working out the balance factor for a V6 60-degree

[meth]

I have a VG30DETT which I am currently building up to be a race/drag engine, although it will be street driven occasionaly.

It will be making peak power between 5500-6000rpm.

The bottom end is about to be balanced and I was wondering what sort of balance factor to use or how to work it out? I have the weights of all of the standard components, as well as the new components. Is there a guide as to how, or a formula that will give an estimate of what it is? From reading, and asking questions on other general forums, people are stumped and don't even know what I am talking about. The engine is 'internally balanced' as standard, and has a harmonic dampener attached to the crank.

Any ideas/steps/guides as to how to go about working this out would be great.

Regards
Paul

 

[GregLocock]

You are talking about the individual balance for each piston/crank web system?

You work it out, ideally, by looking at the force on each main bearing. This is possible by hand, but not easy. I don't, offhand know of a reference for that method. I can see how to work the forces out, but you also need to consider the stiffness of the crank, and the bearings and the block.

These days we just run the engine simulation and it gives the bearing loads as a function of time.

Bear in mind that this is a separate issue to second order 'balance', and overall engine primary balance.





Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Fabrico]

Dont' forget to figure in the throw arrangement. Not familiar with that engine, but V-6's have shared or offset throws. Big difference.