Can someone educate me on exhausts please!!

S3_Jacko · Jun 9, 2014

Hola migos!

Right... Someone has told me that the cats are located in the downpipes on the s3 8p exhaust and its true it kinda throws what I think I know about exhausts down the pan....

I thought the cats were in the sections after the downpipe!??

Anyway i'm looking into getting a Milltek catback exhaust... Does this bolt right onto the standard, what I thought was the cat section part just after the downpipe without any modification!?

Right my knowledge of the standard s3 exhaust went as follows...

Downpipe... Standard bore 2.5"??? Uprated 3"
then either standard cat/sports cat/or decat
centre silencer/centre section
and then backbox......

just wana try clear this up.....

Brodster · Jun 9, 2014

The cat is located just after the downpipe Jacko and yes the Milly will bolt straight onto it as it comes with an adaptor to fit OEM. If you were going down the BCS route that comes with an adapter piece aswell to fit to OEM.

If its a non-res Milly there is no rear silencer before the backbox.

Hope this helps and yes that other Milltek is still coming.....just hasnt been moved to where I want it yet

S3_Jacko · Jun 9, 2014

Probably be looking to buy 2nd hand Mark as only have a budget of around £350 to spend... So millys seem to be the most available 2nd hand exhaust systems.... Only looking for a small bit of rasp increase, no performance gains so catbacks ideal....

So just to clarify then... This split section is the cat!? Guy was saying that the cat was in the downpipe!??

smurfworth · Jun 9, 2014

That milltek system is a decat.

The round thing just below the hanger on the standard exhaust is the cat.

S3_Jacko · Jun 9, 2014

Ahhh cheers Josh... So a sports cat would be on the downpipe section then!?

Whats that split section called!?

is that just the standard dowpipe and centre section, although it splits!?

Marshy · Jun 9, 2014

On your original downpipe where it bolts to the turbo is a precat then it has the other cat further down.

The precat section is where the big restriction is as the exhaust almost pancakes at this point.

If you buy an aftermarket downpipe with sportscat these don't have a precat so much less restrictive as its 3" all the way.
If your fitting a Milltek catback you'd need an exhaust adaptor with a 2.5 internal diameter and the other end a 70mm outside diameter to fit inside the Milltek.
You can buy these from eBay in stainless for £8 delivered.
I bought one to mate my Milltek to my Cobra downpipe.

If your keeping your standard downpipe I'd go non res Milltek as it'll be quieter than standard with a resonated.

If changing downpipe then resonated so no drone on the motorway but noise when you want it.
As you say Millteks are fairly cheap where you can buy a catback for £250-£300 depending on condition.

S3_Jacko · Jun 9, 2014

Cheers Marshy

manor13 · Jun 9, 2014

If your buying a used Miltek downpipe check the welds on the hangers as these were were they used to brake and might have been re done out of warranty

Dave-S3 · Jun 10, 2014

You can have a non res milltek catback for less than £400 if you shop around, GNJ have the cobra cat back at a very good price too, a cat back is a cat back i don't think theres any more to it than that! For the extra few hundred though when it comes to upgrading the exhaust system i would save up and just get the BCS down pipe with a sports cat - you'd get more grunt & power increases. So I'm told the standard S3 cat back isn't overly restrictive and doesn't really cause any issues unless your running power above stage 2+â¦

Muzza80 · Jun 10, 2014

Downpipe will free up a bag of torque though Jack and would almost certainly be the demise of your already flaky clutch I'd reckon.

Kinda why I'm a little hesitant to put my BCS downpipe on till I've banked enough cash to do the clutch at short notice if I need to.

JJ.Foulds · Jun 10, 2014

Muzza80 said:
Downpipe will free up a bag of torque though Jack and would almost certainly be the demise of your already flaky clutch I'd reckon.

Kinda why I'm a little hesitant to put my BCS downpipe on till I've banked enough cash to do the clutch at short notice if I need to.

My clutch has been slipping since iv had it, around 6 months now. Only slips when its below 6-7 degrees outside lol. which i guess is the extra cooling from the intercooler! Good job its summer now!

The extra torque really can be the difference xD

Brodster · Jun 10, 2014

I have a new supplier of bespoke clutches guys and youll like the prices.......

mechanic69 · Jun 18, 2014

Anyone using one of these?

Audi S3 (8P) (3 door) 06-13 Sports Exhaust | Cobra Sport

tried searching but not much luck.

Marshy · Jun 18, 2014

I'm running a Cobra downpipe with sportscat which seems good quality and a good fit, although I've heard some people say the Cobra catbacks are quite loud.

JFelts · Jun 18, 2014

sorry to just jump in on this guys but what is a milltek turbo back sound like on motorways etc... does it drone?

mechanic69 · Jun 18, 2014

Marshy said:
I'm running a Cobra downpipe with sportscat which seems good quality and a good fit, although I've heard some people say the Cobra catbacks are quite loud.

What back system you running with that?

Marshy · Jun 18, 2014

Had a Milltek resonated but removed and sold it as it was too noisy on com start at 5am
Running standard catback at the minute which is pretty raspy when cold but sound well when warm.
BCS catback is next

mechanic69 · Jun 18, 2014

Marshy said:
Had a Milltek resonated but removed and sold it as it was too noisy on com start at 5am
Running standard catback at the minute which is pretty raspy when cold but sound well when warm.
BCS catback is next

Nice one, you going for the power valve?

Marshy · Jun 18, 2014

I've messaged Nige to see if he'd mate a powervalve to my cobra downpipe as not wanting the hassle of changing that again.
If not then probably prestige sport catback

Marshy · Jun 19, 2014

Had a reply from Nige this morning saying they wouldn't fit the powervalve to someone else's downpipe and its a full system only.
A little disappointed in that but that's life.
I'd asked for a price of a cat back but that wasn't mentioned for the non powervalve.
Oh well suppose I'll need to look elsewhere which is a shame since I've had 2 catbacks off them already.

mechanic69 · Jun 19, 2014

Unlucky mate, thought they'd say that

thetrashcanman · Jun 19, 2014

Brodster said:
I have a new supplier of bespoke clutches guys and youll like the prices.......

interested in one of these mate, PM us a price if you don't mind, apologies to the op for butting in, but thread has helped me as well as i'm a little confused about it all tbh.

S3_Jacko · Jun 20, 2014

The thread is open to all so no apologies needed.... Just good reading what everyones upto

Can someone educate me on exhausts please!!

Registered User

Registered User

Registered User

Registered User

Registered User

Settled in

Registered User

Registered User

Registered User

Registered User

Registered User

Registered User

Well-Known Member

Settled in

Registered User

Well-Known Member

Settled in

Well-Known Member

Settled in

Settled in

Well-Known Member

Registered User

Registered User

Similar threads