i know if i take off my catalytic converter i'd gain horsepower but how much hp? will it be noticeable?

how about the exhaust piping? 2" or 2 1/4" ? i have a bp 1.8 dohc w/ headers and cone filter.

 

The only way you would really gain HP is if your cat is clogged up.

Cats have a bad rep now because when they were first being used the technology was not as good as now , this with a few other contributing factors caused them to clog and rob power.

Now and since the late 80s manufacturers have done a better job of using well designed and sized cats, and have taken them into consideration when building an engine and maping the fuel curve.

in fact sometimes you loose HP when you remove the cat

To find out if would help - remove the o2 sensor and hook up a psi guage, start it up for a minute and rev it a few times, if it builds a lot of pressure like something is clogged then best bet is fo get a new cat maybe a high flow one.



HTH

 

Why don't you just buy a high-flow cat ???

 

yeah get a high flow, I saw in a mag, that the HF made more power than the straight pipe
bruce

 

ist off 91 323 only have 1 o2 sensor (pre 02 sensor)
by removing the 02 sensor the car will die out. y? well the ECU can't read how much air and fuel it needs. so I dont think thats a good idea of checking a clogged cat. anyways i dont want to buy a high flow cat y? cuz if i get pulled over im through!
If i remove my cat i will cover the straight through pipe w/ the civic cat cover so it'll look like stock. Here in San jose Cali. it sucks cuz the cops go underneath ur car and check if u have cat. I know cuz it happend to me before good thing i had mine on.

 

No it won't die out, It does use readings from it to adjust the a/f mixture but for the most part it uses the Air Flow meter (maf/vaf - depending on the car) otherwise you would never hear someone say I am getting bad gas mileage should I change my O2 sensor you would hear my car does not run should I change my O2 sensor. Yes that is a good way to check for a clogged exhaust of any kind, Well I used to work for a mechanic and that is how he did it.

If you live in CA don't you get emission tests, cats help you pass them. I am sure that there are some that have CARB #'s that would make them legal in CA. Right?

 

yeah they have carbs legal but only for civics not 323's. so u want me to just unplug the 02 sensor? then let it run and rev it?

 

There's an attachment to measure exhaust backpressure, that screws into the O2 sensor bung.

Anything above about 3psi exhaust backpressure usually means something is wrong.