Lets talk about the Exhaust Slash Cut method...

Turbo and Supercharger discussion
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By teal_dx
- Thu Apr 26, 2007 8:45 pm #6672 those diagrams will give you good vacuum, but it is done by using the turbo. This means if your catch can ever gets too full, you're sucking oil straight in your turbo and into your intercooler.
Even if you empty your catch can often, be sure that you have a baffle inside of some sort just to be 100% sure that no blowby is getting sucked out of the catch can- expecially if the inlet and outlet are right next to each other as they are on so many catch cans.
The only other negative thing about that setup in the links is you're sucking in hot used air from your crank case and valve cover. With the exhaust slash cut method, the turbo gets 100% clean cool air.

BTW, those compression #'s are not healthy :(
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By york62
- Thu Apr 26, 2007 9:20 pm #6676 haha i knwo the numbers are bad BUT not that bad for a car wile 345xxx on 10psi for about a year now daily driver haha, it will be getting rebilt for boost this winter anyway.

i dont plan on using those methods for the catch can i was just showing way of doing it haha:P
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By ohDirka
- Sat Apr 28, 2007 1:42 am #6819 okay i talked to my dad and he said that on our race car we used 3/4 inch tubing into the exhaust...mind you that was a 620ci motor but it would work the same
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By suspendedHatch
- Sun Jul 01, 2007 2:15 am #12778 One problem with exhaust slash cuts is that the hose gets too hot and bad things happen.

Another thing to keep in mind is that you need to do it downstream of your cat because you don't want any kind of oil vapor going through it.

Those pics came from turboD16.com. My method is sort of a hybrid between two of his designs. I can scan it and post it if anyone wants to see it. I don't believe in venting to the atmosphere or to the ground.

Keep in mind that a turbo PCV system and a N/A PCV system look a little different.

You can get check valves from the brake booster hose on any junkyard car.

By mrbojangles13
- Fri May 11, 2012 12:30 am #304564 This technology has really been studied and the aquarium industry has it down to a science. The toughest part is its not going to be the same for every motor. The 45 degree pipe will vary in diameter and how far it needs to go into the exhaust depending on the flow you are getting out of the exhaust (volume), the diameter of the exhaust, and most importantly the velocity of the flow of air. The higher the velocity or pressure passing by this slash cut the stronger the vacuum will be. If u have the same motor with a 3 inch exhaust the vacuum will be weaker than the same setup with a 2.5 exhaust. Do a search on Venturi. This is all much more complicated than is 3/4 pipe alright?
I know it's application and can design a Venturi for someone's aquarium lol but I haven't looked into the vacuum application.
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