Size of Stock Cat Exhaust Piping?

[IDM]

I'm going to remove the stock cats and put on straight pipes.

If I cut around the cats, what exact size pipe can I use to slip over or slip inside the pipes with clamps? It seems like a straight shot so I don't see why this wouldn't work.

Any suggestions would be appreciated as local shops will not cut the cats out and one seems to be clogged.

 

[Steve-Indy]

2 1/2 inches.

 

[IDM]

Thanks a lot is this OD or ID?

I bought some pipe but the adapters may take cutting the cats off to figure it out

 

[steve e]

The car will run alot better, and sound great, and so much cooler as in temp, but you need to swap out your ECU to an off road ECU, that is not looking for the rear O2 sensors, if you do not change the ECU the check engine light will come on.

 

[IDM]

Or Sims correct? I think sims would be the cheaper way than ECU no?

 

[DaJerseyViper]

The piping is 2.5" O.D. but you have to have both ends swelled to a 2.5" I.D. to slip over. Roe racing sells these in SS for $120 with all the hardware. I just wish someone would make a full straight pipe from the header direct to the exhaust, as I dont want to cut up my OEM exhaust. Also for the o2 sensors, you may have luck with a sparkplug non fouler from Autozone if it threads in.I have used them in the past and its hit or miss. They pull the O2 directly out of the stream so it does not get an accurate reading and tricks the PCM into thinking the rear O2's are working fine..

 

[Sybil TF]

The car will run alot better, and sound great, and so much cooler as in temp, but you need to swap out your ECU to an off road ECU, that is not looking for the rear O2 sensors, if you do not change the ECU the check engine light will come on.

Simms, or you can get a can tune for like 160.00 that turns off the the rear O2's but you you need an SCT tool or some remove the O2's from the exhaust still leaving them connected and zip tie them up underneath and get a screw in plug for the exhaust.

I'm going with the tune and dumping my cats this spring.