crank pulley
That is all great info! Thanks for taking your time and sharing your wealth of knowledge with us!
04-10-2007, 03:31 PM
#45
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Originally Posted by MotoIQ
Originally Posted by kungpaosamuraiii
Those are valid questions so I don't mind. I only hate blanket refusals based on the event of something not happening.
1. I don't know when the book was published but it's old. I'd say early 90's old. It's not my book.
2. Toyota documents that "rubber ring" as damping both NVH and torsional vibrations. NVH is, I think, mostly a comfort/discomfort thing but torsional vibrations took down more than its share of bridges. When the "symptoms" were brewing no one could feel it either. I don't think torsional vibrations are transmitted very well through the chassis but rather, releases its energy through bolts and chains and whatever is directly connected to the crank.
3. The book discusses Toyota technology and the damper technology hasn't changed. The rubber ring sandwiched between plates is probably the cheapest damping Toyota felt was necessary. That book states that it's used for both NVH and torsional vibrations. So as far as the pulley goes, torsional vibrations are relevant to the 2AZ.
4. I don't know too much about that. If that's true, that'd be great news.
Honestly, MotoIQ's post makes a lot of sense. I was referred to those pages by someone who's involved in Supras and of course, those run I6 engines with exceedingly long crankshafts. I think the best evidence for the tC's not detonating, thus far, is that it uses a very stout, short, and forged stock crank shaft.
I'm no expert either. But the tC is my only means of transportation so I would opt to become an expert in whatever I put on my car. I researched pullies a little and found torsional vibrations. MotoIQ presents some new information to me that explains away a lot of stuff. However, I would find out more about resonating metal.
And honestly, the gains really aren't worth running into torsional vibrations. If you take away danger from resonant frequencies then it's still not a very worthwhile mod, in my opinion. I'd rather get lightweight wheels. Not only would they save considerably more weight than a few ounces, they'd look good too.
1. I don't know when the book was published but it's old. I'd say early 90's old. It's not my book.
2. Toyota documents that "rubber ring" as damping both NVH and torsional vibrations. NVH is, I think, mostly a comfort/discomfort thing but torsional vibrations took down more than its share of bridges. When the "symptoms" were brewing no one could feel it either. I don't think torsional vibrations are transmitted very well through the chassis but rather, releases its energy through bolts and chains and whatever is directly connected to the crank.
3. The book discusses Toyota technology and the damper technology hasn't changed. The rubber ring sandwiched between plates is probably the cheapest damping Toyota felt was necessary. That book states that it's used for both NVH and torsional vibrations. So as far as the pulley goes, torsional vibrations are relevant to the 2AZ.
4. I don't know too much about that. If that's true, that'd be great news.
Honestly, MotoIQ's post makes a lot of sense. I was referred to those pages by someone who's involved in Supras and of course, those run I6 engines with exceedingly long crankshafts. I think the best evidence for the tC's not detonating, thus far, is that it uses a very stout, short, and forged stock crank shaft.
I'm no expert either. But the tC is my only means of transportation so I would opt to become an expert in whatever I put on my car. I researched pullies a little and found torsional vibrations. MotoIQ presents some new information to me that explains away a lot of stuff. However, I would find out more about resonating metal.
And honestly, the gains really aren't worth running into torsional vibrations. If you take away danger from resonant frequencies then it's still not a very worthwhile mod, in my opinion. I'd rather get lightweight wheels. Not only would they save considerably more weight than a few ounces, they'd look good too.
The stock damper is not tuned to effectivly damp these out either.
When you go to a lighter flywheel and/or pulley it is not uncommon for these noises to become much louder. Some cars they can become very loud. On my 300zxtt with its twin disc super light. super low inertia solid hub clutch, the harmonic noise is extremely loud at 2500 rpm. If this was a daily driver it would be totaly unacceptable. When you put a light flywheel in a 350Z there is a noticable increse in engine vibrations.
For an all out race engine that dwells about the cranks second harmoinc in its powerband, it can be prudent to got to ATI, Fisher or Fluidamper and work with them on a damper that can help control these vibrations. Some of the signs of problems are broken oil pumps, sheared keyways, cracked cranks, sheared flywheel bolts, sheared pulley bolts, cracked blocks, strange bearing wear patterns.
These sorts of problems are more common in V-6 engines. I have seen them in the following i-4's, B series Honda motors with strokes at 100 mm or greater, Nissan KA24D, and Nissan QR25DE motors and thats about it. These motors were highly modied, spun really hard and were used in drag racing, class 7 truck racing and World Challange sccordingly. The QR25DE has a 100mm stroke and a pretty wimpy low overlap crankshaft.
All of these applications were high dollar, factory race team level racing unter extreme condtions.
I have never seen problems with solid hub pulleys on any street 4 cylinder no matter how hard it was driven and very few race applications other than the above mentioned ones.
So in short, don't worry, the vibrations that the pulley was designed to damp are a different order and lower rpm with less energy that can damage your engine. it might be more noisey though.
im still not sure how much torsional vibration that thin piece of rubber could do, but thats already been settled
anyways, just out of curiosity to support the latter quote, what is the stoke of the tC in mm?
