Catalytic Converter

[Nitrate]

1981, 2000. If I substitute a test pipe for my catalytic converter will it screw up the computer for my fuel injection system? RB

[tima01864]

The oxygen sensor is on the manifold not on the converter.

[TX82FIAT]

chances are the car will run better if the old CAT was obstructed in any way. However, the inputs to the Ljet will remain unchanged with the exception of more air in. The car will be a little louder. The CAT does help reduce some sound.

[Nitrate]

Thanks to both who replied. I have my answer, thank you. RB

[Slartibartfaster]

Though my car is not FI, you may find this interesting (or not)...copying from an earlier post of mine:

I considered swapping in a 'test' pipe...but then started reading so that was out. Not interested in driving a stinky, polluting car.
The car still has fewer than 24k miles so the converter couldn't have been too 'jammed up', but everything I've read about modern converters vs old points to a significant improvement in airflow and better environmental performance of the catalyst. This is the article I found most useful: https://grassrootsmotorsports.com/artic ... ter-face-/

Which catalytic converter was the next question... I'm keeping everything I change on the car and only making bolt-on changes in case a future caretaker wants to return it to stock. This means I'm not cutting the three bolt flanges off the old converter to weld on to a new generic converter. I bought a "MagnaFlow 23501 Direct Fit Catalytic Converter" for $139 prime. I'm continually surprised how hard it is to find specific details about auto parts online - always worried about 'direct fit' replacement actually being so.

In this case - the fit was pretty great out of the box. The flanges and attach points for the springs were properly aligned relative to the old converter and the overall length whole unit was within 1/4". And, you can see light through the inlet pipe...that's got to be good, right? The old one is like a maze inside. Best of all was the unexpected weight savings! Old unit was about 15lbs, new one is only 6lbs 3oz.

So, does it feel different? Yes - definitely a power improvement and maybe a bit better sound as well, hard to tell. I don't like hard wrenching under the car but this was no too bad...a few hours start to finish. Used copper rtv, no gaskets and let it sit for 24 hours before starting to cure. Overall well worth the $140 and time spent!

[Nitrate]

Thank you for the new vs. old cat converter info. As it turns out the PO had installed the Magnaflow as a replacement for the original, so I'll leave every thing alone.