How much does a lighter crank help...
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Race Director
Joined: Nov 2000
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From: stop the fun suckers
How much does a lighter crank help...
I've seen lightweight cranks (44lbs) and can only assume since they reduce rotating mass they will add hp and make the engine rev faster.. however, are there any drawbacks? durability?
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Joined: Sep 2000
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From: The Top of Utah
Re: How much does a lighter crank help... (BluByU)
The crankshaft is rotating weight. A lighter crank really won't add horsepower. At least not anything you could reliably measure. Lighter reciprocating (pistons, pins, rings, and rod small ends) weight can have a greater effect on power output, plus it reduces the loads on the bearings and crankshaft. A light crank DOES reduce inertia, just like a light flywheel, and will allow a quicker response. I think a light crank is a good thing, but there are trade offs. A heaver crank made with the same engineering and materials, will be stronger. Since this doesn't happen, a light crank will cost more. In summery, I think a light crank won't add power, but it could add performance if a given vehicle doesn't need the stored potential energy of the weight. I expect this post will draw a lot of criticism. These are MY thoughts on the subject. I look forward to opposing points of view.
Pro
Joined: Jun 2001
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From: College Station Tx
Re: How much does a lighter crank help... (CFI-EFI)
It won't "add power" it just reduces the power loss due to inertia - the net result is similar - more power to the wheels.
Lightweight cranks are also very pricey. For the premium you pay you would end up making much more power spending the money on head porting, a solid roller conversion, etc.
You can get similar results by going with an Aluminum flywheel also. The lightweight crank would be one of the last things I would do - or only if you were doing a no expense spared all out buildup. If the car was a dedicated road racer then I would give it more consideration - otherwise I would say probably not worth it.
Lightweight cranks are also very pricey. For the premium you pay you would end up making much more power spending the money on head porting, a solid roller conversion, etc.
You can get similar results by going with an Aluminum flywheel also. The lightweight crank would be one of the last things I would do - or only if you were doing a no expense spared all out buildup. If the car was a dedicated road racer then I would give it more consideration - otherwise I would say probably not worth it.
Safety Car
Joined: Dec 2000
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From: Cape Coral fl
Re: How much does a lighter crank help... (ChrisB)
i scored an ultra light Crowr 3.50 stroke crank and a set of Crower 6" titanium rods (reconditioned by Crower) for $2500.00. Would you say that was a good deal to built up a superlight BULLET proof bottom end? I plan to build a 358 that will spin 8000 rpm!
Tony
Tony
Pro
Joined: Jun 2001
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From: College Station Tx
Re: How much does a lighter crank help... (KLLRVET)
The crower crank is top quality and an excellent piece - as are the rods. Be carefull of Titanium on the street though as it tends to work harden and get brittle with street use.
Drifting
Joined: Dec 2000
Posts: 1,255
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From: Clayton, NC north carolina
Re: How much does a lighter crank help... (BluByU)
You also have to concider the fact that with reduced inertia comes less drivability. when I went to my aluminum flywheel I noticed that I have to slip the clutch more to get the car to move. Also she starts to buck at around 5 MPH The 66lb dualmass flywheel dident have these problems because its heavyer. Example: It is easyer to stop a 15 lb object from spining than it does a 66lb object. The car now drives like a 80's mustang GT you have to slip the clutch and feed more throttle to move.
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Thread Starter
Race Director
Joined: Nov 2000
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From: stop the fun suckers
Re: How much does a lighter crank help... (ASRoff)
ASRoff - How do you think it will effect an automatic? Also, It will be used in conjunctoin with a 2600 stall and 3.55's
Drifting
Joined: Dec 2000
Posts: 1,255
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From: Clayton, NC north carolina
Re: How much does a lighter crank help... (BluByU)
With a stall it shouldent be a problem. The stall has the same effect as feathering the clutch.the gear will help too. :cheers: :chevy :seeya
