From Martin Musial:

First let's look at the rods. As you can see the EVO X rod looks much stronger. Physically it's larger in width and thickness across the beam. The X rods have rod bolts instead of studs, meaning you can upgrade to ARP or other aftermarket bolts easily. The big end is narrower but also larger in diameter than a VIII/IX. The narrower bearing width has less surface area to distribute the load but the larger diameter should help a little. The larger diameter will increase bearing surface speed which can be an issue at very high engine RPM (oil shear issues) but also means the rod journals on the crank are larger and thus stronger.

Stock VIII rod width vs. EVO X rod width






You can see the X rod is almost 3mm wider.

Next with have rod beam thickness





The X rod is about 2mm thicker


Here is shot of the rods side by side



You can see the new X rod has rod bolts rather than studs and nuts like the VIII and IX. This makes upgrading to aftermarket rod bolts very easy.

 

sweet!

 

wow...cool information.

 

nice

 

I notice the VIII/IX rods are quite a bit longer. How do you see this affecting HP potential and RPM potential. I know theoretically a "long rod" version of any motor setup should be better to a point because it reduced the side load on the pistons and keeps the piston near the top of travel longer. . .

EVOlutionary

 

Seems to me like the Evo X con rod is also better designed where the rod beam expands out on the big end ... better 'shoulders' (no idea what the technical term is for this). In essence they look a lot more like some of the aftermarket rods out there.

Found this article for some interesting reading on connecting rods (comments by Brian Crower, Venolia, Carillo, et. al.): http://www.carrilloind.com/Portals/1...Connection.pdf

l8r)

 

nice, seems the x rods are almost 1/8" wider and 5/64" thicker, thats a huge improvement. Wonder what they did to counter-balance the extra weight, less meat on crank? Substantial weight difference?

 

This is a world engine right? If so this is the same engine in the Caliber Srt-4? Correct me If I'm wrong from looking at the engine bay they look exactly the same. Only difference is Chrysler used the 2.4L While Mitsu used the 2.0L

 

Correct, the 4B11T is based on the world engine - modified to Evo (i.e. rally homologation) spec.

l8r)

 

wow thankyou martin for the info!