Originally Posted by Nad1370

If you ever seen a Honda block...that's an open deck. Meaning coolant passages around the piston for better cooling.

Originally Posted by JDM_EVOVIII

Facts:


STi
-less stress on the crank
-only can hold roughly 14psi on stock turbo (correction)
-2.5L, more displacement than the 4G63 2.0L
-All aluminum motor, light, but not strong
-top mount intercooler, heat rises
-stock turbo is pretty much maxed out as far as boost
-rated more hp & tqe on paper and to the crank
-rated less hp & tqe on an AWD dyno where it counts than an EVO
-STi has been on the track in every magazine and has became 2nd to the EVO from anywhere from 1sec.-7sec. in track time
-Rear wing bends during highway speeds and produces more drag than downforce
-fast, you bet your A$$
-Active center diff.
-slightly larger rotors than the EVO VIII, few mm
-Cheaply designed Recaros, not very supportive
-No radio at all
-1 Model, only 1 way
-Crappy Clutch and a long throw
-To get to 350awhp, you will need to upgrade the turbo for sure. Already, your almost doubling your cost to that of an EVO VIII.


EVOLUTION VIII
-the 6-bolt 4G63 has been around since the late 80's, is very, very proven
-Iron block, aluminum head (strong as hell)
-Front Mount Intercooler for better cooling of the charged air
-Bottom end of the 4G63 can hold 450-500awhp and has been proven
-EVO handles better and has been proven in every mag
-Stock twin-scroll turbo produces 16-19psi, can raise to 22 safely with a BC on pump gas
-Stock internals are completely forged
-Hollow camshafts for reduced rotational mass, less stress on the valvetrain
-Open front diff., except on the MR
-slightly smaller rotors than the STi by a few mm.
-Fully Carbon Fiber Wing, very, very light and functional, doesn't flex at all!
-More supportive Recaro Racing Seats
-Stock CD player
-3 Models to choose from
-Lighter than the STi (RS that is)
-Prices vary from $26K-$34K Brand New depending what you want.
-Crappy Clutch, but a few guys in my club are pushing 350whp Dyno pruven with the stock clutch with only the following mods: Turbo Trix ECU Flash, Hallman MBC 21psi, Helix 3"DP, 3" custom straight CBE, 3" test pipe, HKS 264 cams, not even the 272's...349awhp/330awtqe


These are some things to look at when you are deciding what to go with. Test drive both, but here are the facts from both ends.

hope this helps.

Originally Posted by GPTourer

Thank you. I thought the whole point about mentioning the 4G63's existence back in the late 80's was just to say its proven and refined over the years, not that it was a 6 bolt.



But what about the USDM clutch? How is that a pertinent fact for someone buying a new STi or a new Evo?

Originally Posted by erikgj

The hollow camshafts have no effect on valvetrain stress only on overall inertial loads on the cam and crank drive. Those reduced loads are not seen by the valvetrain itself.


Additional points.
Evo
+ More detonation resistant head
+ Simpler ECU layout
+ Very effective knock sensing (sometimes too effective)
+ Smaller 85mm bore much detonation resistant than the 2.5 Sti 99.5 mm
+ Many mix and match turbo combos
+ Much more emissions friendly one cat versus three on the WRX and Sti?
+ Large front mount intercooler


- Reversed spinning turbo.


STI


I do not believe anything since the phase II boxer motors are truly closed deck. They are all semi-closed ie. Open deck but with support bridges on top.


+ .5 liters of additional displacement
- ‘05s seem to be down on power from ‘04 STi.
- Fly by wire throttle
- smaller top mount intercooler

Originally Posted by MITSU16G

I have owned a subaru and i like my evo alot better plenty of reason, Plus the STI engine is weak compared to the 4G63.

Originally Posted by JDM_EVOVIII

Both clutches won't last very long especially if your modding it.