One issue is that you're trying to calculate the moment of inertia from mass and disk radius, but you don't know how the mass is distributed on the pulley. The OEM pulley is more heavy on the outside part of the disk and the mass is not distributed evenly like your model. This means that the OEM's pulley inertia is much bigger than your number and depending the manufacturer the lightweight pulley's inertia can be much smaller than your number.
Overall, it is a complicated model with too many parameters and it is the reason to insist that the only way to get a close to reality result is to make your own acceleration measurements or just stay with dyno numbers. I placed the following dyno many times in the past and I'll place it once more.
They don't care to sell by just posting non-sense or telling lies. Obviously getting very complicated at this point. Originally Posted by churchx. The cost vs performance leaves very little to be desired in these types of mods.
I guess if you have to have every little part that helps then its ok but bigger gains for less money are available. I think power and energy have been confused in this case. In other words, lightweight pulleys make less of a difference than the weather. Upside is your math is right and we both estimated similar dimensions.
Originally Posted by nikitopo. But lightweight pulleys come in Colors! Marketing trumps science in the minds of many, plain and simple.
Proper air pressure in the tires and has a greater effect in acceleration than a lightweight pulley, the side benefit of improving handling and braking, and also is dang near FREEEEEEE. When was the last time many of us checked our tire pressure? It's not sexy and anodized so my guess is not yet this week lol!
Along with all those factors you would have to compensate for the new harmonics of the engine. Will a light weight balancer create a damaging crank harmonic at any certain rpm that causes friction on the bearings? Their are a ton of variables that come into play and the only way to answer it is actually test for it.
Math will get you close but nothing is as good as real data. For This Useful Post: weederr33 View Public Profile Send a private message to why? Find More Posts by why?
Interior Parts Incl. All times are GMT The time now is AM. Remember Me? Garage Garage. Mark Forums Read. Page 1 of 8. Last ». Are they really worth it? Why are NST pulleys a popular choice for many of our customers? The alternator, power steering, water pump, and air conditioner are all belt driven units, attached to the crank pulley, that use horsepower from an engine to provide their own services. By replacing factory pulleys with carefully resized units, the accessories are slowed enough so that their performance does not suffer, but just enough so that more horsepower is sent to the wheels and put to the ground.
Where horsepower should be. Normally, underdrive pulleys like the units found at NonStopTuning will increase engine output by 10 to 12 horsepower, with even better power levels yielded from turbo models than seen in naturally aspirated engines. Another great benefit in replacing factory pulleys with NST units is reduced weight. Factory units, also referred to as OEM , are generally constructed from steel or cast iron. Pulley systems like those found at NST are constructed of aircraft quality aluminum, making them extremely durable while at the same time much lighter than their steel counterparts.
Better throttle response, better horsepower and torque delivery, and better fuel economy can all be had when using NST pulleys. All dyno testing performed by third party installers and dyno operators. Baselines and pulley dynos all performed on the same dyno, on the same day, with no other modifications. We know that bullshit spreads like wildfire on that forum and there are plenty too that have had no issues whatsoever.
Which I have! I also didn't think dampening was as important on a boxer engine compared with a standard 4 banger? The point you have to remember is that the stock crank pulley would not have a harmonic damper if it did not need it. Until you've done a decent amount of mileage with a lightweight pulley it is difficult to tell if it's an issue. Low mileage race cars don't really give you that info. I need to get my books out, but those graphs seem to be telling me that the fluidampr is not as good at damping vibration as the stock damper, and the lightweight pulley does a great job, apart from in the 6th order vibration In short, if lightweight pulleys were a creation of the devil, many more people would have problems with them - although, these graphs do show that there is a significant difference in behaviour between stock, damped, and undamped, and therefore definite potential for something to happen Stock: The first crankshaft resonance appeared at 88Hz and was almost below the testing rpm range.
A second crankshaft resonance was also seen near Hz. Lightweight: The lightweight pulley shifted a third crankshaft resonance into the operating range at Hz. The Hz resonance excited 5. High frequency amplitudes carry much more stress than equivalent low frequency amplitudes because they occur more times per revolution.
Crankshaft driven timing components and oil pump drives can be more susceptible to high frequency vibrations. Fluidampr: The Fluidampr performance damper effectively reduced all vibration amplitudes to less than 0. Amplitudes also show a general reduction trend while approaching the upper limit of the rpm range. You need to be a member in order to leave a comment.
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Recommended Posts. Galaxian 6. Report post. Posted February 3, Share this post Link to post Share on other sites. Keethos Stan Hawrylak Throttle response, horsepower and torque are all increased with this easy to install part so 3.
Posted February 4, I have read that having lightweight flywheel AND pulleys can lead to premature bearing failure? Kodename47 My take on this , manufacturer are always looking at saving costs nowadays so if they didn't need to add a damper that helped the harmonics they wouldn't; We have built a couple of FA20 motors both where balanced prior to being built both come back with some work on the front pulley to get the balance spot on.
Posted February 5,
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