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Downpipes and straight through exhausts

Posted: Sun Oct 14, 2007 9:13 pm
by viperbl
Does anyone know the width of the RS4 downpipes?

I assume that 3" downpipes are wider and the optimal width?

Also, how loud would an straight through exhaust be? ie, just a pipe(s) from the downpipes to the back, no box or anything inbetween?? Anyone done this?

As for the 3" downpipes etc, can these be bought off the shelf and fit straight on to KO4's or do they need to be custom made?

Can anyone recommend a company to make the above? prices etc?

RE: Downpipes and straight through exhausts

Posted: Sun Oct 14, 2007 9:16 pm
by MarkB
MRC do the 3" downpipes AFAIK

The RS4 downpipes are 65mm I thick, if you want I can confirm for you, they're just sat in the garage...

Doug was running about 99/100 db at the noise test Saturday with I think just a rear box on his duel system.

Re: RE: Downpipes and straight through exhausts

Posted: Sun Oct 14, 2007 9:23 pm
by viperbl
MarkB wrote:MRC do the 3" downpipes AFAIK

The RS4 downpipes are 65mm I thick, if you want I can confirm for you, they're just sat in the garage...

Doug was running about 99/100 db at the noise test Saturday with I think just a rear box on his duel system.
Cheers Mark,

so thats around 2 1/2 inches ...

My thinking was, depending on price, get a nice striaght through pipe for max performance when needed but a quiter proper exhaust for every day driving, if changing from the downpipes it should not be too difficult or time consuming to change over ...

RE: Re: RE: Downpipes and straight through exhausts

Posted: Sun Oct 14, 2007 9:28 pm
by s4woody
RSfabrication made leons exhaust system and i believe doug's and maybe flashG's...sounds awesome..although leon was thinking of having some sort of extra baffle or noise reduction box fitted cos of the sound/drone..

RE: Re: RE: Downpipes and straight through exhausts

Posted: Sun Oct 14, 2007 11:46 pm
by flashyg
Rs exhaust is top quality, I went for 2 boxes and it is utterly civilised but still damned loud.

Re: RE: Downpipes and straight through exhausts

Posted: Mon Oct 15, 2007 9:09 am
by MarkB
viperbl wrote:
My thinking was, depending on price, get a nice striaght through pipe for max performance when needed but a quiter proper exhaust for every day driving, if changing from the downpipes it should not be too difficult or time consuming to change over ...
Aren't most 'events' noise restricted though?

With the amount of air I should think your turbo's are trying to shift you should see a resonable gain by going for larger downpipes and exhaust.

RE: Re: RE: Downpipes and straight through exhausts

Posted: Mon Oct 15, 2007 9:15 am
by DavidT
Most events are 98db standing, some are 98db driveby. There are very few at 105 or unrestricted.

My car is pretty loud but only read 95db at the noise test on Saturday (Milltek downpipes with 100cel cats & Milltek Dual). Dunno what Doug's was but he obviously passed and was sounding good as it went by the pits. Unlike any other B5 thats for sure :)

RE: Re: RE: Downpipes and straight through exhausts

Posted: Mon Oct 15, 2007 9:18 am
by MarkB
I was told his read 99db before going out. He got called back in to test again and read 100db but they still let him back out.

He was running one of the loudest cars there and did sound quite different to all the other B5's

Re: RE: Downpipes and straight through exhausts

Posted: Mon Oct 15, 2007 9:50 am
by viperbl
MarkB wrote: Aren't most 'events' noise restricted though?

With the amount of air I should think your turbo's are trying to shift you should see a resonable gain by going for larger downpipes and exhaust.
That is true, but the hillclimb out here I think is unrestricted ... can't remember any testing gear last year, and there where one or two very noisy cars ...

I think the Milltek I have is not very good, as its quite restrictive???, its getting on a bit now, one of the first mods I did ...

Picture if anyone can confirm ...
Image

RE: Re: RE: Downpipes and straight through exhausts

Posted: Mon Oct 15, 2007 10:02 am
by MarkB
That does look quite used. I think you need to get a quote for an RS Fabs system. They do look the well made and should flow extreemly well. Think you'll need to go through MRC for it.

RE: Re: RE: Downpipes and straight through exhausts

Posted: Mon Oct 15, 2007 10:06 am
by DavidT
I think someone on here will have the Milltek too :)

RE: Re: RE: Downpipes and straight through exhausts

Posted: Mon Oct 15, 2007 10:09 am
by viperbl
I spoke to Doug about RS when at the ring, and I thinking they are looking like the best choice for this ... although, could I live with Doug's exhaust? Not sure, its pretty dam loud!!

I did see a neat little trick with a Germany RS4, he had a remote control which closed off one of the pipes! and certainly reduced the noise for pottering around town ...

RE: Re: RE: Downpipes and straight through exhausts

Posted: Mon Oct 15, 2007 10:11 am
by MarkB
Is Doug running a single box or dual?

I couldn't/wouldn't want to live with that much noise.

RE: Re: RE: Downpipes and straight through exhausts

Posted: Mon Oct 15, 2007 10:14 am
by DavidT
Nor could I, mine would be too loud if I had to drive every day.

Re: RE: Re: RE: Downpipes and straight through exhausts

Posted: Mon Oct 15, 2007 10:19 am
by viperbl
MarkB wrote:Is Doug running a single box or dual?
Single I believe ...