MANN Provent 200 Air/Oil seperator

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complacent
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Post by complacent » Mon Mar 24, 2008 10:28 pm

Mr Kleen wrote:
snaab wrote:Like Tallen says, do you really want oil that contains HC and CO recirculating?
there are turbo cars running around with hundreds of thousands of miles on them that don't have catch cans. they seem to be doing OK. :wink: I would only worry about a catch can (separator, whatever...) if I had a very large aftermarket turbo running much higher boost then stock.
That's the point I've had in my head all along.

But there does sound like some interesting points being made about blowby and oil consumption here. I dig the concepts. ;)
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Post by Sabre » Tue Mar 25, 2008 12:53 pm

snaab wrote:Sorry to jump in late on this, but I have a genuine question. Both serious explanations and Julian's explanations are welcome.

Like Tallen says, do you really want oil that contains HC and CO recirculating? What they taught us at school is that car oil has become cleaner thanks to efficient removal of blowby gases. It seems counter to my armchair engineer logic that oil, that has been blasted by said gases if passing through this filter, is placed back in the system.

Furthermore, it seems like the amount of oil returned would be negligible, and that where you are wasting oil is really just in the lubrication of the cylinder walls.
Mr Kleen wrote:
snaab wrote:Like Tallen says, do you really want oil that contains HC and CO recirculating?
there are turbo cars running around with hundreds of thousands of miles on them that don't have catch cans. they seem to be doing OK. :wink: I would only worry about a catch can (separator, whatever...) if I had a very large aftermarket turbo running much higher boost then stock.
Hey, I make good posts sometimes! :oops:

I can understand the reasoning behind you not wanting to throw the oil back into the engine, but look at this from the other side, a built car on the track. Built motors are looser than normal motors to allow for the expansion of the (forged) pistons. This is what causes that diesel like sound when they first start up. Blow-by occurs when air and moisture are forced past the rings into the crankcase. Since in a built motor, things are not sealed up tightly till they warm up, they get a ton of blow-by normally. As Gabe pointed out, running higher boost pressures also increases blow by. The reason that you would want that oil returning, again using the race car analogy, is because you are usually only running oil for a race or two, so you don't care about the HC and CO that builds up. It's going to get changed out after this race anyway :) What is important is that you don't run out of oil on the race trace, which if you don't keep all the oil you can, will happen. Catch cans are great for street cars (I run one :), but for race cars, you really need something like this.
Sabre (Julian)
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snaab
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Post by snaab » Tue Mar 25, 2008 4:58 pm

Ok, I'll readily buy the race-app things. The way you put it, Julian, puts it into a much more specific context/example.

This week in class I had to do compression tests (dry and wet), cylinder leakdown test, EGR-valve tests, etc. I'm really right in the middle of material applicable to all this. Although, the presentation I have to give on the Evap system this week is going to be boring as all hell. Maybe I'll sidetrack to this Mann-Hummel separator 8)

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Post by Tallen » Wed Mar 26, 2008 10:37 am

I'll be honest with you guys, I have a built motor myself (that I built myself, minus the machining), and when I had a catch can, there was almost never any oil in it. So little that I just recirculated both of the valve cover vents back into the intake. I'll take the better idle instead of lost oil capturing. Now that I think about it, using the above mentioned can, that would get rid of the oil in the lines, and keep me from losing that precious metered air. Though I would just put that captured oil into a catch can of some sort. So maybe it is a cool idea, but still not worth much to me.

On a side note, I just had my intake and one of the lowest IC pipes off the car and had no oil residue I them after a month of recirculating. At some point I'll probably do the ghetto thing and get some clear fuel filters and run them inline, cheap and easy.
-Matt
97 GSX

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Post by Sabre » Wed Mar 26, 2008 10:50 am

What turbo are you using? What things are done to the engine? I'm very curious since I've never know anyone without turbo blow-by or engine blow-by. Reveal your secrets!!! ;)
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Post by Tallen » Wed Mar 26, 2008 3:19 pm

2.3l stroker 8.8:1, Eagle/Wiseco, reman 4G64 crank (duh), calico bearings, .40 over, I did everything to spec, nothing special. Turbo was put together by me to emulate an FP3052 for 1/2 the price. Also custom modified a 4" inlet shrouded housing for the turbo. Now don't think its some magic voodoo, I'm sure there is oil blowby, but not enough to justify the daily drivability and fun of the car. That and the vacuum created by the turbo should help with crankcase evacuation as opposed to a catch can, but who's counting? I usually warm the car up before driving, but not always.
Boost has been generally restricted to only 18 psi while I revamp the fuel system and rewire the pump, currently its only at 12.
-Matt
97 GSX

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