Oil catch can for boost.....is vacuum pull a must....?
Thread Starter
TECH Enthusiast
Joined: Apr 2023
Posts: 533
Likes: 84
Oil catch can for boost.....is vacuum pull a must....? So I need a new oil catch can for the boosted set up.
I saw the Motion Raceworks can that uses no pull of vacuum from the intake, which is what I want.....ZERO OIL MIST GOING INTO THE INTAKE. For like 10+ years, I ran a N/A big LS stroker engine with absolutely no crankcase evacuation of any kid. All vacuum ports on the intake capped off. I put little fuel filter breathers on the valve covers and one on the valley cover port. Oil was always pretty clean at 3,000 mile oil changes.
But about 5 years into owning that big stroker I installed an small electric vacuum pump the size of a pack of cigarettes that constantly pulled a fixed amount of vacuum no matter what rpm, from idle to full throttle. It just always ran. Not sure I ever saw any oil dripping from the line coming out of the vacuum pump. So I'm thinking it just pulled air out of the crankcase. Still, always pretty clean oil at every oil change for the next 5+ years.
So is this Motion Raceworks can the best choice for a boosted set up, with the crankcase pressure itself being the only force that "pushes" that pressure out of the crankcase through the large hoses and into the can? Seems like having zero oil pressure going through the intake is a HUGE plus, and having a catch can also. Instead of just having 3 vents, 1 on each valve cover (2) and 1 on the valley cover port.
This one:
Motion Raceworks Top Loader Billet Catch Can KIT 32-100K
I saw the Motion Raceworks can that uses no pull of vacuum from the intake, which is what I want.....ZERO OIL MIST GOING INTO THE INTAKE. For like 10+ years, I ran a N/A big LS stroker engine with absolutely no crankcase evacuation of any kid. All vacuum ports on the intake capped off. I put little fuel filter breathers on the valve covers and one on the valley cover port. Oil was always pretty clean at 3,000 mile oil changes.
But about 5 years into owning that big stroker I installed an small electric vacuum pump the size of a pack of cigarettes that constantly pulled a fixed amount of vacuum no matter what rpm, from idle to full throttle. It just always ran. Not sure I ever saw any oil dripping from the line coming out of the vacuum pump. So I'm thinking it just pulled air out of the crankcase. Still, always pretty clean oil at every oil change for the next 5+ years.
So is this Motion Raceworks can the best choice for a boosted set up, with the crankcase pressure itself being the only force that "pushes" that pressure out of the crankcase through the large hoses and into the can? Seems like having zero oil pressure going through the intake is a HUGE plus, and having a catch can also. Instead of just having 3 vents, 1 on each valve cover (2) and 1 on the valley cover port.
This one:
Motion Raceworks Top Loader Billet Catch Can KIT 32-100K
So I need a new oil catch can for the boosted set up.
I saw the Motion Raceworks can that uses no pull of vacuum from the intake, which is what I want.....ZERO OIL MIST GOING INTO THE INTAKE. For like 10+ years, I ran a N/A big LS stroker engine with absolutely no crankcase evacuation of any kid. All vacuum ports on the intake capped off. I put little fuel filter breathers on the valve covers and one on the valley cover port. Oil was always pretty clean at 3,000 mile oil changes.
But about 5 years into owning that big stroker I installed an small electric vacuum pump the size of a pack of cigarettes that constantly pulled a fixed amount of vacuum no matter what rpm, from idle to full throttle. It just always ran. Not sure I ever saw any oil dripping from the line coming out of the vacuum pump. So I'm thinking it just pulled air out of the crankcase. Still, always pretty clean oil at every oil change for the next 5+ years.
So is this Motion Raceworks can the best choice for a boosted set up, with the crankcase pressure itself being the only force that "pushes" that pressure out of the crankcase through the large hoses and into the can? Seems like having zero oil pressure going through the intake is a HUGE plus, and having a catch can also. Instead of just having 3 vents, 1 on each valve cover (2) and 1 on the valley cover port.
This one:
Motion Raceworks Top Loader Billet Catch Can KIT 32-100K
I saw the Motion Raceworks can that uses no pull of vacuum from the intake, which is what I want.....ZERO OIL MIST GOING INTO THE INTAKE. For like 10+ years, I ran a N/A big LS stroker engine with absolutely no crankcase evacuation of any kid. All vacuum ports on the intake capped off. I put little fuel filter breathers on the valve covers and one on the valley cover port. Oil was always pretty clean at 3,000 mile oil changes.
But about 5 years into owning that big stroker I installed an small electric vacuum pump the size of a pack of cigarettes that constantly pulled a fixed amount of vacuum no matter what rpm, from idle to full throttle. It just always ran. Not sure I ever saw any oil dripping from the line coming out of the vacuum pump. So I'm thinking it just pulled air out of the crankcase. Still, always pretty clean oil at every oil change for the next 5+ years.
