Custom crankcase breather question

Discussion in 'Performance Mods' started by Longshot, Sep 25, 2020.

  1. Longshot

    Longshot New Member

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    Hi, I'm back with another question. I'm almost done with all my summer mods. I drilled and tapped the valve covers to fit AN fittings but I noticed that the OEM ports had restrictors on in them. I've read so many crankcase threads but they are all slightly different. Some say larger breather hoses help the oil form droplets so that the catchcan can trap them more efficiently. Can anyone help me understand when and what these restrictions are for? Should I add a restriction in my new system?
    Thanks!
     
  2. Aussie Viper Truck

    Aussie Viper Truck Active Member

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    I had to make high flow internal rocker cover baffles to stop mine from pushing oil into the catch can. mine also has after market rocker covers. (the pics show the breathers disconnected) IMG_0500.jpg IMG_0499.jpg
     
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  3. Longshot

    Longshot New Member

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    I figured it out after rereading threads, specifically rottenRonnies Max catch can thread. Thanks rottenronnie!
     
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  4. Aussie Viper Truck

    Aussie Viper Truck Active Member

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    and they have worked a treat, it will probably go between oil changes without having to drain catch can.
     
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  5. Longshot

    Longshot New Member

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    Interesting. I decided to mod because I just hate plastic lines. I didn't like the way they ran under the intake. I'm thinking about doing a dual catch can setup that I can switch to high flow when I go FI without too much trouble. I'm using McNally Gen2 catch cans that I got when they were on sale for $70. With that sweet Roe SC, you didn't have room to tap the OEM casted ports like I did. If anyone wants to do this, there is plenty of material to tap threads there. I read about oil getting into the cans under extreme braking or acceleration and wanted something similar with options but I didn't want to make a plate to put the port in the middle of the valve cover. I'm thinking about connecting both ports with a tee and then a single line to the can. I tapped them for 8AN but the pic has 12AN fittings which I will change. Im trying to figure out what the other lines do on the driver's side cover that has no restrictor. One goes to the brake booster and maybe one down to the fuel vac system. I have an electric brake booster that Ill try out.
     

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  6. AMS3

    AMS3 Well-Known Member

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    Nice piece of hardware sitting on the top of your engine. How much HP you pushing with it?
     
  7. Aussie Viper Truck

    Aussie Viper Truck Active Member

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    It is still running stock bottom end so its only running 5 psi. Roe says it adds up to 150 hp. I am going to get it put on a dyno to check the tune and get a power/ torque read out.
     
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  8. AMS3

    AMS3 Well-Known Member

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    Good deal, let us know how it turns out :)