Do I need a Fluidampr?

I noticed my harmonic balancer was starting to deteriorate so I started doing some research and learned that the stock balancer dampens only certain frequencies with the stock 2.0. The theory is: if a different engine configuration is used, such as a stroker with forged pistons in my case, these vibrations occur at different frequencies. As a result, accelerated main bearing failure occurs.

In the next couple weeks my stroker is going in and I am leaning towards buying one 2 days from now. I was hoping I could get some more info and personal experience with this situation. Most likely I will get one, but I would like to see some talk on it and see if there is any reason NOT to get it.

Just get a stock one, it will be fine. Its just a pully with a little bit of rubber in the middle to help with vibrations. Its not "tuned" for certain frequencies.

I'm going mostly by this thread on tuners: http://www.dsmtuners.com/forums/bolt-tech/249764-anyone-running-fluidampr-pulley.html

Raised a cause for concern.

Although I had not heard of having a fluidampr as a necessity for strokers.

I wouldn't worry about it. I mean damn I run a straight aluminum pulley and had no problems with bearing failing.

How long have you been running it?

Proabably a year and a half. I researched this a lot before I put this on because I have heard of some problems, never found anyone that has had any motor problems cause by the UDP.

:1: I've never heard of anyone having any problems with them, I wouldn't worry too much about it. If worse comes to worse, just take it off and get the one you posted about, but I bet there's a 1% chance you'll have a problem.

My question is do you have the spare scratch for one? If you do and its worth the peace of mind I would be all for it.

They are a pain in the ass to use, if it's the same one that's on my RWD. I'd avoid it at all costs. I'd go back to a stocker, but I think once you're in the single digits you need an SFI approved damper.

As far as I know the fluidampr is only a harmonic damper and not an under-drive pulley.

Fact one on extreme psi's website is this: 1.) Most stock dampers are actually tuned absorbers and do not work when the the engine is modified from the original set-up.

Kevin, how was yours a pain to use? It seems to be a simple bolt on mod.

I do have the money for it but at this moment I need to spend it on other more critical engine stuff.

I don't even want to get into it, but to start I'll say that I had to make my own bolts because they were too stingy to machine out enough room for the bolt heads. Maybe mine is some other kind, but I'm not aware of many options for this part. I this is the only manufacturer.

ATI also makes one but it comes with its own timing gear, and much more expensive. With the research I have done I can't seem to find anyone with the bolt problem you had.

Does yours look like this? http://www.extremepsi.com/store/customer/product.php?productid=19827&cat=1131&page=1

It looks like the damper has recesses for the bolt heads.

I posted this thread at tuners and got this info:

If your driving it on the streets then get it. Why? I thought you would NEVER ask.

1) The vibration of the engine, and its rigid components caused by the imbalance of the rotating assembly. This is why we have counterweights on the crankshaft to offset the mass of the piston, and rod as well as the reason for balancing the components in the engine. Balancing the rotating assemly, and matching reciprocating masses together is very important.

2) The vibration of the engine components is partially due to their individual elastic deformations( the different rates at which they change, and reform shape). These deformations are a result of the combustion impulses that create torsional forces on the crankshaft, and camshaft. These torques excite the shafts into sequential orders of vibration, and lateral oscillation. Engine vibration of this sort is counteracted by the harmonic damper.

Torsional Vibration (Natural Frequency)
Every time a cylinder fires, the force twists the crankshaft. When the cylinder stops firing the force ceases to act, and the crankshaft starts to return to the untwisted position. However, the crankshaft will overshoot and begin to twist in the opposite direction, and then back again. Though this back-and-forth twisting motion decays over a number of repetitions due to internal friction, the frequency of vibration remains unique to the particular crankshaft. This motion is complicated in the case of a crankshaft because the amplitude(intensity) of the vibration varies along the shaft. The crankshaft will experience torsional vibrations of the greatest amplitude at the point furthest from the flywheel or load.

Harmonic (sine wave) Torque Curves
Each time a cylinder fires, force is translated through the piston, and the connecting rod to the crankshaft. This force is then applied tangentially to, and causes the rotation of the crankshaft. The sequence of forces that the crankshaft is subjected to is commonly organized into variable tangential torque curves that in turn can be resolved into either a constant mean torque curve or an infinite number of sine wave torque curves. These curves, known as harmonics, follow orders that depend on the number of complete vibrations (cylinder pulses) per revolution. Accordingly, the tangential crankshaft torque is comprised of many harmonics of varying amplitudes and frequencies. This is where the name "harmonic damper" originates.

Critical RPM's
When the crankshaft is revolving at an RPM such that the torque frequency, or one of the harmonic sine wave frequencies coincides with the natural frequency of the shaft, resonance occurs. Thus, the crankshaft RPM at which this resonance occurs is known a critical speed. A modern automobile engine will commonly pass through multiple critical speeds over the range of its possible RPM's. These speeds are categorized into either major or minor critical RPM's.

Major and Minor Critical RPMs
Major and minor critical RPM's are different due to the fact that some harmonics assist one another in producing large vibrations, whereas other harmonics cancel each other out. Hence, the important critical RPM’s have harmonics that build on one another to amplify the torsional motion of the crankshaft. These critical RPM’s are know as the "major criticals". Conversely, the "minor criticals" exist at RPM's that tend to cancel and damp the oscillations of the crankshaft.

If the RPM remains at or near one of the major criticals for any length of time, fatigue failure of the crankshaft is probable. Major critical RPMs are dangerous, and either must be avoided or properly damped. Additionally, smaller but still serious problems can result from an undamped crankshaft. The oscillation of the crankshaft at a major critical speed will commonly sheer the front crank pulley and the flywheel from the crankshaft. These failures have often required crankshaft and/or gearbox replacement.

Harmonic Dampers
Crankshaft failure can be prevented by mounting some form of vibration damper at the front end of the crankshaft that is capable of absorbing and dissipating the majority of the vibratory energy. Once absorbed by the damper the energy is released in the form of heat, making adequate cooling a necessity. This heat dissipation is visibly essential in some racing applications which channel air from the brake ducts to the harmonic damper, in order to keep the damper at optimal operating temperatures.