N54 crank hub issue - power level?

[Rob@RBTurbo]

It is pretty clear one solution is actually a true, positive lock, setup. Once done, it is done forever, it will never steer you astray, and is clearly serviceable whenever/wherever needed. The other is a solution that is more so a "vice grip" sort of concept and appears to be a bit gimmicky.

The new splined solution although elegantly thought out and a nice overall part, has been marketed to "just dig deeper" if a spin event where to ever happen. This just is not true, obviously, as our fairly constructive post was moved to the octagon and we were banned from posting in the thread for making these comments... par for the course when there is no real rebuttal.

The meat and potatoes of this comes down to really one thing- how much are the splines digging into to the crank and thus what kind of trace mark are they leaving and is it really enough to be considered a positive lock under all scenarios. One must consider to install the splined hub they are literally pressing it on via threading in the hub bolt, if a dedicated install tool is not eventually provided (ie. using a separate long stud, and a thread on nut/washer); which will limit you on the pressing force that even can be achieved in the first place. The question then lies of what kind of negative clearance is utilized using such a process? This is important as this negative clearance is what actually will allow some groove etching to take place, and is likely sub .003" as it would take a LOT of pressing force to etch these parts as the clearance lessens. Too much pressing force, especially without a pressing tool, the inner crank threads could even be at stake. One must also consider that there will likely be some deviation to the timing relationship as the hub is pressed into position due to the non-straight cut splines, and also consider that the groove may not leave a perfect line for future servicing if needed. Honestly I'd suspect straight cut splines would've been just as effective, hold better position for timing relationships during install, provide a more usable path trace for future servicing, and allow just as much groove etching to attempt to hold the components as one.

Ultimately things like this take many samples, many variables, and much time to see how they are going to pan out. A single vendor using the splined solution successfully for 8+ months could be just as good as another vendor using the OEM setup successfully for 8+ months; or in other words be worth no more than the paper the idea is printed on. As always items like this are best tossed out to a group of guys who truly are pushing the envelope, immediately, and all of the time. Give this group of guys a year+ with it, and if they all have positive feedback along with extreme performance results to back it then that would be some compelling evidence. Until then if you want something that is truly a positive lock and a no-nonsense anti-slip sort of product; the Maximum PSI is going to be the way to go. Sometimes you get what you pay for (whether time or money or both) out there, other times you are simply beta testing.

Rob

Received a call the other day on these splines size as compared to the crank recess ID and apparently they are about .009" larger on the diameter, which of course means about .0045" larger on the radius. So it looks like my "likely sub .003"- educated guess" was a smidgin bit off. So now the question lies in how much does this .0045" plus sized spline "etch" into the inner crank hub- as whatever this equates to is all the additional "leverage" that is had post install. FWIW a dollar bill is about .004"- so it is not going to be much "positive grip" regardless.

 

[Panzerfaust]

I don't quite understand what people are missing here. It's a simple enough solution to help prevent failures when combined with the hub capture. I dont think anyone is arguing that this is the same exact thing as or superior to a keyed hub - it's a different option that will hopefully help achieve the same results. Even if it isn't as "bullet proof in theory" as the Max PSI keyed hub or an OE keyed hub, guess what? It doesnt need to be. It needs to be able to stop the hub from spinning so your timing stays correct. Nothing more, nothing less.

The splines are on the outside of the hub, they press in to the crank from the inside (not two tiny jaws holding on to the outside) in a large amount of places, the splines are a harder material than the crank itself and the splines are angled in the opposite direction than the hub spins... those three last things are a big part of how and why it works. As has been pointed out several times even by Chris himself, "digging in further" isn't the best phrasing but it gives a close enough idea for people who wouldn't understand that an equal amount of force from a stronger material would be pressing back against the crank in a slip event, hence the "lock" part.

