Exhaust opinions

[s2_wot]

I must find a euro spec sheet. Trying to source 321 ss dairy tube isn't that easy so I was assuming that the dp's were made from 2.1mm wall BSP 2.5".

Once you know the actual OD & wall thickness it's easy enough to work out the flow in any case. However apologies for sparking confusion.

[terrybullwon]

Thanks Shane with you now

[diesel des]

The exhaust I made for my urs4 is in 3 inch 316 dairy bends and is 3 plus years old. Is perfect with no cracks or rust. 321 not needed for downpipe back.

[s2_wot]

The exhaust I made for my urs4 is in 3 inch 316 dairy bends and is 3 plus years old. Is perfect with no cracks or rust. 321 not needed for downpipe back.

Aha that's good news, I thought the consensus was to use 321 for the downpipe and 316 / 304 for the rest. If that's the case I'll go with the 316 for the downpipe and 304 for the balance. Obviously I've been thinking about an overweight, overspecified item.

[euro_urs4]

Great info guys thanks , and is there anything against running a full straight pipe or is a muffler recommmened? And I'll have to double check what the OD on the exhaust is I believe it's 4 in just worried about clearance with the cv boot and frame

[s2_wot]

Great info guys thanks , and is there anything against running a full straight pipe or is a muffler recommmened? And I'll have to double check what the OD on the exhaust is I believe it's 4 in just worried about clearance with the cv boot and frame

For me I'm going oversized to have good flow but also so I can dampen the sound pretty well. performance = no muffler, but I think you'll have to put something in there.
You shouldn't have any problem with the C4 chassis. The s2 doesn't have so much room.

[UrS4boy]

Great info guys thanks , and is there anything against running a full straight pipe or is a muffler recommmened?

You are obvisously deaf because you are not "listening".

The D-R-O-N-E will kill you.

Unless, indeed, you are deaf.

[newsh]

My 3" system has 2 mufflers and the drone still kills me, I'm interested in what this Stomung system is about.. Any more info?

[HMS-S6]

Firstly i'd like to start by saying i know little about turbo car exhausts to be honest, but my UrS4 has a 2 box 3" turbo back by longlife. It was on the car when i got it. Thing is, it sounds nice with the windows down, in tunnels etc, but in the car its not noisey at all! How is this?

[driftin jo]

Firstly i'd like to start by saying i know little about turbo car exhausts to be honest, but my UrS4 has a 2 box 3" turbo back by longlife. It was on the car when i got it. Thing is, it sounds nice with the windows down, in tunnels etc, but in the car its not noisey at all! How is this?

The may have used a resonator box to prevent the drone , drone is caused by resonance feeding back up the pipe towards the engine , fitting a resonator prevents this. The resonator looks like a silencer form the outside but is in fact a hollow box of a specific size / volume . A lot of OEM exhausts have them to reduce cabin noise.

I have heard that some after market exhaust builders have options on resonators, Milltek have them as an option on some exhausts but not sure if they have ever done one for the S2 systems they make that people have used on here.

[euro_urs4]

yeah i think ill just have to experiment, im not gonna limit how big i go if i can go bigger on the down pipe i will, and from there route the rest, and see if i will throw a muffler on or possibly 034 exhaust or an apple racing exhaust (what you guys think of the apple exhaust?)

[URSIMPO]

I bought an 034 3" turbo back exhaust with sports cat and single Magnaflow rear box. It was ridiculously loud - to the extent that the police told me it was too loud!! Anyway, I decided I needed to quieten it beofre I embarked on a 2k mile Euro trip. So I took it to Hayward and Scott, and they put a custom rear box on. Our cars -especially when lowered, have poor ground clearance, so I didn't go down the 2 box route. Luckily the S6 has alot of room after the rear axle, so the box I have is massive; but, while the car is quite now, it hasn't eliminated the drone completely, so if I was you, I would consider a resonator that people are talking about on this thread.

[DamianURS4]

Guys, on a 3" system the URS4 avant has major issues with clearance when lowered (Koni's all round) - mine had to have a third box put in it because the only time I could tollerate the sound was when I was doing 90. I used mixtures of ear plugs and head phones - I would say however that if you really concentrate you can make it come in and out in time with your ICE which creates tasty bass and is also highly entertaining on motorway drives! Excellent when you are ripping it - sounds like a jet airplane - honestly - Hoffer will tell you - I pulled away from a set of lights testing a new wagner EM and the sound attracted an under cover who was parked up - he pulled me over a few miles later after watching me 'test for boost leaks' - I am now walking till april....... It can barely entertain speed humps although it looks and sounds the nuts.
So really think about the droning because it becomes like chinese water torture - and to resolve it will require additional components which will impact a non-standard ride height!
I still think you need 3" to breath properly.....