benefits to running a catalytic converter as opposed to just a straight pipe?

[Loghead]

sorry if there is a already a sticky i searched for exhaust but didn't come up with anything conclusive. I'm trying to figure out what kind of exhaust to get and wanted to get the best for the motor (h22a) to perform at it's best. I'm not concerned with it being super loud although i would rather it be on the quieter side lol.

[BurtonRiderT6]

The benefit of the Cat is it will quiet the engine and it will abide by most emissions. Not having the Cat you will see more top end gains as there is not restriction and the car will be louder.

[10thAnnivCB7]

Need that back pressure man ,, and not having yoyr o2 sensors will mess up ur mixture which will make u run really rich having to buy a lot of gas ,, unless u are doing drags to loose a bit of weight , u dont anything gain in straight piping a street car but its up to you what u want to do

[BurtonRiderT6]

Need that back pressure man ,, and not having yoyr o2 sensors will mess up ur mixture which will make u run really rich having to buy a lot of gas ,, unless u are doing drags to loose a bit of weight , u dont anything gain in straight piping a street car but its up to you what u want to do

There's no O2 sensor in the cat. It's in the "downpipe" between the header and the cat. A completely stock engine that has no O2 sensor or way to adjust its A/F ratio needs backpressure. The car won't run lean (which can lead to burned valves) because he will still have his O2 sensor. The car won't run rich (which would cost you a fortune in gas) because he will still have his O2 sensor. The engine should be able to breathe better with less restrictions. Now I'm not saying to go get a 3-4" system. 2.25-2.5 is plenty. Exhaust temperatures play a role in the performance and flow of exhaust gases but thats another topic.

[AgentZero]

with a straight pipe your car WILL smell like shit. its going to sound like crap. and you are going to dump bad fumes. just get a high flow cat.

[deevergote]

Need that back pressure man ,, and not having yoyr o2 sensors will mess up ur mixture which will make u run really rich having to buy a lot of gas ,, unless u are doing drags to loose a bit of weight , u dont anything gain in straight piping a street car but its up to you what u want to do

You never need backpressure. In fact... absolutely everything you say is false. Fortunately, it's almost impossible for anyone to understand it anyway!

Removing the cat, as said, will remove a restriction. You will free up some power, but not much. The cat design on our cars is fairly free-flowing. As mentioned, running a cat will keep sound levels down, keep your car emissions-legal, and keep your car from smelling terrible.

The gains to be had from removing the cat are so few that it's not worth making your car noisy, smelly, and illegal. If you want, remove the cat when you go to the track, and replace it when you return.

[JDMDriver]

There's no O2 sensor in the cat.

Just a bit of trivial.

You comments are true for most cars except for people with real JDM cars.

Real JDM Cb's (or most other makes and models) have an added sensor in the catalytic converter iself. I believe its to do with the much stringent pollution controls in Japan.

My CB has a sensor in the catalytic converter and a "red" warning light on the dash.

[BurtonRiderT6]

Just a bit of trivial.

You comments are true for most cars except for people with real JDM cars.

Real JDM Cb's (or most other makes and models) have an added sensor in the catalytic converter iself. I believe its to do with the much stringent pollution controls in Japan.

My CB has a sensor in the catalytic converter and a "red" warning light on the dash.

Understood but he's from the USA and I doubt too many people here are doing cat swaps. Good to know though

[Accrdwgnguy]

lol the OP never mentioned removing the O2 sensor.

Benefits to running a cat are less pollution and cleaner smelling exhaust. Your grand children will thank you one day.

On that note, you can get universal high flow cats from Magnaflow in sizes from 2" and up. Yes you will have to weld it in but if you are putting on a custom exhaust thats not much of a stretch. On that note I need to buy one as I have been running catless for a few years.

[TracieS]

And a honda with out some sort of resonator or cat sounds really raspy sounding.

[BurtonRiderT6]

lol the OP never mentioned removing the O2 sensor.

Read the entire thread

[MortsAccord]

Need that back pressure man ,, and not having yoyr o2 sensors will mess up ur mixture which will make u run really rich having to buy a lot of gas ,, unless u are doing drags to loose a bit of weight , u dont anything gain in straight piping a street car but its up to you what u want to do

Not true




My friend and I gutted an exhaust system off his 99 mazda 626. installed a 4-2-1 header, deleted the cat, added a 18" vibrant XQ resonator and a Apexi WS2 muffler. sounded AWESOME. no raspy noise at all.

If you add in a good resonator where the CAT used t be the noise difference is not that bad. Any straight through exhaust that has wool between the center pipe and the outer wall will do a good job of quieting things down.

Turbochargers are good for this too. <3 a turbo

For emissions, yea its not going to pass if your state/location tests for that . However you can rid yourself of that annoying CEL light because of the cat delete rather easily. Theres 2 ways.

1. Spark plug non-fouler trick. (10 bucks?)
2. O2 sensor simulator(50 bucks)

The secondary o2 doesn't affect performance, its just going to burn a orange light in your eye untill you get the electricians tape out if your too lazy to do one of the above mentioned fixes.

[Accrdwgnguy]

Read the entire thread

I did, thanks. There was no mention by the OP "Loghead" of removing the O2 sensor. He's asking about removing the cat, which does not have an O2 in it or after it.

I'd like to make this clear, our cars are not OBD2, there is no after cat O2 sensor. OBD1 cars only verify EGR is connected and functioning as far as emissions are concerned. You will not have a CEL from removing the cat.

[wed3k]

Not true




My friend and I gutted an exhaust system off his 99 mazda 626. installed a 4-2-1 header, deleted the cat, added a 18" vibrant XQ resonator and a Apexi WS2 muffler. sounded AWESOME. no raspy noise at all.

If you add in a good resonator where the CAT used t be the noise difference is not that bad. Any straight through exhaust that has wool between the center pipe and the outer wall will do a good job of quieting things down.

Turbochargers are good for this too. <3 a turbo

For emissions, yea its not going to pass if your state/location tests for that . However you can rid yourself of that annoying CEL light because of the cat delete rather easily. Theres 2 ways.

1. Spark plug non-fouler trick. (10 bucks?)
2. O2 sensor simulator(50 bucks)

The secondary o2 doesn't affect performance, its just going to burn a orange light in your eye untill you get the electricians tape out if your too lazy to do one of the above mentioned fixes.

you're speaking obd2 language. i have yet to find a 96 cb7.

[10thAnnivCB7]

Lol ok you guys clearly know more than me ,, not ,, by what i read he wants to straight pipe from the header down ,, and i know his cat is not close to the exhaust manifold which will make him get rid of the O2 ,, i want to see a cb7 where the cat is not preety much around the center console