I was referring to vacuum operations.

The boost does not go into the intake pipe. Evo's have a check valve that stops pressure from reaching the valve cover.

 

that's not true, due to the cost issue, factory don't put catch can in the car, they just use the most cost effective way. Skyline spec V, does come with oil catch can straight from the factory, you should not leave your alone, get an catch can.

 

In fact I am not using any catch can at all, I just run a open tube from the PCV valve to the ground (just like most evo don't have cat anyway), the "blow by" gets evaporated almost instantly, so there will be no oil spill issue.

 

exactly!

 

I think that is the best way to avoid oil vapors, but according to the links I provided ventilation is required. Leaving the tubes open to the environment will relieve blow-by pressure, but it does not venitilate the air under the valve cover.

I'm not saying that I'm 100% right and your wrong, but according to the links posted vacuum is needed to aid in removing the blow-by from contaminating.

 

I'm not sure if we're on the wrong page here...

Problem with that venting line is oil escapes through that line at boost with blow by gases and gets into the intake pipe, turbo, intercooler and covers everything with sludge. That's why a can or breather is needed.

I see your point about metered air, but it doesnt matter much - under vacuum, which is idle and cruise you're in closed loop, so the only thing that's gonna happen is the fuel trims will adjust, which is not a big problem unless they are out of wack already.

The way i see it, the only advantage with running a can instead of a breather is that a can is cleaner, and a breather will probably get dirty very quickly.

 

Well you said gasses are pushed out during boost so I thought you meant by the pressures from the intake manifold. But I guess you were referring to the blow pushing itself out?

Well I see what your saying, but from all the previous threads about intake pipes, people are getting affected. Maybe the difference of unmetered air is large enough where fuel trims adjusting is not enough. There was another thread a little while back were a little more technical info was mentioned on why running breathers is not good, unless you get tuned for it.

I dont see open loop operations getting affected by breathers because the check valve closes during boost and all the air entering the motor is metered by the maf.

 

This is the way i see it. Dealers want you to take your car to them for a oil change so they would change out the catch can if it came equipped stock. Besides why wouldnt they plumb it directly back into the motor if it came stock since the average consumer would let it spill over. Mitsu and every car manufactorer in the world spend millions (possibly billions) of dollars of research and development in creating the most efficent reliable vehicle they possibly can. But a bunch of guys in a garage see oil coming out and think they know more.

 

I just ran my catch can off both of them, and it works great

 

Yeah, but its not really venting.
You need the suction from the intake to introduce fresh air.

 

Automobile companies are only interested in 1 thing, minimize costs and sales.

Dont you think that they know stainless steel is better than the crap they use for our stock exhaust? Why use crappy rusting peice of **** nuts and bolts when there is stainless steel? The answer is reduce costs.

F1 cars made 1500 hp with 1.5 L turbo motors and now with the rules and regulations they are controlled down to ~700 hp with V8 I think 2.3 L NA motors. How many Litre engine does the Bugatti have to make 1000 horsepower? How many Litre motor does the Cobra, or Vette have to make 500 HP? Why are we struggling to make more power with more displacement?

If they made our cars soo great, why are we able to tune and make more safe power with minimal upgrades? Why dont they just max things out from the factory?

Its very simple why they routed the pcv lines as we have today. I'll explain why.

The government puts out rules and regulations for auto manufacturers to follow. They have to pass certain safety, noise, emissions etc... tests in order to sell their cars. The pcv system needs to be a closed circuit to pass emissions and prevent blow by gases escaping to the atmosphere. So they ran the pcv system back into the cumbustion chamber to burn in the cylinder. The amount of oil vapor that travels with the blow by from under the valve cover is not enough to do damage to the motor. Over time yes it does accumulate to look a lot, but the minute amounts ingested by the motor does next to nothing when it comes to reliability for the life span of the average consumer. Does unwanted gunk accumulate over time, yes but the car still runs. Might not be as efficient as new, but still does the job as designed to do and that is transport our lazy asses.

