Exhaust options: more "growl" but not too loud?

[TonyHayers]

Done

(It actually isn't *quite* done - I'm in tomorrow to have the "wheel barrow handles" adjusted).

[pDkALO]

Ok a bit clearer. So working towards the engine from the pipes in the diagram there would be the main cats then the pre cats?

As tonyhayers says - yes.

main catalysts and pre (aka primary) catalysts come as a single component part, joined by a flexi stainless mesh "decoupler" - hence the complete OE exhaust system on the RS4 is made up of just 3 components

[MartayMcFly]

Booked my car in to Wallace Per4mance in Aberdeen for pre-cats degutting and a custom x-pipe to replace the res box. I'll have to get some 'before' clips for comparison, and haven't decided whether to go for flanges and collars or just welds.

[m14rrv]

i am looking into exhausts at the min and this x pipe keeps poping up, what does the x pipe do? i am going gutting pre cats, and non res miltek

just like to know difference with the x pipe

[MikeFish]

i am looking into exhausts at the min and this x pipe keeps poping up, what does the x pipe do? i am going gutting pre cats, and non res miltek

just like to know difference with the x pipe

It's been explained a dozen times already. Do a search for scavenging and I'm sure the answer will pop up.

[MartayMcFly]

i am looking into exhausts at the min and this x pipe keeps poping up, what does the x pipe do? i am going gutting pre cats, and non res miltek

just like to know difference with the x pipe

You won't need to get an x-pipe and the Milltek non-res pipes... go for Milltek back boxes and get a custom fabricator to knock up the x-pipe. Otherwise, you'll be paying Milltek for probably inferior steel that you're going to be cutting up anyway.

[MikeFish]

How much will a fabricator charge to make up that section and match it to the cats and milltek back box? The non res section is a couple of hundred quid from memory.

[alex020869]

Mike, I paid around £200 for getting the x-pipe made up to suit the original exhaust on mine.

Alex

[MartayMcFly]

How much will a fabricator charge to make up that section and match it to the cats and milltek back box? The non res section is a couple of hundred quid from memory.

I meant if going for an x-pipe. You could just get the Milltek system and not have the x.

[m14rrv]

i did a search for the x pipe, but not much came up just this tread, what gains do you get? or is it more of sound thing?

[maars]

I'm interested in improving the std exhaust. Lots of great ideas here. My question is ... What's the difference between an X pipe mod and gutting the pre-cats?

[MartayMcFly]

I'm interested in improving the std exhaust. Lots of great ideas here. My question is ... What's the difference between an X pipe mod and gutting the pre-cats?

x-pipe replaces the resonator with a cross=over section of pipe work, just ahead of the back boxes, sort of like a re-imagining of a non-res aftermarket system.

Pre-cats are on the downpipes and gutting them makes the downpipes less restrictive and can add 10-20bhp, but you still have the main cats in place.

They're separate mods, it's not one or the other but often both.

[maars]

Thanks for explaining.

How does an x pipe improve the standard setup?

What sort of noise/power gains does each/both give?

[brian5362]

http://youtu.be/EVM6z4iCMHU
This said it is standard exhaust with a x-pipe replacing the resonator section sound nice IMO

[TonyHayers]

X-pipe is a pretty good mod IMO (I might be biased tho!)
Mine cost couple hundred iirc and sounds grunty but without droning. I've done precats since too and that adds another dimension to the sound - a kind of rawness/throatiness that you get with c63 AMG to my ears.