Downpipe & Sports Cat to Milltek cat back system

Dan-Jnr

Dan-Jnr

Registered User
Joined
Jun 10, 2011
Messages
1,254
Reaction score
404
Points
83
Location
Manchester
I have been looking at replacing the exhaust system on my 2002 S3.

There are many downpipe and sports cats available.

What I want to know is, are they many compatibility issues connecting downpipes and sports cats to a Milltek resonated cat back system?
Are they straight forward flange connections or slip in type?

I dont want to have to cut and weld systems together if you get what I mean.

For exmaple:

Pipeworx 3" downpipe and sports cat to Milltek cat back system.
XS Power downpipe and 200 cell cat to Milltek cat back system.
 
my xs power downpipe, which is 3 inch, goes down to 2.5 inch for the standard exhaust system.
milteks are 2.75 inch, so obviously you would need to get the decat pipe of which ever you buy to be enlarged (i think they stretch them somehow, cant rememeber the process)
im guessing it would be the same story with the pipeworx one.
they are both sleeved by the way

having said that, people have fitted a miltek this week to standard dp/cats and no mention of it.
perhaps the milteks are 2.5 at the end where they sleeve over the cat/decat.
 
Last edited:
Millteks come with a reducer sleeve kit to mate to the standard cat. Depending on the bore size of the decat/cat will determine whether you need the reducer or not I guess? I'm sure you could find out from the companies what girth their bits are ;)
 
I have a pipewerx dp, sports cat and milltek non-res system to fit in about a month, so any hints and tips appreciated :yes:
 
Westy said:
I'm going to be fitting a milltek to my xs DP in a week so I'll be able to let you know if there are any issues with fitting.
Click to expand...

Keep u's up to date as will be fitting a xs dp to daves milltek in the near future :)
 
I have the XS sports cat to Milltek resonated and the sleeve supplied with the Milltek was not right according to my mechanic (i got it to fit ok with standard cats) its currently covered in heat proof silicone waiting to get welded together next week. In other words measure the ends of your systems yourself and make sure you have the right sleeve or get someone to adapt them as someone said above.
 
It appears that the XS decat pipe tapers down to 2.5" to mate up with the OEM back section. This will result in a 3" to 2.5" to 2.75" difference in the pipework therefore creating a bottle neck at the decat tapered end. I will be going to an exhaust fitters and asking them to cut the 2.5" taper and replace it with a larger diameter to avoid this issue.
 
Thanks for the update Westy.

I am trying to find out the diameter of the Pipewerx at the cat end, I don't want to be spending a lot of money on exhaust bits to only have it all chopped up and welded to fit.
From the picture of the Pipewerx it looks like it reduces to 2.75 but I want confirmation first.
 
Dan-Jnr said:
Thanks for the update Westy.

I am trying to find out the diameter of the Pipewerx at the cat end, I don't want to be spending a lot of money on exhaust bits to only have it all chopped up and welded to fit.
From the picture of the Pipewerx it looks like it reduces to 2.75 but I want confirmation first.
Click to expand...

I'm not sure about that mate as my friend Tam has a pipeworx DP and we're sure its 2.5" as it has to mate to the OEM rear section.
 
i may have this completly wrong here but surely with it tapering down to 2.5 defeats the object of having a 3" system??
 
knoxie said:
i may have this completly wrong here but surely with it tapering down to 2.5 defeats the object of having a 3" system??
Click to expand...
the off the shelf downpipe/decats are like this so they can mate to the standard cat back.
Plus, no off the shelf cat back is 3 inch, they tend to be 2.75. So if you wabt a full 3 inch system it has to be custom.
The important bit is the downpipe tho, so having it go into a 2.75 catback is no bad thing at all, as long as its wrll designed and free flowing
 
audi upgrades
I am going to contact Pipewerx direct and see if they can make a downpipe/sports cat 3" to 2.75 to match the Milltek Resonated system.

If Pipewerx can make a full 3" system from downpipe/sports cat to back box what would the pro's and con's be?
 
I received confirmation today that the Pipewerx downpipe/sports goes from 3" to 2.75" so it connects perfectly to the Milltek system.
 
They must supply an additional reducer for the standard system then? Pretty poor if they didnt.
 
im running a xs power v1 downpipe-decat at the min with a non resonated milltek catback and for me it sounds crap i have a beathy and tiny sound coming out beathy is the milltek tiny is the crap xs power downpipe sound and also the vibration of the downpipe that touchies the sub frame is horrible and the make the cat back stick out too much coz its that bit longer or lower.

s3dave has the pipewerz downpipe and decat i have the xs power and daves sounds a dream compared to mine just beathy from daves no tiny ness or owt one big rorrr all the way to red line mine:sorry: for that im going to buy the pipewerz one and ill let ya no the difference all i can say is the quality of material xs power use must be crap my appinion by the way soz.
 
Get you exhaust sorted then mate so it's not vibrating against the subframe. I had the same issue and fixed it by pulling the DP over a bit then holding it in place by using a small jubilee clip on the DP hanger which goes through the rubber. This has pulled it over the 5mm or so that was needed.
 
audi upgrades
ill have a go its quite solid tho westy, ill be getting the pipewerz one anyway mate the sound of daves compared to mine in mint i hate the tini sound also it will pull my cat back up and in abit more to how i want it.
 
s3gazz said:
ill have a go its quite solid tho westy, ill be getting the pipewerz one anyway mate the sound of daves compared to mine in mint i hate the tini sound also it will pull my cat back up and in abit more to how i want it.
Click to expand...

I wouldn't expect the different DPs to sound much different mate and I wouldn't waste my money just in search of a different sound. I have an XS and my mate Tam has a pipeworx and our exhaust notes were the same (OEM cat backs). Mine has slightly changed now since i've fitted the XS manifold.

