308, 355, 360 EXHAUST MUFFLER DESIGN

Very interesting thread...

 

very complicated !
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Very, very nice...

 

The problem is that there's so little information available (although I too would like to know what's inside, I'm not going to cut up a working system ). Someone had posted some nice shots of the inside of an aftermarket 550 (IIRC) muffler/can where the can part was non-functional acoustically -- i.e., the tube just passed thru intact (but I can't seem to find it).
Here's a 328 standard/euro version silencer drawing that someone had graciously posted earlier:
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I've got two ANSAs on the way, I'll put the Sawzall on the old one once it's off.........obviously, great design effort into balancing pulses, etc........

 

By "standard" you must mean NOT "North American" version...as mine had a single input pipe, not dual

 

Yes, you've got the right gist Dave. I guess I don't like using the words "euro version" because that expression doesn't appear in the documentation IME so I usually say "standard version" when it's really a "no version" -- it's just a 328.

 

Well, not that it counts, but here is what I am using on my 3.2 and feel the sound is perfect in tenor and volume. Quieter and deeper than the old tubi and without the metallic tinniness; it wails like a GTC/4 on throttle and is smooth and relatively quiet at idle and cruise. Personal opinion only, but while magnificently polished, the previous tubi was just too loud for a daily or long trip GT. This setup was reached after a lot of experimentation trial and error, and offers for me the finest Ferrari 8 cylinder street sound.
best
rt
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That's a cool setup Russ

 

I have a 308 gtbi muffler bit on the rusty side (non euro style ) which i have cut open, spun out!! to see what was inside (very little ) will post pics next couple days cheers

 

Russ,

Are the internals of the muffler actually how it is in your diagram or are you "simplifying" the drawing?

 

The peach colored areas represent fiberous packing in the muffler and resonators and there the internal tubing is perforated. Other than that, it is exactly as shown and you can roll a ball from the intake then out the exhaust. I used to run open paired 3" tips (shown below), but the resonated Ansa tips really smooth the tone out. Without the resonated tips, it has more volume at idle and cruise and is more pulsitile and 'angry'. Since I use mine as a GT and on trips, I needed a more reasonable volume level in public.
Not sure how important, but everything parts and installation was about $500 with a superior sound to the tubi, imho. Having had a tubi for 5 years prior, that stainless shine does tarnish quite a bit with all the heat cylcing and you can follow the flow by the heat discoloration on the unit itself.
best,
rt
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SNJ5,
Is that last pic the final product? Damn that looks nice. Hey do you have any sound clips of your exhaust. Idle and on throttle. I was about to buy a stebro but if I like the way yours sounds, I'll go that way too. Lots of speed shops in my area. Man, its too bad you couldnt get that shop to churn out a few dozen of those, I bet they would sell.
-Nate

 

Russ you only have one 3" inlet.How did you join both front and rear banks?

 

Maurice - In the 3.2 US cars, the rear manifold points the other way and joins the front connector pipe on the starbord side of the car to join and empty into a single cat, so I just needed one inlet. Two inlet mufflers are also widely available. General rule is the larger the muffler, the deeper and quieter the tone.

Shark - This is all I have, just at idle and low speed - that's also about what it sounds like at cruise; not the best recording, but be sure you have a headset that can pick up the low frequencies as most speakers miss them. This set-up has a much deeper lower tone than my previous tubi. It really changes character and deeply wooooms on throttle opening while not obtrusive at idle and cruise - certainly not the famous 'tubi boom'. I was going for a classic Ferrari Grand Touring sound rather than an modern F1 boy Schumi. Again, without the resonated Ansa tailpipes, the volume was louder and more angry in a pulsitile way. Here's a clip with the Ansa resonators - best with a good headset:
http://media.putfile.com/mondial

 

I remember you posting that one.......sounds good but you gotta do one at throttle!
-Nathan

 

Thanks Russ for the explanation.By the way the exhaust looks great

 

That's interesting - I used to have a similar set up 25 years ago on a Group 1 Saloon Car in Germany but that type of design got banned, apparently because of poisonous emissions resulting from the fibre packing. In fact, the fibre packing used to melt and, after a while, turned into a congealed lump which used to rattle around in the muffler.

Is that type of design a current "legal" option in the States or do the Feds also have an issue with the emissions? Do you know what type of padding is used? I think my old Group 1 had some type of glass wool.

 

Emissions testing here in the States varies state to state, and sometimes city to city. From the catalyst back, pretty much almost anything goes as far as Federal regs. The fiber packed muffler (Dynomax, Magnaflow. many others) and tips (Ansa, others) are widely available and quite popular here. The packing is different between manufacturers, but is often a glass or other wool type.

Other types of performace mufflers (Flowmaster) use an internal cheveron design seeking to nullify reversion pulsing.

Mufflers like the tubistyle are an acoustic box type as the stock muffler I am told.

best
rt