ARH header install experience . . .
01-06-2011, 10:40 AM
#33
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Nope, 6.2 has 3.5" in/out. A beast.
5.3 has 2.75" in/out. A least.
Is the raw gasoline smell gone though?
5.3 has 2.75" in/out. A least.
Can't speak for any other header company's high-flow cats, but I'd imagine they're all pretty much the same. They are quite simply TOO SMALL and apparently flow too well to adequately reduce the emissions enough to keep from setting catalyst efficiency (P0420 and P0430) codes, and of course the OR Y-pipe will set codes as well.
01-06-2011, 01:39 PM
#36
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http://www.gmfullsize.com/forum/showthread.php?t=214186
Here's a whole thread on mine - with video. I can't do YouTube stuff at work.
Here's a whole thread on mine - with video. I can't do YouTube stuff at work.
01-06-2011, 01:39 PM
#37
FWIW - here's a thread over on the Denali Forums about the L92 muffler design - with cutaway pics. It is indeed a BEAST of a muffler!
http://denalitrucks.com/forum/viewto...hlight=muffler
http://denalitrucks.com/forum/viewto...hlight=muffler
01-06-2011, 01:54 PM
#39
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FWIW - here's a thread over on the Denali Forums about the L92 muffler design - with cutaway pics. It is indeed a BEAST of a muffler!
http://denalitrucks.com/forum/viewto...hlight=muffler
http://denalitrucks.com/forum/viewto...hlight=muffler
01-06-2011, 02:04 PM
#40
I was curious what the NBS mufflers had inside that made them sound so nice, so i thought I'd dissect one to see what makes it tick, or roar I should say!
My friend Larry (cable guy) added a Corsa system a couple of months ago and I asked him to ship me his stock muffler so I could perform surgery on it. Thanks Larry!
Here's the muffler after I made a few precision cuts with my air chisel, then had to drill out about a dozen spotwelds.
A few specs, 26" long, 12¼" wide and 7 5/8 high. Steel thickness varies between .062-.080. This is one mighty heavy muffler! Heavy gauge steel is used for a reason, it does not resonate as much as thinner steel does. Think of it as a drum, the exhaust pulses are the drumsticks. Heavier steel dampens the drumming, or droning as it applies to exhaust systems.
Here's what it looks like with the "cover" off. I've marked the path the exhaust flows. Note the large amount of carbon soot build-up. GM likes to run em rich that's for sure!!
Here's a better view of the dual 2 3/16 diameter center transfer tubes.
Another view showing the resonator chamber. The sound shoots into the dead-end chamber and bounces around in there basically canceling itself out. This resonator chamber has a single 2 3/8" inlet.
Here's a view of the inlet end of the muffler. The outlet pipe is the soot covered one on the bottom. The exhaust exits the two center transfer tubes, then has to make a 180 degree turn to enter the outlet pipe.
This is actually one of the best factory mufflers I've seen. The inlet is 3.500 OD and 3.314 ID, the outlet is 3.340 OD and 3.190 ID.
This figures out to 5.20 sq inches cross section area for the inlet and 5.00 inches for the outlet. Each 2 3/16 center tube has a cross section area of 3.44 sq inches x2 = 6.88 sq inches, well over what the inlet and outlet will flow. That is what makes this muffler so good. Normally the interior of a factory muffler has restrictions down to as much as half the flow of the inlet/outlet.
Could it be improved, yes sir, it could!
I've added flow directors in the picture below. Many aftermarket use these and see about a 5hp gain with them. The downside is probably slightly less muffling of the sound which is probably why GM didn't use it.