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    • Another stout N55 - 683 rwhp F30 BMW 335i with BorgWarner EFR 8374 turbocharger

      Finally we are seeing more and more 600+ rear wheel horsepower N55's as well as some nice results for BMW motors with BorgWarner EFR turbochargers. This F30 335i is an automatic and features the BorgWarner EFR 8374 turbo.


      It hits 683 horsepower horsepower and 670 lb-ft of torque to the wheels:


      Boost details and other pertinent info about the fuel system were not shared but this is a built motor N55 which is going to be good or longevity with that much torque.

      The motor is flash only tuned by Motiv through MHD and the manifold/turbo kit is from Speedtech.

      • BorgWarner EFR 8374 Turbo
      • Cast Exhaust Manifold (divided for twin scroll)
      • Stainless Steel Downpipe
      • RH Engine Mount
      • Waterpump Mount Bracket
      • Coolant Hoses and Billet Fittings
      • Oil Lines and Billet Fittings
      • Aluminum Turbo Inlet Tube
      • Silicone Turbo Outlet Tube
      • Silicone Couplers
      • EWG Bracket and Linkage
      • Required Fasteners and Hose Clamps
      • V-band Clamp

      This article was originally published in forum thread: Another stout N55 - 683 rwhp F30 BMW 335i with BorgWarner EFR 8374 turbocharger started by Sticky View original post
      Comments 10 Comments
      1. AWSAWS's Avatar
        AWSAWS -
        Weren't N55s supposed to have weak crank shafts?
      1. bnks334's Avatar
        bnks334 -
        Click here to enlarge Originally Posted by AWSAWS Click here to enlarge
        Weren't N55s supposed to have weak crank shafts?
        People are dumb.
      1. AWSAWS's Avatar
        AWSAWS -
        Click here to enlarge Originally Posted by bnks334 Click here to enlarge
        People are dumb.
        Yeah. That's why cast n55 cranks end up breaking
        Attachment 59789
      1. Weehe's Avatar
        Weehe -
        Click here to enlarge Originally Posted by AWSAWS Click here to enlarge
        Yeah. That's why cast n55 cranks end up breaking
        Attachment 59789
        Yeah, lets find a second instance of that...
      1. Torgus's Avatar
        Torgus -
        not bad at all nice to see more N55s putting in work. 600whp at redline is decent. They need a larger turbo!
      1. bnks334's Avatar
        bnks334 -
        Click here to enlarge Originally Posted by AWSAWS Click here to enlarge
        Yeah. That's why cast n55 cranks end up breaking
        Ghassan probably put that crank in a vice to straighten it and broke it lol People aren't breaking N55 crank shafts. That's literally the only example that exists. At least not at <700whp they aren't. You know what else has cast cranks? All those junkyard 1000whp LS engines people love so much... pretty much the same size 2" rod journals as well on those cast cranks.

        It's almost 2020 and people still believe every word they read on the internet... and from people trying to up-sell them on junk N54 parts none the less lol

        https://www.facebook.com/GhassanAuto...359169692/?t=0
      1. F87Source's Avatar
        F87Source -
        Well if you're worried about the cast crank the m235i, m235ir, and m2 have a forged crank which solves all this weakness issue.

        But like bnks334 said, the only instance of the crank snapping is from Ghassan so not really the most evident proof that the n55 has a weak crank imo.... Especially when there are guys making double the factory whp on these "stage 3" turbos and no one has had any reports of the crank breaking.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by F87Source Click here to enlarge
        Well if you're worried about the cast crank the m235i, m235ir, and m2 have a forged crank which solves all this weakness issue.
        I wonder why BMW offered a cast crank on certain N55's then changed their mind? Probably supply issue I would assume or a purchase contract.
      1. F87Source's Avatar
        F87Source -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        I wonder why BMW offered a cast crank on certain N55's then changed their mind? Probably supply issue I would assume or a purchase contract.
        N55's came out in 2011 so no m235i, m235ir, or m2's yet. So to make mass production engine for multiple platforms including SUV's factoring how many people will race or mod and the 300hp from the factory a cast crank is cheap and easy to mass produce. I guess when they moved to the F series and started to think about a racing chassis for the new generation, one of them being the 2 series, they wanted to give it a stronger set of internals. So that's why (imo) only the m235i and m2 (and x4 m40i) got the forged crank because they're derived from the m235ir and what bmw considers a car that alot of people will trash on and they want it to last. They probably thought the F30 335i (2012) demographic would mainly be daily users and thus gave it a slighly revised 2011 n55 motor until in 2014 the m235i was made when they started to give it a forged crank.

        But yes it could be contracted for the n55 life cycle so some n55's had to take a hit, then they made the go ahead on the m235i so they could reflect their m235ir racing line up and have a car compete against the audi s3 range of cars. Either way m235i cranks are pretty cheap on Ebay and they should be a drop in fit with new rods + pistons of course since its balanced differently.

        But all in all a cast crank really isn't that weak, if it is tuned properly and isn't knocking all day long then it should last, keep that torque curve a little higher in the RPM range and you should be golden. For eg look at speedtech's F30, over 600whp (and probably more now) and it is fine.
      1. bnks334's Avatar
        bnks334 -
        They didn't change their minds about anything. N55's got a lighter cast crank. High output variants got a forged crank (M135i, M235i, M2, 735i...). Regular N55 got a cast crank all the way to the end of production. There are several different engines just like there are several different B58's. High output B58 in the Z4M gets a regular 6 port exhaust manifold. Supra got the medium output engine with the headifold.