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 -for 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 or fastener. 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 -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. The most common failure method was the single grip disc between the timing sprocket and the hub would slip first. Going with a one-piece hub/timing sprocket locked to the crank eliminates that failure point. The second most common failure method is 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 to 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 (until Monday 10/22/18).
We offer the hubs in 3 configs:
Here are a few photos of the testing process (please note these are early samples, the tooth 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 probably triple that is ruined heads dealing with these issues.
You have an extractor with splines machined into it that is pressed or hammered into a broken off nipple or fastener. 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 -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. The most common failure method was the single grip disc between the timing sprocket and the hub would slip first. Going with a one-piece hub/timing sprocket locked to the crank eliminates that failure point. The second most common failure method is 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 to 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 (until Monday 10/22/18).
We offer the hubs in 3 configs:
- 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 SHIP
Here are a few photos of the testing process (please note these are early samples, the tooth 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 probably triple that is ruined heads dealing with these issues.