3" DP question

[OrMar]

I had talk with a man in exhaust shop about makin 3" DP for my Urs6; he said he can do it, but sugested that he take top section of original DP, and make 3" only down from "V" where main and wastegate pipes meet, since (his words) there is anyway no use on 3" above that because of smaller flange.



Opinions?

Thank you,
Mario

[Jamo]

it should use a cone transition from 2.5 " to 3", you've still got a bottleneck if you use the oem top bit!

Example of bits required

http://www.s2forum.com/forum/showthread.php?t=39957

Find someone else to make it, if that's his effort in the pic!

[GazzaG60]

forget that top bit. you want a 2inch or so max conical transition.

look into the wastegate re-entry angle too.

not the best welds but if they hold.......if you did it yourself then least your having a go.

[OrMar]

Picture is what google returned for "audi downpipe" search, just an illustration.

[david]

that should be o.k.
a full 3" would always be better,but not alot difference.this way atleast you don't have the complication of trying to fabricate the whole head.it time consuming and very hard bit to get right.i spend many many hours on just wastegate and flange and made loads of mistake's before i got it right.i was lucky,i had a spare engine to work with and to get the turbo flange and wastegate right,i had to bolt the piece's on the engine before welding.

[Jamo]

that should be o.k.
a full 3" would always be better,but not alot difference.this way atleast you don't have the complication of trying to fabricate the whole head.it time consuming and very hard bit to get right.i spend many many hours on just wastegate and flange and made loads of mistake's before i got it right.i was lucky,i had a spare engine to work with and to get the turbo flange and wastegate right,i had to bolt the piece's on the engine before welding.

There is a LOT of difference, the stock downpipe isn't even true 2.5"

Ask Rusty

If your getting a downpipe get it made right

[david]

There is a LOT of difference, the stock downpipe isn't even true 2.5"

Ask Rusty

If your getting a downpipe get it made right

yes i know,but this way is alot easier than going through the trouble making a full one.
i'm not saying he should not bother making a full 3".
he asked a question and so i'm trying to suggest how he should go about doing it

[Colesy]

Would an S2 downpipe bolt on to an S6? People keep on asking me whether the 2.75" one I have would fit URS4s etc, including OrMar!

[Jamo]

Dunno they are slightly different in shape as there is more room in the s4 / s6, only one way to find out really

[Rusty]

The top part has some nasty restrictions in it (if it's the same as the S2). You can use it if keeping a k24 7000 on the car but I'd want to go to full custom above this as there is quite a difference in area and the OE one infringes on the exhaust gas flow - not ideal at that point!

Going 3" straight away isn't going to make a massive difference for lower power but if you're planning going beyond RS2 then make sure that you do it right first time, don't want to find out the hard way and it's not much extra effort.

You use a conical section from the turbo flange to 3" for the first bend. Mine has 2.5" first bend because I didn't specify this properly, fine for what I use it for now or RS2...

Also, make sure that the WG joins at an angle so that it's heading in the right direction, no point joining at right angles. I've thought about running the WG pipe down to the second bend and joining on the outside of the bend to aid the gas direction change. Complex but it could make a small difference...

[Jamo]

yes i know,but this way is alot easier than going through the trouble making a full one.
i'm not saying he should not bother making a full 3".
he asked a question and so i'm trying to suggest how he should go about doing it

It's not a suggestion that should be made, the stock part is highly restrictive even on stock bhp.

[Thuppu]

Go with a cone transition from 2,5" -> 3,5". With a 3.5" DP you have some backup for later mods. Here is mine 3,5" DP with some wraps: http://koti.mbnet.fi/pro-ht/Audi_URS...tshield_02.jpg

Ps. the weldings in the first post pic is quite... speechless.

[quattro]

I think by the look of the welds that no shielding gas was used! EPIC welds absolute stunning!