Budget catch can and 4”intake project

[Matthew Thieme]

Just wanted to share my little project with you guys because my wife didn’t seem to share my enjoyment of it Seems to be working as planned, the truck feels a bit better according to the butt Dyno, and the catch can is retaining oil. The hose between the can and intake is basically dry, which makes me feel better. The whole thing only cost about 75$ or so and I feel pretty good about it, time will tell if mpg is affected in any appreciable amount. The change in performance and cleaner air intake was worth the small cost, and the turbo sounds pretty cool too have a good one, Matt

 

[Will L.]

Nice looking install job. I noticed you kept the cdr. With the catch can, why?

 

[Matthew Thieme]

Thanks, I kept it because I was under the impression that it acts as a regulator valve to keep pressure at the correct level. If I’m wrong about that please enlighten me and maybe I’ll change it up. Always ready to learn something new.

 

[Will L.]

CDR=crankcase depressurization regulator-
In other words it limits the amount of vacuum to the crankcase.

As the rpm increases the amount of vacuum will increase on the hose that is pulling out crankcase fumes. With a stock system without a CDR it would be sucking too much oil fumes to that in engines intake manifold and cylinders.

The engine oil will work as a fuel, accelerating output of control known as runaway once blowby is an issue. YouTube search “diesel runaway” and you’ll have a panic moment. So the CDR lowers the amount of vacuum going into crankcase as to not burn off this oil as easily.

Using a catch can that stops all the oil from reaching the intake, you can run at full “vacuum” that it will produce.

Running the crankcase in a decent vacuum (8-10” is safe goal for stock engine) to the catch can will increase power. The vacuum is one of the great advantages of a dry sump system. While most power increases are seen 8-16” of vacuum, at around 15hp and 10# torque, this level tends to increase oil flow and 5-7 psi drop pressure. While that sounds scary, more oil flow is a desired item, provided enough oil gets to all components. For us with the vacuum it creates we will not see those power gains or effects. We tend to get 3-4# and 4-5hp with 1psi oil pressure drop WITH THE MOST effective catch can and at high rpm because we simply don’t pull that much vacuum. Most catch can systems will not pull the vacuum required to see any power gains, so it is a cost savings venture only.

The draw back is needing to drain the catch can back into the pan either periodically manually or a drain line that does not allow the vacuum to pull the oil fumes (only liquid) back to the pan.

Also If you have a proper working catch can, there is no function for the CDR, saving the cost of their replacement. Simply shelve the one you have incase you decide to go back to it instead of the catch can. idk anyone that ever has, but...

 

[Matthew Thieme]

CDR=crankcase depressurization regulator-
In other words it limits the amount of vacuum to the crankcase.

As the rpm increases the amount of vacuum will increase on the hose that is pulling out crankcase fumes. With a stock system without a CDR it would be sucking too much oil fumes to that in engines intake manifold and cylinders.

The engine oil will work as a fuel, accelerating output of control known as runaway once blowby is an issue. YouTube search “diesel runaway” and you’ll have a panic moment. So the CDR lowers the amount of vacuum going into crankcase as to not burn off this oil as easily.

Using a catch can that stops all the oil from reaching the intake, you can run at full “vacuum” that it will produce.

Running the crankcase in a decent vacuum (8-10” is safe goal for stock engine) to the catch can will increase power. The vacuum is one of the great advantages of a dry sump system. While most power increases are seen 8-16” of vacuum, at around 15hp and 10# torque, this level tends to increase oil flow and 5-7 psi drop pressure. While that sounds scary, more oil flow is a desired item, provided enough oil gets to all components. For us with the vacuum it creates we will not see those power gains or effects. We tend to get 3-4# and 4-5hp with 1psi oil pressure drop WITH THE MOST effective catch can and at high rpm because we simply don’t pull that much vacuum. Most catch can systems will not pull the vacuum required to see any power gains, so it is a cost savings venture only.

The draw back is needing to drain the catch can back into the pan either periodically manually or a drain line that does not allow the vacuum to pull the oil fumes (only liquid) back to the pan.

Also If you have a proper working catch can, there is no function for the CDR, saving the cost of their replacement. Simply shelve the one you have incase you decide to go back to it instead of the catch can. idk anyone that ever has, but...