Theres nothing "vice grip" about it - this isn't a universal shaped jaw with adjustable clamping pressure that presses on to the outside of something and requires hoping that the thing inside of the jaws doesnt slip if the pressure on that object is greater than the pressure from the jaws. Rob is a smart guy so I'm sure he knows that too, but he has to maintain his anti-VTT and anti-competition viewpoint at all costs for some reason. That analogy is pretty ignorant at best and straight up dumbfounding if you know how tools work. It'd be like saying Rob's external PCV system probably doesnt help stop carbon buildup because cars from the 70s with a VTA dump tube for blow by still can have incomplete combustion - you're looking at two entirely different things even if both involve combustion gases and a hose - although that's still more relative to one another than comparing a splined hub to vice grips.

 

[Rob09msport]

It's a timing chain. The valves would end up out of sync if a clutch was used. The sprocket is doing the slipping (like a clutch) and that's the issue right.
The chain can't move the sprocket and the valves quick enough under certain circumstances.

I thought it had to do with load from the belt as well I guess I was mistaken on the cause.

 

[Chris@VargasTurboTech]

Stock hub size which is a slip fit into crank is 26mm or 1.02"
Our hub splines are 0.20mm or 0.007"

For a 24mm shaft, an H7/U6 fit which is categorized as " Force fit suitable for parts which can be highly stressed or for shrink fits Interference, where the heavy pressing forces required, are impractical"

For that spec of "force fit" MIN is 0.020mm, and MAX is 0.054mm. We have 0.20mm of interference, which is 10 times greater than the MIN force fit and almost 4 times as great as its MAX force fit. This means we are not only 4 times beyond a force fit, since the crank is softer than the hub we are also creating splines 0.20mm deep into the crank to help hold the hub in place. So instead of simply relying on some "grip discs" and bolt stretch, we have splines embedded in the crank 4 times as deep as what spec calls for on a MAX force fit.

Not understanding these specs does not make them less valid.

Honestly it's a reasonably priced, not-too-bad-to-install (compared to competing products) that works extremely well. I have to give a nod to Tony on this one, it's a cool innovation, born out of being tired of spinning crank hubs on expensive motors.

 

[gmagnus7]

I like the idea, and it seems easier than the Max PSi version, but I would also like to know how far it's etched into the crank. A picture would be great.

 

[GreyNBlueE92]

Can you resuse the hub if you ever remove it or had to rebuild the engine for some reason? What does the crank look like when this comes off? Can it be reused as well?

 

[Rob@RBTurbo]

Stock hub size which is a slip fit into crank is 26mm or 1.02"
Our hub splines are 0.20mm or 0.007"

All good information but for the sake of clarity are your hub splines are +.007" on the diameter or on the radius? The phone call we'd received said +.009" on the diameter which is .0045" on the radius. But if it is really +.007" on the radius that would be +.014" on the diameter, and while this seems to be the way it has been presented I am not sure if that is the case or not?

What sounds most likely is that it is +.007" on the diameter meaning it is +.0035" on the radius, as the other way around seems like a TON of pressing force would be required which is a lot to expect from a "bolt-on pressing process".

Thanks,
Rob

 

[Panzerfaust]

Stock hub size which is a slip fit into crank is 26mm or 1.02"
Our hub splines are 0.20mm or 0.007"

For a 24mm shaft, an H7/U6 fit which is categorized as " Force fit suitable for parts which can be highly stressed or for shrink fits Interference, where the heavy pressing forces required, are impractical"

For that spec of "force fit" MIN is 0.020mm, and MAX is 0.054mm. We have 0.20mm of interference, which is 10 times greater than the MIN force fit and almost 4 times as great as its MAX force fit. This means we are not only 4 times beyond a force fit, since the crank is softer than the hub we are also creating splines 0.20mm deep into the crank to help hold the hub in place. So instead of simply relying on some "grip discs" and bolt stretch, we have splines embedded in the crank 4 times as deep as what spec calls for on a MAX force fit.

