Does anyone know if the Cat converters from a 2003 C4S will fit a 1999 C2. The only noted difference is the placement of the oxygen sensors. On the C2 Cats the sensors are before and after the Cat. On the C4S Cats there is one before and one in the middle of the Cat.

Has me a little confused as the tech sheets for the 996 show the sensors before and after the Cat (same with the ones on my C2). But the Cats I have from the C4S have a senor mounting hole before and then one right in the middle of the Cat. No mounting hole after. The tech sheet for the 997 shows the sensor in the middle of the Cat but the ones I have are clearly stamped 996.

 

I try a set of 03' 996 gt3 cats on my 99' 996. everything fits, but the angle of the O2 sensors. The O2 sensors opening are at an angle which will not clear the under support mount.

 

Thats interesting because the tech manuals for the 996 C2 and the 996 GT3 show identical placement of the sensors on the Cats. The GT3 Cats look like they should fit. Part numbers are very simular too. Must be one of those little differences.

 

Ya, everything looked good. That is why I invested the time to try the install. needless to say I was disappointed.

 

What did you end up replacing with?

 

had the stock one put back in. The GT cats were my friends and he replaced it with a fabspeed set. It was just sitting around, So I thought I'll give it a shot. Look like it'll work at the time. Never thought the O2 opening angle would do the project in.

 

Plug up the existing o2 hole and havea new 'stock' o2 bung welded in.