04-10-2007, 04:21 PM
#47
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[quote="3min3m2"][quote="MotoIQ"]
first i wanna say thanks for the decent answering...
im still not sure how much torsional vibration that thin piece of rubber could do, but thats already been settled
anyways, just out of curiosity to support the latter quote, what is the stoke of the tC in mm?
96mm.
Originally Posted by kungpaosamuraiii
first i wanna say thanks for the decent answering...
im still not sure how much torsional vibration that thin piece of rubber could do, but thats already been settled
anyways, just out of curiosity to support the latter quote, what is the stoke of the tC in mm?
04-10-2007, 04:29 PM
#48
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Soem good basic info
check this out guys, it is a good and simple explnation of what we are talking about.
http://www.indiacar.com/infobank/tor..._vibration.htm
http://www.indiacar.com/infobank/tor..._vibration.htm
04-10-2007, 05:35 PM
#49
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Resonance can be avoided by either damping the system, or by making sure that the engine cannot be run at the major critical speed. The shortness of four-cylinder cranks results in a major critical speed of well over 9000rpm, so that a torsional damper is not essential on a four. It is still sometimes fitted to take care of the minor critical speeds. These are the speeds at which resonance of a lower amplitude occurs because the forces involved are smaller, or are damped by other induced vibrations.
The straight-eight engine, used extensively for racing between the world wars, resonates at about 3100rpm, where the forces are low enough to be dealt with, either by making sure the crank is robust, or fitting a damper, or having the power take-off in the centre of the crankshaft. In the latter case, the crankshaft behaves like two four-cylinder cranks. V8s and V6s have shorter cranks, but modern designs are fitted with dampers. The six-cylinder engine is the difficult one, with a major critical near 5000rpm, where the forces are high enough to render a good damper essential.
The straight-eight engine, used extensively for racing between the world wars, resonates at about 3100rpm, where the forces are low enough to be dealt with, either by making sure the crank is robust, or fitting a damper, or having the power take-off in the centre of the crankshaft. In the latter case, the crankshaft behaves like two four-cylinder cranks. V8s and V6s have shorter cranks, but modern designs are fitted with dampers. The six-cylinder engine is the difficult one, with a major critical near 5000rpm, where the forces are high enough to render a good damper essential.
why v-8s normally have harmonic balancers, and four cylinders dont...
thanksMotoIQ
04-10-2007, 06:11 PM
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Very nice.
It's about time someone from the "other" side brought up viable facts.
This also explains why the Horizon NA tC uses ATI's damper, which is heavier than the stock one. That tC needs it to make 10's without blowing up.
It's about time someone from the "other" side brought up viable facts.
This also explains why the Horizon NA tC uses ATI's damper, which is heavier than the stock one. That tC needs it to make 10's without blowing up.
04-10-2007, 07:15 PM
#51
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Originally Posted by kungpaosamuraiii
Very nice.
It's about time someone from the "other" side brought up viable facts.
This also explains why the Horizon NA tC uses ATI's damper, which is heavier than the stock one. That tC needs it to make 10's without blowing up.
It's about time someone from the "other" side brought up viable facts.
This also explains why the Horizon NA tC uses ATI's damper, which is heavier than the stock one. That tC needs it to make 10's without blowing up.
04-10-2007, 07:58 PM
#52
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The difference is the colorful Horizon tC is NA. That thing needs to be spun up and wrung out to make 10 seconds; it's probably spun up to around 9,000~ RPM. Any other 10 second tC is probably turbo'd and might not need a damper.
04-11-2007, 12:56 AM
#53
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Originally Posted by kungpaosamuraiii
The difference is the colorful Horizon tC is NA. That thing needs to be spun up and wrung out to make 10 seconds; it's probably spun up to around 9,000~ RPM. Any other 10 second tC is probably turbo'd and might not need a damper.
04-11-2007, 04:46 AM
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Originally Posted by 3min3m2
why v-8s normally have harmonic balancers, and four cylinders dont...
thanksMotoIQ
thanksMotoIQ
04-11-2007, 08:22 AM
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Originally Posted by 3min3m2
Originally Posted by kungpaosamuraiii
The difference is the colorful Horizon tC is NA. That thing needs to be spun up and wrung out to make 10 seconds; it's probably spun up to around 9,000~ RPM. Any other 10 second tC is probably turbo'd and might not need a damper.
I think we're in agreement, just with misunderstandings...
04-11-2007, 03:41 PM
#57
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Originally Posted by kungpaosamuraiii
Originally Posted by 3min3m2
Originally Posted by kungpaosamuraiii
The difference is the colorful Horizon tC is NA. That thing needs to be spun up and wrung out to make 10 seconds; it's probably spun up to around 9,000~ RPM. Any other 10 second tC is probably turbo'd and might not need a damper.
I think we're in agreement, just with misunderstandings...
04-13-2007, 02:12 PM
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Originally Posted by rippintC
well let me throw this in here too, is there any truth to the concerns about running both an a/m pulley and light flywheel?
it might make a little more noise/vibration, but it will also spin a lot better
04-13-2007, 04:19 PM
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Originally Posted by rippintC
well let me throw this in here too, is there any truth to the concerns about running both an a/m pulley and light flywheel?
A light flywheel usualy increses noise and vibration more than a crank pulley, yet people are way more paranoid about the pulley.