catalytic converter "rattle"

[anthony]

Ok, the catalytic converter is going. I dare say a improvement in performance. When I converted to 3.5 I left the exhaust system of the 2.8. I did swap the 6 port exhaust manifold for two 3 port. but that is all I did. The 2.8 has a smaller diameter pipes. The muffler guy had to put in a reducer at the cat. so the question is: Is it possible to put on a e28 system? Or what parts work? What don't? I was planning doing this on my time, but the cat is interfering and has caught me off guard. Naturally I have to balance more power with money.

Anthony n San rafael

[Mike W.]

It's possible, I've got one on my E12, but it's not sorted out yet. Aside from having to fabricate hangers in the back, E28 downpipes hit the idler arm. Less now that I've put a few miles on it, but still some. It can definitely be done, but it's not a straight bolt up. And I doubt you would get a significant increase in power.

[Lenny D.]

Perfect timing (pun intended) - I now have developed the rattle of a converter going. So - what are my options? Put in a new one? Replace it with a piece of pipe? I have no smog restrictions in this state, so other than the 'green factor', opinions regarding options are welcome!

[Odometergears]

If you want a new cat, I have one I installed about two months ago. It will not be going back on the car. Doing some major changes to the motor right now. If you want it, it's on the garage floor right now. Call me

Jeff

757-593-3478

[1st 5er]

What about the O2 sensor w/o a cat?

[alotawatts]

What about the O2 sensor w/o a cat?

You would leave it (O2 sensor) as is I would think. There is only the one upstream from the CAT.

[Karl in KS]

for another alternative...I put e34 exhaust manifolds, downpipes and dual cats under my car to dump the exhaust from that 3.5L engine. It did not interfere with the idler arm, but I had to put in spacers for my MM sway bar (under the firewall) to clear the down pipes.