ok i went to a couple cutom exhaust shops to see about duals for my 04 f150. they gave me a price all were different ranging from 250 to 480 for the same set up. cat back flowmaster 44 series dual out the back. i asked them if they can take the cats off and they said no and it would lose performance. is this true? i saw a couple videos on youtube.com and there was some with no cats. i kinda want to get true duals. so tell me if this is possibile or not for this truck. thanks

 

I did on my 04 and it run's fine.You take the rear 2 cat's that are behind the o2 sensor and you'll be fine.I had the rear 2 removed and the ypipe cut out and ran the 2 pipe's into a magna flow DI/DO muffler and it sound's awesome it really woke it up and helped the torque during normal driving

 

ok here is probably a stupid question but i never done anything with exhausts but does any muffler come with a dual in dual out or is it only certain ones? im going to get the flowmaster series 44 i know it has a single in and dual out but not sure if they come in dual in dual out. is there any big addvantages of have dual in over single in? i know these are stupid ?s to you guys but im a carpenter i dont wana screw my truck up lol

 

Mufflers come several ways depending on manufacturer and type. As Evil said, you can get dual inlets with dual outlets, but then this isn't a true dual system. But it's definitely better than a single inlet/dual outlet system. If you want a true dual system, cut your rear cats and the Y-pipe. Run each side through a single Inlet/Outlet muffler and you'll be good. I'm thinking of doing this on my 04, but with a pair of magnaflows. Flowmasters are too peaky for my taste. Go to flowmasters website and see what configurations the 44s come in. Good luck with the mod...

 

Cats are there for a reason, they reduce the toxicity of the exhaust fumes, why mess with them?! I still can't figure out why you guys put those annoying loud dual exhausts on your trucks, I thought they went out of style around the time Nirvana was popular. Just remember when your driving by people their not staring because they think it cool, they are staring because they think its lame...trust me on this one.

 

1.) Leave the cats on.... modern catalytic converters do not restrict the exhaust flow like models of yesteryear.

2.) Smart exhaust shop. Tampering with any emissions critical device can cost a shop $10,000, as well as jail time. Similar offenses can be noted for individuals who do this.... its a federal offense.

3.) Simplest approach is to do single in, dual out. For what its worth, the best "performance" system is single in, single out. A single 3" pipe will flow more than the duals... believe it or not (a 3" mandrel bent system can flow enough air to support ~360rwhp). Honestly though.... an exhaust system upgrade is for looks and sound only. The true "performance gain" is minimal (unless we are talking about a forced induction system).

 

ok thanks guys i will probably leave them on i just hear so many different things. thanks though

 

you won't gain enough to make it worthwile to remove the cats...just do a cat back....plus you won't ever have to worry about epa fines, ect...

 

ya i dont wana mess with any fines them get expensive

 

Still Smoking,

Don't you guys have to have your vehicle inspected every year????

You cut those cats off it will never pass inspection, even if it is just a visual inspection, here in NYS it will fail automatically...........

 

no we dont have inspections

 

ok buddy i'm not quite sure loud exhaust on a V8 ever went "outta style". i hope it never does. everyone i know from my 4 year old nephew to my 60 year old dad, my 20 year old girlfriend to my 55 year old mom love the way my F150 and my Camaro sound. and they're both pretty damn loud. i couldn't care less if people are staring at me or why they are. u don't have to like it, u just have to live with it. loud exhaust is lame on 4 or 6 cylinder engine simple as that. sounds wicked when done right on a V8. And from what i was told (might not be 100% accurate) the first two cats on these trucks are for emissions and the back two are strictly for noise reduction. makes sense since the sensors are after the first two only. that's why i cut the back two off. definitely noticeable difference in volume. and for the $30 i spent on pipe and the hour it took me to do it, it was well worth it

 

is that true you dont need the rear cats?

 

They are a trip hazard if you remove them and leave them laying around the garage. I'll take them off your hands and even pay shipping.

 

don't know what you mean by need them.... in the US i'm sure u have to have them on by law. well you do here in canada too, but our emissions laws aren't as strict. but from a technical pov, the O2 sensors are before the rear cats, so removing them doesn't trip any codes or anything. i took mine off a couple months ago or so and couldn't be happier