Now that the sti and evo have been out for almost a year, what seems to be the consensus regarding engine potential (both on stock and aftermarket turbos)? I know the sti is cursed with a small turbo, poor wastegate design, and crap injectors. I would think this would give the evo the clear advantage retaining the stock turbo. Also, there seems to be some debate as to whether the sti has forged pistons (aps claims no, some claim yes). Also, which motor has the upper hand in terms of longevity? (I realize this is speculation) People on nasioc and club wrx seem to be a little delusional, claiming a well taken care of sti should last 300k on original engine. What's everyone’s take on these issues?

 

The engine in my Sti is a lot smoother than my Evo's. It seems that it just doesnt run as hard as the evo's does.

If the engine were older i would take a bet that the Sti engine would last longer. But since its a brand new engine with problems, id put my money on the evo

 

They arent delusional they will get 300K cause no one over there turns the boost past 20 PSI on any kinda buildup They also have trouble overboosting and inconsistant behavior with just an open exhaust. There is not much in the way of EM right now (xede) so lets get down to details. The EJ257 is unproven 1st gen design. The JDM 207 is a great engine near or on par with the 4G63 but no way can we say that with the 257 yet. The USDM 205s cylinder walls oval under extended heat and load. I feel we will see this with the 257 when the STis are modded well and not tuned perfectly.

Im amazed with the 4G63 over the years a lot of mistuned blue boxes and cranked mbcs- that couldnt and didnt happpen to the wrx. The 257 is essentially the same block size, Al, but with better (not like the 4G63) internals I cant remember the name of that supposed new metal name but Ill look.

I love subarus Im more of a subie guy than EVO I put 15K into my wrx and If I buy a subaru agin it will be only ecm and exhaust upgrades unless its a 207

 

you wont sell you EVO for a subaru

 

Ummm NO

 

I want to see you run in the 12's............I just bought a laptop so I can tune my XEDE, just need to get that baby installed now!!

 

That's mainly due to engine design, a boxer engine naturally balances itself better than an I4. The Evo does run a bit harsher than my old WRXs, nature of the beast. For real buttery smoothness the I6s from BMW are hard to beat.

 

It also has to do with the fact that mitsu chose some fairly stiff engine/tranny mounts to keep the drivetrain from doing the salsa during hard acceleration, etc.. They transmit more vibration to the passenger cabin.

 

ding ding ding we have a winner

neither engines are internally balanced.

 

ummm..actually the Subaru engine is, and always has been internally balanced.

STi most defiantely does NOT have forged pistons, though the rods are forged. The pistons are high pressure cast, but are actually quite nice, and if you look at one, had much more attention than previous Subaru engines (which look like overgrown lawnmower motors inside!)

4G63 defiantely has the better reputation for taking abuse. So far, noone has really pushed the STi at all - its not nearly as popular of a car to mod as the Evo seems to be (for many Subaru enthusiasts, they waited so long for the STi, that to them, its pretty well setup from the factory, and to a large degree, I would tend to agree).

 

Actually, your wrong. A horizontal 6, inline 6, 60 degree v12 are the only internally balanced engines. A flat four is NOT balanced.

 

That is simply not true....not all inline 6's are internally balanced (many examples).

Subaru's flat 4's definately are.

 

I always thought that internally balanced meant that an engine doesn't have to run any specially counterweighted flywheels and pulleys (external parts) to keep the engine from shaking itself apart.

 

I am refering to the inherent characteristics of the engine layout. ALL flat 4's suffer from a moment of inertia inbalance. I'm trying to dig up the chart with the actuall equations on it.

 

So are you saying the EJ engine has no harmonic balancer or balance shafts? From what I know unless the crank is balanced the engine is not truly balanced.

The 4G63 has been around much longer than the EJ257. More people trust something that has been around longer. Take the Chevy 350, all the muscle car guys say this engine is the best thing since the ice cube. My only disappointment about the STi is that they had to increase engine displacement to up their power. For this reason I would repsect an STi far more if they would have made the EJ20 more stout, rather than add another engine into the lineup.