Which replacement cat is good?

[Mrluckies]

I’ve got a p0420 code on a used 2009 a4 that we just picked up. It has a replacement engine with a generic aftermarket cat in it. My mechanic said that Audis don’t like aftermarket cats and didn’t see any other issues with the car/cat. Does anyone know a good brand cat I can buy to replace it? I assume the $100 eBay cats are probably the same as what is already in the car and will cause issues? There was an “allstar exhaust systems” cat on eBay for $110 that made in Canada - anyone used these?

Are the walker epa approved direct fit 16595 or AP Eastern epa approved direct fit cats 644025 any good? I don’t mind spending a little more to get a cat that will fix the CEL, but I can’t spend $3k to get an Audi brand replacement cat. I don’t care about high flow or any of that. I just want the check engine light to go out so I can pass inspection. They only plug in the scanner and look for codes. However, you can’t have anything turned off. If you erase the codes, you have to drive the car 50-100 miles so that all the checks come back online.

Appreciate any advice on brands that work.

[scsu]

I’ve got a p0420 code on a used 2009 a4 that we just picked up. It has a replacement engine with a generic aftermarket cat in it. My mechanic said that Audis don’t like aftermarket cats and didn’t see any other issues with the car/cat. Does anyone know a good brand cat I can buy to replace it? I assume the $100 eBay cats are probably the same as what is already in the car and will cause issues? There was an “allstar exhaust systems” cat on eBay for $110 that made in Canada - anyone used these?

Are the walker epa approved direct fit 16595 or AP Eastern epa approved direct fit cats 644025 any good? I don’t mind spending a little more to get a cat that will fix the CEL, but I can’t spend $3k to get an Audi brand replacement cat. I don’t care about high flow or any of that. I just want the check engine light to go out so I can pass inspection. They only plug in the scanner and look for codes. However, you can’t have anything turned off. If you erase the codes, you have to drive the car 50-100 miles so that all the checks come back online.

Appreciate any advice on brands that work.

The NAPA house brand work fine. I've used dozens and never had a problem. I don't know what company makes their house brand.

Sent from my SM-G981V using Audizine Forum mobile app

[Mrluckies]

Thx. Was this on any Audis?

[scsu]

No. Closest would be a couple of VW.

Sent from my SM-G981V using Audizine Forum mobile app

[Mrluckies]

Ok thx. I imagine the computer software/sensitivity is probably the same.

How many miles have you put on the NAPA cats?

I believe Walker makes the NAPA cats (it’s the same numbers). I know they make a bunch of the other exhaust stuff for them. And if I remember correctly they make dynomax too.

[scsu]

I can't really say on the mileage as the vehicles are part of a fleet. Some only get maybe 2,000 per year, others 40,000. The only one that sticks out is a 2015 Lincoln Navigator that gets around 30,000 per year and its cat was replaced sometime in 2017. I can say that we haven't had a NAPA fail.

Sent from my SM-G981V using Audizine Forum mobile app

[Mrluckies]

Awesome, thx!