*UPDATED with Pics and Vid* new exhaust installed

[jmgtp]

No sound clip yet, but I'm not digging it.

Here is the system:

Borla knockoff unequal length headers
Custom built 2.5" mandrel bent to a high flow catco cat
from the cat it feeds into the resonator off an sti exhaust
custom 2.5" mid section
into a modified sti axle back / muffler

quick version:
unequal length headers
high flow cat
sti resonator
sti muffler

The volume level is just right but it isnt that rumbly. My real gripe though is a terrible raspy sound! Now, the axle back gasket is leaking a bit, I know this because when i started the car for the first time I could see some water from condensation leaking from the flanges but I don't think the leak was significant enough to make such a rasp. I'm going to be replacing the gasket and keeping my fingers crossed.

Thoughts? If this rasp was gone I think I would like it.

Also how necessary is the front mount for the exhaust? The one that is held on by a bolt and not rubber hangers? It seems like it is the cause of some exhaust clunking when I decel from a higher rpm.

[Huffer]

unequal length headers = it isnt that rumbly.

[jmgtp]

Huffer, not sure what your post means? is that something I typed a long time ago?

Either way, right before the current setup I had borla knockoffs stock everything else, and a flowmaster on the end. It was rumbly and sounded great, but was just too loud. When I first installed the headers the rest of the system was 100% stock and it didnt sound much different than stock.

Anyway, back to current.....

I got back under the car today and ran it, the leak at the flange was so minimal that it couldn't be the raspy sound - its more like a pinhole leak at the flange. Having someone else rev it with me behind the car I can say with 100% certainty that the rasp, buzz, whatever you want to call it is coming right out of that nicely polished sti tip.

Feeling around, I bumped the muffler.... and heard an internal rattle. So I pulled the axle back out and shook the whole thing and sure enough rattles are emanating from the muffler. At this point I'm thinking my problem is the sti muffler is bad. So I went for it and cut it open and discovered a loose baffle:
http://img510.imageshack.us/img510/8091/1001120mz9.jpg
I guess that is what you get for buying a muffler on eBay.
You can see how the baffle looks a little crooked in line with the muffler because it isn't secured. And yes, I am wearing Velcro sneakers. What can I say other than they are completely awesome for yard and auto work.

So I went at it and welded the baffle so it is no longer bouncing around in the muffler and then welded the casing closed. Gave it a good shake and no more rattling. Sweet.

Thinking my problem was solved I put it all back on the car. Started and revved it up and to my dismay the buzzy zing is still there. What will rid me of this? A larger resonator? I used the one off the sti exhaust but it is only 12 or so inches long.

Here is a video: http://video.google.com/videoplay?docid ... 4483&hl=en (http://video.google.com/videoplay?docid=9065340432286054483&hl=en)

The buzzy zing is evident, but believe me it is worse in person. It reminds me a bit of a Honda with a 4" exhaust that sounds like a chainsaw. If the buzzing wasnt there I think I would really like this setup. What can I do to rid it? Big resonator is the only thing that comes to mind. Ideas? Feedback much appreciated!

[MoclovFlop]

Ah yes, classic flashback. Problem is the stock STi resonator. It is TINY!. I had the same problem as you probably exactly. What I did is put another resonator in the mid pipe, you can do this one of two ways:

1) Put in an actual resonator.
2) Put in a "cherry bomb"

I chose option #2, why? it's cheap and easy and works like a charm.
If you feel like a douche, don't tell any one you did it and paint it black, but I'm telling you it changes the sound in such a good way because all it is, is a long resonator. It has improved the sound so much that I'm going to remove the STi axle back (because it's a muffler, keeping the sound quieter than I prefer right now) and install a straight-though style muffler.

In short, you + resonator=happy.

[jmgtp]

Thank you MoclovFlop! I'm glad to hear that.

After a bit of thinking I came to the same conclusion that the resonator is just too small. I was actually looking at cherry bombs online earlier today! They are very cheap.

I had a similar issue on my other car and rather than going cheapo cherry bomb I used a Moroso spiral flow. It did the trick but I think I spent 3x as much for no reason. Granted there is not glass in it so it should last longer.

Cherry bomb it is! Who cares if it is red, it does its job well and is out of site!

What length did you use? I think they come as long as 24" or so. Did you use it in conjunction with the sti resonator or did you ditch the sti resonator in place of the cherry bomb?

Thanks again! I'm feeling some relief!

[MoclovFlop]

No problem, to answer your questions:

I'm pretty sure I ended up with either the 20" or 24", Not sure which but if you can get under your car, check to see how long the longest straight part is in your mid-pipe. I had JUST enough room for mine in between the cat and the stock STi resonator (which answers your other question... I kept the stock resonator too).

You should be fine with any size, but based on no experience what-so-ever, I'd say go 20" +/- 4"

Remember, it will quiet it down a bit. Not stock quiet, but it pulls out the "tinny" sound which is part of the overall volume, hence the reason I'm getting a new muffler ( I want some volume now that I have the right sound).

[jmgtp]

Thanks again, your responses are much appreciated.

I just measured and I have almost exactly 30" between the sti resonator and about as far back as I would want to go before the axle back section.

That said, I found a 29" cherry bomb for $25. I think I may end up using that and ditching the sti resonator. If 29" of glass pack doesn't take the zing out than nothing will!

[2.5GT]

i kinda like the way it sounds.. :eek:

[jmgtp]

haha thanks, I do too but its the buzzing that kills me and the video does not do the buzzing justice. But buzzing aside I think it will sound good, a bit of boxer rumble and the right volume level. Just waiting on my resonator to arrive and then there will be new sound clips.

[2.5GT]

you're running a 2.5" piping? how does it match up with the header?

isn't that 2.25?

[grayguy]

yeah, the knock offs are 2.25in. I loved my old exhaust, knock offs, 2.5in to the moroso spiral flow, 2.25 through a 14" magnaflow resonator, then the last 18" where the muffler used to be was 2.5 in. it sounds AWESOME but was probably louder than what some people want.

[jmgtp]

Yes the header is 2.25" I used a left over 2.5" stainless mandrel bent pipe from another project to make the initial 90* bend off the header and into the cat. I used a 2.25" diameter 2 bolt flange and welded it to the 2.5" to mate to the header. I had a lot of spare and leftover exhaust parts from different cars lying around and I pieced this together, my only purchase was the sti axleback and mid pipe.

I know that 2.5" probably isn't the ideal size for a normally aspirated engine of this displacement but I haven't noticed any ill effects. The low end is still there without noticeable difference and it feels to have a bit more torque in the mid range on the highway in overdrive. The car actually seems to idle smoother but I think that is because I don't have a flowmaster thumping on the end anymore, it is much quieter now.

The reason I went with 2.5" is because the sti parts I was using are 60mm I believe which is close to 2.5" - they mated up very closely when I welded them, I was able to flare the 2.5" piping just enough to make a tiny slip fit over the sti stuff.

I think I have a fairly good flowing exhaust. I'm contemplating an intake now but I don't know if it is really within my goals. I'm not really looking to make more power, I just wanted to have a nice sound and any added umph is just a bonus.

[Airgne]

sounds not that bad. when i get my camera back ill post mine. borla header 1 cat 3in all the way to a apexi n1 muffler.

[jmgtp]

Big resonator installed = rasp gone :smile:

boxer sounds only. sound clip when i'm less exhausted.