PoWeRtRiP

its one thing to mispell in a post another to mispell something in a email to a company official that is supposed to represent our interests, im just saying lets try and make sure he understands that we are intelligent people who want professional answers.

Sly_Z

iTrader: (18)

I understood you the first time I was just adding some humor.

jpc350z

[QUOTE]Originally posted by SoCalTed
FYI...

These are questions raised over in the G35Driver forum that I am sending in to UR for response. please let me know if you have any questions for them too!




As I told the folks on G35driver...... Shawn is the President of UR. In his email response to me, he asked that I pull all questions and comments together and send them to him and another exec he has put me in contact with.

I don't want to be in the gatekeeper position, but I also want to keep the goodwill open between me and him. As you can understand, this has flowed over to the my350z forum, and if I release all the contact info, he will be inundated with the same questions over and over again.

I promise to be honest and post all his replies as I receive them (minus any personal info ... like my home # or his direct line etc..) I hope this will suffice for everyone. BTW, I do not have the pullies on myself, they are a part of my plan and I am close to having them installed. It is not a question of if, but when for me. I will probably install them when I get my SAMCOs and tranny cooler. I am not receiving any discounts from Shawn, nor am I connected in any way with his company. I am not being sponsored by them either!



Cheers, ted
Click here for MODS

P.S. i know I've only got 2 posts on my350z, but you all have sick rides and I can;t help lurking. I've got nearly 1200 posts on G35driver, most of which make some sense. [/Q

I would be interested in how they know the pulleys are "perfectly balanced". Dynamic balance test's (not static) on every one they manufacture.(Tolerances) Unbalance will introduce unsymmetric loads on bearings which in time contribute to bearing failure.. Also what about the roundness of the pulley? do they measure all manufactured pulleys and what are the acceptable tolerances?.. Thanks

SoCalTed

Uhh.. who you gonna trust, Bill Gates' contractors or Webster's dictionary?

Main Entry: en·quire , en·qui·ry
Pronunciation: 'in-"kwIr-E, in-'; 'in-kw&-rE, 'i[ng]-

variant of INQUIRE, INQUIRY

Chears, Ted

mofoz

iTrader: (1)

just because its lighter, its still balanced. i will be putting one on my car.

Sly_Z

iTrader: (18)

It seem as though he returns with a good defense. So, powertripp who are you going to trust GAtes or WEbster.

PoWeRtRiP

2 entries found for variant.
To select an entry, click on it.
variant[1,adjective]variant[2,noun]

Main Entry: 1var·i·ant
Pronunciation: 'ver-E-&nt, 'var-
Function: adjective
1 obsolete : VARIABLE
2 : manifesting variety , deviation, or disagreement
3 : varying usually slightly from the standard form <variant readings>


just because its a variant does not mean its the right one to use in that context. colour is as correct as color but we usually use color since its societies accepted form.

sixfive

lol - maybe your and mine's society - but not everyone's. He's not looking for work there! jeez

Sly_Z

iTrader: (18)

LOL

neffster

iTrader: (2)

After quite a bit of researching, reading and speaking with people who have rebuilt and blueprinted engines for a living I’ve been able to gather some useful information, which I’ll be using to make my decision about the UR Underdrive Pulley. My thoughts on this whole debacle are listed below.

First, I have a pretty good understanding of Physics. As I’ve stated before I graduated from UCF with a BSME in 1998 and have been working as a Senior Research Engineer in the Precision Mechanical Design group at Lockheed Martin Missiles & Fire Control, Orlando for the last 6 years. Given my educational background and the fact that I work with an amazing group of people who are extremely knowledgeable about dynamics, engines, design, machining, assembly and testing, the information I’ve been able to gain is not prejudicial or irrelevant in the least bit. I’ve spoken with more than a few of my co-workers about this issue and will include some of their comments below. Enough about me, on to the Pulley issue…

My take on this issue is actually pretty simple. If the crank is internally balanced and the pulley is also symmetrically balanced about its rotational center, when the two of these items are assembled they will be “statically” balanced. When the crank pulley rotates on the crank without any belts attached, the system should be “dynamically balanced” as well. The accessory belts are not rigid bodies and cannot be easily modeled in a computer to get “good enough” dynamic or harmonic measurements.

