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.

 

Good info I suspect you guys will have more info soon! Cant wait.

 

jesus, I feel like my Evo VIII motor is so weak in comparison! Glad Mitsu stepped it up and made things beefier where it matters. . .

 

Lets just wait and see how the block holds up big boost.. Call me skeptical.. LOL

 

awesome, but what about the block? I think that's where the most concern is right about now. Hey, here's a great comparison: since the sti is a semi closed deck, aluminum block, how about comparing the two to see which one is stronger/better reinforced? That would be a great comparison.

 

are the X cast, forged or shot peened compared to the VIII? do they weigh the same?

 

I have a feeling you will be eating your words

 

That info is readily available on mitsu's website via the latest news/media section. The rods are very much forged, and I'm not sure about the weight.

 

Thanks AMS. Love the tech threads!

 

I would guess the block has to be a bit tougher given that its running 24psi from factory at the largest load point. If we are going to compare stock to stock, then that would mean no ARP studs / bolts etc and then do the boost comparison. Then I think you would find that the new motor is quite a bit stronger in this area. However, add studs etc, its all unknown.

 

I doubt it.. well see soon enough i guess.. when sleeves start shifting,splitting and warping i wont say i told you so..

 

stock to stock i dont doubt 1 bit the X block is better. Lets see what happens when you throw 40-50psi of boost at it.. Nothing more aggravating then sleeve issues IMO..

 

Apology accepted ;p

This is definitely going to be an interesting ride. Its very exciting to have a new motor with unknown attributes. We all knew what we could or couldnt do with the 4G63, and now we get to start that roller coaster ride all over again!!

Thanks to AMS for sharing so openly!

 

I'm done yet :-)
I'll have weights later today. I have a bunch of tech stuff in the works. Head stuff is next, some cool stuff.

 

Yes, the block will be interesting. We'll be taking a close look at that.