Catalytic converter?

What would happen if I put a bigger catalytic converter on my jeep? would it help it pass the e-test as it has failed? or would it make it worse? I bought an after market cat and now I have people telling me that it might be too small....|||Putting a bigger cat on will not help you pass emissions. Usually it will fail Nox if the cat is bad or trip a code 420 or 430 on a newer vehicle. Do you have obd1 or 2. Is the check engine light on or did you fail the old tailpipe test, if so what's all the readings?|||If it is too small and flows too little cfm (exhaust flow) it COULD choke your engine a little at higher rpms. It should not effect how you do on testing though as all of that stuff is down at lower rpms.|||It won't be to small, Converters only convert the gases from the engine from carbon minoxide, to carbon dioxide. That is all it does. So as long as your catalyst is still good in the one u put on it will be fine.|||as long as the cat is good it shouldn't affect your emmisions test.....there are federal and california standards that cat converters have to abide by.....there is something else causing you to fail your emissions test.....a good technician can diagnose and fix for you!!!!.....good luck!!!|||It might just need a tune-up ~ have the enging run on a computer at a shop, they can tell you the problem. You can't always believe what you see here because we don;t know the engine size|||Unless you're in California where they are really picky about everything then I am 99 percent sure a bigger cat converter will now make you fail an emissions test.