catalytic converter ???'s

[808M3]

My cat is shot. After hard driving or 1/4 mile runs the exhaust smells like rotten eggs.
Is anyone running a straight pipe or supersprint resonators?
How much louder does the exhaust become?
Can you pass smog check? (I live in Hawaii which has no smog check but might be moving up to Cali or Oregon)

808M3

[djbeemer]

a friend of mine is running supersprint headers
and straight pipe and supersprint exhaust, no cat,
on his e46 323i .. his last dB reading was 119.7dB
at the last show... which is pretty loud!

[djbeemer]

he puts the stock exhaust system back on for smog
check cos he doesn't pass with his current setup

[cek2]

For what it's worth:

A friend of mine had similar symptoms and removed and replaced the catalytic converter...still had the rotten eggs (sulphur) smell. The probem turned out to be the fuel pressure regulator. It was running too much fuel pressure.

I would at least check the fuel pressure before dropping big bucks on a new cat.

I replaced my leaking fuel pressure regulator with a genuine BMW part for ~$60.00usd.

If I recall the fuel pressure on the stock M50 should be ~43psi.

Good luck.

[540Rob]

My cat went at 55k... BMW said that the cat was underwarranty until 80k so they replaced it for free.

[ELIBEEMER]

I had a bad Air mAss sensor for about a year..

The car ran rich the entire time and eventually burned out the cats.....OBDII cats... and wow car ran great, lots of torque and power...

yet my car would not pass emissions!

recently bought the OBDI cats and I can feel the loss of power...

Along the acceleration band specially!

BTW, I bought the Miller cats(not BMW) and they bolted on with ease and passed emissions..

I sold the three series, but If it was up to me, I would swap back !!

ELIBEEMER

[knomad]

Originally posted by 808M3
My cat is shot. After hard driving or 1/4 mile runs the exhaust smells like rotten eggs.
Is anyone running a straight pipe or supersprint resonators?
How much louder does the exhaust become?
Can you pass smog check? (I live in Hawaii which has no smog check but might be moving up to Cali or Oregon)

808M3

In Hawaii, a state that is facing serious environmental problems, I would think you would want a catalytic on principle, regardless of whether the law mandates one.

On the mainland, no less and no more, running a modern car without a catalytic is the moral equivalent of dumping your used oil down the sink drain. Please don't do it. My kids will need to breathe for many years yet.

[QuestMCoupe]

How do I check my fuel pressure? I get the rotten egg smell sometimes too.

djbeemer, is your friend's car loud as in deep loud or annoying whining loud?

Thanks