Hey guys, I have a 2004 f150 that I bought last August 04. I was wondering what the do's and dont's are for putting on some aftermarket exhaust. I want to cut 2 of the cats off and put glass packs in there place and run all the way back. I have a 3 yr. 35,000 mile warranty and was wondering if this would void the warranty.

 

I could be wrong, but isn't removing the cats illegal? I am pretty such Ford would say something about the removal of cats to reject any claims for the engine.

 

Yes, you remove those cats, not only will you be violating federal law, but totally void the warranty. The cats do not rob power like years past. Why do you want to remove them? They are there to help the air we all have to breath. I do get bothered by the states in the rest of this country that do not have mandatory emissions testing.

 

No purpose. New cats are very low backpressure and unlike the old cats, actually help the air be cleaner.

You go to an 18'' Magnaflow and duel outlets, you won't have enough back pressure to mean anything. Might kill your bottom end, a little, as overscavaging is not conducive to low end power. These motors are NOT high RPM designs.
Torque, not horsepower, is what you drive.
Chris

 

Yea, I was pretty sure cutting the cuts would void the warranty. Here in Indiana we don't have those emissions testings or whatever, so you can do whatever you want. The reason I want to cut atleast 2 of the cats is to make it alot louder, but I don't think I'm gonna do that though.

I think I'm gonna do what I did with my 2001 F-150-have the muffler cut off and make a y pipe and dual it out the back. This would be decently loud. Would this void the warranty, by just taking off the stock muffler??

 

No, most of us have Catback systems. As to loud, just put in a y with no muffler at all.
They don't have muffler requirments in Indiana?
Here, cops give me a dirty look with a 24 inch Magflow. I could have been ticked with the 18" that I had on for awhile.

Even with no laws, the drone from open exaust gets a little tiring when you drive, and it actually ruins your hearing over a fairly short time. You don't get that hearing loss back, ever. We used to use pretty heavy ear protection at the track, and even so, my old partner (who drove more than me) lost about 40% hearing in less than a year. He had to start using hearing aids at 35, and that was given as the main reason.
I'm 30% deaf in my right ear from years of handgun shooting. I almost always used muffs, but it still ads up.

Just a friendly suggestion.
Chris

 

Thanks Chris. Never heard that said about exhaust before, but I can bet you're right.

Nope, no muffler or cat requirements that are actually enforced in Indiana. So running a Y pipe after the cats would not void the warranty?

 

what kind of exhaust is this on your truck? i'm in the market for exhaust for my 04fx4, but can't find anything that is loud enough. i've heard the 40 series flowmaster is probably the loudest? how do you compare this with your magnaflow and also is it just out the side? any suggestions are greatly appreciated.


Upper Case edited out by FTE

 

My truck had the Catback Magnaflow with the 18 'straight through' muffler, ending with a 5 inch outlet. It was annoying on any kind of hill. Steady driving it was lowder than anything but very loud music. My wife didn't want to drive the truck. Not loud compared to open headers on a Rat, of course, but too loud for actual enjoying your driving. I've had open pipes on a Spitfire, several VW baja bugs and buggys, a Tr4A (built engine, straight pipe) but never on a street V8. Frankly, overscavaging the exhaust makes them very peaky. Great on a racing engine, but nonsense on something you drive to Burger king.
Even the single chamber Flowmasters have a lot of harmonics in the body that are unpleasant.
Powerful sounds are one thing, loud is another.
I prefer to actually hear fire trucks, my stereo, my passenger.

One other thing, my truck is a regular cab, so it's a bit louder inside than the Supercrew and Supercabs. You are closer to the exhaust outlet.
Chris