Decat options
Decat options
Anyone running full decats? how bad is the extra noise and smell? Trying to decide on full decat or just gut precats thanks
Re: Decat options
My old B7 S4 was decatted and I plan to do the same to the RS.
The S4 was loud as hell and a bit smelly but I soon get used to the smell and I never really got tired of the racket it made! The Mrs absolutely hated it, too loud for her.
The set up was 2.5" custom DP's and non res Miltek cat back. Worth noting when the DP's were added I did notice more rasp high up on the revs.
The RS has gutted pre cats and stock cat back just now so it's really quiet compared to what I'm used to. I'm considering binning the resonators for a bit more sound until I decide on what system to get.
The S4 was loud as hell and a bit smelly but I soon get used to the smell and I never really got tired of the racket it made! The Mrs absolutely hated it, too loud for her.
The set up was 2.5" custom DP's and non res Miltek cat back. Worth noting when the DP's were added I did notice more rasp high up on the revs.
The RS has gutted pre cats and stock cat back just now so it's really quiet compared to what I'm used to. I'm considering binning the resonators for a bit more sound until I decide on what system to get.
Current - 07 Sprint Blue RS4 Avant Black optics / Buckets / FBSW / MRC Stage 2 / De flapped Manifold / CAF / BMC filter / Decat / Non Res Miltek / Bilstein B16's / Tarox discs, pads and lines / H&R ARBs / 19x9.5 Ispiri ISR1 wheels / MPSS tyres / DTM carbon splitter
Previous - 06 Sprint Blue B7 S4 Avant JHM 91 tune / 2.5" Custom Cat-less DP's / Miltek Non Res Cat back / BMC filter / H&R springs / 19" Fox MS007 wheels/Good Year F1's / EBC TG discs / Yellow stuff pads
Previous - 06 Sprint Blue B7 S4 Avant JHM 91 tune / 2.5" Custom Cat-less DP's / Miltek Non Res Cat back / BMC filter / H&R springs / 19" Fox MS007 wheels/Good Year F1's / EBC TG discs / Yellow stuff pads
Re: Decat options
It's good for a giggle but otherwise I don't find a full decat suiting the car much. It's supposed to be at least somewhat grown up and civilized - not a scoobie or EVO driven by a chap with his cap on backwards. The smell is worse for the people behind you in a queue, not so much an issue driving the car. It's also likely to smoke a little without any cats. It's just unnecessary.
Keeping the main cats and fitting a suitable exhaust is way preferable. You can make it more than loud enough whilst keeping the main cats and avoid most of the "clatter" sound.
Keeping the main cats and fitting a suitable exhaust is way preferable. You can make it more than loud enough whilst keeping the main cats and avoid most of the "clatter" sound.
B7 RS4 saloon Misano red, comfy seats, JHM tune & JHM full exhaust with cats and resonators - gone.
C5 RS6 Avant Daytona/Cognac - gone.
981 Cayman GTS Gray/Orange.
My youtube
C5 RS6 Avant Daytona/Cognac - gone.
981 Cayman GTS Gray/Orange.
My youtube
Re: Decat options
I have Milltek decat pipes and a non res valved exhaust. There is no smell other than a normal exhaust and it's quiter than with OEM cats and the same exhuast. Valves closed helps.
RS4 B7, Mugello Blue, K&W V3 & HR ARBs, set up by Centre Gravity, Milltek Valved Non Res & cat bypass pipes, BMC air filter, braided hoses, DOT 5.1, Terraclean, MRC Full Carbon Clean, MRC remap 448PS 477NM, 20" S7 alloys with 4mm spacers & Hawke spigots 66.6 > 57.1, AP Racing front discs. Sold Sept 2019. Now rocking an F80 M3
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RossDagley
- Top Gear
- Posts: 2334
- Joined: Mon Mar 17, 2014 11:53 pm
- Location: Bedford, UK
Re: Decat options
But... flames!
http://www.youtube.com/watch?v=8J3E5IebpkM&t=0m56s
That's full milltek, non-res, non valved. I wish I'd kept valves tbh simply for when you do want it quiet but when you want it loud, it's like the devil gargling nails.
