[Sabrewings]

Originally Posted by GrimmSpeed

hey guys, thought i would poke my head in here. There is no way for the air to skip to the outlet as the chambers(levels) are isolated. Once you put the core(in the pic above) into the body, it separates the inlet and outlet sections. the air is forced down just like in the pic above. you can see at the very bottom of the pic there are two holes, one connects to the inlet level and one connects to the outlet level.

as far as routing, the 2 lower ports are the inlet ports(1 port comes from t'd off heads, and 1 port comes from crankcase). the 1 upper port is the outlet that goes back to the intake pipe.

these have actually been on our shop cars for 9-10 months now and on about 15 other tester cars around the country for 6 months. we used that clear pipe section so we could keep an eye on the outlet air of the AOS to analyze how well the AOS doing its job.

Thank you very much! But I'm still confused.

Per that diagram, air from the oil fill tube is allowed right up into the outlet. I know when I pull my oil fill cap off I get a lot of air and oil droplets coming out. What is stopping these oil droplets (and likely atomized oil) from going straight up the oil fill tube and out the outlet for your AOS?

I'm not doubting that it works, just wondering how.

[Digitalfiend]

Originally Posted by Sabrewings

Thank you very much! But I'm still confused.

Per that diagram, air from the oil fill tube is allowed right up into the outlet. I know when I pull my oil fill cap off I get a lot of air and oil droplets coming out. What is stopping these oil droplets (and likely atomized oil) from going straight up the oil fill tube and out the outlet for your AOS?

I'm not doubting that it works, just wondering how.

I'm probably wrong but what that diagram likely doesn't show is that the hole that leads to the upper chamber probably doesn't line up exactly with the port that outputs to the turbo inlet. So I assume that the oil droplets (i.e. something with "substantial" weight)might have a chance to collect on the walls before being evacuated out the outlet port.

I must admit, I've never noticed any oil droplets coming out my oil filler neck.

Now, will this provide air that is as clean as the Crawford unit? I guess only time will tell. It does seem that GS was at least monitoring for oil in the outlet tubing and if it has been tested on 15 other cars, it sounds like they've put some care into ensuring this product actually works.

I'll let you guys know how it works once I get mine.

Edit:

Looks like your question might have already been answered: http://www.iwsti.com/forums/2727536-post480.html

[Sabrewings]

Originally Posted by Digitalfiend

Looks like your question might have already been answered: http://www.iwsti.com/forums/2727536-post480.html

That doesn't really answer it at all. The air comes into the intake level where I assume it goes into the "impact coalescer". After that, the air and oil droplets go out the bottom of the AOS. The air is then supposed to return up a secondary hole, going to an outlet level, and then on to the turbo inlet. What stops atomized oil from the oil fill tube (which is open to the crank case and all of its blow-by gases) from going straight to the turbo inlet as if the AOS isn't there?

What about the PCV? Isn't that supposed to be a big source of oil when under low load? Isn't that why Crawford eliminates it?

[Digitalfiend]

Originally Posted by Sabrewings

That doesn't really answer it at all.
...
What stops atomized oil from the oil fill tube (which is open to the crank case and all of its blow-by gases) from going straight to the turbo inlet as if the AOS isn't there?

Doesn't it have to go through the second chamber, "changing direction", if you will, and causing the oil to collect on the walls of the upper chamber?

I definitely agree that it makes sense SOME small amounts of oil will make it through but I imagine there should at least be a decent reduction in overall amount of oil making it to the intake tract.

[A-man]

This picture plainly shows what I think are the shortcomings:


First, with the factory PCV in place, you are still drawing oil vapor straight from the crankcase into the intake manifold in off boost conditions, which is the vast majority of the time on a street car. You wouldn't see this in your hose window on the tester because its in a separate part of the PCV system.

Second, when on boost, the crankcase side of the PCV system shifts its vacuum source to the turbo inlet which is what the GS piece uses as a vac source to circulate blowby vapor through its separator. Since the separator sits on top of the oil filler neck, what stops the separator from having oil vapor sucked back up through the filler neck as blowby comes up from above (and it does)?

As a corollary to the above, the factory PCV is imperfect in its closure when IM vac switches over to turbo inlet vac so blowby still gets shunted into the turbo inlet as well as the IM.

