96 f150 with 302
So I have my cat back system installed but it's not loud enough. It is 2.5" from the cat back with a FM 40 series delta flow. I had them exit the pipe in front of the rear tire because I wanted a little more sound. The guy at the shop said he couldn't tell the difference between the sound of a 40 series original series and the 40 series delta flow so I figured it would sound ok. Flowmaster says that the interior noise is less with the delta flow so I thought that made sense.
I decided on 2.5" because the shop recommended it and I got the same story from FM when I called them about pipe sizing. I didn't want to chance losing torque since that is the majority of the power used in everyday driving.

I really like the FM sound but just want it to be more noticable. I can hear it from the inside but it doesn't sound too much different than stock - maybe the delta flow "lower interior noise is true".
I am still running the stock cats - I know this cuts alot of sound down.

So I figure my choices are:

Go to 40 series original.

Go to 3 inch pipe exiting before the tire.

Go to 3 inch pipe exiting after the tire.

Don't know how much difference the 3 inch pipe will make and whether or not sound is better or worse depending on where it exits. Is it true that pipe sizing and routing doesn't matter much after the muffler? I was told that the sizing thing comes into play between the cat and the muffler.

Any opinions?

 

exiting in front of the tire was a problem for me. It ate the chrome off the center cap. Does yours have a tip or just the tailpipe? I ran 18" x 3" tips out the back and its not too loud in the cab but it is loud to drive behind or beside.

 

The 40 delta is quiet compaired to the 40 original. Flowmasters do tend to get louder after some break in time....

 

Yeah the deltaflow is a bit quieter than the Original...
Ask if its possible to swap out mufflers since he told you there would be no difference. It will get a bit louder after some miles. Maybe have someone drive it around the block so you can hear it... often times it doesn't seem that loud until you hear from the outside for yourself.

 

akford is right....I didnt think mine was that loud...until i got my dad to drive it around the block, and i was like damn! it is loud! lol....If you can, I say cutt of at least one of your cats, I think on the newer models if you cutt of both you may have problems with the check engine light coming on...that is if you have 2 o2 sensors...i didnt so i cutt off both of mine...no troubles here

 

longer and the bigger diameter tip the louder the sound.

 

Since your truck is a '96 I'm guessing you have OBD-II with sensors before and after the cats. If that's the case then you can't cut off any cats without replacing with functional ones that'll give the sensors proper reading. A highflow cat replacing both cats will work and add some volume.

 

2 high flow cats!

 

A friend of mine and myself installed a cat back kit on his 96 F-150 witha 302 a couple of years ago. It came with a muffler witha Y welded behind it. We cut the muffler off and welded on straight pipe. We then took the farthest back converter off of his truck. No sensor lights came on. Ran the same if not better, and was just as loud as any chevy or dodge on the road that had there duals Y'ed off.

just my 2 cents

 

You're right, I have OBDII.. There are 3 O2 sensors: one just down from each exhaust manifold and one between the 2 cats. I don't really want to take the last cat off since I have to pass the visual part of the emissions test. Most mechanics around here are used to looking for at least two cats on the later model Fords.
I know that no muffler sounds near as loud when it is behind cats but I was hoping for something more than what I am hearing.

You make a good point, I need to have someone drive by while I listen. Maybe that will put the smile back on my face.

According to flowmaster the delta flow is supposed to cut down on interior noise resonating into the cab. I thought the output sound was the same. I guess I'm wrong.

I've heard that FM mufflers do get louder over time. Why is that? I can see that with a Dynomax Race Magnum style it could cover the packing with soot and change the sound. Seems like the FM just has all those vanes and compartments - (which I don't understand either).

Thanks for the input so far.

Dan

 

I'm not sure why they get louder either but they definitely do! Mine did and so did my Dad's... Maybe the heat of the exhaust changes the muffler at the molecular level?? LOL I say give it a month or so and if its still too quiet, then swap out to different muffler.

 

You guys that are using flowmasters on your trucks, are you leaving the cats on when you use them? Cause if you are, the reason they are gettin louder is cause your cat is blowing out a little cause of less backpressure. I have a set of flowmasters I have had on a car for 3 years with no cats and haven't noticed any difference at all.. They are the 40 serious non delta flow

 

Both off my current trucks have Flowmaster on them. One has a cat , one doesn't.. Either way both trucks did get louder after time...

 

I have a 96 f-150 with a 5.8 pretty much the same as yours, I started out with a cat back turbo muffler SO/DO into 2 1/4 pipe out 18x3.5 tips angled out the sides and it was to quiet, so I had the muffler replaced with a Y pipe "stright piped" and it sounds much better,nice deep rumble. Its still not loud at all but IMO its the only way to get a truck with the 2 stock cats to sound good..Its still not loud enough for me tho so I got a highflow cat that I havnt installed yet..

 

Ford5.8,
So if I understand it right you completely took the muffler off and just ran straight pipe in place of it?
I'm assuming you angled the tips out behind the rear wheels...