Not understanding these specs does not make them less valid.

Honestly it's a reasonably priced, not-too-bad-to-install (compared to competing products) that works extremely well. I have to give a nod to Tony on this one, it's a cool innovation, born out of being tired of spinning crank hubs on expensive motors.




View attachment 20748View attachment 20749View attachment 20750

Thanks for the solid data Chris, as always its appreciated that you guys actually offer that kind of thing on your products. Unfortunately I think your blind detractors are going to ignore any positive information you offer up though.

As a side note I'm not too sure why Rob has it in his head that the spline is installed with a limp wristed twist while only the pulley is off, I recall my directions explicitly stating timing tools are needed to lock things in place as well as the proper tools to install the hub itself along with torque and stretch specs for everything involved in the full kit (iirc in a former post he said he "at least wished timing tools were requires to install so you could be sure it'd hold"). He has me on ignore so I wont be able to correct him, but hopefully someone can point out to him that theres a legitimate, specific install process.

 

[Chris@VargasTurboTech]

Rob, I'm not sure how to explain it all to you better but do appreciate the opportunity for entertainment.

Anyway, several have asked what the created splines look like once the #SPLOCK is removed, if you wanted to remove it for some reason. See below.

 

[Panzerfaust]

Oh no! Teeth marks?! Surely that must mean the crank itself is more likely to break, as the stock crank has no teeth marks for a reason, we would think. We appreciate your photography skills, but we must get back to the masheding of potatoes and our precious...err, exclusively shipping truckfull amounts of turbos, and definitely not slinging mud on the internet when a competitor has a new product.

 

[Rob@RBTurbo]

Chris,

Not sure what is entertaining about asking for clarification about interference fit specs when you do not specifically indicate whether a "+" size is on the radius or the diameter, especially when manipulation of information is typically a specialty of your team. Much like this picture which should've taken about 2 minutes to provide yet instead for whatever reasons it took 2 months, keeping in mind it was asked from numerous forum members. Back to the aforementioned manipulation of information, if this is the reality of the "etch" then I'd say I'm quite impressed as that IS quite the dig from the splines. Now looking forward to see if this is repeatable from others who have installed/removed the hub.

Thanks,
Rob

Rob, I'm not sure how to explain it all to you better but do appreciate the opportunity for entertainment.

Anyway, several have asked what the created splines look like once the #SPLOCK is removed, if you wanted to remove it for some reason. See below.View attachment 20851

 

[Hydra Performance]

Here you go Gents:
Interference fit is 0.25mm = ~0.010" on the diameter
More interesting crank hub pics coming shortly

 

[Rob@RBTurbo]

Here you go Gents:
Interference fit is 0.25mm = ~0.010" on the diameter
More interesting crank hub pics coming shortly

View attachment 20854View attachment 20855
View attachment 20856

Thanks for the clarification. Fortunately some customers are able to provide such simple things that the vendor for whatever reason wants to dance around.

This perfectly backs up the other call we had which reported ~.009" on the diameter (ie. ~.009" and ~.010" are pretty damn close).

So obviously this means it would be ~.005" on the radius... which brings me back to the picture there is NO way that DIG from the picture is from a ~.005" etch IMO.

Looking forward to another etched pic from an actual customer, as there could be some more of the typical foul play going on here it seems.

Rob

 

[gmagnus7]

Here you go Gents:
Interference fit is 0.25mm = ~0.010" on the diameter
More interesting crank hub pics coming shortly

Yes please do. I'm really hoping this idea will work but 0.12mm depth doesn't seem like much. However, I'm still giving the benefit of the doubt because I'm not an engineer or a specialist. Maybe it'll be just enough to stop the metal from slipping?

 

[Rob09msport]

Yes please do. I'm really hoping this idea will work but 0.12mm depth doesn't seem like much. However, I'm still giving the benefit of the doubt because I'm not an engineer or a specialist. Maybe it'll be just enough to stop the metal from slipping?

