I know.. But the X has a better rod ratio

 

Click on the link I posted and you will see that lighter is not necessarily better. Ditto for steel vs aluminum vs titanium.

IMO, the 4g63 stock rod design is so ... 90's ...

l8r)

 

LOL meant my General Foreman at work =)

 

I was thinking along the lines of durability. But I could be wrong...

 

There's some balance of weight/strength, but the lighter you can make it while still being 'strong' enough, the better.

Part of that is all the G forces put on the recipricating parts. Those rods, pistons, etc, experience acceleration forces in the 100s if not 1000s G range. The heavier something is, the more force it takes to accelerate it, F=ma. So the heavier your rod, the more force it puts on the rod bearings, etc.

 

Understood, but then again.. wouldn't the heavier the rod - the less likely to break if placed under enormous stress?

 

Weight has nothing to do with strength, its more material, design . as mentioned when you are moving the weight up and down this is what creates the force. heavy wt moving very fast means alot more load to break. light wt moving very fast less load. this is very basic but is a good starting point alot of small factors play into this as well. nice to see beefy internal to start with. looks like they did some R&D over the last 2 years.

 

Having said that, suppose you have 2 materials that are identical and one is heavier than the other. I would think that even though it takes more load to move the heavier weight up and down, that if there was a force opposing the weight (ie. detonation), that the lighter weight would break under less stress than the heavier.

 

I think thats why the head gaskets are made the way they are. It dies and saves more expensive parts when exposed to excessive knock.

What about that heavier rod when it reaches tdc and bdc, the bearings will be screaming at high revs along with the thinner neck portion of the rod. At some point the weight becomes an enemy. The newer rod design has been beefed up in all the right places and lightened stategically. Dr. Evo has made the best Evo engine ever...... until it is overhauled and redisigned for direct injection.

 

Very true.

 

some of this discussion is about what is best for each application. rotational forces will always be better if you are lighter. sometimes it just isnt feasable to have super lightweight and enough strength to be durable. as was mentioned before F= MA , the heavier rod will have more force applied to it the faster it goes. so if it has a break force of say 40 and mass of 4 then at an acceleration of 10 it will break. if you could lower you mass to say 2 then you could maintain an acceleration of 20 before it breaks. very simplified, faster/higher revs, what we need is some
unobtainium to build your engine with.