Now that looks like a quality bit of work. Where was that exhaust made?
It was made by an independant in Nottingham, 'Wright Bro's Autos' and the guy's name is Dale. Doesn't have a website unfortunately but he came recommended to me and has done a few other audi exhausts.
He sent me a few pics of others he's done, A6, RS6 and Carl's A4, which I can forward if anyone's interested: drop me a PM
Would you mind saying what the setup is in full, for example regarding the catalyst, DPF, secondary cat, silencers etc. I'm looking to get something to improve my exhaust note on mine and unleash the growl (2k rpm +) of the V6 but don't want something too loud as I'm on the motorway everyday and have had bad experiences with boomy exhaust systems.
Setup is as follows: 1st CAT & downpipe is standard, from the downpipe back has all been replaced. Already had the DPF gutted/mapped out so no additional mapping was needed for the new exhaust. Downpipe goes into a straight through silencer (maybe 14" long?), then the pipe splits just before the quattro box and goes round the support struts/ARB etc, then two 4" tips on the end (no backboxes).
I was after exactly the same thing as you MaJiK, but honestly there is a bit of drone which unfortunately falls just at cruising speed (1700-2000rpm). Now I've been looking into ways to counter this and aside from coating the floor of the car in sound deadening material, I found the concept of adding a 'Side-Branch Resonator' which can be used to eliminate specific resonant freqnencies. Sounds like a good idea and it's what companies like Miltek use inside their backboxes to give a 'tuned' system:
According to my calculations (lab coat on at this point), for a 6 cyl engine with a resonante freq of 'X', the pipe length should be 'Y':
RPM = 1700 L = 1.009m
RPM = 1800 L = 0.953m
RPM = 1900 L = 0.903m
RPM = 2000 L = 0.858m
RPM = 2100 L = 0.817m
RPM = 2200 L = 0.780m
So ideally you'd make the pipe length adjustable to change the frequency response, as the res freq changes which exhaust gas temps (hence why the sound different on start-up and after a run) and it's not an exact science. But if the side res runs parallel to the main exhaust it HAS to be a mandrel bend, otherwise it messes with the pressure waves and doesn't work correctly...
Found this on a US forum for Corvettes and Trucks, a lot of those guys swear by it. Having said that those guys have V8s which require a shorter pipe length to get the same res freq...