tcollins

Has anyone went cat less and had any problems ??

aklim

In my car, the catless or gutted cat option made more noise than necessary. I have been pulled over because the cop thought it was too noisy and they have a noise ordnance. So what are you meaning by "problem"? Will the car have an issue? Your's might have an "after cat" O2 sensor so you will need O2 sims to make it run without throwing a MIL. It might encourage a cop to take a closer look at you. It won't gain performance

tcollins

I'm gonna gut them and put a super 44 on it just for the sound. I was told there wound not be back pressure and a would drop s valve

aklim

Is there back pressure issue and why would it drop a valve?

TorchTarga94

tcollins

Because that's what I was told if there was none that it would happen and I just don't wnat it to happen

aklim

I doubt it would. Maybe if you cat was completely plugged. You can run the car with open headers and I have doubts it would happen. As to back pressure, I think there issue might be that if you have too low a back pressure by dumping a large pipe, you might lose scavenging which hinders mid range performance.

AgentEran

Don't need a sim for this anymore, you can use spark plug non foulers. I used to have a MIL due to inefficient catalysis, but haven't had an issue since installing the spark plug non foulers on the after cat O2s.

aklim

So what reading does the ECM see from that circuit?

AgentEran

It will show a voltage that is different/lower than that of the upstream O2s.

aklim

Had no idea it was so crude. My 99 S320 need to see a lower voltage AND will trip a code if it doesn't meet expectations

tcollins

I only have a o2 in front on my cats so it won't throw a code