Has anyone deleted their cat?

Im not sure this is correct but I've read on here saying that the front o2 will use the rear o2 to reset itself. And thats why you may get poor mpg, you can also get poor mpg from a cat thats falling apart, and that will throw the code.
You also said the ecu with switch from lean to rich for the emissions system to work, but it switches because its constantly trying to adjust the a/f based on conditions to reach stiochemtry conditions of 14.7:1 ratio. It doesn't just switch from Rich to lean on purpose, its just adjusting to get to 14.7:1. Your short term and long term fuel trims are measuring the amount of this adjustment.

 

When my cat came apart the only time it negatively affected anything was when chunks tried to go down the exhaust and plugged it up. This caused a noticeable power loss but other than that I dont remember any other issues. Even the light only came on once or twice by that point and by then there was pretty much nothing left of the cat other than the chunk blocking the exhaust.

 

Back pressure is NEVER good for an exhaust system. The faster the gasses get out the faster air can get in through the intake and into the engine to complete the next cycle. If you restrict the exhaust it only reduces the efficiency of the engine. The common mistake is between back pressure and scavenging. Scavenging is basically the effect of the high velocity gases in the exhaust actually sucking other gases out behind them. This is why headers have to be at specific angles and diameters, so that the velocity leaving the engine will allow for scavenging which again increases efficiency. No where in an exhaust system do you want any unnecessary restrictions. If you want better performance and efficiency you would want no restriction. On the other side of the coin if you make your exhaust too wide then, according to Bernoulli‘s principle you decrease velocity and increase pressure which is not good. There’s a sweet spot for it and that’s why it takes engineering to design an exhaust system.

 

Thank God some people here actually understand exhaust!

I always laugh when people say that stuff. It's funny how many people just go on believing the old school misconceptions without bothering to actually read about it.

 

Thank you for setting the record straight 3 years and 11 months later...

 

and theres the "youl burn your exhaust valves up guys"

 

I’m seriously considering deleting my cat..

That is to say that if my fiancé’s cat pisses in my house one more time I’m going to delete the shit out of him!! Likely with my 300 win ultra mag

 

While I agree with your end result here, I think that 300 Win Mag might wreck the upholstery if you do it inside. Better stick with something cleaner and quieter, like "taking them to the beach" (crate and a water trough), or a simple 9mm hollow point.

But if they're an outdoor cat as well, then blast away with the Win Mag and see if anything is left...

Was my hatred for cats too graphic? Sorry.

 

I’m catless and it’s noticeably louder. The CEL will come on if it idles too long. If you stay moving it stays off. But seems to get a mile or two better per gallon when the CEL is on and it’s open loop.