I am building a 55 chevy wagon in a 60's mild custom style, but it will have more of a hot rod engine. The engine is a gm zz430 350 430hp. I will be using this car as a fun cruiser that the whole family can ride in and plan on using it very often. I don't want a car that sounds too loud, like your average street strip nova or something more for friday night drags. I liked the sound of smithys gl***packs on my old stock 283 with 2" pipes, but that is not going to do it on this engine. The gl***packs sound really raspy it seems when you have this much motor. I have sanderson headers and plan on 2.5" exhaust, but am unsure what to do after that. I have some 2.5" smithys and thought about toning it down with turbo style mufflers and maybe a H pipe before the smithys to calm it down and get it quieter. I don't need it silent, but don't want a constant drone. Kinda want a sleeper that will suprise ya when you stomp it. Any ideas, or recommendations?
On my bbc Biscayne,running a pretty big cam, I ran a 2 1/2" exhaust with 3 chambered Flowmasters. The sound was pretty mellow unless you floored it, then it sounded un****ed.
Had good luck on several systems (SBC) with the GM Turbo mufflers, might be less than 2.5 dia though.
My advice it to get a Y or collector pipe and bring both sides together rightafter the headers, then run a single 3 inch length of pipe to the back and then split it again to 2.5 or 2.25 inch pipe and then out to a mild set of mufflers. That will give you a real nice mellow sound and since you blended the exhaust pulses they will be distributed over two mufflers evenly and you will have great flow with little back pressure. Even with some quiet oem 2.25 inch mufflers it will support 350HP easy. Use a set of performance mufflers and you can support 400HP. I have the privledge to work under many BMW M cars producing 360 to 500HP and that's how they do it quietly. The truth is H pipes dont do much for sound and X pipes look cool but only work on flat plane V8's and V12's where the exhaust pulses are spaced exactly even on each side which is necessary to get the scavenging effect right/ The double or back-to-back Y pipe like I described above is the way to go for your needs. check this out http://api.viglink.com/api/click?fo...h/index.html&jsonp=vglnk_jsonp_13431741649943
How much you looking to spend and how often will you be transporting family? The mufflers we made, and that are sold by Waldron now, are the best of both worlds. Loud when you want them but silent when you do not. Made from stainless and having lots of expensive parts in them, they are indeed costly but cheaper than two full exhaust systems and definitely fun to play with! At a minimum, you can expect to see 7 dBA difference between open and closed and that gets you "flowmaster" loud versus "stock" quiet. Tom
Good info, the link was a good read but possibly left me more confused than before other than the simple muffler cfm calculation. How does one figure the correct collector length, and what exactly is a resonator box?
Just let it sink in and perhaps re-read tomarrow. The details & specifics are not that important unless you have a controlled enviroment and a dyno. Just simplify the ideas. Collector length becomes critical and important with long duration cams running 6000+ RPM. Your ZZ4 cam will be fine with a set of normal headers. Also consider this great reseource on the idea. http://www.castheads.com/2into1_systems.php A resonator box is just a large space square, oval or tube where all the pulses collect, blend and equalize. Ideally it has to be large enough to allow the exhaust pulses completly to blend. The idea is a smooth flow of exhaust gas will move through a muffler quieter and more effeciently than a pulsed flow.
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