3point5SE_Auto,

We'll need to "agree to disagree" on the long term effects of running without a harmonic damper. Steve Dinan's explanation of how harmonic dampers work is quite excellent. His explanation applies to all engines with external harmonic dampers.

I respectively disagree with your statement "The pulley does not have any rubber nothing on it." The crankshaft pully on the G35 & 350Z VQ35 Engine incorporates a harmonic damper into the design. Please look at the picture closely. You should be able to see the "bonded rubber" ring.

Finally, I would install UR's Underdrive Pulleys on my G in a New York Minute... if the crank pulley could be bolted to the harmonic damper.

DaveO





91951-UD Pulleys - 6 Stock Harmonic Dampener.jpg

 

Slightly 'off topic', but I've always wondered, why are 'New York Minutes' considered so darned short?[img]/w3timages/icons/smile.gif[/img]

<font color=green>GG</font color=green>

 

ever been to NY?

Luv My G

 

I will have to agree to agree with you if that is the G's crank pulley in that picture. IT IS different than the altima one. My shop manual shows a slightly different looking pulley and the one in there looks just like this altima one sitting on my desk. I will look at my G to make sure later.

Sean

Better Life thru Chemistry

 

I had pulleys on my Mustang GT. I put them on even though I had heard that if you don't properly torque down the crank pulley it can wobble at high RPMs and literally tear up the engine from the inside out, as described in the article linked above (I heard of several people that ruined engines this way on mustang forums.) Long story short, mine wasn't cranked down properly at first either and I got it a check engine light. I was scared shjitless b/c I thought I might have really messed up the engine, but I got it torqued down properly and don't think I did any perm damage. I really liked it (enginer revved faster and had noticeably more power), but I was nervous about it until I sold the car a year later and I won't try that particular mod again. Look into something safer, that's what I'm doing.

 

This is a response from the President of UR racing.

Tom,
Please read our FAQ section for the facts on how our pulleys work.
No vehicle we make pulleys for uses a damper to protect the engine. We have
had our pulleys on the market since May of 1997 and our customers have
driven billions of miles using our pulleys, they only have great things to
say about our pulleys and other products. That does not include the endless
number of race teams that have been using our products since 1997 from Pikes
Peak to Pomona to Watkins Glen. The things you may have herd are urban
legends or we would have been out of business a long time ago. You'll be
impressed by the performance our products offer. Dollar for dollar nothing
else will give you the gains you will see with our pulleys or flywheels.

See the Response below I posted to Steves Article back in 2000.

Thanks for your interest,
Shawn Baumgartner
President & Founder
Unorthodox Racing Inc.
www.unorthodoxracing.com

Response to: The Danger of Power Pulleys & Understanding the Harmonic Damper
by Steve Dinan