When you factor how many splines their are it has to make a difference. Remember this isn't the only thing holding it is in addition to the factory setup.

 

[MoreBoost]

When you factor how many splines their are it has to make a difference. Remember this isn't the only thing holding it is in addition to the factory setup.

Willpower doesn't count Rob

 

[Panzerfaust]

When you factor how many splines their are it has to make a difference. Remember this isn't the only thing holding it is in addition to the factory setup.

The amount of splines, depth, material strength, and comparison to the stock fit (literally no grip onto the crank from the hub itself. It slides right in) is what makes a difference here. Rob is a smart guy, but I think this is a classic case of being blind to his own biases due to it being a competitor. I think he understands what the spline lock is doing and how it works just fine, but it's a VTT product - he has to cast doubt even if it goes against logic and he has to do his signature backpedaling.

It doesnt take an engineering degree to understand how this would help prevent the hub from slipping. Factor in that slipped hubs still aren't even a guarantee at high power levels (Motiv has the stock hub on Jake's car still), which means the stock setup *usually* does pretty decent, and all those other things add up to an obvious conclusion. Like has been said a hundred times - if you want a keyed hub you have that option, but for the cost, work required, and (lack of) risk involved in this product it's pretty damn sweet what Tony came up with.

 

[ShocknAwe]

The only problem I have is given how infrequently and without any sort of pattern or cause the hub slips, there is absolutely no way these products can be tested to make a claim of reduced slip. Aside from keying the hub of course. If the claim is made that it has been thoroughly tested and works, then the vendor knows under what conditions the stock setup fails, but aren't sharing that essential information. I'm assuming that isn't the case here.

I'd like to believe, but at this point that's all it is, an exchange of money on the premise of wishful thinking.

 

[Rob@RBTurbo]

Having finally the picture in hand I was able to reach out to our lead machinist (25 year experience) this morning to discuss. He has stated that as a guesstimate he could see this etch being created by a +.005-.010" (radius) interference. As such it does make sense that the picture is an actual resultant that should be repeatable- which is a good thing which hopefully time confirms.

As I've stated prior the concept should certainly aide the "grip", and by actually observing these achieved patterns (and knowing the specs) it should be quite a bit of help. The only thing left is that the splines would likely have been better left as straight cuts, to aid during installation to keep the timing in proper degree orientation as it cuts in its path (with the understanding that the splines aren't going to "dig deeper" when challenged- regardless) and also likely during installations as well.

In short thanks for the picture, t'was a long wait and a hard time to get there- but the etch does in fact look good.

Rob

 

[Panzerfaust]

Having finally the picture in hand I was able to reach out to our lead machinist (25 year experience) this morning to discuss. He has stated that as a guesstimate he could see this etch being created by a +.005-.010" (radius) interference. As such it does make sense that the picture is an actual resultant that should be repeatable- which is a good thing which hopefully time confirms.

As I've stated prior the concept should certainly aide the "grip", and by actually observing these achieved patterns (and knowing the specs) it should be quite a bit of help. The only thing left is that the splines would likely have been better left as straight cuts, to aid during installation to keep the timing in proper degree orientation as it cuts in its path (with the understanding that the splines aren't going to "dig deeper" when challenged- regardless) and also likely during installations as well.

In short thanks for the picture, t'was a long wait and a hard time to get there- but the etch does in fact look good.

Rob

And finally he sees the light! Not trying to be condescending at app, but I'm actually kind of proud that RB is able to give props where they're due - aside from the minor complaints, but I'll take it.

Personally I think the angled splines are superior in design to what straight splines would do considering we're dealing with something (the crank) spinning in the opposite direction of how the splines are angled, but that's just simple logic and conjecture. Considering VTT went through multiple variations in design before the public release I wouldn't be surprised if they had tested both, but that's something @Chris@VargasTurboTech could answer for you.