You have to remember that your car and Dave's car are different. He has a different turbo and manifold to your car and this will all change the sound of the exhaust.
 
Westy, no need to contact XS power, they're pretty useless anyway.

the XS DP IS absolutely 100% 2.5'' at the end, down from 3'', because my 2.5'' milltek A3 system is sleeved over the end of my XS ko4 downpipe.

I should have the decat section (flange back) part of my XS downpipe spare in the pretty near future if anyone ***** one up :p
 
I'm still trying to work out whether i need to buy anything else to make this fit?

This is the Milltek I bought and a couple of pics of the 2 clamps that came with it:

Back box end:

c4401cf8.jpg


9c156d3f.jpg



Mid section:

d14f9a45.jpg


86643774.jpg



Am I going to need to buy a sleeved clamp for connecting the mid section to the de-cat pipe or can I use the existing sleeve and clamp I already have that connects the XS de-cat to the OEM cat back system :think:
 
You need a 2.75 to 2.5 reducer from what we can all gather in that last thread. The Milltek is 100% 2.75 as stated on their own website and the XS downpipe is 2.5" to fit to the standard system and Prawn was 100% on this.

If that system you bought doesnt come with one which i think you said it didnt?

Although just remembered you`re having the 2.5" section removed arent you?
 
Jason.s said:
You need a 2.75 to 2.5 reducer from what we can all gather in that last thread. The Milltek is 100% 2.75 as stated on their own website and the XS downpipe is 2.5" to fit to the standard system and Prawn was 100% on this.

If that system you bought doesnt come with one which i think you said it didnt?

Although just remembered you`re having the 2.5" section removed arent you?
Click to expand...

I'm not going to faff about with getting bits cut off and welded so I'm just going to fit it as it is. I'll order a reducer as I've booked off next monday to fit the system.

1 of these should do the trick then?

STAINLESS EXHAUST PIPE REDUCER adaptor/step/joint/sleeve 70mm 65mm 2.75" 2.5" | eBay
 
Last edited:
Looks about right that reducer Westy alot cheaper tthen milltek to paid £30 for mine posted with an extra clamp :(
 
Ah yes, i saw that one on ebay when you first posted pics up of the exhaust. Seems like it`ll do the trick :)
 
audi upgrades
Westy said:
I wouldn't expect the different DPs to sound much different mate and I wouldn't waste my money just in search of a different sound. I have an XS and my mate Tam has a pipeworx and our exhaust notes were the same (OEM cat backs). Mine has slightly changed now since i've fitted the XS manifold.

You have to remember that your car and Dave's car are different. He has a different turbo and manifold to your car and this will all change the sound of the exhaust.
Click to expand...

westy mine just sounds so tini compaired to daves and was without the mani on when i put my foot down or slightly its just a tini crapy sound and thats with a milltek cat back wich just is not that beefy compaired to daves with the same. my milltek was a resernated but had the resonater tuck out so non resonated now
 
s3gazz said:
westy mine just sounds so tini compaired to daves and was without the mani on when i put my foot down or slightly its just a tini crapy sound and thats with a milltek cat back wich just is not that beefy compaired to daves with the same. my milltek was a resernated but had the resonater tuck out so non resonated now
Click to expand...

Mate my OEM cat back is loud enough at the moment with no cats, 3" DP, and tubular mani, so I'm sure mine will sound good with the Milltek. I'll get a video once it's on.
 
Yeah my non res sounds awesome now it's coked up a bit. Not too loud like all the jap ****boxes kicking about but nice sounding. You'll love it...
 
I had the Relentless downpipe and decat pipe fitted at the weekend, it was hard work getting the downpipe on due to the space available, but does go on, thou the decat pipe angle was way off when it was lined up, it was aiming over towards the passenger seat and not along the exhaust tunnel. Sadly it had to be grinded off and rewelded by my mechanic. (Sadly they did not take any pictures of this issue), but you can tell it was done by the quality of my mechanics welding over the good welding it came with(Will need to chase this up with Sam).
decatreweld.jpg
[/URL][/IMG]

I have the Milltek non resonated cat back on mine and I have to say that the downpipe and decat does make it sound a bit tinny from inside the car, but nice from the back of the car on idle.

You do get a more sporty sound from around 3500k onwards, and yet it is pretty good on the motorway at a steady speed when the sound is noticable, but not annoying. Give it some throttle and it has a nice meaty sound.

Hoping the tinniness will die down a bit when I have put some miles on it.
 
Is anyone's downpipe hitting the heat shield in the tunnel near the flex pipe? Mines almost sitting on it do was think this is normal?
 
Darren4 said:
Is anyone's downpipe hitting the heat shield in the tunnel near the flex pipe? Mines almost sitting on it do was think this is normal?
Click to expand...

Yes mate I had to move mine away. What I did was get a mate to push the whole exhaust towards the passenger side of the car. Try to get 1-2cm of the DP hanger pushed outside the rubber on the mount then bang a small jubille clip on the end to stop it moving back over to the right. You'll only need a few mm to clear the tunnel.

I'll try and get a pic if this makes no sense.
 
You must log in or register to reply here.

Similar threads

ShaunS3
XS Downpipe/Sports Cat/Miltek Cat-back
Replies
2
Views
762
ShaunS3
ShaunS3
S3-Chris
Downpipe? sports cat?
Replies
35
Views
5K
Ess_Three
Ess_Three
I
milltek sports cat
Replies
4
Views
827
imported_glen_jai
I
g10chy
Milltek Cat-Back
Replies
28
Views
2K
g10chy
g10chy
B
Milltek cat back
Replies
2
Views
802
mazzy
mazzy
Top
Back