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    • Horspower Freaks (HPF) 335i N54 single turbo kit update - HPF aiming to get the N54 over 800 wheel horsepower

      News on the HPF single turbo 335 N54 kit had died down for a while but HPF renewed interest by posting photos of their currently development. Rest assured, it is coming. What struck us is that Chris (owner of HPF) stated they intend to get this motor over 800 wheel horsepower. A lofty goal indeed as fueling and tuning solutions still need to take place. If anyone is going to make it happen it looks like a good bet is HPF.





































      This article was originally published in forum thread: UPDATE: HPF single turbo progress started by Forcefed View original post
      Comments 189 Comments
      1. fundahl's Avatar
        fundahl -
        Click here to enlarge Originally Posted by Rob@RBTurbo Click here to enlarge
        They will likely need that low pressure check valve but more importantly a pressure reducing check valve. This system where it is getting the oil feed typically sees 60-70psi. This single probably should see no more than 30-35psi.
        Some of the newer turbos have "built-in" restrictors, but yeah I hope they remembered to get the appropriate oil feed orifice...

        I don't think they would forget something like that though. Do the OEM turbos have restrictors, or are they built-in?
      1. oddjob2021's Avatar
        oddjob2021 -
        FWIW, my turbos at cold start make the same-- well i guess, a similar turbo (turbine) spooling noise, WITH an exhaust.. without one? i cant even imagine. once cold start is over i can get similar spooling sounds by either revving in neutral (both spool up and de-spool) or engine braking in first or second to idle. its especially apparent in garages. RB's do too no? can RB guys comment? my guess is a camera mic wont capture the true essence of the sound though, and for the camera here to capture it fairly well tells me it has to be louder, which is expected, larger turbo, more sound, albeit in their shop (closed space). just saying that turbo noise is nothing new, and i'll be happy to capture it if you guys are interested.
      1. Rob@RBTurbo's Avatar
        Rob@RBTurbo -
        Slicktop most turbos have built in restrictors of sorts leading up to the bearings. Where our oiling feed is plumbed however is higher pressure, fine for most journal bearing turbos but fairly excessive for ball bearing turbos. That will be one major issue. The second issue is the bleed down since the turbo is mounted so low, I'd imagine that be a lesser problem though. Easy/cheap cure either way.
      1. HPF Chris's Avatar
        HPF Chris -
        We've resolved all the oiling issues on our other kits where the turbo is mounted below engine oil. We're simply applying the same check valve system.
      1. Rob@RBTurbo's Avatar
        Rob@RBTurbo -
        Looks great Chris. Just something to consider pending on where your other kits source the oil feed vs. the N54 source... That can make a substantial difference in these things.
      1. fundahl's Avatar
        fundahl -
        Click here to enlarge Originally Posted by HPF Chris Click here to enlarge
        We've resolved all the oiling issues on our other kits where the turbo is mounted below engine oil. We're simply applying the same check valve system.
        We use the same idea for HVAC systems with long vertical refrigerant line runs. (They circulated oil mixed with refrigerant)
      1. klipseracer's Avatar
        klipseracer -
        Thanks for the update chris.
      1. Square&Level's Avatar
        Square&Level -
        lol...what a beast. Thanks for the update.
      1. solekeeper's Avatar
        solekeeper -
        sounds pretty awesome.