Hey I am curious what the major difference is other then cosmetic of the 2 exhausts. I plan on purchasing one of these tonight thanks to the sale but if there isnt an HP gain from the Dual over the Single I am going to go with the single I am a total noob when it comes to this stuff and I do not want a crazy loud exhaust just something a little more aggressive and I have heard that the Dual Exhaust is very very loud. Any help is appreciated.

 

With a single exhaust:
-less total weight
-less total resistance (backpressure)
-less silliness because we are an inline four (not a V6 or V8)...

But without a new rear diffuser it would look.... lame.

 

Wait, wha..? Using a similarly designed muffler canister on both setups, two pipes will always outflow 1, even if the pipe reuces to 2.5" at the "Y". The flow of air will not be so linear, with the split, but backpressure will not be increased.

I agree with the rest, though.

 

I have a dual turbo back ultimate racing exhaust for sale. message me if interested

 

The resistance to flow of two 2 inch pipes is greater than for a single 3 inch pipe.

Picture the drag along the wall. If the total percent of the cross section is more wall then you affect flow.

 

Just so I understand your perspective in the argument, you are talking about potential drag from friction due to increased piping surface area, right? If so, then I understand where you are coming from. We are talking about 2 different things, and I apologize for the confusion. You are obviously referring to resistance as in the physical friction(and possibly turbulence)-based resistance due to overall internal surface area increase, I am talking about flow volume resistance.

When taking into account the relative carrying capacity of a pipe of the same material, carrying the same gas, the 2 2.5" pipes will still outflow the single 3". Not to say that our car (especially with the stock turbo) will ever outflow a 3" exhaust, but I still believe that the split design has less potential for backpressure.

Correct me if I am wrong, because I am no engineer, nor to I pretend to be, the math just makes sense in my head.

 

In my example i used two 2 inch pipes. The two 2.5 inch pipes in your example would flow equal~ish to a single 3.5 to 3.75 inch pipe. So now that you have the same flow as a single 3 inch pipe - the single 3 inch pipe total system weight should be less...

2 x 2.5 does not equal '5' in flow - it is more like 4~ish.
2 x 2 is more like 2.75~ish.

 

Right, I get it. ~3.14(1.5^2) vs ~3.14(1.25^2)*2. We are on the same page, then.

 

I have the UR single on order -- it's supposed to be quieter than the dual is what UR says and I like the single look. Performance wise....same-same really. I'm on the stock turbo so it doesn't matter in my case.

 

Post a video of how it sounds when you get it installed.

 

This ^ plus if you have a sportback or a gutted interior the single will produce less resonance noise in the cabin because you don't have a huge can or two medium cans laying flat a couple inches bellow the middle if the truck pan.

 

Got the single installed today -- seriously impressed. I have the resonated midpipe and you can tell it's louder at idle but generally it's only a bit louder than stock with light throttle. No droning on the freeway either (rather, no unpleasant or unwanted resonance I should say). Step on it and it sounds delightfully hooligan-ish!

I've had aftermarket exhausts before and it's quieter than the 2.5" double resonated exhaust I had on my 1.8t A4 and about the same volume as my friend's stock Type R with a semi-gutted interior. That 7" can at the back really is better than an oval muffler. The dealer installs lots of the UR duals but this was their first single -- manager said it was quieter, with a smoother tone than the UR dual which can be too raspy for some.

I'll try to work on a video this weekend!

 

Where is said video?

 

I can get you guys a video of the UR single exit that I switched to. Much quieter than the dual, but probably because I am tuned for it now. Current setup is UR catback with no res, or mini muffler option and Invidia N1 long downpipe/testpipe.

In the meanwhile, heres my UR dual exit with 3 inch piping and stock cat. Untuned so it was super loud and throaty. Kinda miss that though.

 

do you have a video of your current set up, cause i got the invidia longpipe and testpipe too and was wondering what it sounded like?