So is this Motion Raceworks can the best choice for a boosted set up, with the crankcase pressure itself being the only force that "pushes" that pressure out of the crankcase through the large hoses and into the can? Seems like having zero oil pressure going through the intake is a HUGE plus, and having a catch can also. Instead of just having 3 vents, 1 on each valve cover (2) and 1 on the valley cover port.
This one:
Motion Raceworks Top Loader Billet Catch Can KIT 32-100K
My current catch can is similar, just a bigger can but still uses dual -10AN lines from each valve cover.
I've been making street pulls all summer and still haven't had to empty it so the Motion unit would be fine.
The big thing with cans that vent the pressure is having large enough lines so the pressure can exit easily, the more power you make, the more venting you'll need.
Thread Starter
TECH Enthusiast
Joined: Apr 2023
Posts: 533
Likes: 84
Motion makes solid products that they test on their in-house racecars so I wouldn't have any problems using it.
My current catch can is similar, just a bigger can but still uses dual -10AN lines from each valve cover.
I've been making street pulls all summer and still haven't had to empty it so the Motion unit would be fine.
The big thing with cans that vent the pressure is having large enough lines so the pressure can exit easily, the more power you make, the more venting you'll need.
My current catch can is similar, just a bigger can but still uses dual -10AN lines from each valve cover.
I've been making street pulls all summer and still haven't had to empty it so the Motion unit would be fine.
The big thing with cans that vent the pressure is having large enough lines so the pressure can exit easily, the more power you make, the more venting you'll need.
No problem?
I ask because all I’ve heard for 20 years is that you MUST pull vacuum to get rid of the toxic gasses. As I said I got away with having no vacuum pull but……..that was an N/A Steiner engine that had 3,00 mile oil changes.
Now it’ll be boosted pretty good.
ok, so you’re set up has no oil entering the intake? This is my main question, I’ll be around 15-18psi realistically. Brand new motor. I can simply cap off my vacuum ports and have no crankcase vacuum taking place.
No problem?
I ask because all I’ve heard for 20 years is that you MUST pull vacuum to get rid of the toxic gasses. As I said I got away with having no vacuum pull but……..that was an N/A Steiner engine that had 3,00 mile oil changes.
Now it’ll be boosted pretty good.
No problem?
I ask because all I’ve heard for 20 years is that you MUST pull vacuum to get rid of the toxic gasses. As I said I got away with having no vacuum pull but……..that was an N/A Steiner engine that had 3,00 mile oil changes.
Now it’ll be boosted pretty good.
My car runs around 14 lbs. currently but will see 20+ in the future and I'm very confident I'll have more than enough to vent that.
You can do a PCV catch can that works off engine vacuum, the Mighty Mouse PCV can works very well in that regard.
I ran one for years and never got any oil in my intake, keeps the oil smell out of the engine bay and the cab as well.
Even with the open can I run now I still don't get any oil smell in the car, probably depends on where you mount it.
If you mount it on the firewall close to the cabin intake, you'll probably get the smell, mine is mounted up front by the radiator.
Thread Starter
TECH Enthusiast
Joined: Apr 2023
Posts: 533
Likes: 84
Nope, there is no attachment to the intake, it's a vent to atmosphere only setup.
My car runs around 14 lbs. currently but will see 20+ in the future and I'm very confident I'll have more than enough to vent that.
You can do a PCV catch can that works off engine vacuum, the Mighty Mouse PCV can works very well in that regard.
I ran one for years and never got any oil in my intake, keeps the oil smell out of the engine bay and the cab as well.
Even with the open can I run now I still don't get any oil smell in the car, probably depends on where you mount it.
If you mount it on the firewall close to the cabin intake, you'll probably get the smell, mine is mounted up front by the radiator.
My car runs around 14 lbs. currently but will see 20+ in the future and I'm very confident I'll have more than enough to vent that.
You can do a PCV catch can that works off engine vacuum, the Mighty Mouse PCV can works very well in that regard.
I ran one for years and never got any oil in my intake, keeps the oil smell out of the engine bay and the cab as well.
Even with the open can I run now I still don't get any oil smell in the car, probably depends on where you mount it.
If you mount it on the firewall close to the cabin intake, you'll probably get the smell, mine is mounted up front by the radiator.
Trending Topics
Thread Starter
TECH Enthusiast
Joined: Apr 2023
Posts: 533
Likes: 84
So vacuum pulling from the crank case just isn;t needed....???? Just let the crank case pressure push itself out....yes...?
Why are cars made with vacuum if its not needed?
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo Thread Starter
TECH Enthusiast
Joined: Apr 2023
Posts: 533
Likes: 84
OH....I'll be running around N/A for a few months at most. So do I need some kind of vacuum pull on it????
