crusininda944

So, my car had been sitting for 3 months and now that it is being driven again it seems that there are some issues.

My car is really noisy, and I got it checked out and the mechanic says it's a bad catalytic converter. Naturally, he pointed me in the new parts direction which was 1600 for oem cats via the dealer.

I have read on here that you can replace the factory cats with universal aftermarket, and am looking in that direction.


However, I am not sure as to the specific aftermarket cat to purchase.
I have been on hottexhaust.com looking at universal cats, but am having problems deciding which would is the one I need.
I'm looking towards hi-flow cats, but cannot find the correct size.

What size cat do our cars take? 2", 2.5", or 3"?
Also, they have to have the O2 ports, right?

Who else has replaced their cats with aftermarket ones?
I could use some ideas.

Thanks.

EDIGREG

You can get universal Magnaflow units pretty cheap...the stock piping is approx 2.25''. I went with 3'' inlet/outlet since I'm using only one. Recently passed emissions with flying colors. The universal units dont come with O2 bungs, but you can have the exhaust shop weld them in quickly/inexpensively.

<a href="http://edsaudi12v.com/audi/mfexhaust">My exhaust</a>

islingtonaudi

The size is 2.25". Try Hottexhaust.com for good prices on universal cats, under $100.

crusininda944

2.25 inches and it's a high capacity and high flow cat with a built in O2 boss. Would this work with A6 O2s?<ul><li><a href="http://www.hottexhaust.com/detail.asp?PRODUCT_ID=93535">http://www.hottexhaust.com/detail.asp?PRODUCT_ID=93535</a></li></ul>

EDIGREG

The only difference is OBD2 has post-cat O2 sensors. That cat looks perfect, but I wonder why it's so expensive compared to my larger 3" which was only $64? Ebay prices are consistent with that site, around $110.

EDIGREG

FWIW, I know Mance used/uses Magnaflow #94009 (same cat as my OBD1) on his OBD2 90.

EDIGREG

Auction says it's OBD2 compliant as well, although not in CA.<ul><li><a href="http://cgi.ebay.com/ebaymotors/2-25-2-1-4-Magnaflow-Catalytic-Cat-Converter-94105_W0QQcmdZViewItemQQ_trkparmsZ39Q3a1Q7c66Q3a4Q 7c65Q3a15Q7c240Q3a1318QQ_trksidZp3286Q2ec0Q2em14QQ hashZitem150283353039QQitemZ150283353039QQtimeoutZ 1218755

SCarGo02

"Mances OBD2 90"? All Pre-'96 Audis were OBD I...

EDIGREG

<img src="http://edsaudi12v.com/obd2.jpg">

SCarGo02

...factory. No 90s were ever OBD II though, just 2 pre-cat O2s. :-)