DAPSUPRSLO

07-11-2006, 09:34 AM

Ok, after starting my 434 with the 3.5" magnaflows it seems as if I need an alternative to quiet this car down. I'd like a full exhaust that's both quiet and doesn't restrict this motor. Now i've always been interested in Vizard's comments regarding exhaust flow, wave tuning, and the design of his terminator boxes so here's what a friend and i've come up with. This is for my 434 which should be in the 650-700 fly wheel horsepower range.

The car has 3.5" merge collector headers and a sb2.2 intake. Being that the sb2.2 intake has short runners I figured the lower rpms could use a boost of power to bring average power up via exhaust tuning and my th400, 4000 stall, and 4.56 gears will have some somewhat significant rpm drops (from 7500 to 4600ish in 1st to 2nd and 7500 to 5000ish from 2nd to 1st). That being said i've got approximately 18" of 3.5" pipe from the primaries to the terminator boxes (18" collectors so to speak). The terminator boxes are 4"H x 8.5"W x 18"L. This give me a cubic inch size of 612 which is well over the required volume of 8 times the cubic inches of one cylinder (434 cubes in this case) as per vizard's recommendation. Now here's where it gets tricky.

Since I want this thing quiet the smaller the diameter of tail pipe out the back the better i'm sure. Dynomax claims their 2.5" mufflers flow 1133 cfm each. I only need a total of 2.2 cfm per horsepower total muffler flow which in the case of my projected power is 1540 cfm or 770 cfm per muffler (this is based of off 700 project fly wheel horsepower). Now theoretically these 2.5" mufflers will work perfectly.

What do you guys who follow vizard's exhaust articles think of all this? Do you think the 2.5" tail pipes will be restrictive with this kind of power?

Sure would be super cool to have a real quiet exhaust system which didn't restrict this motor hardly at all!!!

Nick

P.S. Here's the muffler i'm speaking of.

http://www.dynomax.com/

http://www.dynomax.com/ecat/ecat.asp?page=180

The car has 3.5" merge collector headers and a sb2.2 intake. Being that the sb2.2 intake has short runners I figured the lower rpms could use a boost of power to bring average power up via exhaust tuning and my th400, 4000 stall, and 4.56 gears will have some somewhat significant rpm drops (from 7500 to 4600ish in 1st to 2nd and 7500 to 5000ish from 2nd to 1st). That being said i've got approximately 18" of 3.5" pipe from the primaries to the terminator boxes (18" collectors so to speak). The terminator boxes are 4"H x 8.5"W x 18"L. This give me a cubic inch size of 612 which is well over the required volume of 8 times the cubic inches of one cylinder (434 cubes in this case) as per vizard's recommendation. Now here's where it gets tricky.

Since I want this thing quiet the smaller the diameter of tail pipe out the back the better i'm sure. Dynomax claims their 2.5" mufflers flow 1133 cfm each. I only need a total of 2.2 cfm per horsepower total muffler flow which in the case of my projected power is 1540 cfm or 770 cfm per muffler (this is based of off 700 project fly wheel horsepower). Now theoretically these 2.5" mufflers will work perfectly.

What do you guys who follow vizard's exhaust articles think of all this? Do you think the 2.5" tail pipes will be restrictive with this kind of power?

Sure would be super cool to have a real quiet exhaust system which didn't restrict this motor hardly at all!!!

Nick

P.S. Here's the muffler i'm speaking of.

http://www.dynomax.com/

http://www.dynomax.com/ecat/ecat.asp?page=180