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Old 08-04-2004, 02:14 AM   #26
apt
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I have the Borla Hush and GT Spec Headers on my Wagaon and it doesn't drone at all. Had on my car for about 8 months and it actually gets quieter after about 1000 miles. I don't even worry about cops because I know I'm not loud at all. O by the way I hate loud exhausts give me headache.
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Old 08-08-2004, 11:36 AM   #27
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i took a look yesterday to see how i could fix the, off to the left look that the hush was giving me. i hadnt seen when installing the exhaust that on the left side of the muffler where the hanger is attached to the car; is actually bolted. so i got 12 #10 hole size fender washers and used 6 on each bolt to give me about a 1/2" space from the underside. but i still need better hangers.
does anyone know how long the K/B long hangers are? i love the gap between the hush and bumper, but the hush isnt being all that hushy.
damn thing is bouncing off my rear diff bolt and driving me nuts. will the regular K/B hangers be fine? i really need to find out the lengths of each.
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Old 08-18-2004, 11:42 PM   #28
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Would having the catted helix dp minimize some of the drone...i love the look of the hush but dont want the drone.
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Old 08-19-2004, 12:56 AM   #29
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mine doesn't drone. well at least i don't think so. but i'll let you know when i install my cobb catted dp.
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Old 08-19-2004, 02:00 AM   #30
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I think the wagon in general is just a droning nightmare. I've got the APS twin-tip full 3" turboback on my wagon and it's getting pretty irritating on the inside, while on the outside it's throaty but not particularly loud. Driving someone else's sedan with virtually identical exhaust it sounded SO much quieter inside than my wagon. I'm thinking about several options for sound deadening right now, I'll post if any work well!
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Old 08-19-2004, 03:55 AM   #31
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I put two layers of Dynamat on the floor under the spare tire, and it helped somewhat. I still get some droning, so I'm going to do the wheel wells and the floor next.
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Old 08-19-2004, 10:32 AM   #32
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I was thinking about doing Dynamat also. How come you didn't do the whole trunk floor to begin with? Was the install difficult?
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Old 08-19-2004, 11:30 AM   #33
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Dynamat is not the answer if you're looking for a noise barrier. It helps kill panel vibrations, but if you want to shut out the outside noise, you need an insulating barrier like a 1/4" or 1/2" foam material. The Raam audio guy in the car audio section of NASIOC has some good suggestions.
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Old 08-19-2004, 12:35 PM   #34
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Quote:
Originally Posted by Nikko
I am installing the Kartboy long poly hangers on my Wagon with Borla's "Hush" in less than a week to fix my droning/resonating issue. I don't have it drone often, but it was often enuff for me to pay the $30.00 for these new hangers. I'll let you guys know how mine sounds after.
I have the kartboy longs with the hush on my sedan. I love them.. they're rock solid.. no shifting or movement. It also allowed me to get the system aligned 100% perfectly to my liking. But... I'm not sure how using the extra longs would change the sound, or drone in any way at all.
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Old 08-19-2004, 01:34 PM   #35
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Quote:
Originally Posted by Yogiwerx
Would having the catted helix dp minimize some of the drone...i love the look of the hush but dont want the drone.

yeah, a cat should help things out. if you have a stock upipe that should help alittle to since it contains a cat...how much will it help, i dont know. i drive a sedan, however i could defaintly tell a difference in my exhuast note each time i replaced a cat/s.
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Old 08-19-2004, 01:45 PM   #36
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What about wrapping some of the exhaust piping in header wrap?
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Old 08-19-2004, 01:56 PM   #37
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the exhuast noises come out of the tail pipe, not through the pipe. you need something to obstuct the flow of the ehxuast or to bounce the sound waves around(muffler) to quite exhuast.
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Old 08-19-2004, 02:13 PM   #38
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A cat helps quiet things down but in my experience didn't eliminate the drone.

I just measured my in-car noise with a SPL meter on the way to work and I'm at 78 dB cruising steady at about 75 mph, and 84-85 dB when I floor it (not getting up to redline, it probably gets a bit louder).
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Old 08-19-2004, 03:15 PM   #39
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I have just a Bosal single-tip now, and soon I'm gonna be eliminating the DP cat by installing the Bosal twin-dump DP. The mid-pipe cat will still be on my car.


How much of a sound increase should I expect when eliminating the DP cat?
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Old 08-19-2004, 03:53 PM   #40
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SOLUTION:



These things cost $15. They're made for race cars that run open collectors but need some sound control. Supposed to offer virtually no backpressure (though I'm sure there is SOME) because it doesn't obstruct flow, it simply redirects it into multiple paths. This thing completely KILLS resonance.

My numbers above - 78dB in cabin at cruise, 85 at WOT...

now it's at 72-73 dB cruising, 80-81 WOT.

The difference is HUGE. My APS 3" twin-tip still sounds deep and throaty, especially when I roll the windows down... but inside the car, killing the resonance makes all the difference in the world.

Warning - the insert is NOT built to the highest standards, so it doesn't fit perfectly and immediately; I had to bend a couple of the fins a bit with a hammer and then tap it into place with a hammer. (I put it into the midpipe at the axleback flange) Took me about 20 minutes to install. I feel no losses on the butt dyno, but I'd like to explore that later. I'm just TOTALLY amped that it sounds so much better inside. This could be THE solution for wagon owners.

Purchased here: http://www.speedwaymotors.com/produc...No=1&redirect=

haven't seen any other dealers that sell them, but they're sitting on a goldmine.


Note: I don't want to take credit for this, I got the idea from another user in a post long ago, but I haven't seen anyone else do it since. I hope my actual tested SPL numbers inspire some others to try this out!!
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Old 08-19-2004, 04:00 PM   #41
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Quote:
Originally Posted by 0db
SOLUTION:



Yes, I remember that. I'm no fluid dynamics expert, but that just has to mess up flow at least a little, although it is a little encouraging that you couldn't 'feel' any difference.

