Alan

I think its easy to get more than 200l/m of blowby under worst case conditions, if the filter is already laden with oil it doesn't flow well enough to exceed this design spec point even for a little while. For a GTS @ 6750RPM, 90% VE, 3% BBR you could have over 450 l/m worst case - I think 3% is high but not totally unreasonable for an instantaneous max.

On a Provent 200 all the oil has to go THROUGH the filter element - there isn't anywhere else for it to drain. You say drop straight down - the inside of the filter section is solid at the bottom end. Jake has drilled the bottom of his Provent to allow this - however that also allows a path around the filter section - and if there is sufficient restriction built up in the filter the fluid flow could overwhelm the vacuum suction side scavenging effect.

I think a better solution would have had separate internal and external drain channels: one on the prefilter side and one on the post filter side (as stock) I think it could work better, and allow a higher pumped flow, (but only for a vacuum pumped system). Would substantially complicate sealing to the filter element though.

Alan

Ducman82

the little holes i drilled may be a moot point now. i get sooooo little oil in the provent now, i could replace with a new filter and have no issues. originally i drilled the holes int he bottom of the filter thinking it would help expel the "over flow" of ail (increased flow from the pump). i was having the over pressure valve on top leak oil after awhile. i fixed it so that would not open, and made the little holes. i have not had any oiling issues after a i fixed the upper area on my timing tables.

my only issue with the provent is me not knowing if the vac pump is moving to much air at higher RPMS for the provent to handle.

all is well as of this typing

ptuomov

The Provent element is sealed, so everything has to go thru the filter. However, the top part has just a hole in it in the center, there's no cyclone mechanism in this separator.

I don't think GTS gets 90% VE at 6750 rpm.

One CFM gives about 2.2hp. CF is 28.3l. At 350hp, we're looking at about 9900l of air. ProVent 200 is within it's capacity, as long as the GTS blowby rate is 2% or below.

Lizard928

With having the inlet off to the side it does create some swirl to help knock the oil out.

FredR

Tuomo,

It is a cyclonic separator of sorts- that is why the inlet is tangential. The theory being that heavier liquid particles get flung to the outside wall where they coalesce and drop out. Then as the gas swirls around the chamber through the path bound by the outer wall/screen face it occupies a greater area slowing it down some and then it migrates across the screen wall where more oil particles coalesce and drop out.

A true cyclonic separator has the liquid coming out of the bottom through a narrowing taper and the gas out of the top so in that sense what you say is correct.

It is a very neat piece of kit albeit I understand Colin has some doubts about its capacility which may be down to it simply being overloaded- I have no idea what its capacity is- the pro vent documentation suggests engines up to a certain capacity I seem to remember- there is a bigger version I believe but have not seen it offered- then again I was not looking for it.

Regards

Fred

FredR

Jake,

In its stock configuration I presume the outer chamber collects oil until it overflows through the screen. Drilling a few small holes to allow oil to drain into the outlet chamber should be no problem- indeed probably the way it should have been designed in the first place.

Regards

Fred

FLYVMO

Just a snippet from the manufacturer's website, listing the HP limits for each Provent Model. Seems the Provent 200 would be marginal on S4 and up models.

Cheers!
Carl

ptuomov

That's based on the rated flow capacity of 200l/min for the 200 model, the model number equals the flow capacity. 200l/min is enough for a 350hp gts with 2% blowby. This is a conservative rating, if there are pre-separators before the ProVent, then it will likely flow a lot more.

Alan

Its the other way: the inner chamber collects oil until it overflows through the bottom of the screen to the outside chamber - the outside chamber also collects oil that runs down the screen having been separated as the blowby flows through. The bottom of the outside chamber is not sealed to the chamber walls so the oil drains down. If you drill holes in the bottom of the inner chamber oil and blowby has a path around the filter element. Depending on the hole sizes - this might work OK in a vacuum pumped scenario where the drain is scavenged - in a non-pumped system its just a direct bypass path = bad idea.

Alan

Ducman82

1/16th holes, just a few. the filter media still screens out any oil vapor, i can tell that just by looking at it :-P

i still have a feeling that the pump moves more air than the stock filter media can handle, thats why i was getting a little seepage from the pressure valve under the cap. no issues for a while now. ill keep checkin...

Alan

As someone else noted Mann Hummel lists an Ultra Efficiency Element - but nobody seems to stock it? Anyone seen one, have one, know where you can get one?

Now its not clear to me if the HE would be better for flow or better for seperation (and perhaps even more restrictive)... can't find any details that illuminate this (but since it seems I can't buy one either its a bit moot).

Jake did you say you sealed the cap pressure relief valve somehow? you sure that's a good idea? I thought it was set for ~10psi...?

Alan

FLYVMO

ptuomov,

I have by no means the expertise that you have, so please take my statement as a newbie question, but in my limited experience, 2% blow-by would be on a new engine (or rebuilt, correct?) I would think most owner's installing the Provent are doing so because of increasing blow-by issues (or supercharging) on their engines in an original "untouched state" as far as cylinder walls and piston rings go? Hence, their blow-by would probably be higher (3%-5%) which puts the Provent 200 in the marginal area. Again, as a non-expert, it was my impression that an engine with a leak-down test varying between lets say 160-170, it would have around 6% blow-by? Or am I misunderstanding how one comes up with the blow-by number?

Interesting link added: http://www.106rallye.co.uk/members/d...hersystems.pdf

Cheers!
Carl

Ducman82

i suck some washers under the cap to keep it from opening and letting mist out. but since i have added the little holes for better flow/drainage , I'm sure i don't need that cap mod.

Ducman82

i have yet to see/find that other filter as well...

ptuomov

I don't have any more expertise or experience on this than you do. I am just interested in it and have taken some time to think about it. If what I say makes sesnse to you, maybe you want to consider some of it when implementing your solution in your car. If I don't make sense to you, please ignore me. If someone claims to have some double-secret speed tricks, I am just assuming they are full of it, unless they can explain it to me like to a six year old.

I like the document in your link. That's the type of common sense, back of the envelope calculations that I think will help all of us. I was going with something similar, guessing that a 350 hp engine will produce about 200L of blowby per minute, if the blow-by rate is 2%. At the peak power rpm, it's probably less than 2% for an engine in a good shape, if you look at the blowby maps in your link.

Thinking about ProVent, if there's a pre-separator inside the valve covers and the oil filler neck or wherever the gasses are routed from, I think the 200 model will probably be ok for most normally aspirated engines that people have. The 400 model doesn't want to fit anywhere under the hood.

One more thing to consider. One wants to return oil to the crankcase but not return water to the crankcase. Not only does oil need to be separated from air, but water needs to be separated from oil. Because of this reason, it's always better if the separation happens in the engine block and oil filler neck or inside the valve covers. Those places are hot enough that water stays as steam and passes, while oil is still liquid. One of the potential downsides with the ProVent is that it's remote installed and may condense a lot of water to the oil drain. One potential solution to this is to leave the metered orifice from the driver side of the oil filler neck connected to the intake manifold as before without modifications and without passing thru ProVent, which will suck out water vapors when the engine is decelerating. This will however add some more demands on the pre-separator under the oil filler neck.

I initially thought about Ducman's solution of drilling tiny holes to the filter element bottom as a hack, but I am warming up to the idea as i think about it more. If the system sees only two kinds of mixture flow, very clean and very dirty, then the holes are not a problem in the first case and in the second case they will be filled with oil so the gas will still have to pass thru the filter. So maybe it's ok for our cars.