personal experience. but many people said it works on canceling the highway drone we all hate.

basically a calculated length of pipe capped at the end and "t"ed into the rear pipe section. resonant frequencies get canceled when the exhaust sound waves bounce off the capped end of the pipe. no power loss at all other than the added weight of the extra pipe
most guys run them parallel with existing pipe but I dont think there is enough room under Evos to run this?
not the greatest looking either but just tell people you have dual exhaust

anyone try one yet? I dont have he time to test tweek this but it maybe another option?

just drove a 9 for 3hrs on the freeway with no stereo with a TB Tanabe and cant stand it!!

 

So I like my neighbors and I drive my kids around in this thing. I have a built 2.0l and just about every possible mod. I approached this problem from the opposite direction in that I'm keeping the OE cat back and I'm willing to work on every thing else in order to reach my power goals. I do run a hiflow cat(300cel metal substrate) and a DP albeit 70mm and at some point you run into the physical laws of nature, but strategy-wise its kind of like restrictor plate racing in reverse. I can get great torque but I have to keep my turbo choice small and balance knock and boost to get decent power. Still a work in progress and maybe hopeless, but a fun project...

 

Yes I am centered around a completely 3" setup with absolutely no tapers and preferably running catless.

But just realize, the VT muffler is basically a cutout but its controlled by exhaust gas pressure.

If you have 100.00 and dont mind spending it on something to be the first to test out on, there is something you could try to do.

Buy the Dynomax VT muffler and either drill a couple holes on the plate inside to help relieve some of the pressure pulses from kicking it open or cut it and experiment with different spring tensions.

And no, running 2 bullet muffler with a cat will not be very quiet. The bullet muffler is a great lightweight muffler but not a great quieting muffler.

 

Lieesssss!

See:
Found at project-buschur-double-magnaflow-quiet-exhaust thread.

However, if you have a video clip I'm willing to watch it. I originallythought I would go with the RRE Stealth until I started reading these "quiet exhaust project" threads.

Got a video/sound clip?

 

...i primarily drive my car, not coast down.....the latest exhaust in-cabin is quieter than the stocker while @ 2800 rpm...

i would have done a fwy cruise, but i was doing this during my lunch break back then & fwy testing wasnt an option due to the distance from my work.

your only real option is to run the stock exhaust w/cut-out as shown above or man up & live with it.

no matter what, there is going to be a compromise somewhere....backpressure created within the exhaust is whats going to quiet your exhaust note / sound......