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    • VTT "Spline lock" N54/N55/S55 Crank Hub Solution Now Available! #SPLOCK

      VTT is proud to finally announce our "Spline Lock" crank hub solution for the N54/N55/S55 BMW platforms. After 8 months of testing, and 10+ design changes we arrived at our final design, and exhaustively tested it on the bench, and in our shop test vehicle!


      The way this product works is very much like a Splined extractor
      (Example: https://www.toolsource.com/images/pr...200Wx1200H.jpg).
      You have an extractor with splines machined into it that is pressed or hammered into a broken off nipple etc. As you turn the extractor one direction it will lock itself to the nipple, and spin it out. Our hubs are machined to a very close tolerance and are a specific press fit for the crank. You use the crank bolt to install the hub just as you would a stock hub, but for these, you have to lock the crank first, and as you tighten the bolt you will press the splines into the crank creating teeth, and it will be locked. The teeth are designed in such a way that if you have an event that would normally slip a stock hub the teeth will be forced deeper into the crank not allowing it to spin. The benefits of these are two-fold. 1. a positive locking hub. 2. No additional labor to completely disassemble your motor, drill, and pin your crank.


      Some may wonder why did not make a complete CNC hub including the oil sprocket, that is a good question, and one we tried while testing. We found the oil sprocket is almost never to blame when you slip a hub. You are trying to maintain the crank to cam timing, and this is lost either two ways in almost every test we saw. 1. The single grip disc between the timing sprocket and the hub would slip first (most common failure point). Going with a one-piece hub/timing sprocket locked to the crank eliminates that failure point. 2. The bolt itself would spin loose causing this first grip disc to slip, and timing to be lost. Coupling the "Spline Lock" hub with our Crank Bolt Capture eliminates this failure point as well, which is why we suggest running the CBC with the Splined hub.

      Couple photos (Yes we know the oil gear is on backward, was easier to get the splines in the photo that way)


      We created a testing rig using cut off the end of an N54 crank, and a hydraulic pump t simulate the crank spinning on the hub. We used this to see how easily we could slip a stock hub compared to our new design, after about 10-12 revisions we had one that broke the rig before slipping. We went with that design, and have since had it in our shop car without issue spinning high RPM, and making around 900WHP.

      The hubs are CNC machined from very tough hardened 14-7SS, and can take anything we can throw at them.

      The Hubs are available in these configurations, and we will run an intro special for the rest of the week.

      We offer the hubs in 3 ways.

      • Hub Only - $699 (Intro Price $599)
      • Hub plus OEM bolt, OEM Oil pump sprocket, OEM oil sprocket retainer - $749 (intro Price $649)
      • Hub Plus OEM bolt, OEM Oil pump sprocket, OEM oil sprocket retainer, and VTT Crank bolt capture - $799 (Intro Price $699)



      IN STOCK READY TO SHP

      Here are a few photos of the testing process (please note these are early samples, the teeth design was revised to perfectly match the stock hub) We spent north of 5K doing this testing (one off samples are expensive!) as it was something very important to us as it has cost us prob triple that is ruined heads dealing with these issues.

      This article was originally published in forum thread: VTT "Spline lock" Crank Hub Solution Now Available! #SPLOCK started by Tony@VargasTurboTech View original post
      Comments 20 Comments
      1. Sticky's Avatar
        Sticky -
        Excellent work and will promote to the front page shortly. Will need to format some things slightly differently.

        I heard some N54 mode years have different crank hub designs but have no idea if this is true.

        Regardless, well done as there are higher power N54's out there spinning crank hubs that are kept quiet.
      1. Tony@VargasTurboTech's Avatar
        Tony@VargasTurboTech -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Excellent work and will promote to the front page shortly. Will need to format some things slightly differently.

        I heard some N54 mode years have different crank hub designs but have no idea if this is true.

        Regardless, well done as there are higher power N54's out there spinning crank hubs that are kept quiet.
        In all my research this is the full part number list for crank hubs and corresponding parts. I have never seen another part number for the N54 except for superseded numbers, going to new designs, but they fit all N54's

        Attachment 57754
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Tony@VargasTurboTech Click here to enlarge
        I have never seen another part number for the N54 except for superseded numbers, going to new designs, but they fit all N54's
        Interesting. Someone said something about a change in 2009. May have been @d21spike I don't remember exactly as I haven't studied the topic like you guys.

        Regardless, guys will want this solution from VTT.
      1. Tony@VargasTurboTech's Avatar
        Tony@VargasTurboTech -
        A great question was asked on facebook regarding the crank, and its hardness in that area to hold the spline created by the hub. When we cut the cranks up for our test rig, I took one to the local company that does all our annealing, hardening, heat treating, metal analysis, etc. BMW has the crank in that area very hard for durability, and longevity. We took this information, and used it when developing the hardness of our hubs. 17-4 is a SS that can be hardened through annealing, and heat treating. We made sure even though the crank was very hard in that area, our hub was even harder to ensure proper spline creation when the hub is pressed into the crank. For comparison. A stock hub would not even read on the Rockwell scale when tested. Thats how soft they are.

