http://www.enoisecontrol.com/related_ar ... r_wall.pdf


tailpipes and resonators start at page 35

I think the drone can be elimanted with a 1/4 wave resonator.......

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Interesting reading, Ed.

Olaf.

(...now let's see; taipipe 5 ft., first over the rear axle, then 2 turns around the gas tank, could add some trombone effect there, elminate the spare wheel, yup, it's possible!)

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Aspenized

Instead of dynomax or flowmaster or magnaflow how about

www.cherrybomb.com

www.spintechmufflers.com

I have never heard the SpinTech muffler on a SL6. Judging from the V8 sound samples it may be very raspy. I have heard plenty of Cherry bomb style glass packs and Smitty mufflers over the years. They all have a raspiness too them that I don't care for. I just don't like that buzzy sound.

Since installing the big body FlowMaster 70 I have been impressed over the other mufflers in their line like the FM 30 and FM 40 which are fun for a day or two, not great for cruising at high rpm. The FM 70 has a deep low burble on the SL6 and is very quiet at cruise. No raspy sounds when you rev it up or at higher rpms. It just fits in the stock location with out much room to spare. On the Freeway cruising it has been fine. No resonance and no complaints from my wife. I have not run it up to 90 mph yet at the strip to determine if there is any resonance over 3000 rpm, but around town and running down I-90 has been great so far. The rpm range I cruise at is 2000 to 2650 rpm which equates to 50 mph to 65 mph. No resonance in these ranges. All I get is wind noise around the body of the car.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Cherrybomb has more than just glasspacks. I have a their vortex muffler on my truck and it's nice and quiet.

Snarl,

What is the part#? and or dimensions?
I see it is similar to a MagnaFlow only square, using absorbtion packing.
What rpm do you cruise at?

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

The truck is a chevy with a 4.3 v6. Not a slant I know. Cruise at 70 is 2000 rpm.

http://www.cherrybomb.com/Catalog/Categ ... _oval.aspx

part number 88104

you could probably use the 88101

http://www.cherrybomb.com/Catalog/Categ ... _oval.aspx

Snarl,

So how does it sound at 2500 to 3000 rpm?

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

I can appreciate this logic, Dan. I posted to the other thread you mentioned. But the article wjajr posted intrigues me as well, and has me thinking about the internals of a muffler. It mentions a few Dynomax models (by the way, notice the new "drone free" model at the top there - I'm still not familiar with said drone). Joshua Skinner mentioned his Dynomax Super Turbo - Joshua, where would you rank that model on the noise scale, 1 to 10 (for a slant 6).

I installed the 2bbl manifold and the 32/36 Weber to achieve the possibility of higher gas mileage and performance. Beyond that project and this one, I won't be making any more performance upgrades. Would any others agree with Dan's assessment that a high performance muffler offers zero advantage over the oversized stock-type muffler for someone in my situation?

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J.R.
Tucson, AZ
'68 Dart 270 with a '76-'80 engine

I wont say (and I think Dan would agree) that it would offer NO advantage over a stock type muffler,but I will say there would not be a huge difference either; 1-3hp maybe!? Also the stock type muffler would be better suited for a daily driver app. where the driver does not want any drone,or excessive exhaust noise. If you like it loud and raunchy go for the perf. muffler Im only 23,and I do love a nice loud exhaust,but not for an everyday driver. It can get on your nerves after a while,especially on road trips.

If 10 is open headers and 1 is Chrysler Imperial quiet. The Dynomax Super Turbo on a 2 1/4" pipe from the stock exhaust manifold with a nearly stock 225 is no more than a 5 and probably more like a 4. With more cam and compression it would be louder. Did you see the video? http://youtu.be/g4fv0N3LvAw

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Joshua

A small remark on noise/drone: On some mufflers with a large, open entry chamber (like FM), by letteing the intake pipe stick into the muffler instead of cutting it so it fits exactly, you can move the sound/drone at certain engine speeds by varying the length of the pipe inside the muffler. We talk about some distance like in the region of 0.5-3.5 inches here. This need testing out on the engine in question, I don't have any formula for how much. In practical terms, you change the internal resonance capacity of the muffler.

Olaf.

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Aspenized

Took the truck out and got it up to 2500-3000 rpm and the muffler had some noise (not drone). At speed it's drowned out by wind noise for me.

Hey there, gentlemen. I wanted to follow up on this thread and let you know how things turned out. I decided to go stock-type as an intimidating exhaust just isn't my thing, and I couldn't really settle (confidently) on a happy medium. My Dart is more of a weekend/road trip driver, so I wanted to make sure highway driving was pleasant.

I took my car to a second shop (see post #1 in this thread) and he wanted to do the same thing as the first shop! So, I found yet another that seemed to have a good reputation, described to them what I wanted (2.25 manifold to tip, an oversize Walker muffler), and left it in their hands. I picked it up the next day and the work looked good. I Googled the Walker part # listed on the receipt, and found this:

http://www.summitracing.com/parts/WLK-17808/

According to this thread, the size on this is good. But the market price for this muffler is a lot cheaper than I expected (the shop charged me more than that, of course), so I hope it's sufficient quality. What thinks y'all? I'll take some pictures if you like.

By the way, Josh, yes, I watched the video several times, and it helped in my research. Thank you.

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J.R.
Tucson, AZ
'68 Dart 270 with a '76-'80 engine