I'm thinking that if my catless DP is too loud, this might be a cheap option, and if it doesn't work - hell - it's just $15.
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Old 08-19-2004, 04:05 PM   #42
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Quote:
Originally Posted by snvin
Yes, I remember that. I'm no fluid dynamics expert, but that just has to mess up flow at least a little, although it is a little encouraging that you couldn't 'feel' any difference.

I'm thinking that if my catless DP is too loud, this might be a cheap option, and if it doesn't work - hell - it's just $15.

That's what I figure. Yeah, maybe it introduces some loss... but if you're worried about noise, it's probably your daily driver... and regardless of all the penis-measuring that goes along with the dyno numbers, if it's your daily driver, losing a few hp isn't gonna kill you. It's not going to be the difference between winning and losing an impromptu stoplight drag (which I STRONGLY disapprove of!!! )

In my case, it WILL make the difference between whether my wife will ride in my car or not, it WILL make the difference whether I have a headache when I get to work or not... that's worth it right there. It's also a LOT cheaper than dynamat and sound insulation, and the HP loss is probably less significant than the weight I would add if I stuck in a few rolls of mat.

So far I'm impressed.

When I put the 20G and FMIC in, I'll start worrying about how much power it's costing me.
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Old 08-19-2004, 04:06 PM   #43
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Oh, and of course... it only takes a few minutes to remove (as long as you didn't wedge it into place too hard when you hammer it in... I decided to leave it sticking like 2" past the flange and slipped the axleback pipe OVER it, so I'd have something to grab onto and pull when I need to remove it, or possibly drill holes so I can hook something into it. I suspect it will be wedged in pretty tight after running in the exhaust for awhile.)

Regarding fluid dynamics, from what I know of flow (i'm no specialist, but I am a mechanical engineer with some fluids under my belt) I believe a perforated resonator or muffler which allows the exhaust to expand and then forces it back down to pipe diameter presents a greater pressure drop than this piece would. I'd like to get it on our flow bench and check it out though.
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Old 08-19-2004, 04:21 PM   #44
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Quote:
Originally Posted by 0db
I decided to leave it sticking like 2" past the flange and slipped the axleback pipe OVER it, so I'd have something to grab onto and pull when I need to remove it, or possibly drill holes so I can hook something into it. I suspect it will be wedged in pretty tight after running in the exhaust for awhile.)

Good thinking. I know I probably would've never thought of that.
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Old 08-19-2004, 04:46 PM   #45
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0db do you still get all the burbles and intonations of the aps exhaust? ive got the 3" tapering to 2.5 and its crazy loud inside the cabin. as long as it still has charecter ill probably order one. also is it in there pretty good? the aps system tapers at the midpipe so id have to put it before the midpipe, dont want it rattling around under my feet.
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Old 08-19-2004, 05:09 PM   #46
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Quote:
Originally Posted by elsanto
0db do you still get all the burbles and intonations of the aps exhaust? ive got the 3" tapering to 2.5 and its crazy loud inside the cabin. as long as it still has charecter ill probably order one. also is it in there pretty good? the aps system tapers at the midpipe so id have to put it before the midpipe, dont want it rattling around under my feet.
Like I said, I had to beat on it a bit to get it in there at all... it's definitely not rattling anywhere!

I still get the grumble-grumble-pop-popp sound when I start up in a parking lot, I still get the growl... to be fair, it does "smooth" out some of the roughness of the engine, but only as you rev up... at low revs it sounds virtually the same to me, I just have to roll my windows down to hear it!

To me, in fact, my full 3" APS on my wagon now sounds VERY MUCH like my buddy's 3"->2.5" APS on his sedan... which is what I wanted in the first place!

For $15 you don't have much to lose. I guarantee it will calm things down in the cabin... whether it calms things down TOO much is going to be your call. Do yourself a favor, though... since you can't leave it sticking out into your axleback section, you might want to drill a hole sideways through the "center pipe" part that you can stick a bolt or something into if you ever want to pull it out.
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Old 08-20-2004, 02:02 PM   #47
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0db, how much does the Auger muffler quiet down things outside of the car?
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Old 08-20-2004, 02:08 PM   #48
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Quote:
Originally Posted by driggity
0db, how much does the Auger muffler quiet down things outside of the car?

Hard for me to say, I don't spend much time outside my car... last night I was sitting outside when my wife drove off in the WRX and it still sounds pretty mean and nasty... but then i was following her in another car with the windows down and I could hardly hear her over the wind noise unless she really got on it. I can't IMAGINE it being loud enough at this point to draw any undesired attention, but like I said, it still sounds pretty "growly" when it's at low RPM. I'll see if I can't get some sound clips.
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Old 08-20-2004, 05:59 PM   #49
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I've got an STi up, Stromung downpipe, and stock cat/ cat back. I just got myself a ,hush and I'll let you know how it sounds when I put it on this Sunday. I plan on keeping my stock third cat, which is supposed to help limit noise... even with a hush system.
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Old 08-20-2004, 06:25 PM   #50
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Quote:
Originally Posted by 0db
Hard for me to say, I don't spend much time outside my car... last night I was sitting outside when my wife drove off in the WRX and it still sounds pretty mean and nasty... but then i was following her in another car with the windows down and I could hardly hear her over the wind noise unless she really got on it. I can't IMAGINE it being loud enough at this point to draw any undesired attention, but like I said, it still sounds pretty "growly" when it's at low RPM. I'll see if I can't get some sound clips.
Thanks, I need to figure out a way to quiet down my Perrin catback so I run something other than the stock catback but still keep the neighbors happy.
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