What is the best crank hub solution?

[NoMoreAudi]

No I don't consider your post an attack. I never saw the F8x platform as fast as it just isn't built for it. 2WD just can't compete with AWD. There are fast vettes and vipers in the 1/2 mile but we all know that AWD is king.

4 seconds is amazing on a 2WD for 60 to 130. 5 years to me is still pretty young but that's open to interpretation. How many places can an S55 owner go to for head work or to get a billet crank?

[FriedPiston]

Originally Posted by NoMoreAudi

No I don't consider your post an attack. I never saw the F8x platform as fast as it just isn't built for it. 2WD just can't compete with AWD. There are fast vettes and vipers in the 1/2 mile but we all know that AWD is king.

4 seconds is amazing on a 2WD for 60 to 130. 5 years to me is still pretty young but that's open to interpretation. How many places can an S55 owner go to for head work or to get a billet crank?

I always find it interesting how people believe that AWD is faster than RWD, when the fastest cars in the world are RWD including 2WD converted R35 GTRs...

There's HeadGames for valvetrain work, and CarBahn for local engine build. VHP (VTT) in Hayward and even BMW San Rafael are more than capable of doing an engine build also. The factory crankshaft is made out of forged magnesium-alloy material, so there's no need to go the custom billet-aluminum route unless you're looking to go full race, and completely change the engine characteristic.

Correction on the most notable stock S55 longblock power output. Kratos actually managed to squeeze 812whp with their setup on full E85: https://f80.bimmerpost.com/forums/sh....php?t=1557398

Again, a lot has changed since 2017. I highly recommend doing a little bit more research on the S55 platform since it appears you have not been following it closely.

[9SECDD]

Originally Posted by Sales@KRATOS

We took the car to the 1/2 mile event in Ocala s few months ago. Unfortunately, we only got 2 passes in due to a factory injector failure which is not all that uncommon when running E85 the majority of the time. Being that the airstrip was pretty sketchy and that fact that we wanted to get a feel for the track, we had the boost turned down to about 900whp. That being said, we still ran 181mph on the first pass and 183mph on the 2nd pass when cylinder 1 injector failed in 5th gear causing a major misfire where we had to back off. At the end of the day we still took home 1st Place for the Fastest 4 Door and also 1st place for the Fastest Overall Exotic/Import with only 2 runs. All in all, we expect the car to easily break into the 190's at the next event. You can see footage of these 2 runs on our Instagram account ASR.KRATOS. You'll see, car was a handful and spun like crazy until 4th gear even with boost by gear and 18" R888R's. We'll be better prepared next time out.

Heh. Cool. I was there with my black AIM Performance/ESMotor 991 Porsche and finally joined the 200mph club. Sorry I didn't get to meet you guys, there. Your turbos are impressive and 180s are still very fast, especially with problems. I'm sure I'll be seeing you around.
-Dave

[kevin85]

how many hours are needed to replace the stock crank hub with aftermarket ones?

[tom @ eas]

Originally Posted by kevin85

how many hours are needed to replace the stock crank hub with aftermarket ones?

We have an overview of the VTT install here: https://f80.bimmerpost.com/forums/sh....php?t=1561598

[PhaedeDPGH]

Currently getting my crank hub fix installed. The guy doing the work for me sent me this.. Was pretty close to having a failure I would imagine as the washer is broken in half. My car has 20k on it.

[tom @ eas]

VTT SplineLock Crank Hub/CBC holding up on this 800whp beast:

[Mikez306]

Originally Posted by Chris@VargasTurboTech

All you really need to do is look at the method used to secure the hub, then read up on what experts, not us say about these methods. We use splines, others use keys. I won't say anything else that is of our own opinion, just some links, and 3rd party quotes from people who have most likely never heard of VTT or driven an F8X.

Link 1: https://gearsolutions.com/features/inside-splines/
Quote: "The benefits of using a splined shaft in the place of a keyed shaft are many. The spline connection provides an equally distributed load along the sides of the teeth. This shared load provides a longer fatigue life verses a keyway drive. Different types of spline tooth forms allow for stronger drives, the ability to slide, transfer of rotational concentricity, allowance for misalignment and, in the case of helical spline drives, the transfer of axial and rotary motion at the same time."

