Audi A4 3.0l V6 - obd 421 & 431 - cats are going
 

Hi,
I have 200k on my 2003 A4. Started to get cel with 421 & 431...cat efficiency low. Cel is annoying.
Otherwise, no performance deterioration at least i can sense.

Few weeks ago passed the etest with flying colors. Am not sure why i am getting this fault code. I read somewhere Audi's ems is too sensitive to cat thresholds...

Anyone had similar problems?

Talk to the dealer who wanted $2060 parts + labour; for 2 cats;

Aftermarket cat prices range between 300-500.

Some mechanics are suggesting that the aftermarket cats won't last as long.

Anyone dealt with same problems? Which cats; OEM or aftermarket (Magnaflow,eastern,DEC, Bosal)
Thanks

Re: Audi A4 3.0l V6 - obd 421 & 431 - cats are going
 

Try LaBree Motorsports. http://labreemotorsports.com/products_vw.html
https://www.audiforum.ca/attachment....ine=1331174832
These are for a manual trans only. Didn't check for automatic.
Thats what I was sent. $1100. total for the pair to the door.
Only one problem the flexpipe is too low and hits my trans support and makes noise
when you get on the gas hard.
And a year later I am getting the same low efficientcy CEL codes again.
Sorry i don't have a better answer for you but NO one does good CATS and downpipes for
the 3L.
I am trying to get a company called 42Draftdesigns
http://www.42draftdesigns.com/ to make me a good set but I haven't
gotten them to do the R&D for them yet.

Send them an e-mail saying you want them to make you a set if you have a manual.
I am trying to get them to use my car for the R&D.
Hope you solve your problem soon.
Good luck.......

Re: Audi A4 3.0l V6 - obd 421 & 431 - cats are going
 

Thank you for your feedback.
I spoke to one audi mechanic and he strongly recommended me not to get after-market cats because in his long years of experience the cel reappears within a short while. Apparently the after-market cats are cheaper because they use less of an expensive metal (Platinum) that is needed for the cat's core. I was skeptical about that, but your experience seems to confirms his opinion.
Have you come across any independent evaluation of after-market cats? Why didn't you go for the most commonly known cats; Bosal, DEC, Magnaflow etc. who seems to offer 4yr/50k warranty.

Re: Audi A4 3.0l V6 - obd 421 & 431 - cats are going
 

Also Audi's ECU has a high tolerance and the aftermarket CATS just don't cut it.
I hear no CATS and chipping it solves the whole high cost of replacing them over and over.

Labree says 5 years also. Fit almost perfect.
Problem is with Bosal, DEC, Magnaflow they have to be fabbed to fit.
I did research and everyone said they all suck.
So I went with LaBree.