*sigh* Another Exhaust Question Thread Thingy

[packman]

You guys think using two different types of muffs is a bad thing? If I mangle the exhaust tubing while trying to get the Summit muff off, I will just cut the muff off at the ends and replace it with a longer Dynomax Hemi Super Turbo. I figure that the lopo won't care if there's two different muffs. Though, will another engine that is a little more performance (street) oriented, be sensitive, or does it not matter unless I got a racing engine in there? I know this is a loaded question, but I'm just curious.


Packman

[gadget73]

won't matter a bit. The crossover pipe should balance out any minor differences in flow between the pipes. The Mark 7 actually came with 2 different mufflers from the factory to cancel out exhaust resonance.

[packman]

Awesome! I can almost say that I can't wait to get whatever muffler installed. I sorta wished that I spent the extra $40 to get the Dynomax Hemi Super Turbos. They look like they can really quiet down the exhaust and still have a little rumble.


Packman

[1987cp]

I remember reading that Ray Flugger, who founded Flowmaster, originally got really interested in exhaust sound when he was putting glasspacks on a car and didn't have a matching pair. Story goes that he tried one mismatched combo and it sounded lousy, then tried another mismatched combo and it sounded great! Go figure.

[packman]

It worked out. I installed the Dynomax Super Turbo and everything is A-okay. The CV is a little quieter too. I kinked the pipe when I was prying the muffler off and I couldn't straighten it out with the exhaust pipe expander gizmo (it was too small), so there maybe some exhaust flow wiredness there. I was going to try and get the Hemi Super Turbo up there, but the muff is too long for the driver's side of the exhaust. I did hook it up and ran it briefly. It definitely quiets down the exhaust a bit; the only thing you could hear was the other muffler on the passenger side. When that muffler dies, it will be replaced with the Hemi Super Turbo (it will fit on that side).

Pirate was right; the catalytic converter does indeed produce some sort of acid (I think he said a weak sulfuric acid) that ears away at the exhaust. The Summit welded muff was almost completely eaten out inside. No rust or dents on the outside to warn of the troubles inside. The inlet tube separated from the chambered inards of the muff. I don't expect the other muff to be in any better shape. Hopefully I luck out and it lasts a little longer.



Packman

[1987cp]

That's funky. Isn't the "Hemi" Super Turbo just a 20" case? Stock muffler is 19" case - you'd think a 20" case would fit just fine.


(BTW, AutoZone rents both "large" and "small" tailpipe expanders. I used the "large" when I was working on some 2.5" stuff that needed unkinking.)

[TomO]

Way back when, I purchased a brand new '86 Mustang GT (302 H.O.) I distinctly remember that the factory mufflers were two different sizes. One was longer and narrower and the other was shorter and wider. As Gadget has already said, I believe the purpose of the different sizes was to decrease resonance.

When the original mufflers wore out when the car was about 5 years old, they were replaced by two identical mufflers and I had resonance. Never did get rid of the resonance throughout the remaining 18 years I drove the car and the 4 or 5 sets of replacement mufflers I had on it (it would wear out a set of mufflers in about 4 years or so).

[1987cp]

^^^ VERY interesting information!

Hm, maybe I'll have to obtain a large-case Hemi Super Turbo and investigate. I suppose maybe a different style muffler right and left would do the same thing? Doubt there would be any side-to-side flow problems if using an X pipe (and I've got one).

[packman]

Well, as you may already know, my exhaust is far from stock. I have the cutouts taking up some space between the H-pipe and the mufflers and both sides are unequal length. In any event, I'm intrigued by Gadget73's original comment about the unequal sized mufflers eliminating resonance. I will try that when the other muffler rots out. I will have two dynomax mufflers; one Super Turbo and the other a Hemi Super Turbo. We'll see how that setup works. Hopefully I won't have to add glasspacks at the tailpipes afterwards.


Packman

[turbo2256b]

Not only were the Mustang factory muffs different sizes there were some serious flow restrictions inside them as well as some restrictive seams between coring tubing. I have been using IMCO mufflers there 2.5 inch premium on both my GM and now the same muffs on my 400+ HP 460 dually. There turbo muffs seem to be good too. They are also built like OEM stuff. Also they are coated inside and out not just the outer case as the Walkers are . They also bought out Cheery Bomb a bit back. There product is made in the USA too.

[johnunit]

^^^ VERY interesting information!

Hm, maybe I'll have to obtain a large-case Hemi Super Turbo and investigate. I suppose maybe a different style muffler right and left would do the same thing? Doubt there would be any side-to-side flow problems if using an X pipe (and I've got one).

I could see length having to do with it. It gives you unequal length of piping, so different resonating frequencies on each side.

[packman]

Wow, it's like clockwork. The other muffler decided that it didn't like the company of the Dynomax muffler and broke in the same exact spot the other one did. So, I will be changing the second muffler next weekend. Yay me:smirk:. I kinda want to do other projects, but I would like to get the maintenance stuff done before it starts getting too cold. So I guess a muffler's lifespan is 4-5 years. Unless you get an expensive muff; or stock muffs.




Packman