Now as tweakers, tuners, and enthusiests as ourselves, we want to make everything as perfect as possible. Fix what is not broken, and tweak everything to its full potential. The oil vapor over time collecting and or mixing with the a/f causes unwanted results for us when we race our cars. It lowers the efficiency of the intercooler when accumulated inside, messes up our intake temps, raises chances of knock, and creates unwanted and avoidable mess. That is why we go through the trouble. The automobile manufacturers are not building race cars for us and not cars to last us a hundred years. They are building cars for us to travel from point A to point B safely and reliably within government rules. Some cars they skew a little closer to race cars performance wise for appeal to enthusiest consumers like us, hence we have C6 ZO6, Mitsubishi Evo, STI etc.... They do these things to market sales, attract buyers with money.

Remember its all about reducing costs and raising sales = increase in profits. Some small exceptions follow for exotic cars , but even they need to make money and thats why they are not mass production cars but rich enthusiests intended cars.

Oh and as previously mentioned in which I didnt even know; I guess Nissan Skylines came with factory catch cans.

I remember when I had the Dodge SRT-4 we had the engineers from Chrysler/Dodge come on for us to ask questions and get feed back. A lot of time when we asked why X was built as soo etc... They answered, its because they had a certain platform to work with only and a budget to follow with many rules as to how far they can go. Example they had the neon chasis to work with and a certain budget to build around it.

How much do you think a catch can will cost an auto manufacturer? Lets say a good 50 dollars each car including a discount for mass production. 50 X 20,000 cars built = 1,000,000 dollars of pure expense money that could have stayed in there pockets! And not only that people dont even check their oil, brak, powersteering fluid levels, tire pressure etc... What makes you think they will check the catch can? It will either have to fill up and dump in the streets = emissions violation or choke the motor some how. People will then start complaining and bringing the car to the Steelerships for service.

Lately I've been reading race teams filling foam in the chasis to stiffen it without much added weight. And its been working with great results for the miata and s2000. So why dont car companies do that too? MONEY! Thats why. Why were we non auto manufacturers the ones to think of it?

 

I see the point you are trying to make. But TRD once spent "millions, maybe even billions" researching and designing a toyota-factory-warrantied supercharger. When the toyota guys started experiencing a little tiny annoyance called "pinging" a lot of idiots sounded just like you do right now. Then their engines blew up, and eventually TRD discontinued production and offering, and replaced a $h!tload of engines under warranty. I'm not comparing the two, I'm just saying that hypothesizing about money spent on R&D to justify not doing a simple mod like this is not worth much.

Besides, those "couple guys in a garage" are the ones turning the Evo from 271 crank to 1000whp and setting records.

Mitsubishi doesn't make the "billions" is can afford to spend on R&D by equipping their cars with every device in existence, just the ones it has to.

No, there really is nothing GOOD about having oil blow-by in your intake, no matter how much money was spent on R&D.

 

Thats not the best solution. All thats doing is allowing the blow by gas to float around inside still. So you have that blow by gas filling under the valve cover contaminating the oil.

Also

Running just breathers only allows pressure to escape and not build up under the valve cover. But the blow by will still be present contaminating the oil under the valve cover. You need to create a draft inside, to ventilate and remove the gas. So basically you need to run one side of the pcv to a vacuum source. The other side you can run a breather with out problems to draw in fresh air for certain cars. But for our cars (EVO) with out a tune it will cause idle problems during normal operations.

A lot of race/drag cars run one side of their pcv down to their exhaust system and a breather on the other side. They use the venturi effect from the exhaust gas flowing to draw blow by out gas out and ventilate under the valve cover sucking fresh air in from the breather.

 

well maybe i should clarify a little when i mean a few guys in a garage im referring to the companies that make the catch cans not us the tuners. I read a article wish i could find it now that shows that a catch can does not allow the pcv system to work properly because of the added restriction coming from the intake. It wont allow it to have enough vacuum for it to operate correctly. Dont get pissed about this because this is a on going debate at every forum. Im just throwing my 2 cents in.

 

The restrictions most catch cans put are not enough to cause any effects such as you speak of. I ran a few different types of catch cans ebay, diy etc... with my previous car, and the vacuum produced was still the same. Now I didnt test the vacuum with a gauge, I just used my finger to check the suction power of the vacuum tube.

Now the ones I had did not have any medians inside. Maybe the ones with baffles and material inside to help trap oil might cause the restrictions. But from the way you were comming at this was as if all catch cans are useless.