Ok, so I did understand it correctly in concept then, but didn’t realize that pulling more vacuum would never be an issue. I’d like to remove it and have less connections if possible so thanks for the input.

 

[Matthew Thieme]

CDR=crankcase depressurization regulator-
In other words it limits the amount of vacuum to the crankcase.

As the rpm increases the amount of vacuum will increase on the hose that is pulling out crankcase fumes. With a stock system without a CDR it would be sucking too much oil fumes to that in engines intake manifold and cylinders.

The engine oil will work as a fuel, accelerating output of control known as runaway once blowby is an issue. YouTube search “diesel runaway” and you’ll have a panic moment. So the CDR lowers the amount of vacuum going into crankcase as to not burn off this oil as easily.

Using a catch can that stops all the oil from reaching the intake, you can run at full “vacuum” that it will produce.

Running the crankcase in a decent vacuum (8-10” is safe goal for stock engine) to the catch can will increase power. The vacuum is one of the great advantages of a dry sump system. While most power increases are seen 8-16” of vacuum, at around 15hp and 10# torque, this level tends to increase oil flow and 5-7 psi drop pressure. While that sounds scary, more oil flow is a desired item, provided enough oil gets to all components. For us with the vacuum it creates we will not see those power gains or effects. We tend to get 3-4# and 4-5hp with 1psi oil pressure drop WITH THE MOST effective catch can and at high rpm because we simply don’t pull that much vacuum. Most catch can systems will not pull the vacuum required to see any power gains, so it is a cost savings venture only.

The draw back is needing to drain the catch can back into the pan either periodically manually or a drain line that does not allow the vacuum to pull the oil fumes (only liquid) back to the pan.

Also If you have a proper working catch can, there is no function for the CDR, saving the cost of their replacement. Simply shelve the one you have incase you decide to go back to it instead of the catch can. idk anyone that ever has, but...

By the way those runaway diesel videos make me cringe when I see them. Just hoping I never have to deal with it on my vehicles.

 

[Will L.]

On the run away- Yeah, someone out there is going to start making air cut off valves in the 3” size for cheap and make a lot of sales.

More pricey and shiny options are a available at places like summit racing for $700 ish to start- Too expensive for 95% of people to bother.

 

[ak diesel driver]

The CDR was an emissions device for the manufacturer with the side benefit of making seals last much longer. So if you do remove it expect the seals on the crankcase to start weeping a little.
My understanding is you'll only see any real gains in high rpm engines. FWIW our engines don't see anywhere close to the amount of vacuum Will is talking about, I had to use a digital manometer to even read it. Wouldn't even register on a water column.
CDRs very seldom fail and can be cleaned, I tested every chemical in my shop to see if it would affect the diaphram in it and nothing would hurt it. Just be careful to not get anything in it thru the pin hole in the back side as I would imagine liquid sitting against the diaphram would affect it's operation.

 

[ak diesel driver]

Oh and also the only time the CDR closes is in a high vacuum situation

 

[Will L.]

The gains being seen in only high rpm range are on gasoline engines that have half or less the compression we do. I cannot comment to the amount of vacuum created by the stock system with just cdr removed. When I did it it was using an extrernal vacuum pump that I had set @ 12”. But I saw gains in the 6.5 as low as 3”, which is crazy lower than gas engines- they usually see nothing until 8”. My total gains were over 15 hp, but pump diesel that is obtainable.

And yes cdr is emissions because without cdr the hose off the valve cover would just be open to atmosphere to bring crank case pressure to ambient. And the pressure can be built up in crankcase faster than it will evacuate, so peaks in pressure will occur.

And there is the argument of instead of oil leaks, you could suck in dust with a bad seal.

My thing is, the pressure is created by the pistons operating in the crank case and from the small amount of blowby that occurs even in a new engine at idle. But the higher the rpm the greater the crank case pressure is. Also the higher the compression ratio, the greater. So the highest pressure is created at highest rpm. But that is when the cdr closes.

There really shouldn’t be any noticeable difference of just adding a catch can in power unless you were pulling in some descent oil and leaving a smoke sign from it.