After speaking with an engineer who works in our Dynamics Lab, I was lead to another gentlemen, Gary, who worked on the “BO LAW” drag racing team for a little over 5 years. After speaking with Gary, I learned a thing or two about engines, cranks and pulleys that I had not really thought of, nor had I come across in my search on the Pulley Debacle. This person has built and balanced many engines. He has built 3000+hp diesel dragsters in the late 60’s and early 70’s and rebuilds the engines on old Chevy Nova’s as a past time hobby. He also works as a lead test set-up engineer for dynamic analysis of extremely sensitive optical systems, missiles, bombs, etc... The following is a loosely worded description of his explanation of a standard pulley set-up according to Gary.

“If a pulley is balanced about its rotational center and it is applied to a crank that is internally balanced you’ll be fine in an ideal world as far as not hurting the bearings. If the pulley has a rubber ring on it be careful. The rubber ring is used to dampen out the harmonics of the belts. Belts are not rigid bodies and they are constantly changing length and tension. They get a very slight amount of slack in them at one point in a single rotation and then they get more taunt a split second later. This happens on a constant, random basis depending on the engine loads and other variables. These variances cause loads to change, which translate into harmonics, which are bad for the bearings. The job of the rubber ring is to dampen out these harmonics (or unwanted frequencies). This ring is actually absorbing the vibrations caused by the belts and is not allowing those vibrations to be seen by the crank or the bearings (this is a very good thing). If the lighter weight pulley were designed to have this rubber ring, it would have to have a larger rubber piece than the stock pulley does, since the aftermarket pulley itself is lighter. The stock pulley, being heavier, also helps to dampen out the harmonics from the belts, which help preserve bearing life.”

He also said, “today, most precision machined parts can be designed and manufactured so that an engine can be built without having to have a pulley on the crank to balance an engine. Most 4 and 6 cylinder cars are designed like this (something to do with a 120-degree orientation of the engine internals… I got lost here). Older 5 and 8 cylinder cars often times have pulleys that are asymmetrical, or have counter weights designed into them. This way they can take one stock pulley off of a car and add another stock pulley without having to rebalance the engine.”

“For the added benefit of 2% to maybe 3% performance gain, I personally (still Gary speaking) would stay away from any pulley system and look into a performance chip that adjusts the ECU. If you started having problems with your bearings, this would just be the first of many expensive repair bills as a result of the damage to the engine.”

I absorbed all of this and took some quick notes, as I didn’t want to forget anything that Gary said.

As some of you might understand, there is this other half of me that says there are plenty of other people with UR Pulleys on Nissan Maxima’s with the same VQ35DE who have many miles on their engines. They have allegedly reported no sign of bearing wear, engine damage or anything remotely negative, so why should I worry? Also, there are people who have installed the UR Underdrive Pulley and they are doing Black Stone Lab. Oil analyses and are not seeing elevated lead content in their oil, so their bearings must be fine, right?

The mod hungry side in me is trying to justify adding the pulley, but the logically minded side is saying, “listen to the Physics, they don’t lie”.

As recently as this afternoon I was ready to install this pulley, going back and forth between shipping back the box to Performance Nissan and going ahead with the install. The bottom line for me will be reason and logic. I will be sending this pulley and belts back to Performance Nissan and getting my money back (less shipping charges of course). The small performance increase is just way too low compared to the potentially staggering costs relating to damages with might occur, if I were to install this pulley. Couple this to the fact that my local Infiniti dealership is vocally not mod friendly, so I’d be 100% out on a limb should anything bad ever happen.

For anyone interested I have a brand new pulley bolt that I ordered from Orlando Infiniti that I’d be willing to ship to you if you pay the $5.75 and shipping costs.

Good luck to those of you who have the pulley or are still planning on doing the install. I wish you all well and many untroubled miles with your G’s or Z’s.

Thanks for reading. -Neffster

350zluvr

Wow Neffster, great post. Thanks for confirming all this information with a physics guru as well as strenghening my decision to pass on the pulley modification. Very much appreciated.

DrVolkl

I would suggest anyone who needs to convince themselves to get this pulley or not, should simply not get it. Since there is only theory behind possible failure, I would say the unit relatively safe with an amazing track record, especially compaired to most of the other mods out there...but still, people are worried.

Perhaps a rubber ring could be attached to the pulley and that would satisfy all the harmonic's that everyone is worried about. I don't recall a rubber ring on my stock pulley, but I'll take a look.

