Silencer ring?
#11
05-21-2009, 03:56 AM
Diesel Wrench
There's a few separate items in discussion here:
The silencing foam in the intake tube (between the air box and the compressor housing inlet elbow) can be removed - it's there at the NVH engineers' request.
The snap-in grid which the foam attaches to should be left in place, as it's curved exit extends into the compressor boot to improve laminar airflow around the elbow.
The "silencer ring" pinned to the compressor housing inlet must be left in place, since unlike the 5.9L silencer ring (which is only there for NVH at DC's insistence - Holset doesn't consider them to have an effect on performance), the 6.7L's HE351VE uses it as an MWE aid.
Compare it and the 5.9L's HE351W side by side and you can see how the larger VE version is designed to enhance the compressor's <acronym title="Manifold Absolute Pressure Sensor">map</acronym> width.
Of course, on the 5.9L - both the silencing baffles in the intake tube and the silencer ring can be removed, but the white plastic curved vanes must remain the 90* inlet elbow to maintain good laminar flow to the inducer.
The silencing foam in the intake tube (between the air box and the compressor housing inlet elbow) can be removed - it's there at the NVH engineers' request.
The snap-in grid which the foam attaches to should be left in place, as it's curved exit extends into the compressor boot to improve laminar airflow around the elbow.
The "silencer ring" pinned to the compressor housing inlet must be left in place, since unlike the 5.9L silencer ring (which is only there for NVH at DC's insistence - Holset doesn't consider them to have an effect on performance), the 6.7L's HE351VE uses it as an MWE aid.
Compare it and the 5.9L's HE351W side by side and you can see how the larger VE version is designed to enhance the compressor's <acronym title="Manifold Absolute Pressure Sensor">map</acronym> width.
Of course, on the 5.9L - both the silencing baffles in the intake tube and the silencer ring can be removed, but the white plastic curved vanes must remain the 90* inlet elbow to maintain good laminar flow to the inducer.
Well put.. Thanks Mike.
#12
06-21-2010, 09:36 AM
Banned
The "silencer ring" pinned to the compressor housing inlet must be left in place, since unlike the 5.9L silencer ring (which is only there for NVH at DC's insistence - Holset doesn't consider them to have an effect on performance), the 6.7L's HE351VE uses it as an MWE aid.
Compare it and the 5.9L's HE351W side by side and you can see how the larger VE version is designed to enhance the compressor's map width.
#14
06-21-2010, 10:06 AM
Banned
The simple fact that all applications are offered without them. The only difference to its presence is sound. Dodge chose to spec it with one because they want to minimize noise and other unpalatable (to many customers) traditional diesel sounds.
The pin was used instead of a snap ring to reduce the potential of the ring coming out or breaking and causing damage, something that would cost Cummins AND Dodge money.
There is also the benefit of reduced manufacturing cost. A few cents may not seem like much, but multiplied over a million engines it really adds up! Its also a convenient anti-tampering tool for Dodge given that they're on an anti-modification rampage with the skyrocketing price of using diesel engines.
The pin was used instead of a snap ring to reduce the potential of the ring coming out or breaking and causing damage, something that would cost Cummins AND Dodge money.
There is also the benefit of reduced manufacturing cost. A few cents may not seem like much, but multiplied over a million engines it really adds up! Its also a convenient anti-tampering tool for Dodge given that they're on an anti-modification rampage with the skyrocketing price of using diesel engines.
#15
06-21-2010, 10:40 AM
Why do you think the VE's NVH ring is so different from the W's, considering they both use the same compressor?
HE351s were already available with or w/o a silencer ring - compressor FOD from them hasn't been an issue on the radar...
Makes sense that the OEM would try to tamper-proof it & cut production costs, and improve MWE in light of the 3-20cm VE exhaust housing.
HE351s were already available with or w/o a silencer ring - compressor FOD from them hasn't been an issue on the radar...
Makes sense that the OEM would try to tamper-proof it & cut production costs, and improve MWE in light of the 3-20cm VE exhaust housing.
The following 2 users liked this post by XLR8R:
BACONBITSFORU (07-27-2011),
dodgeram082500 (06-22-2010)
#16
06-24-2010, 10:04 PM
bunch of guys I know have been there done this guys and its not worht the risk IMO the ring is actually a little more involved than just a silencer in the VGT turbo its also a directional function for the VGT some of the guys that pulled them (drilling the pins out) said yeah it makes a difference many said a bad difference some said good) but not really worht the risk. someone decided to actually mill the portion of the ring that is used to wuiet things done some and had success without the negative effect of messing with the airflow but again NOT worth it. get a good CAI and other air mods if you want to hear her whistle.
#17
06-26-2010, 05:38 PM
Banned
bunch of guys I know have been there done this guys and its not worht the risk
some of the guys that pulled them (drilling the pins out) said yeah it makes a difference many said a bad difference some said good
get a good CAI
Last edited by ForcedInduction; 06-26-2010 at 05:42 PM.
#18
06-26-2010, 07:19 PM
Perhaps the newer "advanced" NVH ring would be advantageous in a 351W retrofit - who couldn't use an extra 1%?
#19
06-26-2010, 09:10 PM
Advancements in fluid dynamics knowledge and better silencing. It probably does affect MWE, not in the manner of enhancing its effect, but less restriction to it. Even 1% compressor efficiency at 20psi of boost makes around 40*F difference in charge temperature. That means less work for the CAC, cooler intake temperatures and reduced NOx formation in the engine.
Then why even come to a performance discussion board if you're afraid to take chances?
Thats the issue with anecdotal stories, there is no way to scientifically verify a person's opinion.
You got one from the factory. Changing to aftermarket junk "CAI" systems only increase dirt ingestion, especially in "performance" filters.
Then why even come to a performance discussion board if you're afraid to take chances?
Thats the issue with anecdotal stories, there is no way to scientifically verify a person's opinion.
You got one from the factory. Changing to aftermarket junk "CAI" systems only increase dirt ingestion, especially in "performance" filters.
but your right thats just my opinion but I thought thats is what he was asking for what guys thought or had found out that already took it out so thats what I was sharing. As for scientific proof how many threads would be left if we only went off scientific proof. the vast majority is passed on from other nonscientifically proven experience 
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double ought (10-31-2011)
#20
06-27-2010, 01:46 AM
Banned
