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Old 10-14-2004, 07:30 PM   #1
PhoKingWRX
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Perrin Parts Slut

Default thinking of putting back stock muffler

hey all,

so right now im completely catless via perrin's exhaust system. now that winter is approaching, the exhaust sound is a bit loud. i want to be a bit more quieter.

i was thinking of just taking off the perrin muffler and installing the stock wrx muffler in its place until spring. would this be a problem? im assuming some kind of "bottlenecking" would occur but the sound would be quieter. or would it just be safer to take out the entire turboback and put the stock one in until spring? i guess my main concern is long term effects on the engine if im installing a quieter muffler.

other options i was also considering would be purchasing a prodrive axle back or maybe the sti one. (which ever is cheaper really.)

any help would be greatly appreciated.
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Old 10-14-2004, 07:32 PM   #2
ZapZilla
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well i know the perrin axleback will not fit the stock center pipe, not sure if the stock axleback will fit the perrin center pipe. You can fit the stock cat-back to the perrin downpipe i'm sure, it fits HKS downpipe. It will be quieter and theres not a big difference in performance from what I can tell.
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Old 10-14-2004, 07:49 PM   #3
hondaeater69
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Zap is right. I was in your same boat catless with a stromung, and the muff was loud as balls. I put the stocker back on and couldn't notice a difference in power. You'll be much better off just putting the stock cat back on as opposed to the entire turbo back. Just about all of the restriction is in the first two cats.

I had my car dynoed this last weekend too, and my numbers were right in line with what other cars were posted with a TBE.
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Old 10-15-2004, 12:07 AM   #4
abaxter34
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i have the stock catback matched up to a 3" exhaust depot downpipe. for auto-x's i swap in my axleback straight thru pipe mainly so i can hear the engine better, MUCH better. power wise i cant feel any difference though, even after giving the ecu time to adjust.
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Old 10-15-2004, 12:08 AM   #5
dust12
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I have 3" vishnu turboback exhaust that I thought was a little loud, so I had a muffler shop make a flange for the stock muffler so I can swap either muffler with just a couple bolts...

The stock muffler sure does make it nice and quiet...I don't know how much power I am loosing though...
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Old 10-15-2004, 12:45 AM   #6
jlevy
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Default me too...

I've noticed the same lack of power increase going from stock muffler to a custom magnaflow on a TXS stealth system. On a car with a stock turbo, it just doesn't seem to be a bottleneck. I'm now back on the stock muffler and my wife and neighbors are much happier

These are butt-dyno impressions only.

-my 0.02

edit: Note I have a cobb stage 2 reflash.

Last edited by jlevy; 10-15-2004 at 12:48 AM. Reason: add more info
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Old 10-15-2004, 03:24 AM   #7
awdf00
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I've also wanted to remove my ridiculously loud hks muffler and throw on a quieter or the stock muffler. Would there be a really quiet aftermarket catback or axelback that anyone would recommend?
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Old 10-15-2004, 03:27 AM   #8
feiron
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borla hush? its dual-tip tho... or try MBRP, american brand, 2.5" piping
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Old 10-15-2004, 01:00 PM   #9
camz911
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where is the GMK when we need him?!?!

HELP DWIGHT HELP!!!
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Old 10-15-2004, 01:29 PM   #10
JonR
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I see that a few of you claim no increase in power from the replacement of the stock axleback. Two pieces of information to possibly contradict that:

1) In this thread, the guy had TXS stealthback with stock muffler, then went to full 3" TBE with one cat and gained 20 HP.
http://forums.nasioc.com/forums/show...XS+stealthback

2) A friend and I were dyno'd same day on a dyno dynamics dyno...mine is an 02, his an 04. He is catless with stock catback. I have a 3" TBE with one high flow cat in the DP. All other mods the same. I put down 204, he put down 190. Here are the plots:

His:
http://www.ktrperformance.com/galler...phen_e_wrx.htm
Mine:
http://www.ktrperformance.com/galler.../jon_r_wrx.htm

Seems the data supports the idea that the stock axleback is restrictive even with just the stock turbo. Anyone have any data that can challenge this?
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Old 10-15-2004, 02:07 PM   #11
hondaeater69
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Good effort Jon, but not quite good enough.

