Porting Stock Exhaust Manifolds

[mp5la]

Has anyone done this yet? I've been looking into headers to get a little more power to the wheels, but I'm not sure I'd be able to live with the noise. I also don't want to deal with losing the cat for emissions checks.

I don't have a loose exhaust manifold to look at right now, but does anybody think there could be much, if any, gain from doing this?

 

[thuzil]

IMHO Probably not worth the trouble at all.

 

[tweety2300]

Not worth it for an na car. The only power gains that come from after market headers are the pre cat delete. You still have the main cat which does all the work, the pre cat only helps with cold starts.

 

[hornsfan10609]

The ZE manifold is slightly better flowing but very rare and it deletes the primary cat. Best off with a header but I completely understand not wanting your car to sound like a honda with the header.

 

[tweety2300]

Keep the rest of the exhaust stock and Itl be quiet

 

[mp5la]

I was thinking about going with the racingbeat protege5 specific exhaust, and I'm already worried even that might be too loud.

 

[tweety2300]

It's quiet, my mp3 has the axle back from the factory IMO its too quiet for my tastes but its a daily so it needs to be

 

[MazdaSpeeder]

A header and cat-back exhaust should be fine as far as noise, especially if you go with racing beat or magnaflow (I love mine). If you replace the midpipe, you get a REALLY loud exhaust, even if you have a catted midpipe.