On a side note, since we're talking about internal harmonics...what type of harmonics are buzzing through your engine when you drive over railroad tracks, steel bridges, and your basic feathered 350Z tires? I would have to imagine that would do just as much damage, correct?

jesseenglish

Any vibrations caused by railroad track bridges etc, should be cancelled out by the rubber engine mounts. Even if there are vibrations on the crank it's a short term thing as opposed to the constant undampened vibration on a solid crank pulley.

jpc350z

Great write up and seems as you say logical.. However, in an effort to get some real 'Data' on the rubber damping effect on any harmonics that could develop and which would not be damped on a lighter pulley would appreciate it if you would ask the Dynamics guy if a twang test with accelerometers attached to a stock pulley (with belt)as well as a lighter pulley would provide some real data on the effects of the rubber on damping..Dont want to give up too easily on the 2-3% gain without some solid basis. Thanks

neffster

iTrader: (2)

First off, I'm not planning on installing the pulley so there is no comparison test that I personally will be doing.

Secondly, wouldn't accelerometers which are attached to the pulley cause an inbalance themselves. Wouldn't they create a vibrational mode even if they are equally opposed (they'd never be perfectly opposed right)? Also, attaching a wireless, tri-axial accelerometer would be tricky. Glue would be the only way to attach the accelerometers to the pulley. Ever try adding an EXACT amoung of glue to an EXACT spot? Odds are that the accelerometers themselves would cause as much or more damage than you'd be trying to measure. As you can see this is not an easy task.

For the 2-3% gain, it's not worth my time. I'll stick with my Crawford Plenum, RT Cats, intake and exhaust mods for the time being. Maybe I'll get the TS ECU or something equivalent in the near future, but for now MY pulley debacle is over. If you are not satisfied with the data I've provided, feel free to pick up where I left off. I only ask that you post back here so that others can learn from your hard work. TIA for volunteering ...

all_bark

iTrader: (5)

so how does performance nissan feel about pulleys?

what IF someone had a pulley and then developed engine problems, how would they handle it?

Jeff or Jason?????

ALong

iTrader: (12)

I hate to jump in to this snake pit but must add my 2 cents. I come from the BMW world and have a lot of experience with aftermarket mods in the E36 M3. Attached is a link to information written by Steve Dinan of Dinan BMW fame, explaining the dangers of lightweight crankshaft pulleys. For those of you dont know who Steve Dinan is, he is one of the most respected BMW tuners in the USA, also his company is the only aftermarket tuner, whose parts will not void the warranty on a BMW and the only BMW tuner whose parts are approved to be sold throught BMW dealers.

http://dinancars.com/whitepapersFile.asp?ID=5

I know BMWs and Nissans are not the same car, but the principals behind how a crankshaft pulley/dampner work are the same.

neffster

iTrader: (2)

Actually I think an Inline 6 and a V-6 are entirely different regarding this issue. Also, Steve Dinan has hacked the heck out of many Z-8's while charging tens of thousands of dollars. He's also proven to add no horsepower to the E46 M3's for about $10,000. I think this article, albeit interesting, is not applicable to the VQ. Sorry if this comes across as harsh, but I too am a big BMW fan, but am not a huge Dinan fan.

Your mileage may vary...

ALong

iTrader: (12)

Neffster, this is OT but have to disagree with you regarding Dinan. One of my customers owns the first Dinan Z8 and it is definately not "hacked". They did a very nice job on it and the car is VERY FAST. As far as the M3 goes, if you are baseing your statement that they are not getting any extra Hp out of the car, on the Car & Driver article then you are wrong, they even admitted in the article that the testing conditions were not the same. I have driven several customer M3's with the Dinan engine modifications and can assure you they are noticably faster than a stock engined car.

Comparing the straight six with the VQ V6, yes they are different motors but the pricipal of a cranshaft dampner is the same for all motors.

Personally I would not put a lightened cranshaft pulley on my racecar, IMHO, too much of a risk on an expensive motor for what, 3-5hp? Not enough HP to even feel a difference on a 3000+lb car.

I guess we will see in the next year or two if there is a number of failures due to this or not.

neffster

iTrader: (2)

Along,

Check out this link DINAN hack job

THIS IS A MUST READ!!! All looks good until "dclare" posts the 11th post (start from the beginning and then keep reading)... This should blow your mind about Dinan and the Z8 hack job. This is my last post regarding Dinan (you can PM me if you’d like to continue this conversation off line)…

… now back to the pulley conversation...