[Kingtal0n]

Originally Posted by jr_ss

No offense, you can spit theory all you want, I?ve used the exhaust Venturi system on my car and have created plenty of vacuum using such kit.

What does that have to do with anything? If you can maintain a vacuum on the crankcase is all that matters. Use exhaust, use intake, use pump, use whatever. I don't care how you do it lol. ???

No factory car has. We aren?t talking factory cars here dude? You?re missing the point. We don?t care about a factory car setup.

Ah, This is a problem. You started to think your car is 'special' because you changed something like an air filter or engine. This is a dark path that leads away from reliability because it undermines the engineering that went into the drivetrain if you let it. *You* didn't design the engine, the factory did. It is a factory engine- so its a factory car. If we put a Chevrolet into a Nissan, that doesn't mean that *we* built the car. Chevrolet built the engine, its a factory car still, just a hodgepodge now of factory parts. If we rebuilt the transmission its still a factory transmission makeup. If we rebuilt the engine with a bunch of aftermarket parts- that will reduce reliability of the factory engine. Its still a factory engine, its just been made less reliable because we messed with the factory internals in a way that undermines the original engineering. Aftermarket internals don't make an engine more reliable, quite the opposite. Just like fucking with the factory PCV system doesn't guarantee a superior PCV system. It is how we qualify and determine whether our modifications to factory parts actually improved the reliability or not that matters, not whether or how we make those modifications. IF I attached a electrical vacuum pump to the crankcase that assured will function for 200k miles providing a full time vacuum as good or better than factory, on the crankcase then it is just as good as any factory PCV system. The trouble is finding and implementing such a device as it does not exist and even if it did may incure maintenance and complexity issues unforeseen without testing.

What I am getting at here is a perspective method for maintaining reliability. Stop thinking of your vehicle as a special or 'racing' vehicle no matter what power or function it has. Factory parts *are* racing parts, most are superior to anything aftermarket due to the decades of revisions and statistical interface that guided their ultimate function and production.

Do you know how I got 50,000 miles from a Chevrolet engine that already has 200,000 miles to begin with, at 800brake horsepower, while keeping all the factory internals and drivetrain in a daily driver configuration? My mentality to keep all factory parts and understand their limitations and producing the environment in which they operate under the same conditions or similar to what the factory had intended.

Also, a car with a dry sump setup (corvettes) doesn?t need a catch can, the crankcase is already under constant vacuum.

Why are you saying this? The catch can has nothing to do with vacuum on a dry sump. Dry sump provides kinetic energy to evacuate the crankcase so the engine's pistons don't need to. They can install all the catch cans they want, because there is a vacuum pump system to provide the energy to drive the fluids. Many dry sump users add catch cans, it hurts the vacuum signal a little bit but the difference is negligible when the can is installed to the intake suction side, there is a line directly from intake manifold to crankcase on those engines with NO PCV valve at all, its just a orifice. I feel like you are grasping as straws without really understanding the purpose of dry sump or PCV. Vacuum is a means of oil control, but it isn't the sole oil controlling feature on an engine.

The LS is also notorious for pooling oil in the heads under hard driving. RB?s are notorious for spewing oil out of their motors. Hence splash plates and added baffling systems. Even then they still need the catch can.

You say that but, I've setup hundreds of these engines and removed every catch can in sight and never had any issues. The real problem is people don't measure their crankcase pressure and set it properly, thats all I found over 25 years of doing this.
Here my 2.5L RB 600rwhp



NO catch can. No oil pooling. The RB has a head drainback modification which prevents oil from pooling in the head. This is the correct way to deal with oil accumulation in the engine baffles- NOT a catch can. Catch is a band-aid for idiots who don't know how to return the oil to the oil pan. Its how I can tell whether somebody actually knows what they are doing or not, instantly.

Drag cars or any car modified for serious power have different ring gaps, which allow differing amounts of blow by than a factory car. Forged pistons, are a change from factory, which may allow more blow by.

My RB has loose ring gaps and forged pistons but I properly set the crankcase pressure and there is no blow-by or issue with blowing oil out. If I had not properly measured then of course it would flood the intake with oil. The key, just like with fuel pressure, is to measure and set it properly. Tune it. Engine tuning is not just in the computer. Its how you setup and tune every component of the vehicle.

There are a thousand scenarios where one could use a catch can to prevent recirculating nasty by-product hydrocarbons through their motor.

Education time. You are incorrect and here is why. Blow-by gas and hydrocarbon partially reacted compounds found in combustion is a gas state. It is hot, high velocity gas.

Gasses cannot be captured in catch can or any kind of solid vessel. It would be like trying to catch the helium from a balloon in a can- impossible. The only way to catch blow-by products is to dissolve them into engine oil, which is exactly what the PCV system is intended to prevent. You don't want combustion products to dissolve into engine oil because then they circulate around the engine causing deposits and atherosclerosis of oil venules/capillaries, leading to eventual wear and failure.

Catch cans are the worst thing you can do to an engine crankcase system.

E85, another example, generates a lot of nasty stuff, I would rather have purged from my motor and sucked into a can.

Alcohol turns to gas and solvates into engine oil and water alike. Alcohol forms combustion products CO2 and H2O just like gasoline. It also attracts water. You don't want CO2 or H2O In the engine oil. When they leave the combustion chamber they are hot, high velocity gasses, the objective of the PCV system is to whip these hot fast moving gasses back into the combustion chamber which is where they came from a moment ago. If you add lines and a catch can now you will slow and cool the gasses causing water to fall out of a gas state and begin to collect in the lines, oil, can, etc... which means now you are catching around 5% of the water produced by combustion (a negligible amount) and allowing the water to stay inside the engine's crankcase system where it can mix with engine oil and increase the water content of the engine oil while the engine is off at rest and during cold operation.

Again, its the worst possible thing you can do the crankcase of an engine