[Mr. 5]

Originally Posted by dzenno

Do you know the details around torsional analysis or can you point at a link with more info on the subject? Can this even be done by NST? How scientificly involving is it and wouldn't this only be a subject n54 design engineers would be able to address?

I'll try to get more info for you but I'm pretty sure it can be done by measuring the frequency with the OEM pulley and then with the aftermarket pulley and comparing results.

[dzenno]

see last edit..NST mentioned 10K rpm as the 2nd harmonic spot...That number is calculated not tested against I'm assuming since you can't rev our engines past 7k

[Ryan@Motorwerks]

Originally Posted by dzenno

I talked to the president at NST today and first and foremost, two thumbs up for a very helpful individual who goes the extra mile when it comes to communicating to his customers and answering questions, of which I had naturally many...

Back on topic, in terms of NST pulley vs OEM, he's told me, and he's also written on N54Tech, that the OEM pulley doesn't have a "rubber" damper inside as they DID cut through it AND he also said that the OEM pulley DOES have liquid inside.

Here is a link to the n54tech post so I don't copy/paste (see their post below mine that references e90post):

http://www.n54tech.com/forums/showth...d=1#post100250

He's also mentioned that they have a decade of experience in PULLEY DESIGN and that EACH AND EVERY CAR THEY TUNED had a rubber element to the pulley that was removed and replaced with a 100% aluminum pulley and there have never been any reports of engine damage due to usage of their pulley, EVER!

Now, I know that this isn't relevant to N54, at least not YET as we didn't have enough members on this or the other forum running this pulley for a considerable amount of time and racing with them installed BUT for whatever its worth it does serve as a testament to their quality and R&D.

The ONLY case engine damage COULD happen (and note this is a remote possibility) is in really high HP applications where engines are pushed way above their stock limits, exposed to MUCH higher RPMs (over 10,000 RPM) for longer periods of time, which in our case is NEVER! Even in those situations, NST pulleys were NEVER reported to have been the cause of any engine damage, if anything all engines where NST was run responded favourably (you can treat this as an NST "statement" but feel free to go through the links they provided).

Personally, I just don't have it in me "AT THIS TIME" to put this pulley on MY car and be one of the early N54-NST crankshaft pulley real world guinea pigs. I really do believe that NST isn't here to screw with our cars and they state this openly as well, or that they're here to throw out a product with a $200 price tag that could potentially ruin their decade long solid reputation.

NST, being a company that strongly believes in its products' quality have also provided me with an option to FULLY REFUND my NST pulley purchase which I will do this time around.

I am not by any means discounting this very pulley as a mod down the road given proven track/daily driver use...

I'll try to go through the links they provided and read about other engines their pulleys are installed on to educate myself better on the topic before going back to purchasing it as I'd like to understand how this would be a bad mod on N54 given all other engines having similar pulleys/vibration damper setups...

Glad you got this straightened out. Here is the general concept behind the fluid dampened pulley: http://www.freepatentsonline.com/5749269.html .

I agree with Mr. 5 though, determining at what RPMs harmonics occur will be the only surefire way to determine if going undampened is completely safe. On the other hand, there is a very good chance its perfectly safe, but personally I'm not going to take such a risk.

If you read the patent PDF, its VERY clear that the OEM BMW piece does much more than reduce "noise/vibration/harshness" as NST has suggested. That doesn't necessarily mean this dampening is needed.

[johnny_boy]

Originally Posted by dzenno

EDIT to my original post:

If you read NST's post on n54tech you'll notice they indicate that the dangerous 2nd harmonic occurs at around 10,000 rpm on our engines:

"The engineering reasons are that most modern engines have a short, strong crank with, a relatively high natural frequency. The dangerous second harmonic that can cause damage occurs at an rpm that this sort of engine will never see, in the area near 10,000 rpm. Even the stock damper is not tuned for attenuation at this sort of rpm so the argument is somewhat of a moot point."

Did you read their post?

Torsional analysis would be a good read, post when you can..

He actually does NOT say N54s do not create 2nd harmonics until 10,000 RPM. He says most modern engines do, and he is assuming that N54 falls under that category.

