My M45 has four catalytic converters, that have degraded. They are quite expensive over here in Lagos. I'm looking for away to used spacers on the O2S ports, as a means of deceiving the ECU in to thinking the Catalytic converters are functional. This is because I have read over the internet that spacers could be used instead of a catalytic converter, if emissions tests aren't the concerns of authorities.

In my locality, emissions passes are not a requirements, so I'm safe.

Has anyone ever tried using a spacer on their exhaust system? If so, how did you implement the the spacers on the exhaust manifolds?

Thanks while we await your replies.

I never used spacers, but I did use something called an 'o2 simulator' on my 1997 Maxima to get around the O2 sensor related codes after doing a full header back exhaust. It basically gets installed in place of the O2 sensor (in the wiring path to so speak) and sends a good signal instead of whatever the O2 sensor was going to send. Perhaps something else to consider.

The correct word you're looking for is "test pipe."

It's simply a length of open pipe, with a flange on each end, that takes the place of your converters.

The signal from your secondary cats is irrelevant except for emissions compliance, it does not affect ECU tune.

AZhitman wrote: ↑

Sun Mar 08, 2020 7:18 pm

The correct word you're looking for is "test pipe."

It's simply a length of open pipe, with a flange on each end, that takes the place of your converters.

The signal from your secondary cats is irrelevant except for emissions compliance, it does not affect ECU tune.

Has anyone done that modification on an M45, and wouldn't there be this BUUUUUU kind of noise after the whole job?

Test pipes have probably been done on every car ever built.

Slight increase in sound is to be expected, but I've never heard one drone after testpipes.

BTW, from now on, we will refer to drone as BUUUUUUUU

AZhitman wrote: ↑

Mon Mar 09, 2020 8:33 pm

Test pipes have probably been done on every car ever built.

Slight increase in sound is to be expected, but I've never heard one drone after testpipes.

BTW, from now on, we will refer to drone as BUUUUUUUU

You are so funny!

Test pipes are going to be harder to do on an M45 because the catalytic converter is part of the exhaust manifold, its not a bolt-on.
Anything you do with regards to replacement is going to be custom. Some people choose to gut the catalytic converter - beating it up until it break and thus creating a hollow pipe. Of course the exhaust will be louder due to that.

For an o2 sensor spacer, I have heard of a few people doing that successfully on these cars. Basically, get an adapter that threads in place of your secondary oxygen sensor and then also allows the o2 sensor to thread into it on the back side.
No specifics to share unfortunately.

I have a question, how do you know your cats have degraded - did you get codes?
2, what grade of fuel have you been using in the car?