Munki

The other day I had the cats removed on my 545i and the car seems a bit faster and sounds ALOT better. After about 40 min of driving my check engine light came on (O2 sensor)... Once the light came on I noticed the idle wasn't as smooth anymore...

So my question is, does anyone on here know of a way to bypass the 02 sensors? I heard of people doing this before and they were supposedly successful doing so.... I've never done this nor do I have a clue how to do it...

texasmr2

Why would you do such a stupid thing is the real question!

Munki

Why do people put exhaust systems on their cars? Same reason....

My catalytic converters were ruined anyways... I'm glad I cut them off, sounds so much better and feels a bit faster as well. Just gotta find a way to bypass the o2 sensors.

FormerE30Owner

Even if you do find a way to bypass the O2 sensors, your engine will not run as designed and that means less power. The engine is designed with cats in mind and the air fuel ratios are set accordingly. The o2 sensors monitor the exhaust of the engine before and after the cats and the engine parameters are adjusted according to those readings. If the sensors are not working or you bypass them, the computer will fall back to a default air fuel setting, which, unless you reprogram the computer, will not be optimum and most certainly be on the safe side to protect the engine, i.e. rich, with the accompanying loss of power and increased fuel consumption.

I am not sure that a "better sounding" engine is worth the price, no matter how "faster sounding" that might be.

Salut, Bob P..

texasmr2

Not exactly but I will play along. I fully understand your desire for a more aggressive exhaust note but what I do not understand is why you removed critical parts that are a necessity. The cats and 02 sensors are neurons of the cars operating system and if even just one neuron is removed or broken there is a communication breakdown. Critical information does not reach the cars cortex (ECU) and there will be issues.


Do you know why your cats were ruined and what the cause was or were they truly ruined? Also you could have installed aftermarket 'hi-flow' cats for hundreds less than factory cats. What are you going to do when it is time to renew your inspection?


Listen, I have been modifying my own cars since 1985 so I am no stranger to this and I only want to help you . Since you are also in Houston I will help you in any way I can and you can increase performance and sound and still stay legal. Maybe my former career as a Deputy Sheriff is getting the best of me but I hope you will accept any advice and help you get.


Regards,
Gregg

Munki

My cats were ruined... One was clogged so bad there was 0 air flow going through it. That one was completely collapsed, meaning it was ruined. the other side was on its way out as well...

I have ran completely open exhaust even without mufflers on several cars including the gallardo and i have never had anything bad happen to my engines due to gutted exhaust... I know for a fact my engine on the 545i will be ok with no cats. I'm also pretty sure everything will be ok once i get one of these,

http://www.magnumtuning.com/en/detai...lator/BMW/545i

Just found out about that simulator so i'll have to give it a shot!

texasmr2

Good luck.

Blackwolffm

You better get a K&N air filter. I got one with no sec cats. Best $55 I've spent

defc0n

Registration with no cats , easy...
It's just 220.00 dollars , no car needed.

I am also in this process at the moment.