S4 avant Full stainless exhaust swap.

Glenryck

Registered User
Hi all I have a b7 s4 auto and it has a full hand made stainless exhaust inc 200 cell sports cats, the previous owner had it made and fitted at a cost of over £2000 it sounds awesome when under power and tick over but it has the dreaded drone when normal driving around town motorways are fine above 60 mph. So my question is do I just get a standard exhaust inc cats and swap it over or would it be worth changing the back boxes for another set of larger bespoke items or even get a standard set of back boxes made to fit my system also does anyone know if the s5 back boxes are the same as the s4. Thanks.
 

Nollywood

B7 420-R Avant
S5 rear mufflers are different, so won’t fit, not without significant reworking though.

As for getting rid of the drone...it would depend on what part of the stainless system is causing it. Cutting out mid or rear mufflers is really a hit and miss affair. Despite the previous owner saying it cost over £2000, it could still be a cheap system, and so will drone at different frequencies. It could even be the CAT’s causing the drone.

For the money spent, I would have gone with Milltek, which is a quality, tried and tested system. Your easiest option right now, is to revert to stock. You may well chop up the current system, and not get rid of the drone, or shift it further or lower down in the rpm range. Of course, this will make it hard to sell.
 

Baka

Registered User
I was reading a blog where a guy got a 2000 rpm drone after fitting a high flow cat and down pipe to his MK7 Golf.

He spoke to a exhaust company, and they explained that the new parts had moved the resonant point away from the one the factory resonator was designed to deal with. They fitted a slightly larger resonator and he was very happy wit the results, might be worth looking into?
 

Glenryck

Registered User
Thanks guys I am going to see a specialist v8 engineer/ mechanic later this week the exhaust is a work of art it’s a shame you can’t see it but like you have both said it could be cats, center res box or back box the only thing I would say is that the back boxes are fairly small and they are straight through you can see the perforated pipes and straight into the 65mm tube.
 
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