[fiveiron9688]

So I have a friend who is able to fab up a stainless steel 3" turbo-back exhaust for me, and I wanted to get some feedback from you guys about some specific questions I have...

So you know where I'm coming from, I currently have a stock downpipe mated to a 2.5" catback with NO mufflers or resonators. The sound is a little bit louder than my liking when I'm just idling and putzing around. What I'm looking for is something that doesn't call so much attention, but offers good performance and, if possible, a more unique sort of sound...

I'm planning on buying the high-flow cat from GS, but the muffler is where I am struggling right now...What sort of muffler should I get? And should I place it towards the front or the back? I'm looking at Magnaflow...but I don't want to break the bank TOO badly either. Ideally I'd like a dual exhaust "tip" out the back, as opposed to one large opening like I currently have...but I don't know if that is very cost-effective or not.

So, any thoughts? Feel free to post exhaust vids if you have them (and tell me what sort of muffler setup it is, etc.)...I looked at the exhaust thread which, although it has some excellent exhausts, is mostly composed of non-custom systems.

Thanks all!

 

[coldskiesfullofblue]

I'm running 2 1/2" with magnaflow and it sounds amazing. I highly recommend it.

 

[fiveiron9688]

Did you mount the muffler towards the front or back? Good to hear that it sounds good....you don't happen to have an audio clip do you?

 

[coldskiesfullofblue]

I don't but I could prolly make one this weekend.

 

[mysterion]

I've found that 3" exhaust tends to boost your cylinders pressures if you use stainless. The platinum molecules in the cat react with the nickel in the stainless to make weird quantum level resonance effects. If you don't have the muffler placed in exactly the right spot then high pressure pulses will hit your turbine blades and pass through the turbo entering the cylinders as the valves close. This results in very high cylinder pressures.

If you're going to put on your own exhaust either stay away from stainless or perform a very in depth resonance analysis first.

Also make sure you don't use a flex pipe they tend to wear out quickly when the engines shifts back and forth.

You could always buy a subaru. They're immune to all resonance effects because of the boxer style engine.

Even better than Subaru is Honda..... Moobasy go MOO!

 

[grkguy89]

tottaly didnt post that

 

[fiveiron9688]

How does that sound familiar to you? That was my roommate being "helpful"...mysterion....hmm.

 

[fiveiron9688]

Do you play Combat Arms, perhaps? That's where the "Moobasy goes moo" comes from...

 

[costas14]

im planning on removing the cat and making it 3 inch all the way straight with an hks muffler in the rear, and then up the boost

 

[fiveiron9688]

im planning on removing the cat and making it 3 inch all the way straight with an hks muffler in the rear, and then up the boost

Nice. HKS mufflers are kinda hefty in price, though (or maybe I'm just cheap). I would run it w/out the cat, but I don't know if/when I'll ever have to pass emissions...

 

[costas14]

meh there 200-350 depending on which turbo one you get, then find a custom exhaust shop to do it, should cost under 500 total, ive done it to a couple of my dsms. never use one a borla muffler or dual tip or whatever on a turbo vehicle, straight piping all the way back. and if your car is making more then 300 do a 3 inch piping and then right before it goes under the subframe make it 4 inch to a 4 inch muffler, but you have to be pushing a lot of hp for it to work

 

[fiveiron9688]

Brief update:
Buying a cat from ebay-63.99 w/shipping
two flex portions - 66 w/shipping
Muffler - found a T304 SS (RS muffler I think) with a silencer you can put on the back for 32 w/shipping...good deal?

My friend says 3" pipe won't fit up to the turbo...so do you just start smaller and go up to 3" right away? I'm assuming that's the only way you could do it...how do other 3" downpipes you all are using look? Thanks for any input

 

[fiveiron9688]

Well I ordered the stuff: a cat, 2 flex portions, a Magnaflow 3-chamber muffler, total $198.97 from ebay. Based on my quotes for labor and the stainless piping itself, this project will run me just shy of $550.

Quick question though. I'd like to replace the O2 sensors as long as I'm in there. I heard that the second one isn't really that important, so do you all think I can just replace the front one? Also, how about buying it from rockauto.com? It's not OEM, but it's made by Bosch and specified for certain Saabs, Volvos, and Porsches. Any thoughts/ideas are greatly appreciated.

 

[tdrudd87]

I don't have any experience with aftermarket sensor quality, but as far as the rear sensor goes, it has no control over fuel trim. It is only used to monitor cat performance, so it cannot affect fuel economy or performance like a bad front can. If it is working now, I'd save the money for something else.

-Terry

 

[fiveiron9688]

Thanks Terry, that's what I thought. I'm going to replace the front one as I'm at almost 135k miles now...

I found a sensor on ebay. It's a 4-wire Bosch like OEM, but for $100 less. Would that be okay?

Or this guy? I feel a little better about this...maybe just because it costs more?

 

[Messinian900S]

The rear sensor will throw a CEL though, unless you retune the ecu and turn off that sensor input.

Just for perspective, I just bought a full turbo-back JT 3" for roughly $550 shipped and installed it last night. Its awesome, perfect sound...not too loud not too quiet (1 muffler no cat).

Custom systems usually end up costing more than prebuilt, I just see no reason to do it besides stubbornness or the absolute need for SS (since there pretty much is no SS catback system available for our cars barring ordering from Europe) if your area uses salt or is really humid...

As far as mufflers go, I would have opted for a straight through perforated design over chambered mufflers as air/gases doesn't like being slammed into walls and shoved around lol I've had good luck with Vibrant mufflers...i used to have a flat black one on my old old LS/Vtec eg6. made it sound good.

 

[fiveiron9688]

So you think I need to replace both O2 sensors then, to avoid a CEL? Or can I ignore the CEL for now (wouldn't it only be a catalyst issue) until I have the oppurtunity to retune? Currently I have no CEL, but I figure it'd be good to replace the front one while I'm in there.

The reason I'm going stainless is because Milwaukee heaps an insane amount of salt everywhere during the winter. The current 2.5" catback is rusting away horribly. Otherwise I would buy the JT system for sure:cheesy:

 

[Messinian900S]

I figured on the salt lol

Sorry, I should have clairified. If you unhook the rear sensor, you will get a CEL until you turn it off in the ECU.

 

[fiveiron9688]

Oh I see. Thanks for the help. We will be installing it next weekend...I'm excited:cheesy:

 

[sailorcolin]

The rear sensor will throw a CEL though, unless you retune the ecu and turn off that sensor input.

Just for perspective, I just bought a full turbo-back JT 3" for roughly $550 shipped and installed it last night. Its awesome, perfect sound...not too loud not too quiet (1 muffler no cat).

Custom systems usually end up costing more than prebuilt, I just see no reason to do it besides stubbornness or the absolute need for SS (since there pretty much is no SS catback system available for our cars barring ordering from Europe) if your area uses salt or is really humid...

As far as mufflers go, I would have opted for a straight through perforated design over chambered mufflers as air/gases doesn't like being slammed into walls and shoved around lol I've had good luck with Vibrant mufflers...i used to have a flat black one on my old old LS/Vtec eg6. made it sound good.

do you have a sound clip of your exhaust mine is coming in the mail and i would like to know what it sounds like.