Link 2: https://www.eng-tips.com/viewthread.cfm?qid=159057
Quote: "GregLocock (Automotive)4 Jul 06 20:39
A key should not be designed to transmit torque, in general. They should be used for alignment. They can be used as mechanical fuses, but are rarely satisfactory when used like that.

Roughly speaking the torque capacity of a spline will be n times that of the same sized key, where n is the number of teeth. In practice since splines are often rolled, their torque capacity is even higher than that.
Cheers
Greg Locock"

Chris

I know this is an old thread, but having had my M4 for less than a year, this S55 crank hub issue is new to me. Thank you Chris for posting those links, I was really torn between all the options out there, until you brought up the spline vs keyed factor. That really got me thinking. The issue with crank hub failure as I understand it, is one of two....either the loosening of the crank hub bolt due to harmonic vibration of the crank....or the crank hub being spun based on being over torqued by the engine a sudden increase in RPM. Well the VTT kit I think is a clear winner here.....nothing against the others, in fact i'm positive they work as well.....but if the enemy here is torque, where do you find the most torque in any vehicle? The axels and differential obviously....is it coincidence that these components also use splines to manage torque? I don't think so, its just proper engineering. Think of a drag car, launching on slicks at 5000-6000RPM in order to manage that load axel shaft diameter is larger and more splines are added... I've yet to see a keyed axel anywhere......again just my two cents on a complicated matter, but I'm going with the VTT solution.

[TopJimmy]

Originally Posted by Mikez306

I know this is an old thread, but having had my M4 for less than a year, this S55 crank hub issue is new to me. Thank you Chris for posting those links, I was really torn between all the options out there, until you brought up the spline vs keyed factor. That really got me thinking. The issue with crank hub failure as I understand it, is one of two....either the loosening of the crank hub bolt due to harmonic vibration of the crank....or the crank hub being spun based on being over torqued by the engine a sudden increase in RPM. Well the VTT kit I think is a clear winner here.....nothing against the others, in fact i'm positive they work as well.....but if the enemy here is torque, where do you find the most torque in any vehicle? The axels and differential obviously....is it coincidence that these components also use splines to manage torque? I don't think so, its just proper engineering. Think of a drag car, launching on slicks at 5000-6000RPM in order to manage that load axel shaft diameter is larger and more splines are added... I've yet to see a keyed axel anywhere......again just my two cents on a complicated matter, but I'm going with the VTT solution.

The woodruff key solutions are long gone. Chris has the spline-lock on VTT and the other guys (now) use 4 steel pins to lock into the crank. Both solutions are great, but make sure you put the CBC on top.

[Msm1984]

Insane performance hub for 12k miles here on full e85. No issues. That being said, there is not one single post I can find nor any vendor has shown me where the hub still spun with just the 100$ CBC installed ( outside of massive money shifts ).

All I have seen is vendors just say they have seen it happen before, but never seen someone actually post it nor have heard of it happening to anyone.


To be fair, In theory, it can absolutely still spin with only the cbc because the hub can spin at the friction plate without the ever bolt backing out, but I haven't ever seen this happen besides a big money shift

[tomlong]

What else can be done (preventive maintenance or performance upgrade aside building the motor) if undergoing this procedure and knowing the s55 is going to be taken apart to this extent? Would want to fully leverage the 18-20 hours of labor since we're in there.

[Mikez306]

Originally Posted by tomlong

What else can be done (preventive maintenance or performance upgrade aside building the motor) if undergoing this procedure and knowing the s55 is going to be taken apart to this extent? Would want to fully leverage the 18-20 hours of labor since we're in there.

This time would be a perfect opportunity to get anything done really.....from charge pipes to turbos. Of course the maintenance stuff is a given. Oil pan gasket, valve cover gaskets, plugs/coils, maybe even new vanos solenoids depending on your mileage.......I'm positive I'm forgetting stuff.

[spdrcrgtr]

Okay, sorry to bring up an old post, but could someone answer a question for me regarding the Vargas option. I do think that splines seem to be able to handle more torque than 2 or 4 pins, but from the pictures on Vargas' website, the crank hub still looks like 2 pieces.

Basically, the main hub with one of the sprockets (which has the splines) and the other sprocket fits onto it. Since the 2nd sprocket is not keyed or somehow locked into the first sprocket, can the same thing happen as the OEM?

Yes, yes ... I know you guys have used it on 800+ WHP cars, but by theory, it could still happen ... whereas a keyed approach (in terms of connecting the two sprockets together - not the drilling) would lock the two sprockets in place and they wouldn't be able to disengage from one another.

