I recently got some headers and installing it made required me taking off the cat. I've read the posts on backpressure and cats but im still not sure. Since removing the cat creates more airflow, doest it also reduce velocity and pressure? lowering the speed?

 

No you will be fine, only thing that would happen is if you have an OBD2 engine would be that you throw a CEL unless you have an O2 simulator. and may not pass inspection.

 

IF your area even requires you to pass an inspection.

 

it'll make your exhaust alot louder also, and if the cops are ****** they can look for no cat and give u a ticket for it, i would read up on the laws also

 

Yea my car is pretty loud actually its REALLY loud, but its kindaraspy.

 

loud and raspy are both bad IMO, put that cat back on

 

the only time installing a header removes the cat is on a DX, so i imagine youre in the same situation as alot of us (myself included), are you getting a CEL? If so you're in limp mode, which takes away power and makes your gas mileage go to sh*t. You need an o2 simulator from www.o2simulator.com to cure that problem. But regardless of the CEL, you wont pass emissions now, so if youre in a state with emissions laws get a universal cat welded somewhere in yourmid-pipe ASAP

 

^ damn thats sux

 

you could always look into geting a exaust system from a EX since the cat is behind the header.... BUT ya still might have th eproblem with the O2 sensor....

from my experience its best to keep the O2 sensor in the stock location... i had to drill a hole in my header in the rear to fit a weld in O2 bung cause my header didnt have a location for my rear O2 sensor...

 

So if I get the cat do i still need the simulator, or not? I'm pretty sure im running in limp mode cause it feels like it. As for emissions, i'm pretty sure im not passing, but i got the sticker from one of those rink a dink shops who only check brakes and lights so i passed.