B7 S4 V8 downpipes blocked, stuck for what to do?

[ramboDTM]

My Auto B7 S4 had miltek sports cats fitted to it when I bought it, which at the time was great. However, according to the ECU, both cats are now blocked/restricted. Seeing as the sport cats are basically just a pre cat, with no main cat, it means I cant just smash the cats out.

So I'm either on the look out for a pair of standard Auto downpipes which I can fit, or I get an exhaust shop to cut the pre cats out, and weld in some new cats further back. Which also brings me onto...any ideas on a suitable pair of cats that can be welded in? lol

any info on anything downpipe related would be great, as I really want to avoid spending over a grand to buy new OEM downpipes, and then piggy them lol!!

 

[Sam1989]

I think 200 cell sport cats would be ok. I was thinking of having some made for mine. I didn’t think the miltek ones fitted as it says they are just for manuals but must be a way around that! I’m dreading taking mine off. If I’m brave enough I’ll tackle it to gut the precat. But from what I’ve heard 200 cell sport cats pass emissions fine

 

[ramboDTM]

As far as I know, the Miltek's are 200 cell, but I could be wrong on that lol. But if that is the case, then yeh, you're right, a 200cell would be fine!

If you look hard enough, you can find places that used to sell the automatic miltek downpipes, so I assume thats what is fitted to mine, but for some reason they dont do them anymore. I personally wouldn't bother with the milteks anyway because they cause the same problem as the standard downpipes do. The sports cat is in the same place that the pre cat is, so right next to the exhaust manifolds, restricting flow and increasing back pressure.

If I was you, just gut the precats, as its been proven in USA that gutting the pre cats on a standard exhaust does more than an aftermarket sports cat with cats close to the exhaust manifolds.