Has anyone deleted their cat?

Makes sense, hopefully someone with a more intimate understanding of rear o2 sims than you or I can chime in. On a related note, some people have found that the rear o2 sensor will work without stock exhaust if you add a few washers between the flange and the sensor so as to move the sensor back a bit from the flow of exhaust. I wonder if this would allow for the reading to fluctuate within the range of acceptable voltage? It would presumably be better than a constant reading..

 

That is what I thought you were initially referencing when you said $10. There is a "spark arrester" i think it's called that people use to space out the o2 sensor to change the readings.

 

Once my suspension is on I'm going back to my exhaust guy to get my flange welded on for the rear sensor, I'll let ya know if it works with/without adding washers. I still have one of my cats, I'm sure that all it does is restrict exhaust flow. Damn thing rattles if you even look at it

 

Im clueless? No, im just a realist. That "canister" on a two stroke dirtbike's pipe you're referring too is called an expansion chamber. To sit there and compare these two instances is unrealistic. I have owned many many many different makes and models of Vehicles with true H.O. Engines. Tacoma owners just happen to be more delusional than skyline owners and bigger liars than "big 3 american diesel" owners.

 

Yes you are clueless and more of a idiot than a realist.

 

I live in the most restrictive state when it comes to Emissions laws! Good ol California! I have 235,436 miles on my exhaust emission components. I wonder how much longer I have? How do you know besides sound? Your truck will throw a code? Luckily never been in the salt but...

 

Mines making a sound but you can smell it too. The code is what P0420? Something like that. I'm lucky I don't have emissions period but my truck will all be solved soon

 

Yep, clueless

 

You say clueless but you cannot prove one thing ive said, wrong. You tacoma guys act like theses motors are formula 1 motors! Its beyond rediculous.. "Restrictor plates" needed in place of the cat? Hardly. Look, i dont have time to even begin to teach you the effects of the motors compression on scavenging, how it can be affected by cams, timing, etc. when it has taken me years of school. I have explained what i have done and will again, DT shorty headers into an X pipe, moved mufflers towards block 6", dumped tips out under rear bumper. This setup along with the other mods fore mentioned have worked VERY WELL for not only I, but a friend as well. Of course your dummy o2 has to be done and a couple of other things, but this is the setup that has worked very well for me. Now, prove me wrong and prove me clueless. . .

 

I'm not taking a position, in fairness I've not read all the thread. But I did see this statement, and the curiosity cord was struck.

Please define 'worked very well'. What exactly does that mean, and how do you objectively measure it?

 

Hey man, this is only what ive done to exhaust. The other things ive done ive stated earlier in forum. These trucks fuel eco sucks big time and when i put 285/70's on, it REALLY sucked! when i say worked well i am referring to fuel economy. And My low end is quite a bit more snappy. These motors fuel eco is pure shit. . And its hard to squeeze more out.

 

The rear o2 has nothing do with the a/f ratios. Thats the front one. The only thing the rear one is doing, is checking if the catalytic converter is operating correctly. So no cat, mean the rear o2 is going to throw a cel. While it may not be effect anything in a huge sense, sometimes the front o2 uses the rear o2 to reset itself. So you need the rear o2 to be reading that there is a cat there and it is working correctly. Deleting it isn't going to prevent performance or low end or anything. If you think you need back pressure in an exhaust system go do some more research. It's not true. What you do need is gas velocity.

I had a bad cat on my 96. It rattled and was failing. We took it out, put a pipe in and used a rear o2 sim from urd. Truck ran fine, no difference in power, a little louder was all.

 

It will only throw the code if the cat gets clogged. If the elements inside break up it doesn't do anything until something get stuck where it's not supposed to. Mine have been rattling around in my cat for a year without throwing a code. Something tells me it wouldn't pass an emissions test, but I don't have to worry about those here thankfully!

 

If the o2 sensor is reading that the cat is not working properly it will throw a code. And you could possibly get a little better gas mileage if you get that replaced.

 

My O2 sensor's sniffer must not be working right then. I'm not too worried about it at the moment, when I do replace it, the truck will be getting a full exhaust system, plus cat delete from the manifold to the tailpipe since the whole system is currently rust flakes anyway.

 

Rear o2 does NOT affect performance its simply there to turn the light on if the cat is not functioning properly. Efi cannot keep the fuel air mixture at optimum ratio constantly so it is constantly switching from rich to lean rich to lean. the front o2 sensor is what controls this, it sees lean and makes computer go rich then it reads rich and makes computer go lean and this happens constantly. The cat is there to clean this up before it exits the tail pipe, the cat converts the gas into a steady stream and this is what the rear o2 is looking for. For the rear o2 it doesn't matter whether it sees a rich stream or lean stream, just that it sees a steady o2 reading. When the cat fails the its no longer cleaning up this flow so the rear sensor starts seeing the rich lean fluctuations and triggers the light. I've been running a gutted cat for almost a year with no light with the rear o2 sensor tucked up in the heat shield reading off the open air, and during the summer I was averaging 22-24 mpg with my 4x4 4 banger.

also 4strokes do not require backpressure, you want as close to zero backpressure as you can without affecting velocity. Think of it like water flowing through a hose, to big of hose and there's no velocity and the water just trickles out the end. To small of a hose and the velocity speeds up but so does the back pressure. The trick is to find the best balance of flow and velocity

 

THIS^^^ Exactly! Its all about gas velocity, getting the most amount of gas out as fast as you can. Too big of a pipe gas won't flow fast enough, too small it creates backpressure

 

Mine begged to not be deleted...



But I deleted it anyway...Nothing left but the eyes.



On a side note, my truck still runs purrrrfectly.

 

Exectly.

Please read the thread i made on this.

https://www.tacomaworld.com/threads/addressing-some-common-misnomers-of-the-p0420-code.396763/