Would it be okay to use a higher rated catalytic converter, CID, than the actual CID of my engine?

Question

I'm replacing the stock manifolds on my car 3.5l and need to relocate the catalytic converter. I cannot fit two, stock setup, in the down pipes with the new manifolds so I'd rather use a single larger converter underneath and am converting the exhaust to a dual setup. In order to do so I'd like to use a converter with dual outputs. Otherwise I'd need to take the two downpipes convert them to one input for a single converter then take the single output and convert it to two for the dual exhaust.

The only models that come with dual outputs are for larger engines 5.7L+ and up, would using one be alright for the flow? I know using a smaller rated catalytic converter on a larger engine will restrict the flow but just want to make sure going higher won't cause problems with the flow since the engine isn't putting out the same power as the converter is rated for.

I don't know if the higher rated converters are more 'restrictive' since they are designed/rated for more powerful engines

Answer 1

you can buy high flow converters so a larger one will work. just make sure if your car took multiple oxygen sensors, you use them in the new exaust system. Since it's designed for a larger engine the temperatures in the converter may be a little lower.

Answer 2

Not a good idea. You could over heat the single converter by running both banks into it.
this is a dangerous situation that could result in a fire or engine damage to the exhaust valves. Scrap that cat can and put on some flowmasters and let her perk!

Answer 3

It would flow better but it probably won't get hot enough to work properly.

Answer 4

better go with what fits.sounds like your gonna
have a cool car.I like the set up your using.
I WISH YOU A LOT OF LUCK,AND LOTS OF G/F IN THE BACK SEAT.

Answer 5

it'll work just fine! higher is GOOD