A different exhaust type question

**1_ate_t** · 12-01-2008 02:02 AM

I was wondering if anyone has replaced their oem mufflers with larger oem mufflers with 2.5" or 3" inlets and outlets? I'm thinking about making a 2.5" turboback with high flow cat and have it Y off into 2.5" or 3" oem mufflers.

Anyone else try anything like it? What did it sound like? Performance gains? TIA!

**B6Lovin** · 12-01-2008 02:04 AM

nobody has done it... because audi doesn't offer our muffler with a 2.5 or 3" inlet/outlet...

that's what aftermarket mufflers are for.

**1_ate_t** · 12-01-2008 02:18 AM

what about different manufactures oem type mufflers. I'm just trying to get more exhaust volume out of the engine with the least amount of noise possible.

**durfA4** · 12-01-2008 03:42 AM

you can look into b6 s4 exhaust it will fit the back half. thats gonna be your best bet, i dunno the the diameter of the piping

**pondside36** · 12-01-2008 06:50 AM

Most people get Magnaflow mufflers for custom catback exhaust sytems they off a few different types with varying sounds levels.

**A4 Moda** · 12-01-2008 07:42 AM

Believe me when I tell you, the mufflers constitute one of the highest exhaust restrictions on our cars Period.

You can save the factory straw sized piping if you want. Just make sure you DO purchase a Magnaflow STREET muffler to replace the factory muffler.

You will not get any performance out of the factory mufflers. It's a guarantee.

Good luck

**05A$SE** · 12-01-2008 10:20 AM

would hacking off the stock ones for straight pipes do for performance

**1_ate_t** · 12-01-2008 10:48 AM

If I did a 2.5" downpipe that split into a dual 3" piping going into a factory style 3" inlet / 3" outlet exhaust still flow good since there will be about 6" of volume going through two mufflers?

**A4 Moda** · 12-01-2008 11:04 AM

It will definitely open up your acceleration a lot more. And It would also give you some more top end. you will pull to 120-130 mph without feeling a thing. I promise you that much. Stock mufflers are extremely restrictive. It's not even a question

Originally Posted by 05A$SE

would hacking off the stock ones for straight pipes do for performance

**A4 Moda** · 12-01-2008 11:05 AM

I think you got it backwards here.

You want a 3" Test pipe, to a 3" downpipe, to a 2.5" split pipe.

Going the other way will give you minimal gains, MINIMAL while increase the noise to unbearable levels.

Originally Posted by 1_ate_t

If I did a 2.5" downpipe that split into a dual 3" piping going into a factory style 3" inlet / 3" outlet exhaust still flow good since there will be about 6" of volume going through two mufflers?

**05A$SE** · 12-02-2008 02:49 PM

on a k03 wouldnt 2.5 to 2.25 be better then 3 all the way to dual 2.5? its not about how open it is if im correct. back pressure is bad however velocity is the main focus. having a system that is to free flow will have less velocity then one that has optimal pressure with smaller piping. Thats pretty much what ive learned thats why i was wondering about the mufflers but now that i think about it there is already enough velocity from the stock piping being as small as it is. no its not optimal but it is good enough on stock turbo. looks like im going with ebay straight through mufflers!

**A4 Moda** · 12-02-2008 05:03 PM

Yes, 2.5 - 2.25 would be perfect. But with 2.5 i'd probably just keep it 2.5 all the way back. No sense in redoing the piping again if you ever want to go with a k04 or a BT for more power. Having 2.5 all the way through will allow you the versatility later on that will save massive time and headache.

Picture, BT install, then Valve cover gasket goes, Maf Goes, sparks all go, timing belt goes, the list goes on....

of stuff that you will have to regularly maintenance and keep up.
wouldn't you want your exhaust to be the least of your worries?
Just set it and you're DONE.

I should know. I've gone through over 10 exhaust setups in 6 years. This doesn't include all the small adjustments and pipe diameter changes in between. I'm talking 10+ FULL Exhaust setups.

Originally Posted by 05A$SE

on a k03 wouldnt 2.5 to 2.25 be better then 3 all the way to dual 2.5? its not about how open it is if im correct. back pressure is bad however velocity is the main focus. having a system that is to free flow will have less velocity then one that has optimal pressure with smaller piping. Thats pretty much what ive learned thats why i was wondering about the mufflers but now that i think about it there is already enough velocity from the stock piping being as small as it is. no its not optimal but it is good enough on stock turbo. looks like im going with ebay straight through mufflers!