They only need to test both sides if the sides are not connected with H pipe or X pipe. On A8 or S8 it is enough to test just one as they are connected with H-pipe. Also on true dual system where pipes are not connected I though if one side is over limit it is a fail, they do not take average, just the highest of 2 readings.

Well I managed to package both cats into a bicycle cardboard box and ship them via UPS and xxxxxxxxxx for just under £30 on Monday. They've been received today and I've paid the invoice via IBAN now I've had the total confirmed for refurbishing them both.

With exchange and processing fees from my bank the refurbishment and return shipping has come in just under £720

Not sure when they'll be shipped back to me - I suspect it will mostly depend on how long the payment takes to reach them, rather than the actual work!

ETA - have removed the reference to the company I used for shipping. They have 'hero' in their name but I cannot recommend their services, based on the speculative invoice for an extra £50 that they've sent me after the fact, claiming I misrepresented the dimensions of the box after an 'audit' by UPS of my parcel. Funnily enough UPS have confirmed they've done no such thing...

Well the cats arrived unannounced at David's workshop yesterday, all safe and sound :)

New internals visible through the ends:

http://forum.a8parts.co.uk/attachmen...1&d=1478004767

They've both been fitted, together with a new post cat lambda probe on the nearside.

I haven't picked the car up yet as David's going to road test and check over, but should have it back later today :)

Apols the photos are on the wonk!

Those cores look much better than the ceramic Audi stock ones. The new ones look like metal, spiral wrapped, hopefully should last much longer than the ceramic.

The S8 is now back home with me - a total of 8 working days turnaround from cats coming off to car being completed. They were shipped on a Monday, arrived Weds in Germany and as far I can tell were probably return shipped on Thursday, given that they turned up on the Monday morning in the UK!

As I mentioned before the cost of re-coring both cats, including return delivery was just under £720, plus £30 to get them to Germany, so call it £750 all in for the cats.

Removal and fitting, the cost of which you'd have whether fitting new or refurbished, came in at £270. Lambda probe was the only unexpected element at £110.

So all in I've spent £1,130 to have it back how it should be....

Sounds a lot, but if I'd gone the OEM route I would've spent £950 for one cat, plus probably £180 for fitting, just for the offside one so exactly the same spend!

I haven't driven it far yet, but the exhaust now sounds a lot sweeter - I suspect the failing cat was upsetting the exhaust balance. Not having a distinct rattle coming from under the car is also reminding me how smooth it used to sound!

It will be interesting to see if I can detect any difference in performance once I've had an opportunity to warm it through properly and exercise the engine a bit more :D

My cat had broken up so much, a large piece was at a 45 angle to the rear of the cat and partially blocking the exhaust. Its amazing how different the car feels now in 1st gear, I've got a bit of quattro-shunt, and now with the damaged cat gone its much less pronounced and smoother. Maybe a big part of the 'shunt' when going on and off throttle in 1st was due to the cat blocking the pipe.

Hi Adrian - I've got the same Cat problem - nasty rattle. Makes a nice noise when under full chat but I'm definately feeling a loss of performance since the Cat started rattling. Sounds nice but it seems to have lost its smooth pickup and shove above 3k revs.

Did you experience the same and was there a noticeable performance diff when you got your new cats on?

Mossy

Hiya

Mine developed a pretty mild rattle at idle - mainly when hot - and performance wasn't altered. I think usually that only happens if the cat breaks up and a piece gets stuck blocking the exhaust.

My car had a Milltek and I did notice it was a little more metallic sounding with the new metal cats (sounded better to me!) but I didn't do that many miles on them before I sold the car.

Hopefully the cats are working well - current owner may chip in :D

exhaust
 

Hi
talking exhaust can anyone tell me if the front box the one that bolts to the cats is this still available? also is this crossover box needed? any help would be great as my car is jacked up with no exhaust. cheers