| Mekanik22 |
| I've heard a few things going around that a lightweight crank pulley (Eg. By Unorthodox racing) and a lightweight flywheel can snap your crankshaft?! Is this true? Something about the crank pulley not being able to absorb the harmonics from the crankshaft and it just snaps apart, literally. So what is your input on this? |
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| SilverNeonRacer |
| I had a UDP it was fine, I miss fired at 5500rpm, but that was it. If anything the UDP reduces strain on your crankshaft as your accessories(PS Alt, AC) are easier to turn. |
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| GOT BOOST |
quote:
Originally posted by Mekanik22
I've heard a few things going around that a lightweight crank pulley (Eg. By Unorthodox racing) and a lightweight flywheel can snap your crankshaft?! Is this true? Something about the crank pulley not being able to absorb the harmonics from the crankshaft and it just snaps apart, literally. So what is your input on this?
Hi Mekanik22,
I have the Unorthodox Crank Pulley on my Sentra. I have had no problems with it. I installed it around 155,000 kms. The car has almost 339,000 kms on it and still runs like it is new.
I think it all depends on the vehicle to better answer your question. For instance on the Supra's 7MGTE from the research I have done it is strongly reccomended that you can do the light crank pulley, and the flywheel. You will feel results, but if you are upgrading your turbo, you need switch back to the OEM pulley or you will say good night to your motor. Why this is, I do not know, I can only speculate. But if you are just doing the pulleys and the flywheel and no other upgrades ie) Turbo, Supercharger, Nitrous, then you should be fine. I too have heard the other side about how the lightened pulley is the devil and it will destroy my motor in less than 5,000 kms. Well, at almost 339,000 kms I am still running on the same motor and have not noticed any negative effects. :D
Some other FYI, Depending on the car, you may need to change your belts to accomidate the pulley size changes. If it is a serpentine belt then you do not need to change the belt size, but still a good idea to put a new one one.
Hope this helps.
Mike Nikolai |
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| Bucktown |
not to sure about other makers but hondas crank pulleys are harmonic balancers, and i would think that adding an unbalanced part to a balanced engine would throw something out of whack. though, crank would be the last thing to break as far as i would guess. (hondas are renowned for the strength of their cranks. cant speak for other makers.)
also in hondas the oil pump gearset is made from sintered metal and an un-balanced assembley could cause this set to disintegrate. i can only assume that this part would break due to unbalanced parts before a crank. what happens after that cant be good.
also, i think that a flywheel would be machined to much more strict specs than an aftermarket crank pulley (even though the pulley sets are billet, usually) and i would worry less about aftermarket flywheels. (think about grease ball outsourse machine shops resurfacing them all day long. not to many broken cranks kicking around tho.)
that being said, if the rotating mass was balanced, and the new part was balanced as well, then there would be less parasitic losses, and the mass would rotate easier. (obviously where the gains come from)
i think the lightweight flywheels are a great mod, but i would think twice about the pulley sets. the few (1-4) hp gained from these mods do not equal the risks unless you are prepared for it.
if you have a car thats modded to the tits and your looking for evey spare hp you can get then go nuts. keep in mind a good set is expensive, and the supporting mods are even more money. (cost to balance a motor is lots, and my toda gearset was something like 500 bucks) also, the billet aluminum pulleys are weaker than oem. personally i bought some (unorthodox) but apparently im a maniac. |
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| Mekanik22 |
quote:
Originally posted by Bucktown
not to sure about other makers but hondas crank pulleys are harmonic balancers, and i would think that adding an unbalanced part to a balanced engine would throw something out of whack. though, crank would be the last thing to break as far as i would guess. (hondas are renowned for the strength of their cranks. cant speak for other makers.)
Yeah, all manufacturer's crank pulleys are harmonic balancers. They are the same thing. I usually call them harmonic balancers but I just said crank pulley to make my question as clear as possible. But with evidence supporting crankshafts acually snapping, I'll stay away from those god awful pullies, lol. Must be the material or the mass of the factory harmonic balancer that keeps the harmonics from the crankshaft to a minimum. Thanks for those inputs guys. |
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