Remove mid muffler or not?

[kas_lar]

I’ve had my 1995 model for about two months, and the exhaust is completely stock with catalytic converters, mid mufflers, and rear/end mufflers. I’d like a bit more sound, but not too much.

Some people have recommended starting by removing the mid muffler and replacing it with straight pipes.

Do you have any suggestions? Should I just cut out the mid muffler and clamp on a 2.5" pipe? Check out the pictures to see the exhaust setup.

 

[RAU03MACH]

i would i did
that is just me

 

[badass98svt]

Remove all those cats. I'd say to just buy an Off-road H pipe, but I dont think anyone makes them anymore.
Looks like a California bought car.

 

[Mustang5L5]

Those are cat converters, not mufflers. Your mid-pipe has 2. 2 near the heads, and two main cats where you indicate.

Up to you if you want to remove them.

 

[ttocs]

The exhaust will have a heavier smell and it can build up and be a bit much sometimes with out them. Also FYI there are precious metals inside of those so do not just pitch them out check out recycling yards or online there are people that will buy them.

 

[Musturd]

I’d get an exhaust shop to make you a off road mid pipe

 

[ttocs]

but also be aware that if you live in an area that does emissions testing that you will not want to get rid of those.

 

[kas_lar]

Hi everyone,

Thanks for replying and sharing. I’m learning more and more about this car, and it’s great that you guys told me that the mid muffler is actually a catalytic converter—I didn’t know that!

We do have emissions tests here in Denmark, but once the car hits 30 years, many vehicle inspectors are more lenient with smog and emissions.

Would I get a better, deeper sound if I keep the mid-cat and install something like a Flowmaster Thunder(17212) axle-back exhaust instead?"

 

[ttocs]

any change to the exhaust will make some kind of change in sound. Now if it sounds better or worse is kind of subjective.

Greetings by the way, My dad immigrated from Denmark when he was 15.

 

[Musturd]

They sound better with out cats IMO . A lot of people who have emissions testing usually have two mid pipes and just spend the 20 mins swapping for the test .

 

[Daryl]

My suggestion, FWIW, would be to simply swap the mufflers with a deeper sounding set. I live California so I have all 4 cats in place but I run a FlowMaster cat back with Super 44 mufflers (the 40’s were a tad much for what I wanted). A bit of a drone sound around 2200rpm, but it’s short-lived. Car has a nice, subtle idle sound and coworkers have “said” it sounds like a NASCAR at speed and high rpm’s. Hard for me to tell from inside and maybe they’re just being nice, IDK. But I like how it sounds.

 

[ju015dd]

Off road h or x with some flow master mufflers always sounded the best

 

[ZachS.]

Removing the cats and leaving the stock mufflers sounds great. No drone, nice deep rumble, and only loud when you get on it.

 

[ttocs]

How strict are the cops on loud exhausts there? If they crack down on loud cars I would give it some serious thought. I had a catted X and the cats went bad so I went catless as I was curious how much louder it made it. My final opinion(mind you I also have side exhaust) was that it was just a little louder than I liked. I ended up coming across a set of unused high flow cats online for $100 so I cut the pipe and installed them and I was happier both with the sound and the smell. With the side exhaust it didn't take much wind to blow it straight into your face while at lights and I can say I kinda like the smell of exhaust to a point but it was just too much for me.

 

[Mustang5L5]

Being this is a convertible, I would probably lean towards leaving the cat converters and changing the mufflers for the tone.

Reason I say that is because fumes from the exhaust tend to waft back into the pass compartment a bit easier on the convertibles with the top down. There’s a certain speed (2-5mph) in which the exhaust gets pulled up and over the trunk lid so low speed cruising can be annoying.

I know with my convertible when I first got it it was overly rich due to bad o2 sensors. With the top down, my kids would complain about the fumes.

 

[kas_lar]

Thanks, Mustang5L5. I’ve got kids and a wife too, and they’re already quite picky about heat and smell. I’ll have to take your experience into consideration as well. This will only be a 'summer car,' and this autumn, we’ve been driving a lot with the top down.

 

[kas_lar]

How strict are the cops on loud exhausts there? If they crack down on loud cars I would give it some serious thought. I had a catted X and the cats went bad so I went catless as I was curious how much louder it made it. My final opinion(mind you I also have side exhaust) was that it was just a little louder than I liked. I ended up coming across a set of unused high flow cats online for $100 so I cut the pipe and installed them and I was happier both with the sound and the smell. With the side exhaust it didn't take much wind to blow it straight into your face while at lights and I can say I kinda like the smell of exhaust to a point but it was just too much for me.

They can be quite strict, but only if someone is really high-revving at a car meet. I don’t plan on a side exhaust since it’s not legal in Denmark, but I’ll reconsider the catalytic converters.

Would one cat just after the header be enough, or does the mid cat also help with reducing smell?

 

[I_LIKE_TURTLEZ]

Those 4 boxes from the transmission cross-member going forward, are catalytic converters, from what I can see you have 4 of them.
You only need 2(one for each cylinder bank) to pass emissions.

I'm not sure about the 1994-1995 5.0 cars, but the 96-98 models came with 6 converters which are incredibly restrictive, removing them alone adds about 20 horsepower.
My first instinct is to chop all the converters off since your car is about to turn 30 years old but since you're concerned about wife & kids, I'd keep 1 on each side but replace them with high-flow variants to let the car actually breathe.
Keep in mind the factory exhaust pipe sizing on these cars is 2.25 inches, not 2.5

As for mufflers, sound is highly personal, you will have to look up exhaust videos to make a decision on what sounds good to you. Definitely ditch those factory mufflers though, they're 30 years old and clogged up just like the converters.

 

[shovel]

242k miles on this 94 gt cat... it's heavy but it's definitely not clogged up

 

[kas_lar]

Hi everyone, just a quick update.

I decided to start by changing out the rear mufflers first. I found a seller in Germany who could provide a Flowmaster American Thunder cat-back and ship it in just a few days.

I removed the old exhaust yesterday, and wow, what a sound without any mufflers! I was afraid to rev it higher than around 2000–2500 RPM!

I’m also replacing a few suspension parts, so I’ll have to wait a bit before installing the Flowmaster and giving it a listen.

I decided to keep the mid-cats for now because I didn’t want fumes or a bad smell, and I can always remove the mid-cat later if needed.

Thanks for all the advice! I’ll keep you posted on the progress.