Trying to get my e350 ready for the road and I just couldn't believe the original owner (I'm the 2nd) had never touched the factory exhaust in 250k miles. I took it to the muffler shop to have them check out the cat and mufflers and they were pretty rusty but not leaking anywhere. I thought the cat had to be robbing me of some power since it was that old. Since we have no emissions he quoted me about the same price to go from the Y pipe back, no cat and an aftermarket (supposedly quiet) stock muffler, 3" pipe all the way back as he would just to replace the cat. I thought it would be more free flowing and perfect sounding like oem. The result is exactly what I had hoped NOT to happen. Yes it rumbles nicely at idle, not too annoying, but I didn't buy this thing to sound like a hot rod. On the highway it is LOUD and the drone drives me crazy, especially pulling when it's always working hard.
It's going back and probably going to cost me a few more dollars to quiet it down, but I'm looking for advice on what do do. If I add a cat back in to the system will it quiet it down, or could I just add a resonator or something? Power doesn't really feel any different and haven't measured mpg yet. The muffler is an aftermarket stock replacement, not a Flowmaster or anything that is supposed to be loud, but it is much smaller than the oem 100lb muffler.
Sorry for the long post.

Thx

 

stock is hard to beat for being quiet.
Which motor do you have?
On my 7.3PSD van I ran straight pipe, loud yes but worth it when I gained 2mpg and dropped egt by a few deg.

 

460 gas. Kind of wish I had just left it alone. I bought this van for road trips only so quiet is important. I hope someone with experience with my problem chimes in, I'm willing to add a cat converter back in to the system, but oif I did that and it didn't help I'd be REALLY pissed!!!
Thx Dbasso

 

You should have gone dual exhaust with 2 small mufflers...is it fuel injected or carb ?

 

Fuel injected, and I did one. If I do that, you thunk it will be quieter without a cat? Only problem is that big oval flange where it comes in to one behind Y pipe is still there. I guess I could ditch it and have true duals.

 

I would avoid Installing a CAT..... I would go true duals and get decent mufflers which should quiet it down...upgrading the Mass flow sensor and air filter should give you 10-15 % fuel economy...It will still rumble but the drone should be gone....Big Blocks need to flow to get better fuel ecomony...If it is still too loud you can put the fuel savings towards dynamat or other noise reducing insulation....

 

Thx blageurt! I appreciate the advice.

 

Get fairly big mufflers. Theyll be more quiet than small mufflers.

 

Did a performance exhaust with my 95 351w, dual this dual that. All kinds of problems. Got rid of everything, went to stock, which was the quietest and strongest.

Remember, enlarging the "exit hole" only does nothing or sometimes even cause problems. Engine, intake, exhaust, etc. etc. were designed as a system, and you must address it as a system. If you can't, leave it alone, before you do more harm than good.

 

Just got home from a camping trip pulling my trailer. Horrible exhaust noise, and my torque is down too. If felt like it was struggling on hills and never did before. Since the 460 has a big oval flange going in to the cat converter and comes to one pipe into the converter and then 2 out of it, i think i'm gonna just add a converter back in between that flange and the 3" in and out muffler i got, anyone thing that will add some backpressure (torque) and quieten things down?

 

Your Cat is probably plugged solid...Get rid of it and go single but bigger ( like 3") and get a Turbo muffler if you really don't want to go REAL duals....Torque is a function of reciprocating mass NOT backpresssure....Backpressure affects cylinder scavenging but in your case, with EFI , the Oxygen sensor is a critical part of the system as well and readings from that affect performance as well.... Have you upgraded the Air intake ? My 77' 460 makes ridiculous torque ...although it is slightly modified and has a few goodies ....Your engine is being choked , trust me...

 

Blageurt, I have no cat so it can't be plugged, i was talking about adding a new one back in. Right now i have 3" pipe from the back of the Y pipe (the big oval flange) through one muffler and 3" back to right side rear exit, like the stock exhaust ran. I haven't upgraded the intake yet but have been thinking of that too. You think a K&N will help? I wasn't thinking of doing a full intake but am open to suggestions. Also, how do i upgrade a mass air flow sensor? I'm not familiar with this.
Thanks!

 

There are some parts available here ...7.5L/460 - E-350 ECONOLINE - FORD - 1996 - SummitRacing.com The biggest problem with the 460 is the ignition and exhaust flow..I went accell and MSD on the ignition end and have a free flowing exhaust along with a Edlebrock performance intake and a big holley carb . As was stated above it is indeed a "system" but the 460 is choked like no other engine. If you search in the specifi sections you will some stuff that will work for you ...

 

Thx! I'll take a look.

 

Since you removed the CAT i would add a resonator before the muffler. Just add a big old straight thru glass pak and that should help. Adding a "real" resonator would quite it down even more.