Clickity clickity clack

[smorgan87]

Dont forget if u reroute the inlet to put a filter on it.

[Nilao]

Piping it to the intake will put it under vacuum constantly. There's a publication from wabco specifically stating not to move the compressor inlet from the booster side to the filter side. I will look to see if I can locate it.


It's an email from Bendix regarding an inquiry about changing from boosted air to the naturally aspirated kit.

Quote:

There are many advantages to turbo charging an air compressor. Compressor output is improved and the positive pressure on the top of the pistons helps control oil passing. On naturally aspirated compressors with separate air filters, oil passing is created as the filter gets dirty. As the air filter becomes restrict with dirt the compressor starts pulling air out of the crankcase and the oil comes along with it thus resulting in oil passing.

When connected to the engine air cleaner directly the compressor fights the engine for air thus reducing efficiency. On a normal highway vehicle the compressor may only compress air for 5% of the time. When the compressor unloads and quits compressing it is still rotating. During this time the engine draws air through the engine air cleaner putting a vacuum on the 1" hose. We now have a straw in a pop bottle. The compressor is rotating, oil is on the cyclinder walls and the vacuum starts to draw oil to the top of the pistons. When the compressor loads again the oil on the top of the pistons will flow out into the air system. Turbo charging the compressor puts a positive pressure to the top of the pistons thus holding the oil down and helping to prevent oil passing.

[Rawze]

(11-21-2017 )Nilao Wrote:  Piping it to the intake will put it under vacuum constantly. There's a publication from wabco specifically stating not to move the compressor inlet from the booster side to the filter side. I will look to see if I can locate it.


It's an email from Bendix regarding an inquiry about changing from boosted air to the naturally aspirated kit.

Quote:

There are many advantages to turbo charging an air compressor. Compressor output is improved and the positive pressure on the top of the pistons helps control oil passing. On naturally aspirated compressors with separate air filters, oil passing is created as the filter gets dirty. As the air filter becomes restrict with dirt the compressor starts pulling air out of the crankcase and the oil comes along with it thus resulting in oil passing.

When connected to the engine air cleaner directly the compressor fights the engine for air thus reducing efficiency. On a normal highway vehicle the compressor may only compress air for 5% of the time. When the compressor unloads and quits compressing it is still rotating. During this time the engine draws air through the engine air cleaner putting a vacuum on the 1" hose. We now have a straw in a pop bottle. The compressor is rotating, oil is on the cyclinder walls and the vacuum starts to draw oil to the top of the pistons. When the compressor loads again the oil on the top of the pistons will flow out into the air system. Turbo charging the compressor puts a positive pressure to the top of the pistons thus holding the oil down and helping to prevent oil passing.

Makes me wonder why the new prostars come with it plumbed into the air filter then. Where is this quote from?

[dhirocz]

That is interesting.

I bet the new prostars have that elbow where it passes into the intake duct to help direct air into the compressor, like some of the isx's do. Point it into the airstream and it should lessen the vacuum compared to just teeing it into the pipe.

Good points made here. Now I'm curious and want to call wabco about that, and see if they have a reason it's different on the new prostars.

One interesting thing to note, I put some lube into the inlet of the compressor...no more noise. Whatever the issue with it is appears to be in the compressor head. It's still going to get replaced, if nothing else, based on mileage alone. I'm also interested in this parts rebuildability.

[Rawze]

Personally, I think they likely did it to stop the ingestion of soot. There is no other advantage for installing it art the air filter instead of the air filter. Here are my thought on it. I tested this once a few years back.

http://rawze.com/forums/showthread.php?t...95#pid4395

Also, anyone replacing one should make sure it is properly timed ..





I know the video is unfinished. That is all I could save of it.

[dhirocz]

Still waiting on word from cymmins engineering for justification on why the prostar compressor inlet is moved on the newer models. Wabco told me it was their cummins choice, not theirs.

I can agree with the soot theory though. Question would be, why not add that pipe in the intake then? Im really curious to know if there's more to it. You'd think they would do that across the board.

Curious if anyone knows if there are any issues with the older compressors for the cm871? My unit calls for a 4318216rx, but I found an older NIB unit that is a 3104216nx for a song and a dance...which, according to quickserve, was the old number. Any issues with this before I pick it up? Way too cheap to pass on a new part with no core.