5.0 exhaust ?

[Atom 8]

I bought an 2001 Explorer 5.0 the other day. It already has a Flowmaster on it, it has all 4 cats still on it and what I assume is a resonator after the muffler still on it. Will it make much difference in the sound if I remove the resonator, and I noticed alot of people have taken the second set of converters off, will that make the check engine light come on? Thanks

 

[Sams01XplrSprt]

is it single flowmaster or dual

 

[X6StringerX]

Removing the resonator makes a very noticeable difference. As far as the rear cats go, I don't believe it will trigger a CEL because the 02 sensors are after the 1st pair, but before the 2nd pair. Also, you should know that it is a major violation to remove cats... just throwing that out there. BIG fine.

 

[rileyrs]

take the resonator off.

if you wanna mess with the cats, check and make sure there are no sensors after the second two before you touch them at all.

then instead of pulling them off, since it is super illegal, get a magnaflow cats and put them on there.
that way its not illegal, or at least really illegal lol,
but the magnaflow cats will flow better and sound good

 

[Atom 8]

It's a single inlet, single outlet Flowmaster, don't know what series, I'm not happy with the way it is put together, but i don't have the money for a whole new exhaust at the moment.

 

[explorinitup]

i have the rear two cats off cuz they are not monitered. so no check engin i also have true duels to two 24" glass packs and dump just before the axle and is not as loud as i was expecting but when i get in to it it will scream but like he said no cats is super illegal

 

[Sams01XplrSprt]

atom u got pics of ur flowmaster setup

 

[Atom 8]

no, no pics yet. it just Y's into 1 pipe before the muffler with the stock tailpipe still on it.

 

[Sams01XplrSprt]

nice

 

[CDW6212R]

You can remove the resonator, it does lessen the noise a bit, and guys are correct when they say no cats will be illegal. The fact that there are four means that in intelligent states you can safely remove the rear cats.

Ford did not know how or if emissions could be met with one cat per side. They also didn't know that emissions could be met without an air pump, or air injection into the cats. Here we are years later, learning from earlier stupidity.

One high quality cat for each bank is sufficient to reduce the two chemicals being tested for. never mind that other chemicals are created by the cats, chemicals which may be just as dangerous to the environment. No one thinks through these things, a few stupid government officials get together with some tree huggers and make up some crap laws.

Best 302 exhaust, replace it all, headers to tail pipes. Make it dual mufflers, two cats(for the greenies), two tail pipes, 1.625" or larger headers, and at least 3" piping throughout. If you do that, which is the best exhaust, then you will have to retune the PCM. That is too much of a reduction in restriction for the computer to handle. The engine will run lean, and need more fuel. Regards,

 

[Atom 8]

ok, thanks for the info. I looked at the exhaust again yesterday, I was beginning to wonder if there was enough room under there for 2 flowmasters.

 

[CDW6212R]

There are a few mufflers which are too large to stand up side by side under the Explorers. I'm planning on two of the 70's eventually. The 50's are too thick, they need to set up at a slight angle to vertical. With Flowmasters you can have the two directly in contact, and weld them together, not needing space between them.

 

[X6StringerX]

Don,

What is your opinion of a 2.5" dual inlet/outlet muffler such as the Flowmaster Super 40? I had one on my last 5.0 Explorer and loved the sound it produced, but I regretted having dual pipes because I had to remove my spare. Keeping the spare would have meant I would have had to route the driver's side pipe between the spare and the fuel line... that made me way too uncomfortable with a 31" spare. Many forum members suggest that a dual 2.25-2.5" inlet and a single 3" outlet setup is much better for the 5.0 than a true dual or dual outlet setup. I believe the reasoning behind this is that we lose too much on the low end with a dual setup, but I'm not sure.

 

[CDW6212R]

The key is the computer tune. Any decrease in restriction of the exhaust or intake leans out the mixture slightly. Depending on how close the new resulting mixture is, the PCM may or may not richen the mixture enough to compensate for it.

I prefer to speak in ideal terms, so you will always here me say open up the exhaust as much as possible. The headers are the big restriction, those are really really bad, horrible is a kind word for them. The exhaust behind the headers should always be made as large as will feasibly fit.

If the cost is about the same, go with the bigger parts. Ideally if you modify the exhaust or intake, more air flows through the engine, and a better PCM tune will help a lot. Depending on how far the current tune is from ideal, the change will be minor or large. The more that you feel a change afterwords, it's likely that the tune is off more than if you feel no change. The seat of the pants feel is typically wrong. If it feels better, it's slower, if it feels slower, it's probably a surge, and slower. Only a real timed test before and after can say, and nobody does that.

Try to get a tuner into your budget and plan to use it after changes like that.

 

[Atom 8]

I looked up the part number on the muffler. It's a regular Flowmaster 40 series. It's not very old either so i think i'm just gonna buy another one to go with it and run duel tailpipes. I am worried about interior resonance though. It's not bad at all right now but it still has the factory resonator on it and that thing is gonna be gone!

 

[CDW6212R]

That's a big reason I'm going to run two mufflers and pipes. The larger the total volume of muffler is, the slower the exhaust will run, it should be slightly quieter than with one muffler.

A Flowmaster 40 is not a "quiet" muffler, so it's not the same as adding another quiet type of muffler. It should help though, and get the tips out from under the truck, point them away so the outlet isn't right next to the underside of the body. Imagine water coming out and shooting not straight but at all angles up to about 30 degrees from perpendicular. Don't let the sound waves be able to bounce up under the truck, that's why turn downs and many tips are louder.

 

[TekMan05]

Here's mine. It's a 2.5'' dual In/out muffler with the piping exiting after the rear tires!


skip towards the end of this video

 

[CDW6212R]

That's not too loud, but then again what about when the two cats are gone etc.

 

[CALDWELL]

if all the cats are still on... ???

your X sounds mean !!!!!!!!

 

[TekMan05]

if all the cats are still on... ???

your X sounds mean !!!!!!!!

yup all cats are still on just no resonator!