Stock catback on Stage 1+
weightless, going back to stock if all you have is a catback shouldn't lose you too many hp ... maybe 10-15. To really free up hp, you should be running 3" all the way 
Cajun, I have the same problem with my Vishnu Signature dump back (high flow cat) ... it tends to drone very annoyingly at ~75mph .. .just perfect to drive you insane (strangely enough it's totally fine at 85mph+).
I think what's happening is that at a certain rpm range the whole trunk starts to resonate and amplify the muffler noise. I dynamatted around the muffler, which helped for driving around town, but didn't do too much for the droning at cruise. My next attempt will be to insulate the rear seat better (read: acoustic foam).
l8r)
Cajun, I have the same problem with my Vishnu Signature dump back (high flow cat) ... it tends to drone very annoyingly at ~75mph .. .just perfect to drive you insane (strangely enough it's totally fine at 85mph+).
I think what's happening is that at a certain rpm range the whole trunk starts to resonate and amplify the muffler noise. I dynamatted around the muffler, which helped for driving around town, but didn't do too much for the droning at cruise. My next attempt will be to insulate the rear seat better (read: acoustic foam).l8r)
Originally Posted by bo0oost
l8r)
Evolving Member
Joined: Feb 2004
Posts: 464
Likes: 0
From: Livermore, Ca
Originally Posted by Ludikraut
weightless, going back to stock if all you have is a catback shouldn't lose you too many hp ... maybe 10-15. To really free up hp, you should be running 3" all the way
Cajun, I have the same problem with my Vishnu Signature dump back (high flow cat) ... it tends to drone very annoyingly at ~75mph .. .just perfect to drive you insane (strangely enough it's totally fine at 85mph+). I think what's happening is that at a certain rpm range the whole trunk starts to resonate and amplify the muffler noise. I dynamatted around the muffler, which helped for driving around town, but didn't do too much for the droning at cruise. My next attempt will be to insulate the rear seat better (read: acoustic foam).
l8r)
Cajun, I have the same problem with my Vishnu Signature dump back (high flow cat) ... it tends to drone very annoyingly at ~75mph .. .just perfect to drive you insane (strangely enough it's totally fine at 85mph+).
I think what's happening is that at a certain rpm range the whole trunk starts to resonate and amplify the muffler noise. I dynamatted around the muffler, which helped for driving around town, but didn't do too much for the droning at cruise. My next attempt will be to insulate the rear seat better (read: acoustic foam).l8r)
Yeah when we had shivs car with a 1+ on a stock catback he was right around 10-15 down from a normal 1+ with full exhaust.
Evolved Member
Joined: Jan 2004
Posts: 613
Likes: 0
From: Burbank
Originally Posted by weightless
OK guys I have a bit of a dilemma here and would like some feedback. I'm seriously considering putting back my stock catback on. The noise of my 3" catback is beginning to get to me. Don't get me wrong it sounds awesome when I'm ripping thru the gears but when I'm driving normally it's a bit loud for my taste. I guess I'm getting too old for the rumble. So my question is if I have everything else for Stage 1+ (including downpipe and testpipe, cams, gears, fuel pump, Xflash), how much hp would I lose by having the stock catback on? I've heard a catback is worth 10whp on an Evo and I also remember Eric L telling me that exhausts don't do too much for Evo's where as they do a lot for WRX's. What do you guys think? Unless I lose massive hp I think I will put the stock catback back on. btw, before I had the 3" catback I was driving around w/ downpipe, testpipe+stock catback. It was louder than stock but acceptable to me and the car wasn't much slower (butt dyno though).
Try this:
weld a 3" pipe inside the 4" inch tail pipe section by the bumper. That last piece acts like a megaphone.
Since the diameter is the same as the exhaust line, I wouldn't think you'd loose any power.
I've seen it done and it's quieter, quick and cheap.
Originally Posted by lambtron@vishnu
Yeah when we had shivs car with a 1+ on a stock catback he was right around 10-15 down from a normal 1+ with full exhaust.
Jaylenospoolboy- I like your tip diameter reduction idea. I believe it will help out to some degree.
Originally Posted by weightless
OK guys I have a bit of a dilemma here and would like some feedback. I'm seriously considering putting back my stock catback on. The noise of my 3" catback is beginning to get to me. Don't get me wrong it sounds awesome when I'm ripping thru the gears but when I'm driving normally it's a bit loud for my taste. I guess I'm getting too old for the rumble. So my question is if I have everything else for Stage 1+ (including downpipe and testpipe, cams, gears, fuel pump, Xflash), how much hp would I lose by having the stock catback on? I've heard a catback is worth 10whp on an Evo and I also remember Eric L telling me that exhausts don't do too much for Evo's where as they do a lot for WRX's. What do you guys think? Unless I lose massive hp I think I will put the stock catback back on. btw, before I had the 3" catback I was driving around w/ downpipe, testpipe+stock catback. It was louder than stock but acceptable to me and the car wasn't much slower (butt dyno though).
Originally Posted by weightless
Thanks for the replies guys now if only I can get an answer to my question 
I supposed it's tough to find someone who has tried it and dyno'd it.
ez76, thanks but I've never liked silencers, the ones I've seen look like they would be more restrictive than the stock exhaust, kinda like putting a cap on the tailpipe.
954DRGSR & TisayLuv, I have the AMS catback w/o resonator. Their earlier model had a resonator in it but they say it's only a bit softer sounding not much difference.
Stephen, if you want quiet you'll get quiet w/ the stock catback, I've tried it so I know. The question is are you willing to sacrifice the extra power for it. After considering the downsides (unwanted attention and annoyance) I think I will make the sacrifice. My previous car was also modified and very loud and I think I've had enough.
I supposed it's tough to find someone who has tried it and dyno'd it.ez76, thanks but I've never liked silencers, the ones I've seen look like they would be more restrictive than the stock exhaust, kinda like putting a cap on the tailpipe.
954DRGSR & TisayLuv, I have the AMS catback w/o resonator. Their earlier model had a resonator in it but they say it's only a bit softer sounding not much difference.
Stephen, if you want quiet you'll get quiet w/ the stock catback, I've tried it so I know. The question is are you willing to sacrifice the extra power for it. After considering the downsides (unwanted attention and annoyance) I think I will make the sacrifice. My previous car was also modified and very loud and I think I've had enough.
MagnaFlow's responce
Here is the responce from MagnaFlow.....
===
Hello Chris,
Silencers are not available for individual or quantity sales. They are made specifically “1 per unit “ for our Universal Race Series mufflers and will not work on any other applications.
Richard Anh Trinh
Performance Sales Specialist
Magnaflow Perfomance Exhaust
800-990-0905
www.magnaflow.com
===
In other words.. too bad so sad.
I was hoping that they would offer someting.
===
Hello Chris,
Silencers are not available for individual or quantity sales. They are made specifically “1 per unit “ for our Universal Race Series mufflers and will not work on any other applications.
Richard Anh Trinh
Performance Sales Specialist
Magnaflow Perfomance Exhaust
800-990-0905
www.magnaflow.com
===
In other words.. too bad so sad.
I was hoping that they would offer someting.
Hey guys, I just picked up a silencer off Ebay. It's a generic 4", but should do the trick just fine. The sig. muffler should already have a hole drilled for it if it's the same muffler that I used.
Just search on Ebay for silencer muffler. I'll post a pic and let you guys know how it sounds.
Warren
Just search on Ebay for silencer muffler. I'll post a pic and let you guys know how it sounds.
Warren