Today the muffler and tailpipe broke off at the inlet of the muffler on my 94 F150 with 302. It sounds fine with the stub that's left after the cat. I'm planning on replacing it with just a straight pipe exiting like it did stock but without the muffler. Do I really have to have a muffler because of the way the engine is tuned due to the emissions system. It seems to run fine as it is but the exhaust fumes seem to get in the cab while idling.

 

No you don't need a muffler. I would run a new pipe back so you don't get fumes in the cab. I took the cats off my truck many years ago and just run mufflers. They don't check emissions here. The truck doesn't care if there is a cat or muffler there. There are no sensors after the cats on our trucks. The only thing is you might loose some low end torque if there is too much flow.

 

The Cat's will provide more than enough back pressure and sound dampening if you're worried about it, my 94 F150 5.8 ran and sounded awesome (but very loud) with no Cat's and straight pipe. With the Cats it isn't likely to be loud enough that anyone's going to notice the muffler isn't there, just a nice exhaust growl.

 

Mine did the same thing If you don't put anything to hold the back up it'll crack between the cats like mine did it cost me 67 dollars to get a new pipe coming out in front of the tire and they tied it into the mount that used to hold the muffler

 

With the stock cats in place and untouched a muffler is honestly useless, the two stock restrictive as crap cats make a great muffler by themselves. Just make sure you have enough pipe behind the cab to make sure you aren't fumigating yourself at traffic lights and a hanger and your all good.

 

Oh no... not the backpressure myth again.

Backpressure = BAD. Velocity = GOOD. The goal is to size your pipes correctly so as to maximize velocity while minimizing backpressure. But that hardly matters if you're just messing with the muffler, cause the rest of the exhaust system is marginal anyway.

OP the muffler is about useless. I'm sure you noticed that the exhaust barely got louder. That's cause like Shadow mentioned, the factory cats need to be replaced or removed before you'll hear much of anything. If you're happy with how it sounds now then yeah go right ahead and run pipe where the muffler used to be.

 

That's right the truck is not loud at all because of the catalytic converters. It has a nice growl and sounds really nice. The only thing I notice is it seems that it idles a little higher than before.
I had a rice burner back in the early 80's that seemed to need some back pressure to idle right. I checked everything that made sense and then I found the rear muffler had a hole at the connection. After I welded it up it idled as smooth as silk.
Thanks for the replies.

 

Don't need back pressure to make anything idle right, being the 80's it could of just needed an idle adjustment of some kind if anything. If it had a computer controlled system then it either needed some time to relearn or just needed something played with somehow somewhere.

 

I have always enjoyed the quietest muffler possible. Loud exhaust is maybe cool on a sports car or something but I want comfort and quiet. But that is just me. To each their own.

 

This truck is a work horse so function is most important. A quiet muffler or one in general isn't important to me and an unnecessary expense at this time.
I got a quote yesterday of $150 to have a new pipe installed with new hangers. This seems a bit steep so I may just look to have the old one reattached.

 

I haven't gotten around to either getting a new pipe nor the old one rewelded.
I haven't found any good choices of just a pre-bent length of pipe from the cat back on my own. Does anyone know if anyone sells a cheap pre-bent cat back pipe like I'm looking for?

 

rock auto has pre bent pieces that run out behind the rear tire, but I think you would still need an extra piece since the muffler is gone.

 

I had looked around for a piece of bent pipe that would delete the muffler but would be long enough but had no luck.
I talked to a muffler shop and they said they could still reweld the broken off section back to where it was for around $60 or so but I still haven't done anything yet as the truck is not a daily driver and it's not due for a smog inspection for another year.

 

I used a 90 degree bent piece of EMT conduit cut in the center and flipped to make the dogleg if I remember its about 17" long and a 6 or 7 inch offset

 

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