mechanical engineers please help!
#197636
01/18/09 11:01 PM
01/18/09 11:01 PM
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Joined: Feb 2007
Posts: 5,080 organ
maximum entropy
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organ
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it seems to me that lowering blocks would reduce axle windup, by virtue of the center of rotation being further from the spring, and also from the forward vector of the axle having more leverage to flatten the spring as it moves forward. what do you guys think?
for what is the good life if not doing things thoughtfully?
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Re: mechanical engineers please help!
[Re: maximum entropy]
#197642
01/19/09 12:36 AM
01/19/09 12:36 AM
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Joined: Aug 2003
Posts: 4,386 Madison Wi
NTOLERANCE
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TO put it in perspective, think of a 4WD truck with really big lift blocks in the back. Say like 8 or 10 inch blocks. Without a control device on the rear, those axles will move ALOT.
Seen people driving on the road, with a lifted truck and big blocks, and I can actually watch the spring wrap. Especially if its a stick truck.
I used to care but....... things have changed
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Re: mechanical engineers please help!
[Re: NTOLERANCE]
#197644
01/19/09 02:55 AM
01/19/09 02:55 AM
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Joined: Feb 2007
Posts: 5,080 organ
maximum entropy
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lowering block and axle above the spring. also the traction input has additional leverage on the system. my guess is it cancels out the rotational moment. i'm seriously considering mounting a camera under my car and documenting the shenanegans. thanks for your input.
for what is the good life if not doing things thoughtfully?
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Re: mechanical engineers please help!
[Re: maximum entropy]
#197646
01/19/09 03:35 AM
01/19/09 03:35 AM
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Joined: Jan 2003
Posts: 6,591 Canton, Ohio
Sport440
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Quote:
it seems to me that lowering blocks would reduce axle windup, by virtue of the center of rotation being further from the spring, and also from the forward vector of the axle having more leverage to flatten the spring as it moves forward. what do you guys think?
I think your Dead wrong
Under power the axel is going to try to wrap up on the spring. And it doesnt care if its mounted above or below the spring.
Adding any additional space between the axel and spring by a spacer block will only increase wrap up leverage. Says me and science. mike
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Re: mechanical engineers please help!
[Re: Sport440]
#197647
01/19/09 06:38 AM
01/19/09 06:38 AM
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Joined: Apr 2007
Posts: 871 WA 98043
thecarfarmer
super stock
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Not a mechanical engineer, but a mechanical designer... what I get for dropping out! Here's a thought experiment: Imagine you have your park brake on real tight. Your car's on a lift. You grab that rear wheel and try to turn it - you go grab a socket, breaker bar, and six foot 'cheater' pipe; try to turn that wheel with a lug nut (let's pretend you don't twist that lug off!) You know that you'd feel that leaf spring move around, right? Of course, with that much bar, you could probably knock the car off the lift, too... pretend it's welded on. Now, imagine you had a foot of spacer between the spring and the axle; doesn't it make sense how the rotational forces applied to the axle would tend to grab that long block and twist the spring? Hope this helps. -bill
Seduce the attractive, and charm the rest.
******
489 C.I.D., roller cam, aftermarket heads, tunnel ram, stock '54 Dodge rear axle assembly: which of these doesn't belong?
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Re: mechanical engineers please help!
[Re: Thumperdart]
#197652
01/19/09 02:48 PM
01/19/09 02:48 PM
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Joined: Oct 2003
Posts: 11,702 W. Kentucky
justinp61
I Live Here
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Quote:
Calvert has no issues w/using em eighter.
I have 3/4" billet blocks on my Dart. When I called Calvert, Travis recommended that I not do it . He suggested changing the rear (Mono leaf)segment of the spring.
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Re: mechanical engineers please help!
[Re: Thumperdart]
#197653
01/19/09 02:53 PM
01/19/09 02:53 PM
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Joined: Feb 2007
Posts: 970 Backwater, PA
bwdst6
Bob George Racing #1 Fan
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Bob George Racing #1 Fan
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I am a Mechanical Engineer and my feeling is that lowering blocks won't improve axle wrap. The overall stiffness needs to be increased. Which is why getting the axle closer to the front of the leaf works. Ever notice how Mopar's didn't have the same wheel hop problem back in the day compared to other makes? But obviously if traction bars are used that changes things.
This post is available in double vision where drunk.
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