        Hardness specs as tested

        Crank journal (nitrated) (tested for fun) - 43-47 Rockwell VERY VERY hard as you would imagine it should be for a journal
        Crank hub area - 23 Rockwell (this is very hard)
        Our crank hub - 37 Rockwell (extremely hard, and when you anneal 17-4 it becomes a very durable SS even at that hardness)
        Stock Hub - Rockwell machine would simply put dimples in it, and not read. (Extremely soft)
      1. Terry@BMS's Avatar
        Terry@BMS -
        Interesting approach, I like that it eliminates the need to drill in to the crank for pinning.
      1. F87Source's Avatar
        F87Source -
        I'm going to guess for those of us with lower power levels sub 600whp a crank hub capture would suffice? Not sure when it would be better to go with the capture as you said they spun stock too (S55 only iirc). But all in all great work man it's nice to have solutions available, and it'll pair up nicely with that n55 single you're working on Click here to enlarge.
      1. Tony@VargasTurboTech's Avatar
        Tony@VargasTurboTech -
        Click here to enlarge Originally Posted by F87Source Click here to enlarge
        I'm going to guess for those of us with lower power levels sub 600whp a crank hub capture would suffice? Not sure when it would be better to go with the capture as you said they spun stock too (S55 only iirc). But all in all great work man it's nice to have solutions available, and it'll pair up nicely with that n55 single you're working on Click here to enlarge.
        Well this is where it gets sticky, we have actually spun hubs doing no boost pulls on the dyno testing things, spun it up to 8K, dyno read 350WHP, and it came down with crank to cam correlation codes. You can't put a power number on it, it's more RPM related.
      1. Icewall's Avatar
        Icewall -
        So if we have the billet ati super damper we can only use the splined crank hub and have the potential risk of still spinning the bolt loose?
      1. Tony@VargasTurboTech's Avatar
        Tony@VargasTurboTech -
        We removed our ATI dampers as we had weird vibrational issues that we could not resolve. We went back to the fluid-filled stock damper, and they went away. We made a few captures for the ATI damper, but have not made anymore as its not a product we fully support at this time. If doing the Spline Lock hub we suggest putting the stock damper back on at that time with the capture
      1. Tony@VargasTurboTech's Avatar
        Tony@VargasTurboTech -
        Install guide for those interested. Please let us know if you spot any typos.
      1. Optigrab's Avatar
        Optigrab -
        Click here to enlarge Originally Posted by Tony@VargasTurboTech Click here to enlarge
        Well this is where it gets sticky, we have actually spun hubs doing no boost pulls on the dyno testing things, spun it up to 8K, dyno read 350WHP, and it came down with crank to cam correlation codes. You can't put a power number on it, it's more RPM related.
        Interesting...Did you bounce off the limiter?
      1. martymil's Avatar
        martymil -
        I wish this was out when I was building my engine, ahh well.

        Better late then never, well done guys.

        I can see these basically walking of the shelves in the near future.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Tony@VargasTurboTech Click here to enlarge
        Install guide for those interested. Please let us know if you spot any typos.
        If you don't mind I'll copy this into its own thread. That way install DIY will be easy to find with a Google search plus install questions/tips can be shared in that thread.
      1. Tony@VargasTurboTech's Avatar
        Tony@VargasTurboTech -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        If you don't mind I'll copy this into its own thread. That way install DIY will be easy to find with a Google search plus install questions/tips can be shared in that thread.
        In all seriousness, we made this guide because a part like this requires you have some sort of guide even for the professional to go by when doing the job, but unless you possess the skills required to do a job like this right the first time, every time. This really should not be a DIY project for a guy at home. If you mess this up, and try to start your car, very bad things happen very quickly.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Tony@VargasTurboTech Click here to enlarge
        This really should not be a DIY project for a guy at home. If you mess this up, and try to start your car, very bad things happen very quickly.
        I think what you just posted is important to include but I get your point.

        I'm just sayin the guide and guide related questions would be best in their own topic for reference and help to your customers.
      1. Eleventeen's Avatar
        Eleventeen -
        Looks good! Less labor to install and the price is much better than the competition, too. Click here to enlarge
      1. Chris@VargasTurboTech's Avatar
        Chris@VargasTurboTech -
        SPLOCK!
      1. BlackJetE90OC's Avatar
        BlackJetE90OC -
        Interesting solution.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Chris@VargasTurboTech Click here to enlarge
        SPLOCK!
        Just wanted to say you can use the #splock hashtag which Google picks up Click here to enlarge
      1. Chris@VargasTurboTech's Avatar
        Chris@VargasTurboTech -
        #SPLOCK

        Love it!