Running No Cats?

[OonDeanisS]

can i leave all the smog pump stuff intact and working and just vent the fresh air out the hose instead of into the cats? im thinking this should avoid any trouble that may arise from removing all the smog stuff. i dont want to run into running problems, and i just passed emissions clean as a whistle, but i want that off road exhaust sound without removing the benifits of the egr system or the downfall of tripping codes for the smog pump. id rather just leave everything intact and just run no cats. what are your thoughts?

My car is finally exempt from emission testing, and i dont plan to sell it. If that makes any difference.

 

[MFE92]

You can run high-flow cats and still get the "off road exhaust sound" without the ridiculous stink.

 

[OonDeanisS]

well right now i have BBK long tube headers, and i have a bbk catted X pipe and a bbk off road H pipe. so its one or the other, i cant go buy another pair of cats. Maybe the bbk cats are high flow, i really dont know. but they make the car a lot quieter.

 

[Spaz]

I have BBK long-tubes and I put on a BBK catted x-pipe to replace the rusted out no-name headers and off-road h-pipe. It was way quieter and not as powerful with the catted x-pipe. (With no cats I could just step on it in 2nd gear and blow off the tires, with the new headers and catted x-pipe and no other changes that didn't happen anymore). So at the next inspection I was under 5,000 miles for the year and getting an emission exemption, so I put on BBK off-road x-pipe. There is just a cap on the tube coming off of the crossover pipe and a cap on whatever solenoid is below the airbox. It runs excellent with no check engine lights or anything. And it doesn't smell unless I'm standing behind the exhaust pipes.

 

[OonDeanisS]

That's exactly what I experienced! A significant power loss with the Catted x pipe. Now, I put the o/r H pipe in and I just want to make sure it's ok to leave everything as is, or if it's ok to remove the smog pump stuff like the tab/tad and the diverter and bypass valves.

 

[Spaz]

If all the emission stuff worked before, I would leave it as is. You just have to cap that one hose which went to the original h-pipe. I haven't had any other problems with driveability or check engine lights or anything. I think once you start removing valves and stuff, that's where problems can come. And I wasn't worried about the 10-15 lbs that the pump weighs or the drag on the engine. But my car is my daily driver. People looking for every last ounce of power would have different opionions I'm sure.