Personally I'd say if you've got a friendly MOT place, get it done (but keep a valved system). The sound is amazing.
http://www.youtube.com/watch?v=8J3E5IebpkM&t=0m56s
That's full milltek, non-res, non valved. I wish I'd kept valves tbh simply for when you do want it quiet but when you want it loud, it's like the devil gargling nails.
Personally I'd say if you've got a friendly MOT place, get it done (but keep a valved system). The sound is amazing.
Believe only the man who has nothing to gain from what he says.
2017 BMW M4 Competition Pack - Mineral Grey - 530ps by bootmod3, JCWeldfab exhaust.
Previously:
Renault Megane R26 - Liquid Yellow - 275ps.
2015 Audi Exclusive RS4 B8 - Merlin Purple - JCWF Exhaust
2009 Audi RS6 C6 - Phantom Black - 730ps MRC Tuned
2008 Audi RS4 B7 - Phantom Black - 449ps MRC Tuned
2002 Peugeot 106 Gti - Mauritius blue - 430ps Home built.
2017 BMW M4 Competition Pack - Mineral Grey - 530ps by bootmod3, JCWeldfab exhaust.
Previously:
Renault Megane R26 - Liquid Yellow - 275ps.
2015 Audi Exclusive RS4 B8 - Merlin Purple - JCWF Exhaust
2009 Audi RS6 C6 - Phantom Black - 730ps MRC Tuned
2008 Audi RS4 B7 - Phantom Black - 449ps MRC Tuned
2002 Peugeot 106 Gti - Mauritius blue - 430ps Home built.
Re: Decat options
Covkiller wrote:I have Milltek decat pipes and a non res valved exhaust. There is no smell other than a normal exhaust and it's quiter than with OEM cats and the same exhuast. Valves closed helps.
Really? That sounds interesting. I have a non res valved milly I find it just enough was worried decay might tip it over the edge
Re: Decat options
Serious, my little girl and even the wife thought it was quieter.
RS4 B7, Mugello Blue, K&W V3 & HR ARBs, set up by Centre Gravity, Milltek Valved Non Res & cat bypass pipes, BMC air filter, braided hoses, DOT 5.1, Terraclean, MRC Full Carbon Clean, MRC remap 448PS 477NM, 20" S7 alloys with 4mm spacers & Hawke spigots 66.6 > 57.1, AP Racing front discs. Sold Sept 2019. Now rocking an F80 M3
Re: Decat options
No cats in mine at all, doesn't sound loud to me, noise isn't obtrusive inside the car whatsoever.
Misano Red| Black Optics| Black alloys| Black mirrors| Full CC at MRC| MRC Stage 2 Manifold| MRC Stage 2 Remap| De-Catted| KW V3 with H&R Fr & rear ARB| H&R Hubcentric spacers 8mm Fr, 10mm rear| A few choice CF goodies to go on|
Re: Decat options
Iv heard a fully decatted RS4 at full chat and it was scary loud from the pavement. Literally everyone was turning around and looking and not in a goodway. Sounded like a unsilenced racecar and didnt suit the car imo the low frequency bass was lost , which I love about the car. It was literally just noise, I think a balance needs to be struck with naturally aspirated cars as they can lose some of the character when going fully straight through and becomes just loud noise.
On a turbo charged car I can understand , because the turbos muffle the sound compared to NA cars and least back pressure is mostly better. Dont NA engines require some form of back pressure?
On a turbo charged car I can understand , because the turbos muffle the sound compared to NA cars and least back pressure is mostly better. Dont NA engines require some form of back pressure?
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RossDagley
- Top Gear
- Posts: 2334
- Joined: Mon Mar 17, 2014 11:53 pm
- Location: Bedford, UK
Re: Decat options
No that's a myth. (Unless we're talking about two stroke engines).
Believe only the man who has nothing to gain from what he says.
2017 BMW M4 Competition Pack - Mineral Grey - 530ps by bootmod3, JCWeldfab exhaust.
Previously:
Renault Megane R26 - Liquid Yellow - 275ps.