Before making judgments with such wide implications it is important to
recognize the fact that long-term real world use outweighs theoretical
assumptions. Simply stated we have two years of pre-production testing under
our belt and an additional four years of real world data (over 300 million
miles). Not once in this period have we ever had even the slightest problems
in regard to engine longevity, not one claim or call. The fact is that if
there were a problem with our product we could never have kept it from the
public because of the Internet Unfortunately we have taken the brunt of many
rumors flying around the Internet about our products, like this article. Now
we spoke with Mr. Dinan and he apologized for any undue problems this
article may have caused us as he never directed it towards Unorthodox Racing
Inc. That aside we have tried to take the time to educate our owners and
potential owners of our products about the facts. It always seems to be that
someone's cousin whose girlfriend's brother has a friend that had a problem
with our product. Needless to say we never get a phone call, which we would
think would be the first thing an owner would do if they have a problem with
our product or any product they use that causes a failure. We wish that
everybody would try to learn and think for themselves like the old adage
"Believe non of what you hear and only half of what you see."
First mistake is that the majority of our gains do not come from
underdriving. The majority of the gain from our product comes from weight
loss, removal of rotational mass from the rotational assembly. We also do
not cause problems with accessory output either, as each model we
manufacture is tested to maintain factory acceptable parameters accessory
output. So each vehicles underdrive is tailored to what the specs call for
and never exceeds 20%. This is also concurrent with information we have
received for CARB (California Air Research Board) stating that as long as we
do not push beyond 20% underdrive we will remain within acceptable
parameters set by the factories. They also mentioned that products exceeding
25% underdrive would not pass emissions requirements because all late model
cars would run in a limp mode because of reduced voltage. So Steve Dinan
theory one is wrong when applied to Unorthodox Racing products. Secondly the
gains are not small, we have seen on BMW E36's 5-9 HP regularly and from
13-18 HP maximum. The stock crank pulley/damper is what is called an audible
harmonic damper, in laymen's terms that means control of harmonics you would
hear in the occupant compartment. Similar example is the factory use of
baffles and resonators in the intake manifold. These methods are used
because of the factories fanaticism about quiet in the occupant compartment.
They have nothing to do with engine longevity. The flywheel has dramatically
greater effect on engine longevity.
We have our own engineering and design team but we have also had direct
contact with many of the OE manufacturers on this subject. We have worked
with engine builders, many of who have been in the industry since the mid
fifties. We also have worked with many Speedvision racecar teams with a
number of different vehicle models. One was Last Minute Racings E36, driven
by Alain Chebeir. Last Minute Racing ran our 4-piece pulley kit including
the crank pulley for the entire 1999 season. Not once did he ever encounter
a problem with our product. We also worked with The Wheel Source/Hikari
Supra, driven by David Schart. That engine is very similar in many of its
characteristics when compared to the BMW straight 6. They ran our 4-piece
pulley kit for the entire season, and their motor as turbocharged, making
considerably more power than stock, 500-550 HP compared to 320 HP stock.
They never had any problems with the use of our product. We also worked with
Trac Racings two VW cars, running the VR6 engine. They have run our pulleys
for two seasons now with no problems. We also worked with High Speed Racings
two VW's and they have had no problem whatsoever. All of these teams have
disassembled their engines at various times throughout their race seasons
and have found no abnormal wear or crankshaft cranking. Now those were just
the road course teams. We also work with many drag racers and one Pikes Peak
car (Rod Millens Supra) and none of these teams have ever had problems. Not
only these facts but the fact that we have had over 100+ sets in the field
on street and street/strip BMW's including some turbo models without ever
having any problems leaves you to believe that Steve did not intend to
include Unorthodox Racing. All of our pulleys for other vehicles have never
once caused any problems, in fact aside from the examples stated above, we
have over 250+ million owner driven miles out there with our product.
Steve's association of the stock crank pulley being the primary damper is
incorrect, it is the dual mass flywheel that accomplishes this task. But
even replacing this dual mass damper with an aluminum flywheel would not
cause long-term damage as long as the flywheel were properly balanced. To
give an example lets look at the Turner Motorsports Speedvision cars. Those
vehicles were running underdrive pulleys from another source. To regress
slightly for historical value, we had originally engineered two designs for
the BMW crank pulley section, but both kits were four pieces in total. One
crank pulley design was a six-bolt pulley section replacement like the way
the factory designed theirs. The other design was a complete one-piece
replacement of pulley sections and the hub that mounts to the crank snout.
We had sent some pulleys up to Mr. Turner for evaluation. The prototype
design sent to him replaced the pulley section and the steel hub section
with one unit that attaches directly to the crank, as described previously.
This once piece design help eliminate the weight from the heavy steel hub.
Unfortunately we could not use this design for production because the
aluminum would crack shortly after installation due to the high torque
specification for the bolt that attached that hub to the crank snout. Now
Mr. Turner instead of working with us decided he would not tell us this,
which we found out at about the same time from another local owner that
worked with us. Mysteriously the following race season, with other pulleys
