Removing Pre-cat material

Just a guess: "The long end of a broom handle."

That is, something soft enough to avoid damaging the metals, but hard enough to break/crush the ceramics.

 

There is no best way. Knocking out the guts of a cat is a miserable task. A long "ice pick" and a heavy hammer is a good start. It takes a good amount of force to knock the comb apart.

 

Are the pre-cats ceramic? Many pre-cats are corregated coated stainless steel (or something similar) wound into a tube shape. They would not be easy to remove without cutting and welding.

 

If it is a spiral stainless insert, you will almost certainly NOT be able to "knock" it out with a broom handle, chisel, or any other cave man method.
It is designed to survive a peak thermal envelope operation environment of 2000C! peak and sustained 14-1600C
It "lives" in the flame front of the exhaust and is subjected to reversion and shock waves, stout it is. This is why thge corning/Japanese ceramics were long ago deleted from production use due to liability of usa 7-70 life span requirements

 

Exactly. Its a huge amount of work to gut them, so just do it right and get a new set of headers. That way, you can sell the car with the OEM parts, or just put them up for sale alone.

 

Its not stainless if it was we would not have this problem in the first place.....

Here are pictures of the precat material removed..

The next picture is the factory headers underneath the heat shield.. They look just like the fabspeed ones, I doubt there is much to gain there.

Sorry my Rossa acct is up till tommorrow.. and I'm above my quota. I will post then

 

My pre-cat ceramic material removal method:

1. Place pre-cat in vice.
2. Get long (12") 3/4" concrete drill bit.
3. Insert bit into drill
4. Put on safety goggles and gloves
5. Introduce Mr. Drill Bit to Mr. Ceramic Mesh

It took me about 20 minutes per pre-cat to get all the mesh out. I also removed the crappy outer covering (no longer needed), then bead blasted and painted the little beauties with Eastwood's stainless steel exhaust paint. That was 8 years ago and they are still beautiful.

 

I'm back....


Here are pictures of the precat material removed..

The next picture is the factory headers underneath the heat shield.. They look just like the fabspeed ones, I doubt there is much to gain there.
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That's a pretty good pictures of the pre-cats that have been broken up. They rattle inside the chamber over time and loose their 90 degree edges and becomes round.

 

^That pic is from fchat, I believe its from your car mrp I'm just beginning on mine. Pulling it apart as I type.

 

I may have posted the pic, but the pictures belong to Lou not mine.

 

Yes, they look like pictures I took. The headers were ceramic coated. They aren't as shiny as the ones mrpcar posted, but I think they look cool as hell anyway. I don't see the need for aftermarket headers whose only real advantage is that they already are minus the precats. Too bad the factory shrouds theirs under that stainless cover, but it is obviously their way to deal with the heat.

The two rounded precats were the ones that were pulled from the headers. The headers were cut open at the back of the collector and the precats were just flopping around in each side. Then they were rewelded. The tech that did the work said that cutting away the shroud was tedious, the rest was easy. The third (better looking) precat was removed from a different car. It was starting to deteriorate on the bottom side, but I put it in the pic to show what a good edge should look like.

Heat from the header pipes seems to be a problem even with the ceramic coating. The silver shields on each side of the engine bay next to the headers is a fiberglass sheet over insulation to protect the gas tanks. On mine, after a year they started getting a bit baked and turned brown. I just finished covering those shields with aluminum heat barrier and adding additional NACA ducts to the undertray like the Challenge car has. It will take months to determine if the additional heat barrier holds up, but it is rated to 2000 degrees F. Even accounting for overeager advertising, it should be well above what is needed.

If I ever visit Maranello again, I'd like to have 5 minutes with the citrullo engineer that decided pre-cats that close to the engine with no protection against damage were a good idea. It ranks up there in all-time poor decisions. Last time I politely interrupted the cute guide who was bragging about their great testing ... having a leaky Mondial T at the time, I asked her how they tested their ragtops for longterm resistance to leaks ... she blushed.

Anyway, I digress. There are no easy answers regarding the precat issue. The headers seem very nice to me and I wouldn't go back unless Ferrari came out with a guaranteed solution that could be retrofitted. Very unlikely at this point.


Lou

 

Well I got mine apart and everything looks great. The precats are still white-ish instead of brown. They are also tight in the header not moving at all. The regular cats are good also no loose particles. Hmm, should I leave the precat alone until I hear something rattling?

 

It will be very hard to hear any rattling. The only symptoms were (1) CEL for cat efficiency, which the dealer couldn't narrow down!, blaming the main cats instead and (2) very very subtle hesitation on-off throttle at neighborhood speeds. Hate to scare you, but other than the CEL which was not good enough, there were no real symptoms.



Lou

 

Pics of the Main cat and the pre-catalyst. I'm gonna sleep on it and decide to remove or not tomorrow.
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If you aren't getting a CEL, and don't mind disconnecting and re-inspecting the headers in this way annually, then you may be better off leaving them alone for now. Once you've taken the plunge and removed the precats, you *could* wind up having to find a way to avoid the CEL for cat efficiency (due to the missing precats). We saw in Robin's case that he was OK because he kept the factory main cats. You seem to have the same so you might be OK. Others with aftermarket cats are left having to deal with extenders, which have been shown to not work in all cases.


Lou

 

I have test pipes and hollowed-out pre-cats on the 512TR (94). I disconnected the thermocouple ECUs at the harness. Almost 30,000 miles later, still no problems, no CELs and the sound/power is amazing.