Thanks in advance!

[Chris@VargasTurboTech]

Originally Posted by spdrcrgtr

Okay, sorry to bring up an old post, but could someone answer a question for me regarding the Vargas option. I do think that splines seem to be able to handle more torque than 2 or 4 pins, but from the pictures on Vargas' website, the crank hub still looks like 2 pieces.

Basically, the main hub with one of the sprockets (which has the splines) and the other sprocket fits onto it. Since the 2nd sprocket is not keyed or somehow locked into the first sprocket, can the same thing happen as the OEM?

Yes, yes ... I know you guys have used it on 800+ WHP cars, but by theory, it could still happen ... whereas a keyed approach (in terms of connecting the two sprockets together - not the drilling) would lock the two sprockets in place and they wouldn't be able to disengage from one another.

Thanks in advance!

Your understanding is a little off. Best to review some of the earlier posts and threads, this has been covered in pretty good detail quite a few times, check out these two for probably the quickest way to come up to speed.

https://f80.bimmerpost.com/forums/sh....php?t=1621073

https://f80.bimmerpost.com/forums/sh....php?t=1561598

[spdrcrgtr]

Originally Posted by Chris@VargasTurboTech

Your understanding is a little off. Best to review some of the earlier posts and threads, this has been covered in pretty good detail quite a few times, check out these two for probably the quickest way to come up to speed.

https://f80.bimmerpost.com/forums/sh....php?t=1621073

https://f80.bimmerpost.com/forums/sh....php?t=1561598

I read through that thread, but unfortunately, my question wasn't answered (or I may have missed it). I see that this unit also requires the CBC; is that the "trick" that creates enough pressure to avoid slipping of the two sprockets?

Thank you.

[TopJimmy]

The combination of splined/pinned hub fix, plus the CBC on top is considered "the bulletproof solution".

Some members here maintain that "just the CBC is enough", and that is true if you happen to KNOW that your hub bolt never moved. The only real way to know the bolt never moved is to install a new hub bolt, which requires locking the engine. You might as well do the hub while you're in there. Some don't and ride the risk…

[Chris@VargasTurboTech]

Originally Posted by spdrcrgtr

I read through that thread, but unfortunately, my question wasn't answered (or I may have missed it). I see that this unit also requires the CBC; is that the "trick" that creates enough pressure to avoid slipping of the two sprockets?

Thank you.

CBC is part of the complete solution. There are 2 methods of SCH; crank bolt vibrating loose and losing clamping force (CBC addresses) and outright overpowering of the friction disc design (spline lock addresses by locking assy to crank). CBC reduces the risk, both together retire the risk.

If you prefer a different hub solution, and in our opinion none of the other ones are as good, the CBC still makes sense to use as part of the complete solution.

[Tdog86]

Originally Posted by spdrcrgtr

I read through that thread, but unfortunately, my question wasn't answered (or I may have missed it). I see that this unit also requires the CBC; is that the "trick" that creates enough pressure to avoid slipping of the two sprockets?

Thank you.

It looks like the Vargus would be a two piece crank hub compared to oem 3 piece design. The timing sprocket you see on vargus hub can't spin as it is a one piece design for the hub, I think you use the oem oil pump sprocket to make it two pieces. The splines bite into the crank from the Vargas crank hub and than it uses a factory friction disk with the oil pump sprocket, correct me if I'm wrong. Now on the OEM crank hub the timing sprocket it's separate from the hub as well as the oil pump sprocket that makes it 3 pieces with friction disks in between. I hope that helps spdrcrgtr .

[spdrcrgtr]

Thanks for the input ... this is what I thought, but wasn't sure if I was missing something.

I wish the Vargas version was one-piece (or keyed) plus the spline lock. IMO that would make it even more amazing - it would probably be the best one on the market if that was the case.

[Tdog86]

The gintani crank hub is one piece

[spdrcrgtr]

Originally Posted by Tdog86

The gintani crank hub is one piece

Yes, but no spline lock, and it only keyed with 1 notch vs others that have 4 pins assuming you're going the pin route.

[APR-M4!]

For the drilled crank solutions, are they drilling into area beyond (outside) the last main bearing? It seems like if they drill into an area with last main bearing the end of the crank could fail in some way.

With the splinted versions, do they insert into a factory hole in the end of the crankshaft?