on his car they began to have crank cracking problems. Multiple motors were
broken, all at the main journal before the last rear cylinder from what we
understand. It was also amazing to find out that they were also using an
undampened solid aluminum flywheel. It seems amazingly odd now that the
breakage occurred at the rear of the crankshaft closest to the lack of
damping component. But as stated before if a properly balanced flywheel
would have been used the failures would not have occurred. This is supported
by the fact that all the Speedvision teams, described above, we have worked
with use aluminum flywheels and have had no problems whatsoever.
We have seen a few of these products and they would not even pass inspection
for factory fitment even if they had the rubber isolator. The machining
quality is frightening and the products are also unbalanced. These companies
cut the factory timing ring off the stock pulley and remount it, for 95 or
older model year BMW's, this assumes the balance of the ring once it is
removed. We laser cut our timing ring and check balance during machining and
after assembly. Our tolerances are held to .001" in critical areas, where we
have seen regular tolerances of .005" or more from these other
manufacturers. As stated before we have tried to address these issues at
various times over the years through education to our dealers to FAQ's on
our web page. It unfortunately comes down to the old adage that you get what
you pay for when it comes to quality. There are offshore and on-shore copies
of our other pulley models out there. All of these pieces are sub-standard
and would not even meet factory specifications. So why do owners keep buying
them, unfortunately its lack or education/understanding and plain old
dollars and cents. The same problem occurs with cam sprockets with
tolerances of other products, even at supposed 0 degree factory settings,
not being up to even OE specifications. Meanwhile our own sprockets are held
to again .001" tolerances and have timing marks that are down to the minute
(60 being in a degree). Its price that drives the consumer, so unawares they
are buying product that they cannot properly adjust or product that comes
loose. Our pulleys are 60-70% more expensive than the offshore and onshore
copies and other underdrive only products offered. Our top of the line
sprockets are 60-70% more expensive than these others. We have even
introduced an entry-level sprocket, which is 15% more expensive in order to
be more price competitive while offering the functional quality of our top
of the line without some of the additional lightening machining and extra
hardware.
One other important issue is the rather random attack on a specific
performance adder without looking at power adders in general. If we wish to
get technical about this type of issue then all power adders must be looked
at under a more rigid standard. Based on factory testing and design even
changing the oil to a non-factory used oil puts the power plant or driveline
into a completely different set of parameter results. Lets use intakes
systems as the first example. By increasing the intake airflow response
parameters are changed to some completely different set of parameters from
what the factory tested or designed too. Now this does not even take into
account the change in intake resonance frequencies, which again creates
deviations from the factory design. This does not even take into account
that the engine may make more power from this modification, which again
leaves us with a deviation from parameters the factory designed the vehicle
to be within. Now to be fair lets look at supercharging or forced induction
for normally aspirated cars, which dramatically affects every aspect of
engine function. More boost of course means more power, which in turn means
more engine and drivetrain stress. This is a product that the factory never
designed the vehicle to be used in conjunction with. The drive of the
supercharger puts more stress on the front of the crankshaft. Turbos put
more stress on the exhaust valves from backpressure and heat. Turbos are
also less dependable as far as control goes, tending to spike which causes
severe engine strain. Turbos also require additional expensive products like
boost controllers and turbo timer. This additional stress was encompassed
into the factory design of the crankshaft or the pulley system. If the
factory pulley were a damper in the traditional sense the additional stress
from any modifications would eliminate any special function that the factory
pulley may have had because it was never designed for the additional flex of
the crankshaft nor the faster spool up of the engine. Looking at other
engine systems the fuel pump was never designed to deliver the amount of
fuel needed based on the new demands the supercharger puts on that system.
Flow might be adequate as a function of output but is the pump up to the
day-to-day stress. Another parameter the factory never designed into that
system. We can go on and on with how non-factory parts, even regular service
parts which are non-factory can effect a vehicle. The fact is that owners
that want more power assume the risks of their desire. All the products they
desire to achieve these improvements where never entered into the design
equation of the factory designers.

Respectfully,
Shawn Baumgartner
President
UR


-----Original Message-----
From: Fasano, Tom [mailto:TFasano@ironmountain.com]
Sent: Friday, August 22, 2003 11:05 PM
To: shawnb@unorthodoxracing.com
Subject: Thinking about a pulley

Hello, I am thinking about putting one of your pulleys on my 03 g35 coupe.
I like the idea, but came across this article while doing some research on
the topic. I was wondering if you had read it before, or had any response
as to the validity of the article? please click on the link,
http://www.dinanbmw.com/html/danger_...er_pulleys.htm

Thank You,

Tom



Luv My G

 

I guess he told us the real facts!

2003 Twilight Blue Sedan 5AT, sunroof, Graphite Leather,
splashguards, GG red 8 wire Hypergrounding kit, 350Z intake duct, K&N filter.

 

I don't car, I am still looking for any sign this pulley on my engine is balanced in any way. Any of you that have a UDP or set that you are not going to use, I got 100.00 (shipped) for a crank pulley or we can negotiate for a set. Private message me.

Sean

Better Life thru Chemistry