I am not sure why people are saying since it does not have rubber, it is not a damper (OBTW, it has liquid in it...). The liquid is Silicone gel most likely and it serves similar purpose as the rubber, but better/different.

This is a good article on damper design and applications by a damper design engineer.
http://racingarticles.com/files/gene...-article-2.pdf

[hun77777]

if NST is so sure on that fact that the engine failure will never occur due to replacing their pulley, then put it in writing in form of warranty and that'll end this issue. since they NEVER had any problem on ANY CARS at all and they are so sure about it on N54, that shouldn't be much of problem, right?

something like

" LIFETIME TRANSFERABLE WARRANTY" that does gurantee no engine failure due to NST pulleys if properly installed and rpm doesn't go over 10k. It is transferable to vehicle owner regardless of mileage driven. If engine damage occur due to the NST pulleys, NST shall stand behind it 100%. <-- something along that line

then we're talking... they shouldn't worry about it at all since their anticipation of this engine failure is slim to none anyways...
just a thought...

[Mr. 5]

Originally Posted by hun77777

if NST is so sure on that fact that the engine failure will never occur due to replacing their pulley, then put it in writing in form of warranty and that'll end this issue. since they NEVER had any problem on ANY CARS at all and they are so sure about it on N54, that shouldn't be much of problem, right?

something like

" LIFETIME TRANSFERABLE WARRANTY" that does gurantee no engine failure due to NST pulleys if properly installed and rpm doesn't go over 10k. It is transferable to vehicle owner regardless of mileage driven. If engine damage occur due to the NST pulleys, NST shall stand behind it 100%. <-- something along that line

then we're talking... they shouldn't worry about it at all since their anticipation of this engine failure is slim to none anyways...
just a thought...

That's not good enough for me because all they have to do is go out of business/file bankruptcy and you're SOL.

[hun77777]

Originally Posted by Mr. 5

That's not good enough for me because all they have to do is go out of business/file bankruptcy and you're SOL.

lol...

it was just a food for thought but i'm in construction business and see what you mention above happens all the time sadly... gurantee/warantee is only good while company is around... sad but that's so true...

[ianthegreat]

Originally Posted by Mr. 5

That's not good enough for me because all they have to do is go out of business/file bankruptcy and you're SOL.

NST is a decently sized company.

http://www.nonstoptuning.com/pageProjectsEvents.htm

I understand your point though.

[M_M]

wow... you guys are taking it really serious. to resolve the conflict, why dont you guys pay me something and I'll cut my oem pulley in a half to show you whats inside? lol

btw, I think terry@bms has started carrying this pulley, someone from LA area may just buy from him.

[hun77777]

NST mentioned they cut through the OEM vibration damper themselves and found nothing when it is (oddly i should add) exactly what the guy from motorwerks stated. after motorwerks guy stating it filled with liquid nst replied the same. no picture, no data on their "extensive r & d", so i'm just bit lost. if they have done as they said they did, why not share for their benefit... as they mentioned, it might very well be ok, but i'm sure noone wanna be "THAT GUY" one day over 10whp gain...

[j-andrada]

Originally Posted by Mr. 5

Did you see the link that I posted?
Look in the picture of the damper.Do you see the piece of rubber on the damper?
I'll copy and paste.

I think that below is enough proof.
Look what BMW calls the pulley. It is not a pulley. It is a "vibration damper"

I talked to multiple engineers about this issue and there is a big difference between balanced and dampened.
We DO have a damper. It is supposed to absorb torsional vibrations instead of the crankshaft absorbing them.
Picture a paper clip being bent back and forth over and over again. Eventually it's going to snap.
If there is nothing to absorb the extra vibrations, the crankshaft could end up being the paper clip.

Here's another thing that I'd like to add. I have no doubt that NST makes a good product but the issue that I have is that we are replacing a product with a completely different product.

any Body knows what is the tightening torque for crankshaft pullet
it has 6 bolts
thanks in advance!

[kimoboy]

I know its very old post. I wonder if there is any update on the NST pulley.