[Forged]

Is the extra 0.5HP worth the risk? If so, and you like replacing main bearings and oil pumps, then gopher it. Also, there are some detriments to the valvetrain for the torsional vibration. Basically you can throw the cams off at higher RPMs from the transmitted harmonic distrubance. It's been discuseed more than a few times, and basically it comes down to the engineers vs the salesmen. I wonder who wins that argument?

 

[Forged]

this is all I have to say:

If you don't know what that is don't talking about engineering.

 

[Forged]

point semi taken!?!

I like your "location" kurker.

I'M MATT FOLEY, MOTIVATIONAL SPEAKER!!!!

 

[Forged]

I have never lost at that game where you put your palm on a table and stab a knife between your fingers. I've been playing it for probably 10 years now.

 

[Forged]

Originally posted by inevitablegod@Apr 22 2006, 07:24 PM
The failure of the bridge occurred when a never-before-seen twisting mode occurred. This is called a torsional, rather than longitudinal, mode (see also torque) whereby when the left side of the roadway went down, the right side would rise, and vice-versa, with the centerline of the road remaining still. Specifically, it was the second torsional mode, in which the midpoint of the bridge remained motionless while the two halves of the bridge twisted in opposite directions. A physics professor proved this point by walking along the centre line, unaffected by the flapping of the roadway rising and falling to each side. This vibration was due to aeroelastic flutter. Flutter occurs when a torsional disturbance in the structure increases the angle of attack of the bridge (that is, the angle between the wind and the bridge). The structure responds by twisting further. Eventually, the angle of attack increases to the point of stall, and the bridge begins to twist in the opposite direction. In the case of the Tacoma Narrows bridge, this mode was negatively damped (or had positive feedback), meaning it increased in amplitude with each cycle because the wind pumped in more energy than the flexing of the structure dissipated. Eventually, the amplitude of the motion increased beyond the strength of a vital part, in this case the suspender cables. Once several cables failed, the weight of the deck transferred to the adjacent cables which broke in turn until almost all of the central deck fell into the water.
whatchu know 'bout torsion?

correct except where it say's "the amplitude of the motion increased beyond the strength of a vital part", it would be the strain.

This was not man's first lesson in harmonics. Ask anyone in the military of almost any country, when you cross a bridge your don't march to cadence, you "break step" march because lots of british platoons fell into rivers and ravines for matching the bridge's harmonic frequency. I would love to have seen that.

Not no, solid crank pulleys are fine.

 

[Forged]

Originally posted by Infra+Apr 24 2006, 06:38 PM-->QUOTE (Infra @ Apr 24 2006, 06:38 PM)

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@Apr 24 2006, 07:48 AM
correct except where it say's "the amplitude of the motion increased beyond the strength of a vital part", it would be the strain.

Sorry to nitpick, but in this case the "amplitude of the motion" and the strain are the exact same thing- ie, the displacement per unit length exceeded the maximum allowable strain of the supporting cables.

However, your average person does not know the definition of strain, so it might as well be left out of the explanation. [/b]

read again, i said stress =/ strain. not "amplitude =/ strain". By 'it" I meant "stress". Thanks for playing.

 

[Forged]

stress =/ strain. That's all I am saying.

 

[Forged]

Boy some of you guys are long winded! I don't see the issue, if you wanna run one, do it. If you're trying to convince others it's safe/ok, you'd better dish out some engineering. I like the motorcycle example, but playing roulette with a bunch of IFs in the barrell isn't my bag. Have fun and quit worrying about the engine in your economy toyota trashing a crank. There's more to worry about.