Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Front precat question...

Looked through the seach and could not find anything on this...

I know there are various ways to gut the precat by drilling a small hole in the elbow. Are there any known methods of doing this without drilling a hole...and what tools are you using.

Also, my friend that is doing this [cough], wants to now if there are any ill effects to the sniff test, as they are pretty strict here in PA. My friend [cough] will be keeping the main cat.

I need to get this cough checked out.

The hole drill method is not good.Apart from the brick there is mesh and a mat to get out,which does not crack up like the brick.To do it right cut it open and get all the guts out or you can clog the main cat with the mesh etc you leave behind.

Drilling a hole is only to break up the cat Terry. The mesh and packing material can still be pulled out through the manifold exit. As long as the hole drilled is large enough to see inside, say 11/16" or so, you will be fine. In fact, it's harder to not get the steel wool type junk wrapped around the bit than it is to leave it behind in my experience gutting them.

Still can't scrape the mat of the walls of the can,its silica and will plug the main cat if you leave enough behind,I've gutted em too .

And let me tellya what a good job Brad does in gutting the precats!

Well, actually, they LOOK good...sitting on the floor....

No, havent had time to put 'em on...hopefully when I get a day off in September.

Ugh...stockpiling mods as we speak.....

So what am I to do here...take both exhaust manifolds off, open them somehow??? Take out the cat, re-weld them...and put them back on?

My "friend" used the drill method, and with some care and time you can get the steel wool bands and scrape all the crap off the insides of the cat with a decent enough sized hole. While you are in there, you might want to open up the ports, as there is lots of extra weld goop from where the flange attaches to the primaries. This is not a concern on the rear manifold, as it was made by a differnt vendor IIRC and the welds were done on the outside. My "friend" sealed the hole up by having it welded shut.
I recommend, I mean my "friend" recommends taking the manifold off the car in order to do the job right. The rear CAN be done without removal, just take your time and wear adaquate eye and breath protection!
Cheap mod with good power gains...

Two words, "long screwdriver". With a hammer drill it all basically turns into "cat soup" anyway and flies into the air unless you have a shop vac taped to the end of the manifold while drilling. A helpful hint if anyone tries this, use a resperator (SP?) to be able to live and tell about it.

Long screwdrivers, roto-rooter, thin shop vac hoses, and other weird scraping/probing tools were helpful in doing mine. The rear was completely vacant and the front was in chunks and mostly fallen apart by the time my second cat clogged up. A flashlight and mirror can help you see how the job is progressing. Pull the up stream O2 sensors to avoid damaging them... Mask and goggles a must if your under the car for this job.

I take it then OBD II system/programing is not affected by both sensors reading the same all the time? And the PCM still has the full range lean to rich ability as before?
Thanks Paul