kick the cat out

[veet]

I have an 87 Carrera and if I remove the cat do I need an ecu upgrade or will it run the same?

[VillaRicaGA911]

As far as I know no changes you need to make. I have done the same on mine.

[DRACO A5OG]

You will be fine.

But to be safe, I would test the AFR to insure your will not be running too rich or lean.

When I swap back and forth for Smog Check, I adjust my AFR with my LM2 and tune my base idle at operating temps.

[hcoles]

no change (e.g. ecu map) needed because the O2 sensor is still there and you don't have a cat downstream of the 02 sensor - you will notice the sound will be louder but not by much - when changing keep anything from touching the O2 sensor.

[Bob Kontak]

Originally Posted by hcoles

no change (e.g. ecu map) needed because the O2 sensor is still there and you don't have a cat downstream of the 02 sensor

Assumption is that cat bypass or "test" pipe will have an O2 bung. More than likely it will.

I have read where on the CIS cars there can be some changes in engine behavior because of reduced back pressure. I put a Fabspeed bypass on my 81. Maybe it was called a "pre-muffler". You could look right through it but it did have some baffling. Nothing noted at all really as to how the engine performed in lower RPM's. Touch more noise but was with using the stock muffler