Another issue, seen often, is that by routing the head breathers into the same stream as the crankcase removes one the integral factory designs that actually makes sense in a PCV system, keeping the crankcase side of the system and head side separate. This is important because there are times when the head breathers need to flow both ways. That is, vac being pulled on them but also the heads being able draw in "fresh" air from the turbo inlet.

Something else, the separator piece is awful small. Does it have enough surface area to pull out much oil from the copious blowby volumes these motors see?

Unfortunately, attempts to oversimplify the PCV system for a street driven car always result in compromises that are unacceptable, at least IMO. I've tried myself and I just don't think it works well. My 2 pennies.

[CrawfordPerformance.com]

You are right on the ball with your assumptions. The three crankcase breather ports that this unit connects to all have internal baffles built into them. They are now routed into the oil fill tube which has no baffles at all. This new breather system will let oil out your motor un-baffled. You can see this by removing your oil fill cap at an idle, make sure you have a rag to wipe up the oil that will be spit out at you. Then imagine the amount of oil rushing up this tube while turning right and or at a high RPM. There will be a direct path to the intake system although it must make a 90% turn first.

Team Crawford

[FORCFED]

Originally Posted by CrawfordPerformance.com

I would say this unit was designed by a salesman, not an engineer as it is flawed from many angles with most all of them noted in the above post.

Team Crawford

[GrimmSpeed]

Originally Posted by CrawfordPerformance.com

You are right on the ball with your assumptions. The three crankcase breather ports that this unit connects to all have internal baffles built into them. They are now routed into the oil fill tube which has no baffles at all. This new breather system will let oil out your motor un-baffled. You can see this by removing your oil fill cap at an idle, make sure you have a rag to wipe up the oil that will be spit out at you. Then imagine the amount of oil rushing up this tube while turning right and or at a high RPM. There will be a direct path to the intake system although it must make a 90% turn first.

I would say this unit was designed by a salesman, not an engineer as it is flawed from many angles with most all of them noted in the above post.

Team Crawford

We did all of our testing with the PCV valve in place for two main reasons, which are oil life and emissions. We didn’t want to give up those compromises on our weekend racers.

Unfortunately we do not currently have access to a laser spectrometer to analyze the gravimetric efficiency of our separator in comparison to other systems. This is really the best non-subjective method to compare the performance of a separator. What we have done however is a lot of real world tests on a wide range of modified and stock engines in a lot of different conditions. These tests include monitoring oil consumption, monitoring oil entering the intake, monitoring the amount of emulsified oil and water in cold temperatures, monitoring crank case pressures, and comparing back to back dyno charts (which showed a huge improvement in the onset of detonation which is correlated to the reduced octane degradation from reduced entrained oil particles in the intake charge).

Our goal with the product was to provide a no compromise improvement of the existing PCV system while requiring no new maintenance by the customer.

Is our system 100% efficient? I would be a fool to try and convince this community an impact coalescer was. But for most Subaru applications, it does a more than adequate job in eliminating oil consumption problems, eliminating entrained intake oil detonation problems, and eliminating intercooler oil film problems (reducing their efficiency).

I would like to point out that air coming from the oil fill tube must pass through the impact coalescer before it can enter the intake so this is not a design flaw.

We are not here to pull one over people's eyes. We have just as much interest in providing a system that works as Crawford has in slandering us.

With all that being said, we have had a few testers run our unit with the PCV valve removed and the IM port capped (like Crawford’s installation method) with good performance results but we have not done enough testing to recommend this installation.

[CrawfordPerformance.com]

.....

[kinder]

Originally Posted by CrawfordPerformance.com

I would say this unit was designed by a salesman, not an engineer as it is flawed from many angles with most all of them noted in the above post.

Team Crawford

Wow..... just wow....

I work in sales and one of the things I train my staff not to do is bash a competator. It shows a lack of faith in your own product.

I have been looking at AOS systems for a while now but the benifit to cost ratio has been to high for my application. What I liked about this thread at the start was the questions about how the system works and possible concerns.

What I can say is ALL the systems I have checked out had thier problems. Everyone here has read threads here, NASIOC, Legacy GT.com, WRX tuners etc.. where people had issues with Crawford/Ixiz/Prova etc.

Who's system is better for our cars? Thats for us to decide with our wallets and paypal accounts.