Novice To Moding - Miltek Exhausts & The Differences

[45bvtc]

You just want the secondary catalyst by-pass pipes to suit a 'standard' RS3 exhaust system, Andy.

BOTH the Milltek and Scorpion pipes are 63.5mm (ish) diameter to suit the STD RS3 post secondary catalytic converters exhaust

Having fitted both Milltek and Scorpion to various RS3s the only difference I see, other than the Scorpion being cheaper, is that the Scorpion has stainless steel flanges where the Milltek uses mild steel

Your choice Andy but I went for the Milltek items; removed the 'DO NOT USE' labels, and used stainless steel fastenings to couple the flanges... :thumbsup:

 

[S3 AD]

Cheers John, I have found you fitting guide as well, so hopefully that will minimize scrapped knuckles and swearing

 

[MrAudi]

if your looking to buy a set of miltek ones KELZA on here has just posted up a set for sale

 

[S3 AD]

Thanks for letting me know but for the cost of the Scorpion ones new - I'll go that route as they have a life time garantee and a decent offer should they get damaged to replace them.

 

[Blackbird400]

Daytona500 - I am that man (sorry, only just picked up your post!)

 

[45bvtc]

OK, please forget EVERYTHING I've said before about the 'NUMBER' of catalytic converters being fitted for the MOT test...

Having pre-booked BLUEY in for her first MOT in September at Stafford Audi (a trusted set of guys to lay hands on your motorcar), and having asked of their 'official' perspective on undertaking an MOT with secondary catalytic converters missing and by-pass pipes fitted, I was offered a pre emissions check that I duly accepted and was undertaken today.

The results @ 8350-miles:
CO @ 0.02%, the 'PASS' being 0.20%, and HC @ 0, the 'PASS' being 200

AND am I mega impressed with those figures...

So, as Kohaku reported several weeks ago, Post #33, his RS3 having been MOT'd at Truro Audi, Stafford Audi are concerned only with the emission discharge and NOT with the number of catalytic converters fitted.

GREAT news...

 

[Kohaku]

I did forget to mention.

They did however say there were two places where there were minor leaks of exhaust gases. Centre Front..Left & Right Clamps, not enough to affect the overall result though.

Presumably, a couple of nuts need an extra turn..So in theory all with bypass pipes should pass.

Also asvisory items say. Under-trays fitted obscuring some underside componenets & Engine covers fitted obscuring some components in the engine bay....?????

 

[45bvtc]

I did forget to mention.

They did however say there were two places where there were minor leaks of exhaust gases. Centre Front..Left & Right Clamps, not enough to affect the overall result though.

Presumably, a couple of nuts need an extra turn..So in theory all with bypass pipes should pass.

Also asvisory items say. Under-trays fitted obscuring some underside componenets & Engine covers fitted obscuring some components in the engine bay....?????

A GOOD point, Ian: BUT that'll NOT happen on BLUEY, as 'tis I that handles the spanners...

I even MAKE SURE that the nuts and bolts on the rear slider pipes/tubes are fitted the right way; Audi fit 'em upside (bolt) down...

 

[HullRs3]

Well after 18months from my original post, thanks for everyone's replies, help and advice.
I plan to have the Scorpion Cat Back Non Resonated System @ £870 with chrome tips fitted to my RS3.
These are currently on order so will have these fitted by the end if the month. Although they maybe £783 looking at Scorpions website as it looks like they are on offer at the moment.

 

[45bvtc]

DISREGARD what I wrote on July 30th...

After all my checking and MOT pre-check at Stafford Audi I present the car to them sans secondary cat by-pass pipes, and guess what; a potential MOT fail as the number of cats contained within the exhaust system is just the one and not the three fitted as standard!

And I'm happy with this as it clearly demonstrates again to me that Stafford Audi do the job properly...

And all is well as my favourite Audi dealer are now re-fitting my secondary cats pre MOT.

I'll be interested to feel how the car now drives with the secondary cats re-fitted, as with the by-pass pipes fitted, the engine seemed to breath more freely - and the exhaust noise was so much nicer... I may well be back to the by-pass pipes before we see the beginning of October, no worries!

 

[Paul-RS6]

I'm interested in your findings John, once you have lived with/without them.

Ultimate stealth would be to gut the secondary cats keeping the outer skins oem. I'm just not willing to gut mine or shell out an extortionate amount for second hand ones, if I was gutting them.

 

[45bvtc]

I'm interested in your findings John, once you have lived with/without them.

Ultimate stealth would be to gut the secondary cats keeping the outer skins oem. I'm just not willing to gut mine or shell out an extortionate amount for second hand ones, if I was gutting them.

Hey Paul, for me the difference is incidental, more 5-pot noise sans by-pass cats but not a lot more. I guess running without those expensive secondary cats is a bonus and is why I may well be re-fitting the by-pass pipes, and the noise. And I can re-fit the by-pass pipes in a very short time as I do have the facilities, tools, and ability.

Of greater interest, for me, is the emission difference: without the secondary cats it was:
CO @ 0.02%, HC @ 0ppm, and Lambda @ 1.01
WITH the secondary cats re-fitted the figures were:
CO @ 0.01%, HC @ 0ppm, and Lambda @ 1.02

This demonstrates the use of secondary catalytic converters - almost Zilch...

DO not blame Audi Stafford. DO NOT blame Audi. Blame those dipsticks in Brussels who legislated for use of catalytic converters rather than the use of lean-burn engines.

VW/AUDI for their sins have developed (as have other petrol engine producers) lean-burn engines making the adoption of expensive secondary catalytic converters useless.

I applaud the MOT gentleman at Stafford Audi for doing his job to the letter, and was as I expected anyway...

I have no respect at all for the technically ignorant Brussels politician who signs off such sh** legislation requiring the fitment of expensive secondary catalytic converters where the requirement is totally unnecessary.

GO Audi RS3 : for me the RS3 has the best engine/gearbox combination I've ever driven on UK roads - and I've driven some...