Hey guys, what do you lot make of this? These devices serve the same role as a catch can but drain the oil back into the motor, saving having to empty. I think, depending on the design, they maintain the suction from the intake going into the crank case too. Reportedly it is good to have a little vacuum inside the block so the pistons don't have to push down against a pressurised area. Apparently can make up a little power, but not enough to really be measured. Makes sense. This Grimmspeed item replaces the oil cap, which is a pretty smart way to do it. http://www.grimmspeed.com/air-oil-separator-wrx-sti-lgt-fxt/ Seems like a smart enough idea, does anyone have any thoughts on these? There are other concepts out there that are externally mounted. -A
Hey Anti - Interesting find - disregard the obvious but just to step back first before looking at this invention. In theory you only need a pipe and gravity will separate the solids from the air over time - developing the piping and method is all that is required. So looking at this idea I had to ask myself the question, is there a problem in the VG30DETT oil ventilation system to begin with? No allowance for vapour pressure in the engine crankcase and you end up with a Boiling Liquid Expansion Vapour Explosion (your motor explodes in pieces as it has happened before) and so the current system works fine on most VG30DETT's and has for 20+ years (now is about when the odd person might think of replacing those two PCV one-way valves at the service 100,000 instead of waiting for the service of1,000,000) The VG30DETT oil ventilation conforms to EPA requirements of keeping it all in the engine and hence its design but mechanical engineers also regardless see oil in the vapour system as contaminants of oil burnt vapours. Theses burnt vapours contain many acids, alkaline, carbonised clumps, detergent fumes as well as octane from the oil etc and is hence is why engineers generally state that it should not be returned to the system even if law requires it under EPA legislation if at all possible. (except the octane - lol) So many engineers a long time ago then began on the side making these "returning" vapour catch can systems to both restrict the amount of pollutants returning to the engines but yet still comply with the EPA's "restriction on not allowing these contaminated vapours reaching the atmosphere". Engineers acknowledge the bulk of these vapours are nasty to your engine long term" and especially under harsh conditions like a race engine. Once people actually realise what is in the contaminated vapours analysis, they quickly want to ditch it altogether - and so some people have even occasionally made venting catch can systems (returnless) despite being illegal and subject to fines and defect if they are caught. :rolleyes2: So the true purpose of a returning vapour "catch" can system is to catch all pollutants and only allow gases to return, but vapours are so fine this is now known as the 4th state of mass with gas, solid and liquid so its technically impossible to separate these particles of gases, vapours and liquids in a simple effective way that is suitable for engines. Thus the simple catch can does its best to catch what it can and only allow the finest of the lightest vapours to return. This is another reason why some are filled with stainless steel wool. Ideally we would only allow certain octane chains but this is just not practical let alone sort contaminants. The octane loss from a engine ventilation system is in effect minimal to HP but can have a slight effect on economy over a long distance. So there is no problem with the VG30DETT that has an effective returning catch can system because its does the job as intended if setup correctly for the intended purpose. (Do you want it all returned/ Do you want oil only returned/ Do you want some vapours returned/ do you want all contaminant vapours removed/ do you want all but octanes removed etc. etc.) For the average Z enthusiast The only issue to this date has been fitting these catch cans or the fact that the VG30ETT tends to shoot more engine oil up into the oil vent system when going around a corner (from oil up splash) and if catch cans are positioned low they can in effect fill up quickly under racing So looking at this new device Its hard to say how much separation of vapour takes place and whether that is what you are seeking as a more efficient system at separating liquids from vapours and vapours from gases will also return inevitably return more contaminates! I personally dismiss any claims of more HP automatically knowing that the it will at its best only improve marginally and as a result I get quite sceptical automatically from the presentation of claims. I also get quite sceptical of patented (hidden filtration/ separation systems) and their effectiveness in removing what - ( it doesn't really say - does it!) Having said all of this, from what I can see, it has plenty of piping with gravity involved and so on the outside, it looks as if it has what's required to separate vapours from gases as far as practical in an engine bay. It would also be interesting to see how the mesh performs long term given the contaminants and sludge in the vapours can be quite harsh on any filtration/ separation system long term, even on durable materials like stainless. (besides you get the chance to run some more fancy piping around the bay to fascinate other Z owners as well as confuse those pesky mechanics just that little bit more - :rofl: I also think it would also give a hidden benefit in reducing the effect of the VG30DETT right hand uptake of oil when going around corners given the separator is almost central at the oil cap and has to travel against gravity through piping for a length at the height of the motor. (compared to stock ventilation system or a low catch can system where it virtually level or just above) Just a damn shame that they are $314 US DOLLARS as well as being for subi's only! Patent and materials aside, the price is ridiculous - if they ever want to be serious in sales, they will have to bring price down seriously as only those baffled by their brilliance or bullshit will buy them at that price! :agree: Why? Because good return catch cans do a bloody good already (keep most of the heavy vapours out) and are much cheaper at AUS $20-$60 Sorry - just another rant Cheers for the info find Anti- was interesting would be good if they got to a VG30DETT with a better price - returning the oil almost centrally (oil cap) can also reduce the impact of oil up splash in the VG30DETT - would save me time in designing my return catch can system (I like to return any oil but keep any oil vapour where possible and dispose of in accordance with EPA) JC :zlove: P.S. There is some advantages to more piping in the Positive Crankcase Ventilation System if not for relief by immediate atmosphere alone whilst under extreme racing /conditions. In theory - yes you could gain some small amounts of extra HP by doing this. (many catch can owners can also improve the prevention of one sided uptake by utilising gravity and piping methods as has been discussed over many posts here by others)
Excellent post, whilst not 100% in agree-ence with you opinion on the waste gases from the crankcase vapour the rest is great.
lol, that thing won't do anything except relocate the PCV pick up point to where the oil cap is located. No filtration is going to happen, the PCV system will just suck up whatever air is directly under the oil cap. BTW, try running a VG30 without an oil cap for a while. You'll quickly find out it's not a smart place to put a PCV pick up.
Good point, there is a huge difference between the oil cap location on a WRX (which the cap is designed for) and the oil cap location on a VG30. As you said, according to the diagram air can enter the separator from the pickup tube which effectively makes the factory pickup points and PCV valves redundant. To make matters worse the PCV system is no longer controlled by a PCV valve.