I have a 12v electric vacuum pump that pulls pretty good. I could hook that up to pull crankcase gases full time at a steady rate.
I have a 12v electric vacuum pump that pulls pretty good. I could hook that up to pull crankcase gases full time at a steady rate.
Thats exactly what I want to do. And the can doesn't need to be any kind of expensive can with special NASA baffling, right? Because there's nothing returning to the intake....correct?
So vacuum pulling from the crank case just isn;t needed....???? Just let the crank case pressure push itself out....yes...?
Why are cars made with vacuum if its not needed?
So vacuum pulling from the crank case just isn;t needed....???? Just let the crank case pressure push itself out....yes...?
Why are cars made with vacuum if its not needed?
If you want to go spend a few hundo go right ahead it's still gonna do the same thing.
Picture of the can I got except the fittings are welded on the sides not straight on
Last edited by 91 Z28; Oct 13, 2023 at 08:12 PM.
Thread Starter
TECH Enthusiast
Joined: Apr 2023
Posts: 533
Likes: 84
I bought a cheap can with dual -12an fittings welded on each side with a breather on top off eBay. And I'm using a set of motion race works bolt on valve cover breathers to go -12 off each cover. Crankcase pressure vents out naturally.
If you want to go spend a few hundo go right ahead it's still gonna do the same thing.
Picture of the can I got except the fittings are welded on the sides not straight on
If you want to go spend a few hundo go right ahead it's still gonna do the same thing.
Picture of the can I got except the fittings are welded on the sides not straight on
Staging Lane
Joined: Apr 2018
Posts: 91
Likes: 14
Vacuum is not NEEDED and vented is not evacuation.
It just becomes a question of if you want it.
It can be done. One side with be a breather OR a line to a catch can and the outlet is a breather. Should be big lines like -10 or bigger. This will allow clean air IN and blowby out.
Other side is check valve allowing manifold vacuum to pull on a catch can and stopping boost in the intake from going further. After the check valve is outlet of catch can, the inlet goes to other valve cover.
Most cars do not care for evacuation, especially trailed drag cars but there is no doubt evacuation is a cleaner crank case.on a street car.
It just becomes a question of if you want it.
It can be done. One side with be a breather OR a line to a catch can and the outlet is a breather. Should be big lines like -10 or bigger. This will allow clean air IN and blowby out.
Other side is check valve allowing manifold vacuum to pull on a catch can and stopping boost in the intake from going further. After the check valve is outlet of catch can, the inlet goes to other valve cover.
Most cars do not care for evacuation, especially trailed drag cars but there is no doubt evacuation is a cleaner crank case.on a street car.
Last edited by Rt Jam; Oct 21, 2023 at 10:46 PM.
Thread Starter
TECH Enthusiast
Joined: Apr 2023
Posts: 533
Likes: 84
Vacuum is not NEEDED and vented is not evacuation.
It just becomes a question of if you want it.
I can be done. One side with be a breather OR a line to a catch can and the outlet is a breather. Should be big lines like -10 or bigger. This will allow clean air IN and blowby out.
Other side is check valve allowing manifold vacuum to pull on a catch can and stopping boost in the intake from going further. After the check valve is outlet of catch can, the inlet goes to other valve cover.
Most cars do not care for evacuation, especially trailed drag cars but there is no doubt evacuation is a cleaner crank case.on a street car.
It just becomes a question of if you want it.
I can be done. One side with be a breather OR a line to a catch can and the outlet is a breather. Should be big lines like -10 or bigger. This will allow clean air IN and blowby out.
Other side is check valve allowing manifold vacuum to pull on a catch can and stopping boost in the intake from going further. After the check valve is outlet of catch can, the inlet goes to other valve cover.
Most cars do not care for evacuation, especially trailed drag cars but there is no doubt evacuation is a cleaner crank case.on a street car.
pretty obvious we don’t. It was a 500 RWHP daily driver for 13 years. Oil was always quite good at oil changes.
im just doing the twin -12 line breather can with an air filter on top.
Thread Starter
TECH Enthusiast
Joined: Apr 2023
Posts: 533
Likes: 84
TECH Apprentice
Joined: Nov 2016
Posts: 371
Likes: 18
From: switzerland
there is a difference between a car that is expected to run well for 100k+ miles and our moded cars. i never bothered to do a vaccum evacuation either, be it boosted or not.
tip: in case of nocicable blow by use better oil. makes a hell of a lot of difference.
tip: in case of nocicable blow by use better oil. makes a hell of a lot of difference.
If you're gonna do a vent to atmosphere setup on a streetcar then big, free flowing lines are needed for anything making decent power.
I run 2 -12 an lines off my valve covers into a can and I've got no smell, leaking oil or blown out seals. It's not that difficult