Heh. Well, some of the mystery is solved.

Turns out, I don't have the HFC on my car. I have a test pipe as seen here:







So my thoughts at this point are:
Try to get a custom double-magnaflow made. If this isn't quiet enough, try multiple resonators and a muffler and go from there.

 

This whole time and you never physically checked the exhaust on your car? Although I bought my car new and know exactly everything I have done or gone wrong, I still check everything when I wrench on it.

It might be the angle, but I dont see a muffler at the rear. Are you sure this is not just a full straight pipe muffler less exhaust?

I say go for the double muffler setup and see how you like it. And remember 6" center and 7" rear!

 

I'm going to go dual mufflers. Hopefully it quiets things down.

I think the best way is to run two mufflers. Possibly a buschur midmuff' and a large rear muffler.

 

Knew that was coming, and totally deserved.

In my defense... I DID say I was going to have to physically check it.

Yeah, it is the angle. I saw that and thought: someone is going to say "that's a straight-pipe".

Here is a better angle, and I promise I physically checked for a muffler:


TBH, I'm a little worried about the 6" center clearing the ground. Resonators and such have a nice tapered edge. The 6" magnaflow looks like it is primed for being ripped completely off the car. I think I'm willing to risk ripping my entire exhaust off if it means it is quiet.

 

There is a member here that put a 7" in the center.

This whole winter I have been running with a 6" center muffler. We had a huge snow blizzard here in Chicago and I drove the Evo through that snow. I made a few mistakes and went through residential streets that had really high snow that pretty much slightly leveled my car. The muffler is clear from any dents or damages and never ripped off. But at the same time, I am on the OEM suspension.

If I'm not mistaken its pretty much even with the tie bars that run spacers. There is plenty of clearance from the drive shaft as well. Just go to my thread and check the pictures of my car and another member who did the same.

 

i believe i have the 7" muffler in the middle which clears it (and older style bigger magnaflow muffler in the bacK)- i'm wondering though, if like the mil.spec 100cel catalyic converter will be quieter or louder than that?

 

From everything I have read it is going to be way louder. Most of the responses for HFC's indicate they muffle sound very little compared to an actual muffler.

I drove my Evo tonight, and to be honest, it doesn't seem nearly as loud at WOT as it is from idle-3500. It idles loud and gets louder to an insanely loud, deep frequency at 3500 (this is what I think is drone?), then quiets down to a scream at WOT. The frequency is much higher so it is less annoying above 4k.

In any event, I'm shooting for the custom double-muffler setup in the next week, I hope it works out. It's hard to believe that this car is 2x louder than V8's with full 3" duals. Crazy.

 

gotcha thanks - i used to have single exhaust with test pipe, the dual muffler helps a lot but you get used to it and start looking for even quieter

 

Ok, I talked to the local custom exhaust guy that has done a few Evos.

Remembering that loud is subjective, he told me that dual resonators + my Perrin should be quiet-ish, and that he could add them on the CBE only. I thought there wasn't enough room for it. Anyway...

I told him that I wanted to keep the bolt flanges, he said no problem, he would leave the test pipe in, and put a Magnaflow resonator and muffler in the rear. I asked him about dual Magnaflows, and he said the 6" was too big to be safely done, that it would clear, but he wasn't comfortable with that type of setup. He said that a resonator on the CBE + a Magnaflow would be "not stock quiet", but a hell of a lot quieter than it is now.

So I'm not looking for a hell of a lot quieter. I'm looking for seriously livable exhaust. I tell him to hold off on the order, because I remember that one of the "quiet" cbe's I saw had a resonator IIRC.

So based on him saying that the car should be way quieter with either:
My test pipe + a two-resonator, Perrin muffled CBE, or
My test pipe + one resonator, one Magnaflow...

Then shouldn't my car be quieter than either option with an ebay resonated TP + a resonated CBE? Or should I tell him to do the Magnaflow resonator, Magnaflow muffler CBE, and add the resonated test pipe from ebay, etc.? I'm hoping to land around 8.0-8.5 per the scale above.

 

man I would like to be paid for the hours I have spent researching this nonsense. I agree with what BluEVOIX said in one of the old threads, that one of the tuners should have faced the noise issue and released a system with slight power compromise and near stock noise levels.

On to my point. Looks like Magnaflow makes a "race series" and a "performance series" according to summit. Is the "performance series" version the straight through design? If so, they make a 4" OD, model http://www.summitracing.com/parts/MPE-14419/.

Maybe I'll try to fit a 4" in the test pipe, a 4" in the CBE, and a 7" in the CBE. I'd think the 4" muffler would be quieter than the resonator, and it can't be much bigger, with .5" extra on each side of the exhaust.

Edit: Not trying to waste anyone's brainpower on this... I would have gotten the exhaust done today if he had the parts. I plan on either ordering my CBE tomorrow, or deciding on what separates to order and having the exhaust guy order the parts to complete it next week.

 

Lol I should probably start my own business as an exhaust shop. See your getting good valid and helpful responses at the present time. When I was looking for quiet, there werent really any tests done and everyone thought that Freight trains were quiet. I lost a lot of money buying and selling.

As the center muffler dont go less than 5". It will fit without issues. On the catback if you can fit a 4" then I say go for it ! And the rear do a 7" . You will be quiet. Not an exact OEM but damn quiet for sure. If the 4" doesnt fit on the long section then put 2 resonators there. But what ever you do try not to put less than 5" muffler in the center cat location.

 

that reminds me now - i do have a 6 in the middle and 7 in the rear - also my downpipe is 2.75 in instead of the full 3, not that that's significant. quiet for evo standards but i still consider it pretty loud.. anything else to do outside of swapping another rear muffler? resonators throughout?

 

What db at what rpm constitutes quite? We all have slightly to very differnt perception of what "quite" means. With all these db reads these days even on cell phones we need a set db at a steady 1000~rpm, 2000~rpm, 3000~rpm, and max db WOT.

 

if someone's got an app for droid i'd love to do some tests at idle, cruising and highway 65 75 80 85

 

I used this one.....

https://market.android.com/details?id=kr.sira.sound

But I'd like to try some others if anyone has one.