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Old 03-15-2004, 09:09 PM   #1
Z06-KILLR
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Default Exhaust-less STi? Any problems with doing this?

I am thinking about removing the exhaust completely on my 04' STi and running a straight pipe instead. I just want some more sound without gutting everything or running downpipes/uppipes (warranty issues).

I tried replacing the muffler and frankly, could not tell the difference in sound. However, by removing the exhaust completely, I reached the level of sound desired. Has anyone tried this before? Will eliminating the backpressure of the exhaust have any (if) negative points?

Thanks!~

Angel
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Old 03-15-2004, 09:22 PM   #2
DjDharmaNY
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with the entire exhaust off, did you notice any boost creep? Sounds like a bad idea to be running no exhaust, the back pressure is necessary for proper functioning.
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Old 03-15-2004, 09:26 PM   #3
John Sever
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Uh yah, boostcreep...number one problem with that setup. People are getting boostcreep on stock setups with just a DP...no exhaust and you are inviting BAD things to happen to the motor. At the very minimum...get the wastegate ported...and have a boost guage installled. Also, if the sound is that great(i dont doubt that it sounds sweet) get a EGT guage, and a knocklink or similar device.

Are there no cops where you live??
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Old 03-15-2004, 10:00 PM   #4
Z06-KILLR
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sorry...completely misphrased it. I have removed the "muffler" completely. Everything else is left intact.

It is really not THAT loud...it just has a very unique growl to it. I have a boost gauge and there is no boost creeps throughout the powerband.

I think the excessive amounts of catalyc converters and the resonators are probably enough....again, sorry for the bad phrasing...."muffler" is what I meant...

Angel
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Old 03-15-2004, 10:09 PM   #5
bezerk
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I was going to ask this exact question...will probably try this setup in a few months once the drag strip opens. Unless anyone this that removing the muffler section of the exhaust would be foolish...anyone??
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Old 03-15-2004, 10:24 PM   #6
singletrack
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Quote:
Originally posted by DjDharmaNY
with the entire exhaust off, did you notice any boost creep? Sounds like a bad idea to be running no exhaust, the back pressure is necessary for proper functioning.
The backpressure is only needed to avoid boost creep on the VF39 - just to clarify. The best exhaust on a turbocharged car is one that provides no backpressure.

-st
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Old 03-15-2004, 10:35 PM   #7
Z06-KILLR
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the stock muffler is HUGE!!!???....it has GOT to weigh at least 15-20 lbs.
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Old 03-15-2004, 10:37 PM   #8
singletrack
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Quote:
Originally posted by bezerk
I was going to ask this exact question...will probably try this setup in a few months once the drag strip opens. Unless anyone this that removing the muffler section of the exhaust would be foolish...anyone??
The only thing to worry about is boost creep as others have mentioned. I would still have a straight pipe made for the rear flange so you don't have the hot exhaust dumping under the car.

-st
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Old 03-15-2004, 11:41 PM   #9
Z06-KILLR
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Quote:
Originally posted by singletrack
The only thing to worry about is boost creep as others have mentioned. I would still have a straight pipe made for the rear flange so you don't have the hot exhaust dumping under the car.

-st
As several people have mentioned, it probably depends on the car more than anything. We finished with the straight pipe to replace the muffler. We took the car for several runs and there are no boost creeps whatsoever. The car pulls extremely strong throughout. Boost jumps to 1 bar immediately after given throttle and stays there all the way to revv.

Gotta love the sound
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Old 03-16-2004, 12:25 AM   #10
singletrack
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Quote:
Originally posted by Z06-KILLR
As several people have mentioned, it probably depends on the car more than anything. We finished with the straight pipe to replace the muffler. We took the car for several runs and there are no boost creeps whatsoever. The car pulls extremely strong throughout. Boost jumps to 1 bar immediately after given throttle and stays there all the way to revv.

Gotta love the sound
Yeah, I honestly don't know of anyone who has just tried without the muffler. There also seems to be some variance from one exhaust housing to another, different downpipes, cat-backs, etc etc. What sort of temps have you tested it in - low temps aggrevate the creep.

-st
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Old 03-16-2004, 03:27 AM   #11
Z06-KILLR
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Quote:
Originally posted by singletrack
Yeah, I honestly don't know of anyone who has just tried without the muffler. There also seems to be some variance from one exhaust housing to another, different downpipes, cat-backs, etc etc. What sort of temps have you tested it in - low temps aggrevate the creep.

-st
very good point. The weather was about 45-50 degrees when we tested it. I think I am safe. I am going to try to get a wmv. sound file so you guys can listen to it....
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Old 03-16-2004, 09:49 PM   #12
bezerk
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Quote:
Originally posted by singletrack
The only thing to worry about is boost creep as others have mentioned. I would still have a straight pipe made for the rear flange so you don't have the hot exhaust dumping under the car.

-st

thank you VERY much, I seem to have not thought of this,,,
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Old 03-17-2004, 01:26 PM   #13
Black-X
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i would get the blitz nur spec-R if i were you. sounds mean as crap on my STi!

i think it would be safer than no muffler, and will let you get the desired sound you are wanting (i think).
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