2.5L engine

Is the 2.5 L engine used in the Legacy's starting in 1996 the same base engines used in the 2000 on up wrx's, including the sti?

The WRX's use a 2.0 engine, it's only the US STI which use the 2.5 engine and it's only been one model year, 2004.

yeah but what i am tryin to figure out is has there only been one 2.5L subaru engine cause they also used one in other impreza's from like 2000 on. Like the 2.5RS coupe and so on.

Hmmm.....I can tell you must be very new to Subaru's.

Subaru used a 2.5 DOHC engine in the 1998 2.5RS, and then switched to the 2.5 SOHC engine from 1999 onwards. (that's 2 different 2.5L engines).

The WRX was introduced to the US market in 2002 and used a 2.0L turbo engine, Subaru has continued the 2.5RS alongside the WRX, but prior to the introduction of the WRX, the L was the second Impreza model which was offered.

In 1996 Subaru began offering the 2.5L DOHC in the Legacy GT models, the same engine which was offered in the 1998 Impreza RS.

The new STi 2.5 is DOHC also, while the new N/A 2.5 is SOHC. The STi 2.5 is semi-closed deck also. There there are the obvious changes, completely different rotating assembly in the STi then the N/A models, and even the newer 2.5 N/A's have different (more brittle :( ) internals than the old N/A's.

It's a big confusing mess if you get into it, I'm still trying to figure it all out myself.

Hey Dave, when you say newer, do you mean like our model (bug eye) or do you mean the current?

Never heard the newer models 2.5 was more fragile.

I haven't been able to track down exactly when they changed. Some say it was with the Phase 2, some say it was when it changed to bug eye, some say it was in the middle of 01 models, some say even some of the bug eyes have the old style pistons. I have no idea :dunno:

Oh, the early 2.5RS's had a lower compression ratio too.

And my name is Jason ;)

Yes i am new to Subaru's. But anyways, so if I got this right the Legacy GT's, like 97 used the 2.5 DOHC. The new WRX sti's also use a 2.5 DOHC, but they are turbocharged and other upgrades on them?

The STI's 2.5 is a completely different engine to the one on the Legacy GT.
Different internals, different block......different.

Sorry Jason, got you mixed up with the Bloke, humble apologies.

wait what about the 1997 legacy gt it used a 2.5L DOHC?????

Yes it is a DOHC 2.5

Be careful though, the DOHC engines were prone to headgasket failure in the earlier generations.