There could be a million different things that caused those differences. I'd like to see a graph of a car on dyno with a TBE, then one with the stock cat back on the next run. Now that would eliminate these possible differences in cars. I bet the differnce is more like 1-2 whp on the SAME car, not someone elses car.
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Old 10-15-2004, 02:09 PM   #12
JonR
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The first thread is the same car.

I agree though, that two different cars may or may not be comparable even on the same dyno same day.
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Old 10-15-2004, 02:14 PM   #13
camz911
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Quote:
Originally Posted by hondaeater69
I bet the differnce is more like 1-2 whp on the SAME car, not someone elses car.
of course the stock axel back is restrictive even with the stock turbo. If any of you have actually looked at the inside of a stock muffler, you'd realise that the exhaust has to go through a laborinth to exit the muffler.

There is no arguing that the stock axel back is VERY restrictive, and I would put about a 10hp difference between that and an aftermarket straight through muffler.

Hondaeater69 does make a good point. You can not compare two different cars. There are soooo many variations in how the engine was broken in and there are also flaws in every engine. No 2 wrx motors put out EXACTLY the same power. some guys make 180whp out of the box and some others make 160whp.
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Old 10-15-2004, 02:59 PM   #14
hondaeater69
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It looks like the gains he made were from the DP, not losing the axle back. He said it felt better under 4500 RPM, and around town, that's a spool thing. I"m willing to bet that big ass TXS 4" DP was actually creating turbulence after his turbo because the gases had no direction and too much room to just sit there, and the new bellmouth was smaller and gave him smoother exhaust flow.

I think the stock axle back would be a bigger restriction under higher HP numbers, and probably would hurt you up top your rev range, not in the lower range.

Last edited by hondaeater69; 10-15-2004 at 03:08 PM.
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Old 10-15-2004, 03:21 PM   #15
dust12
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JonR - I'm not disagreeing with you that you loose some horsepower with the stock muffler. I'm just stating that I can't feel it.

If you or anyone else wants to pay the dyno fee to see the difference in the stock vs aftermarket mufflers I'd be happy to help.
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Old 10-15-2004, 04:02 PM   #16
InfamousDX
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My butt dyno from prodrive axle back to stock axle back is quite noticeable, especially on top end. That was with a stromung DP + mbc @ 16.5 psi.
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Old 10-15-2004, 04:32 PM   #17
hondaeater69
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Where you from in NJ DX?? I live in milford pa, which is right on the north west border of NJ.
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Old 10-15-2004, 05:20 PM   #18
Microbomb
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I put my stock cat back on a couple weeks ago. I had a full Helix catless system. I don't notice a difference in HP. I do notice that I don't boost quite as high or as quick as I did with the catback on. I really miss the sound of starting the car in the morning and hearing that low rumble, however it is nice having a little quieter car. I am still unsure if I am going to put my Helix catback back on or keep the stocker on there.
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Old 10-15-2004, 05:36 PM   #19
downshiftdan
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perrin is a very loud catback, heard my friend's the other day catless and it sounds beasty! Many other axle backs/catbacks will be much quieter....greddy, borla hush (my choice), stromung, cobb, bosal single tip, prodrive, fujitsobo, off the top of my head...even a generic magnaflow from midas will be much quieter than Perrin. peace
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Old 10-15-2004, 11:09 PM   #20
PhoKingWRX
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wow. thanks to everyone for all thier input. ive decided to put back my stock catback for now. once the whether gets better, ill put my angry badger exhaust back on. again thanks for everyones input!
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Old 10-16-2004, 12:30 PM   #21
hondaeater69
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When you put it back on, let us know if you feel a difference in power, boost, etc.
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