Capt'n

I would like to do away with the catalytic converter on 2004 RX8. Aftermarket parts has a replacement pipe for around $150.00. Question is, do you have to change any engine parameters or do any other changes. I do not want to have warning lights or chimes coming on after I remove the cat??

Thanks,

Capt'n

BigCajun

iTrader: (1)

You don't have to change anything, but you probably will get a CEL for a bad cat, *0420 code.

RIWWP

iTrader: (2)

1) The less you spend on a pipe, the more you (and your friends, family, significant other, local law enforcement, etc...) will hate it, and you will end up spending the higher amount eventually anyway, costing you far more in the end. Noise, rasp, drone, too loud, etc...

2) Removing the cat will probably mean the ECU will throw a CEL, with a code P0420 (Catalytic converter efficiency below threshhold). If you have OBD2 inspections in your area OR a sniffer test, you will not be able to pass.

3) Removing the cat will reduce the amount of heat buildup between the exhaust ports on the engine and the cat element, which is beneficial to engine health

4) Removing the cat MAY have an impact on lean vs rich conditions on the engine. Tuning the engine to account for the lack of a cat is needed to get the best power gain out of the engine.

5) An untuned catless rotary will stink. Badly. Tuning can help eliminate much of the smell, possibly completely depending on what direction you go with the tune.

6) You will need a reflashing tool such as the AccessPORT or MazdaEdit in order to tune the engine, though this would also enable you to block the P0420 CEL from ever throwing.

WMBRACING

I decatted, took a catback exhaust to a shop and talked to the mech personally, told him to weld any pipe they got to get rid of the cat, in exchange for the cat itself. So 150 for a midpipe, there could be ways around that.

But, like the boss tells you above me, you will most surely fail emissions. I live in MI though ^^