Question about mid-pipes and cats.

mac and mrt both make hi flow catted h pipes.

If you replace your midpipe with 3 inch tubing, you will probably lose a ton of low-end torque because of all the back pressure you'll lose, and the sound difference won't be much if any.. maybe a little deeper, but probably not louder.

It'd be easier for you to just put an o/r pipe on, and swap it back on for emmissions testing like everyone else does.. you'll get the sound you want this way. Once every 2 years or whatever just swap the old one back on a week before and drive it around.. steeda plug in mil eliminators (so you can cover your tracks when you swap the old one back on,) and some highway driving, and you'll knock all the readiness tests out easily.

If you're that worried about emmissions, I wouldn't put headers on either. Some counties with visual inspection will fail you for aftermarket headers, and if you get longtubes (the only ones which will make the sound difference you're probably looking for,) you'll have to modify your mid-pipe or replace it anyway.

aren't all aftermarket mid-pipe with cats, HI-Flow cats?? Like I have a Magnaflow X with cats, aren't they high-flow cats? They must be, because Magnaflow and SLP X pipes have been proven to make the most HP

sgarlic said:

If you're that worried about emmissions, I wouldn't put headers on either. Some counties with visual inspection will fail you for aftermarket headers, and if you get longtubes (the only ones which will make the sound difference you're probably looking for,) you'll have to modify your mid-pipe or replace it anyway.

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The SLP X pipe comes with adjustable pipes. So if you change to long or short-tube headers, you can just add or remove the SLP X pipe pieces they give you. You wont need to change mid pipes if you get the SLP X. The cats are also hi-flow.

Mstg05 said:

Well, I just heard a mustang (same year and model as mine) that had the o/r h-pipe and too me, its stupid loud. I like it and all and wouldn't mind if the car wasn't driven everyday, but..I live in a small town where no real crime happens, so cops pick on anyone and everyone, especially people with nice cars.

But anyway, does the mac catted h-pipe make a big difference in sound? Does it have the o2 sensor bung already welded in?

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Youll notice a difference, but I wouldnt worry about getting pulled for it. And yes it has the 02 sensor bungs and everything.

hmm.. is the best way to make up for the missing back pressure which robs your low end power to just slap gears in so you're not even in that power band long?