NCross

iTrader: (18)

I'm just curious if I were to get bored one day and gut my pre-cats, but retain my main cat... would the aux. ports operate? I don't need to pass emissions. I'd just like to get a bit more flow and sound out of it.

I have the first cat on my other 88 NA gutted, but second cat is normal. It functions properly. I gutted just the first one because it came from a parts car with a blown motor. There were apex seal shards in the honeycomb and I didn't want them to get sucked back into the engine.

Car is an 86 GXL. NA engine in solid running order. Mazdaspeed mufflers, 1 year old OEM replacement main cat, and custom 2 inch Y pipe.

SDrotary-FC

i just run a pipe instead of the pre cats (with new main cat/ mufflers) and my 6 ports still work.

instead of just gutting them have a muffler shop make a piece that you can unbolt (keep pre cats for smog if you have it)

dab a lil grease on the rods and take it for a drive to see if they are working.

NCross

iTrader: (18)

Well, I got bored and hammered the crap out. It was horrible. The mesh was all burnt and tangled up in a big ball blocking airflow. Put it back on with new gaskets and took it for a drive.

Sounds fantastic! No rattles and pulls much harder. It must have put at least 10 horsepower back onto the car, maybe plus some. It even smells cleaner. No more rotten eggs from the pre cats.

A good trick to see if the aux. ports are functioning is to take a tiny zip tie and zip it around the bottom of the rods. After a spirited drive, if the zip ties have moved up (1/2 and inch or so??) they are operating.

Doing this on top of installing BBS convertible wheels and making a "ram air cool air box" for my hot air intake I squeel tires into 3rd gear.

NCross

iTrader: (18)

On the upside I don't have emissions in my county.