2015 Audi Exclusive RS4 B8 - Merlin Purple - JCWF Exhaust
2009 Audi RS6 C6 - Phantom Black - 730ps MRC Tuned
2008 Audi RS4 B7 - Phantom Black - 449ps MRC Tuned
2002 Peugeot 106 Gti - Mauritius blue - 430ps Home built.
2017 BMW M4 Competition Pack - Mineral Grey - 530ps by bootmod3, JCWeldfab exhaust.
Previously:
Renault Megane R26 - Liquid Yellow - 275ps.
2015 Audi Exclusive RS4 B8 - Merlin Purple - JCWF Exhaust
2009 Audi RS6 C6 - Phantom Black - 730ps MRC Tuned
2008 Audi RS4 B7 - Phantom Black - 449ps MRC Tuned
2002 Peugeot 106 Gti - Mauritius blue - 430ps Home built.
Re: Decat options
The vortex exhaust on my car when I bought it was effectively decatted, with no centre silencers, just backboxes. It was way too loud for me (and the wife and the neighbours), and droned pretty badly around 2k revs. The first few times I drove it, I've got to say that the fumes/smell did get to me a bit too. Put a grin on my face when driving on my own somewhere I could give it the beans, but just couldn't live with it.
I've now got OE cats but precats deleted, x-pipe centre (no resonator), and OE backboxes with flaps stuck open. The volume level is just right for me (probably too quiet for some), no drone, and no smell.
Have you considered getting someone to cut the precats out completely, retaining the OE cats, rather than gutting them? Should mean that you have no grief at MOT time too, whilst still getting some performance benefit.
I've now got OE cats but precats deleted, x-pipe centre (no resonator), and OE backboxes with flaps stuck open. The volume level is just right for me (probably too quiet for some), no drone, and no smell.
Have you considered getting someone to cut the precats out completely, retaining the OE cats, rather than gutting them? Should mean that you have no grief at MOT time too, whilst still getting some performance benefit.
2007 RS4 B7 Avant
Phantom Black | Black Optics | MRC Stage 2 | JC Weldfab Exhaust | KW V3 coilovers | H&R ARBs | 20" Ispiri ISR-8 | Titanium wing mirrors | Driving Passion Diffuser | CF Air Intake | Manifold deflap | Alcantara/leather retrim | TT RS Steering Wheel | Pioneer Apple Carplay HU, JL amp and sub, Focal components | Clear Headlight Lenses, Black Internals, 6000K Bulbs | Trups LEDs | LED Tail lights |
Re: Decat options
^I was thinking about X pipe. Is there much tone difference between the X and H? Don't suppose you've got any sound clips?
Current - 07 Sprint Blue RS4 Avant Black optics / Buckets / FBSW / MRC Stage 2 / De flapped Manifold / CAF / BMC filter / Decat / Non Res Miltek / Bilstein B16's / Tarox discs, pads and lines / H&R ARBs / 19x9.5 Ispiri ISR1 wheels / MPSS tyres / DTM carbon splitter
Previous - 06 Sprint Blue B7 S4 Avant JHM 91 tune / 2.5" Custom Cat-less DP's / Miltek Non Res Cat back / BMC filter / H&R springs / 19" Fox MS007 wheels/Good Year F1's / EBC TG discs / Yellow stuff pads
Previous - 06 Sprint Blue B7 S4 Avant JHM 91 tune / 2.5" Custom Cat-less DP's / Miltek Non Res Cat back / BMC filter / H&R springs / 19" Fox MS007 wheels/Good Year F1's / EBC TG discs / Yellow stuff pads
Re: Decat options
Sorry, no sound clips of mine. I did find some on YouTube though when I was investigating before getting it done.ASC wrote:^I was thinking about X pipe. Is there much tone difference between the X and H? Don't suppose you've got any sound clips?
2007 RS4 B7 Avant
Phantom Black | Black Optics | MRC Stage 2 | JC Weldfab Exhaust | KW V3 coilovers | H&R ARBs | 20" Ispiri ISR-8 | Titanium wing mirrors | Driving Passion Diffuser | CF Air Intake | Manifold deflap | Alcantara/leather retrim | TT RS Steering Wheel | Pioneer Apple Carplay HU, JL amp and sub, Focal components | Clear Headlight Lenses, Black Internals, 6000K Bulbs | Trups LEDs | LED Tail lights |
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