Apt.......I just read one of your posts regarding prebent exhaust pipes for magnaflow and or flowmaster. Where do we find this? Can they be found for say a si/do that is being pieced together?

My dilema.......I have a '04 4.6L. I want to do the exhaust and try to save some money by going to "Joe Blow" down the street. Like you, I've done a lot of research on this and I am still confused as hell.

If I can get the mandrel bent piping for a dual out system that goes to the back or at the very least, exit behind both back tires, I'd like to go that option.

Any suggestions as to the setup I should get, ie: Magnaflow or flowmaster, 2.5" in 2.25"out (dual)?

Any help would greatly be appreciated.

Thanks,
TJ

 

I have not found the Magnaflow pre-bent tail pipes for the '04 F-150 and I don't know if the 97-03 ones are will work.Big Exhaust and Full Line both sell the pre-bent stuff for the last gen. Single 3" for $40 or Dual 2.5" for about $80 for the pair. The dual set comes straight out the rear and clear the spare tire and the OEM trailer reciever. Again, dunno about fitment for the '04 yet Either leave them alone or buy some tips. Or, they could be bent 45degrees or so to come out the side behind the rear wheels.

The Flowmaster solution may work better for you. They have universal slip fit tailpipe kits that come in 4 pieces. A little more at about $62, though. I don't know if you could make it come across to the other side of the spare for dual out rear.

You might want to give someone a call or e-mail, either the vendors or the manufacturers. Maybe Magnaflow has a solution coming soon. Maybe Flowmaster has something planned too.

At these prices, I would chose them over having a shop custom bend me something. However, if I wanted stianless, I'd just order a stainless cat-back.

Diameter:
Single 3" should work fine with the 4.6". Dual 2.5" is a lot for the 4.6L, but the OEM y-pipe really was the problem on the 97-03. I haven't seen the '04 design. I know many have come on here complaining of performance loss with dual 2.5" pipe that their shop bent, but I haven't heard of problems from people using cat-back systems with dual 2.5". If life were perfect, I think dual 2.25" pipes would be the best for the 4.6L, but I don't know of any pre-bent solutions for that.

If I were you with an 04 4.6L wanting dual out rear, I would just order tips and let a reputable shop bend 2.25" pipes. I might be willing to buy Flowmaster slip-fit universal, but I don't know how much that would save you.

I am curiosu to what our decision will be and your impressions when it is done.
Aaron

 

Ok, now I'm getting really mad. I just spoke to the service department about doing the exhaust. They told me if I change the exhaust, it will void the warranty on any and all emissions related parts and if it is proven to change back pressure to the engine, then it will void internal parts warranty of some sorts. I'm so so mad.

 

Apt,

As you suggested, I emailed Full Line and asked them about prebent piping. And they said they have it for my truck, $24 each. Now another question. If I buy all the components, does this essentially make it a bolt on system from the muffler back? Oops... two questions. Once I get it on, should have have it tack welded?

Apt, I really want to thank you for pointing out the prebent pipes, I'd have never thought of that.

Thanks,
TJ

 

Kind of bolt on, yes. But, you need hangers and clamps or welds to make sure it is secure. Maybe just order al lthe parts you want (SIDO muffler, twin tail pipes, and tips) and take them to a local shop to install. $50-75 is fair for the labor of an hour or less with those compoents and removing the OEM system.

 

As far as just replacing the muffler and running different pipe back will not void your warranty. The dealership where I bought my truck from actually installs flowmasters w/ dual tips in the aftermarket dept there.

The service guy there told me that as long as the aftermarket part does not cause the problem it is fine.

 

Hey Apt,

Just back from the muffler shop. Had a si/so 18" magnaflow put on along with an 18" tip. Both are stainless. It sounds really good. Gives the rumble I want when I want it and is nice and mellow at cruising speeds. Thanks for the input y'all.

tj