Where is the 2nd catalytic converter on a 1995 Z28? The reason I ask is there is a large cylindrical thing just below the drivers exhaust manifold that I don't have a clue what it is or what it does. I am considering headers and need to know whether this 1995 has single or dual cat's. Thanks.

 

Did you mean passenger side? Where the hump is? That is your cat. I'm pretty sure that '95 was a single cat year.

 

I think 1995 was either or. Maybe a mixed year or something. The drivers side cat is just under the manifold in a vertical position. Its between the motor and wheelwell.

Im confused on what looks like a resonator or something between the pass. side cat and manifold. Dunno what it is.

 

Yes 1995 had both Single and Dual catalytic converter systems but I never new where the second was. Actually I thought the Dual system would look like the later models and have the cats located near each other under the passenger seat. So where does this leave me when I purchase headers? What year was the driver side cat relocated under teh passenger seat? Can I relocate the driver side cat to the later model system? I have not replaced spark plugs yet and I am guessing this will make a couple of the plugs a PITA. Anyone have first hand experience changing the spark plugs?

I am not familiar with or have seen any pics of your exhaust system. Pontiac should have an explosion of your exhaust system. I will try a Google search.

 

Thanks for the information. Do you know if there is an O2 sensor for the driver side exhaust? If not, I guess I could order the Single cat headers and Y-pipe. If so, I could relocate the O2 sensor to be positioned near the passenger side O2 sensor. Flash: if I am right (yeah right!) the exhaust of the driver side cat dumps into the passenger side cat. Is that right? If that is correct I could change the Y-pipe now and get better performance and gas mileage plus be able to get to the spark plugs easier. Any thoughts / suggestions?

 

Only 1995 CA A4 models were dual-cat.

The dual-cat configuration is identical to the dual-cat setup used on all 96 and 97 LT1's. They all have the drivers side cat bolted directly to the bottom of the drivers side exhaust manifold. The passenger side cat is in the same location as the earlier single-cat cars, but serves only the passenger side of the Y-pipe. The drivers and passenger sides merge AFTER the passenger side cat. The drivers side does not flow into the passenger side cat.

You have a pre-cat O2 sensor on each bank of the engine - just like very LT1 ever built. The drivers side is mounted at the base/outlet of the exhaust manifold, the passenger side is just below the exhaust manifold on the Y-pipe. Unlike the later OBD-II dual-cat cars, the 1995 CA A4 dual-cat cars are still OBD-I, and do not use after-cat O2 sensors.