Currently I have a custom 3" true system dumped before the axels and 18" case Dynomax bullets. It was a stopgap or temporary setup. I'm looking to replace the bullets with Magnaflow Perf. or XL chambered mufflers and run tailpipes over the axels on each side per Gripenfelter's setup. The idea is to quiet the car down to near your average Hooker/Magnaflow/non-open Borla catback levels (with LT's and no cats of course). Tame idle and cruise is what I'm going for. I know it'll sound good at WOT so I'm not concerned, its just the daily driving aspect. I like the magnaflow sound on a dualed LT1 and will be staying with that brand.

With that information, can that be achieved on an 18" case length muffler of either of the two types above? Or should I be looking into a stock size dual in dual out muffler in the stock location and redoing the entire setup in 2.5"?

 

keep em dumped....louder, meaner, and not as much as a PITA

 

I'm going out the back regardless. Needs to be SIGNIFICANTLY quieter especially in the cabin. This is a daily driven spring-fall vehicle. I completely agree with your points but my needs are a far cry from the current setup.

 

With an 18" muffler,your going to be hard pressed to get that to fit without a ton of "U" piping behind the bumper.
I went with a 14" muffler..these
http://www.jegs.com/webapp/wcs/store...10002_20853_-1

and they come within 1.5" of the panhard bar after the 90 degree bend on the driver side, and the muffler can't be angled..the pass side would be tight as well because of the angle they have to sit.

Here's a pic of my setup


and a sound clip
http://hometown.aol.com/onebadwskier...dual-sound.mpg

 

Thats a nice setup and sounds good. The mufflers will go just before the axles and piping run over on each side so it'll be a bit different than your muffler placement. After listening to your clip I'm a bit more confident in an 18" to control sound. The question still remains, straight through or chambered?

 

I think if your mufflers are before the axle, then it will be quieter than mine even if straight thru. It just seems that exhaust is louder of the muffler is mounted right at the end of the exhaust like mine. I guess the piping after the muffler helps resonate and muffle the sound even further.
I'm not familar with the mufflers your using, never seen them in person on someones car, but will you have enough ground clearence with them mounted there?

 

This is the thread I was speaking of
Here. Basically what I'm going to try and mimick. From reading through, ground clearance *shouldnt* be an issue. A 4x9 is basically the same height as the bullets I have on now and they've never hit anything. I'm going to make measurements before I make my final decision. I'm not opposed to a dual in dual out 22" single muffler in the stock location but I'm wondering if the tone will be a bit raspy and less refined per a factory style setup as the exhaust will flow through one large muffler?

 

I see. Where that muffler is sitting in front of the axle is the same place my pipes are routed past. My setup before had the bottom of the exhaust pipe exactly 3.5" from the bottom of the floor board right there where the floor board bubbles out/down toward the ground.
It DID hit the ground periodically, not real bad but it did hit. My setup now has 3" of clearence at the same position, hasn't hit yet, but hasn't been on the car but a few days now. Both of my setups were rock solid and did not move/bounce when hitting bumps/dips.
Those mufflers are 4" tall, and you need about 1/2" clearance from the floor board....so that will be 4.5" from the floor board...a whole inch closer to the ground than mine...it will hit.

 

If thats the case I may go over the axles on each side and cross the pipes after the axles with the mufflers there. I'll still make measurements anyway but I dont want it to be anywhere near close. I'm sure the car will end up an inch lower one of these days. Thanks for the info, you've been a great help.