Above Forum Ads



No announcement yet.

How To: Poor Man's Oil Breather/PCV Blockoff

This is a sticky topic.
  • Filter
  • Time
  • Show
Clear All
new posts

  • #31
    The best solution for the ski is what yamaha did - put the correct size pipe into the intake to lower crankcase pressure. It is about horse power.
    Crankcase Vacuum Technical Information - Dry Sump Oil Pumps for Racing Engines - High Quality, Unbeatable Price. Nutter Racing Engines specializes in designing, manufacturing and selling standard and custom race engine oil pumps, hand crafted and built to racing specifications.

    I had a racer tell me to hook the air intake hose from my pair valve to my crank case breather to cause a negative crank case pressure for more HP,has anyone tryed this and dynoed it to see if it helps?
    06 FX HO Cruiser
    750 SS Mikuni & Pipe - Sold


    • #32
      Originally posted by jetskibruce View Post
      As I was looking into the racing engine info on some other web sites it seems that engines like a lower pressure in the crank case. The blow-by and pressure is highest at high rpm and power levels. Solutions are: a separate pump that has the capacity required, the exhaust scavenging, and the intake manifold. Seems like the tradeoff is some amount of hot air in the intake vs better performance with lower crankcase pressure. One potential problem with pressure in the crankcase was the real possibility of forced oil leaks. Seems like the yamaha engineers know what they are doing. lol
      These are the items that will help create a negative pressure in the crankcase to help ring seal......if you look at the dinky large hose that is being blocked off.....you'll see that it doesnt have the rigidity to maintain patency whilst creating the amount of vacuum/neg pressure ur talking about to create a potential ring-seal benefit......make sense? You need a purpose made scavenging pump/system to get the benefit ur talking about....I highly doubt that floppy PCV hose is doing anything but pulling hot air back into your engine.

      Rut-Ro!!! It's a SHO!!!!
      Seeeeea Yaaaa!!!!!!!
      '08 Stage 3+ OffSHOre FX-SHO--->http://www.greenhulk.net/showthread.php?t=114782



      • #33
        So, it probably doesn't make too much difference and you may see a gain. I guess you are changing oil very frequently? There are too many threads on the internet that already discuss this. So, just do it if it makes you happy.
        06 FX HO Cruiser
        750 SS Mikuni & Pipe - Sold


        • #34
          Originally posted by jetskibruce View Post
          The best solution for the ski is what yamaha did - put the correct size pipe into the intake to lower crankcase pressure. It is about horse power.
          Whoa! I had (just sold) a K4 Gixxer and I remember reading about the "pair valve mod" a while back. I thought this sounded a lot like that. Never did it. Does not seem worth it. Nobody has ever definitively documented any gains from it whatsoever.
          2016 310R: R&D reflash - free air mods - R&D sponsons - 71.5 @ 7900 rpm

          2008 SHO: R&D C3 SC wheel - R&D cam gears on S2 setting - R&D R3 reflashed ECU - RIVA manifold upgrade - RIVA FF exhaust -JD's cold air intake - RIVA grate - JD's intercooler and cooling kit - custom Skat long blade - R&D sponsons - Jim's modified stock rideplate - 81.9 mph @ 8500 rpm - SOLD


          • #35
            Originally posted by allstar71 View Post
            Is everyone sure that you dont need the suction from the intake? just a thought...
            You are correct, you do need suction from the intake for a PCV system to function properly. The problem is that when you supercharge or turbocharge an engine, there is pressure in the intake and the PCV system does not function properly. In our vehicles we installed a one way check valve ( the kind that GM used on their AIR system) It effectivly scavenges the blow-by gasses outof the crankcase and just send them out the exhaust.


            • #36
              The hose is connected before the supercharger so there is still vacuum actually it is prop higher vacuum than what you would have in a n/a engine
              Fx SHO non Cruiser: Riva Grate, FF Exaust, Riva Power Filter, R&D Rideplate, Riva Intake Manifold upgrade, c3 wheel, PWR 4x8 intercooler, hks bov, R&D powershot, R2 Reflash, 160mm pump liner.


              • #37
                Disconnect PCV from Intake???

                Been thinking about removing the PCV going into the intake for some time after initially reading this thread. Then, two days ago I got my intake manifold upgrade done and when we pulled my Riva intake pipe, there was oily $hit on the white SC intake adapter! The only thing I can think is that this is coming from the PCV. It looked nasty.

                I have a Groco strainer I was (past tense) going to use for water filtering and thought I'd run the PCV hose into the strainer mounted in the engine compartment.

                Now, I am wondering about this... Anyone have any thoughts? Are you guys disconnecting your PCV from the inlet? Is PCV only for emission purposes?

                '09 FZS R&D Stuff: Intake Grate, C3-11, R3, Powershot, 2nd Thermostat, Billet Couplers and Multi Port Adapter. Riva Stuff: FF Intake/Exhaust, Mani Upgrade, RRFPR (56 & static) and Power Cooler IC. Other Stuff: LC-1 (duhh), TBM Aux Tank, PET 2500, Jim's VX plate and HKS BOV, 155mm 13/23 Skat Swirl Pro Pitch
                Couple Stock Stand-Ups: '93 750SX, and a '91 SuperJet


                • #38
                  I pulled my R&D BOV hose off to replace the valve with an HKS & found an oily film inside. It's never looked like this before, so it must have happened when I overheated it a few weeks back. I was planning to pull the IC anyway to install the diverter, but now looks like I'll have to pull & disassemble the SC housing too in order to clean it out...PITA. A catch can would have saved me a lot of work. I saw JD1's kit eliminates the oil breather box entirely.
                  07 Lowell ported PV EFI GP1390R Built by GPR114, Tuned by Jim's Performance, Ross' Sonic Boom TB's...they rule!!!
                  16 FX SVHO Cruiser "Under Construction"
                  11 Superjet



                  • #39
                    pro stock race cars were running a belt driven scavanging pump to suck down the crank case...they say it made a few h.p. but who really knows except maybe warren johnson etc.
                    1999 Kawasaki Ultra 150 69 gps bone stock....gone, not forgotten
                    2009 yamaha FZR stage 2
                    2003 gpr ported big bore efi...gone but not forgotten.
                    2012 VX
                    R ribbon delete , R&D grate.....gone and not forgotten
                    2017 GP1800 w/ Maptuner-X, solis 13/18, 4inch air, ribbon delete 80gps, retainers and springs, cooling kit, big intercooler.