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Wouldnt a lighter crankshaft reduce parasitic weight and improve performance?

Lets assume that money was not a concern, what would be the best solution for a B16A block in terms of a crankshaft?

I read that removing any parasitic weight from the drivetrain is always good. I emailed Eagle Rods about their crankshafts and they say that theirs weights 26 pounds and the stock one 34 pounds. What kind of improvement can this provide and is it worth it?

Thanks
Ed

 

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lets assume that I already have a lightened flywheel and volumetric efficiency is also good. What can you get with a lightened crank?

 

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That I dont know. Im investigating all the option for reducing parasitic weight down to a bare minimum regardless of the price.

once I know what can be done, I will work on what has the best bang for buck.

Im also hearing about rotating assemblies. If I have understood correctly, its a custom crank that comes with rods and pistons. They (the manufacturers) say that the assembly comes already fully balanced.

Is it worth my while to buy one of these rotating assemblies that come already balanced and are lighter?

Since I have to buy a second hand B16A engine, I am concerned that the internals have been abused and want to take into consideration this wear. I was thinking of replacing the rods and pistons with Eagle rods and Wiseco, respectively or just getting one of these rotating assemblies. But then the whole balancing issue hit me and now there is harmonics.

What would be the best thing todo?

Thanks
Ed

 

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Did a little research on crankshaft harmonics and turned up the following:

http://www.theoldone.com/components/fluidampr/
http://www.fluidampr.com/howitworks.htm
http://www.fluidampr.com/problem.htm

If Endyne "recommends" this dampener for any crank, then it must be good considering Endyne's reputation.
After reading the Fluidampr explanation of it dampener, I should be able to reduce the vibration accross all the RPMs (http://www.fluidampr.com/solution.htm). Eagle Rods says that their cranks are all internally balanced.

What are your thoughts on this MD? How much punishement can a B16A crankshaft take?

I have emailed Eagle Rods about the harmonics on their cranks. I`ll let you know what they say.

The engine will be put into a daily drive. For everyday usage, i`ll probably stay in the lower-mid RPMs (mainly below VTec for fuel saving and speed limit) and on weekends at high RPMs for racing. one can say that my operating RPM range is in the upper RPMs as that is where the most punishment will happen. The powerband will also be up there in the high RPMs.

 

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if the powerband is shifted very high for racing applications, the harmonics created could potentially damage the internals of a shortblock.

(MD, be nice you could quantify "very high". Gives me a number to work with, cause one persons very high could be different from someone else's very high)

 

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DaBoyNBlu: Im first looking to find out what all my options are before spending cash. once I know what the options are, then I can start to see what would give the best "bang for buck" for a given application.

 

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Thats why im here on the foum, doing research. I always do research.

 

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My initial idea (however naive it is) was to redline at 10 000 RPM. That was about 2-3 weeks ago. Since then, I have learnt and that it is not just the components inside but also the head that will take alot of punishment.

In particular the valve seat, i remember reading something about the valve seat taking strain at high RPMs and could result in a loss of CR if the seat was damaged (gap between valve and head). Have to read more into that.

Thinking about it as I type this message, 9000 -9500 RPM may be a better option as going past this would be a bit of overkill and extremely expensive returning less that impressive results for the investment made.

Something relating to balancing of the crankshaft. You say the stock crank if fully counterweighted (I assume your talking about all the B-series crank, both non-type r and type r). Does the balancing of the crank only relate to the crank itself or does the weight of the rods and pistons also affect the balancing?

In my mind (as it stands), if the crank is already balanced the weight of the rods and pistons shouldnt unbalance it provided that the same rods and pistons are used in all the cylinder (aftermarket or stock). Perhaps its a silly question but I would like to be on a solid footing should for myself and should anyone ask me about it. I was thinking of using lighter rods and maybe different pistons to increase the CR.

 

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I dont know about the metal used in the Eagle Crankshafts. Im thinking crower cams and might as well get the crower crank in the same order.

Here in south africa, racing is growing bigger but it is no where near the levels found in the USA. This reduced the amount of "services" available to me in terms of racing.

I dont think anyone here will be able to check the crank for microflaws. So buying an aftermarket crank may be my only solution (or gamble with a second hand one).

 

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Got a response back from fluidampr on the harmonics on the crank (emailed em back to find out if its on the stock crank - im betting it is)

"Ed, Fluidampr is a vibration frequency insensitive damper that works at all RPM and frequencies. Rubber dampers are tuned absorbers and to be effective, they need to be tuned to the critical “order” of vibration in your engine. That’s why rubber dampers can not be one that fits all.

There is no limit to the max RPM for the function of the Fluidampr

As the engine accelerates under load thru the RPM range, the crank assembly will pass thru what is called “critical orders of torsional vibration”. The Honda engine has two critical orders of vibration which are the 4th and the 2nd order. They generally peak near the 6500 and 13,500 rpm range. The mass and stiffness of the crank assembly will affect where these peaks occur in the rpm range.

Thanks,
Fred

Havent heard anything back from eagle rod on the email I sent about the crank. They are a bit slow to respond, maybe in 3-4 days?

Will email AEBS later tonight and crower. Anybody else I should look at?

 

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Thats is correct MD. After reading your engine package article, i see no point in changing my oversquare package to undersquare by stroking. (should we start another thread on square, undersquare and oversquare? There are some bits of info here and there but nothing whole and encompassing of this topic)

As I stated earlier, Im looking to find out the advantages of a lighter forged crank. From my point of view I see that the crank being lighter (same strength or stronger than stock) it will allow the piston and rod to travel down "quicker" as it doesnt have to fight the inertia of a "heavier" crank. I am looking at it correctly MD?

 

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Thanks for your input DaBoyNBlu. I will probably not go for the aftermarket crank given the costs involved as you have stated.

I was looking to find out more about what can be done regardless of cost, so that I know that it exists.

 

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MD: can you explain the difference between counter balanced and internally balanced crankshafts?

one can guess that the one is balanced on the outside and the other on the inside. Any advantages to one or the other?

 

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Does anyone know if a lightened crankshaft is a race only modification and is it still balanced?

Anyone have experiences with the eagle competition rotating assembly?