300E Catalytic Converters
 

Hi all,

I've been searching around for new catalysts for the 300e, and I have two questions:

1. What is a good brand (aside from paying through the nose at the dealer)?

2. I have seen pictures of ones that have the two pre-cats on the headpipes and ones that don't. My car has them, but does it matter if I do away with them?

I'm going to be getting new stainless mufflers from timevalve, and since they no longer make the converter as well, I need to go somewhere else for that.

Thanks in advance for the help!!

-Chris

Precats are for cold starts only. CIS is not very efficient, let alone on a cold start.

Just PM someone parting a 300E and see if they will sell the cat section. You need to be prepared to shell out ~$225 or more as that is the scrap value area for them. 'David Hendy' on the board is parting out a bunch of W124s.

Most aftermarket cats do not last very long and I find it odd your OE assembly died. How did you come to this conclusion? Did you have massive coolant/oil use for an extended period of time? Or did you simply fail emission testing?

Muffler should be able to install a universal cat, magnaflow is a good brand.

Just chop them they are not necessary. As long as the main cat is in good condition, you are fine. I passed the CA smog perfectly fine on my wagon with the precats gone and a new high flow Magnaflow main cat.

Chris,
Just hollow them out if they are clogged as of Jan 2011 all pre ODBII (1996) models are emissions exempt in NY. They will still do a visual inspection to see they are present, but they did away with the Dyno emissions tests.

-Jim

Firstly, thanks for the replies!

My original cats aren't plugged and I guess they still scrub the exhaust ok, but with brand new mufflers, I figured a new cat setup couldn't hurt, especially after 215k miles.

-Chris

By the way, how does one go about gutting their catalysts? I guess you have to cut it open and then weld it back together? I have no idea how to weld.

cut pipe so you can use a long bar of steel to break up material.Becareful when using hammer.

Usually there is a flange connection close enough that you can drop the cat and break out the ceramic matrix with a bar. I use a piece of rebar, with one end ground to resemble a flat blade screwdriver. Chuck the cat up in a vise and carefully tap out the matrix.

Makes a nice faux cat.

Jim

If there is no reason to replace, keep the original cat. 180K on my original and still going strong, passing emissions, etc.

I passed with 270k on the original cat in my 300SEL.

I guess I know what I can do with that old grounding rod I have:D
Thanks again everyone!

-Chris