I am starting this thread because I didn't find it on my search. If there already is one, than I appolagise.

This thread is to figure out what the main diffrences are between the 2.5L blocks, heads and other supporting diffrences that seperate the 210 hp 2.5L, 250hp 2.5L and the 300hp 2.5 sti. Baisicaly what would you have to take into consideration if you were taking the 210-250 hp 2.5L to the sti 300hp levil and beyond.

PS what kind of turbo does the Legacy GT have? is it a tdo4 but with a diffrent compressor housing for fitment to the intercooler?

Thanks Ryan.

All three engines are essentially the same except for turbo and intercoolers. The Legacy GT uses a IHI VF41. The FXT uses a Mitsubishi TD04 (same as WRX) where the STi uses a IHI VF39. There is no 210hp version of the 2.5 liter turbo engine. =P Maybe on paper.

I am starting this thread because I didn't find it on my search. If there already is one, than I appolagise.

This thread is to figure out what the main diffrences are between the 2.5L blocks, heads and other supporting diffrences that seperate the 210 hp 2.5L, 250hp 2.5L and the 300hp 2.5 sti. Baisicaly what would you have to take into consideration if you were taking the 210-250 hp 2.5L to the sti 300hp levil and beyond.

PS what kind of turbo does the Legacy GT have? is it a tdo4 but with a diffrent compressor housing for fitment to the intercooler?

Thanks Ryan.

There is no 210hp version of the 2.5 liter turbo engine. =P Maybe on paper.

http://img.photobucket.com/albums/v113/unclescotty/foresterxt.jpg

I think What he is trying to say is althought the forester is listed at 210 it makes closer to 240 or so

The Legacy GT turbo is a VF40.

I think What he is trying to say is althought the forester is listed at 210 it makes closer to 240 or so

exactly

note the =P
which is the same as :p

Someone did a teardown of and STi engine and a Forester engine, and I belive they found no difference.

I don't remember if the injectors are the same.

So you can do all the same power mods and get the same crank hp for all 2.5 turbo cars. The only bad thing about doing them with non-STis is the weaker drive components and brakes.

I believe the only difference is

STI turbo=VF39
FXT turbo=TD04

STI exhaust=2.5" all the way through
FXT exhaust=2.5" until the axleback and bottlnecks to 2.25" also has a larger resonator than the STI (in the midpipe)

STI intercooler is much larger than the FXT, and the manifold is red on an STI so I'm sure its a little different than the FXT manifold?

oh yeah and ECU mapping.

Injectors are the same for STI and FXT, as far as weak drivetrain components...I believe the 5spd in the FXT has the JDM RA gears and a stronger case. this has been debated before but it is def different than the WRX.

I dont know about the outback/legacy 2.5T setups.

LGT/OXT have
the same short block
same injectors
very differnt manafold /intercooler
very differnt turbo vf-40
simmilar but not the same exaust piping
wacky dual sprung flywheel
simmilar ECU

From what I am told the sti intake manifold is the same it is just coated with a thermo type paint (red). The other difference between fxt and sti is that the sti up pipe has no cat in where the fxt does. Injectors, cams, are all the same. Ecu tuning, 6 spd, axles and what not are different. However, I know that an 04 sti ecu/tmic/turbo will bolt right up to the fxt. Walla, Wagon STI minus the tranny. I am pretty sure that this can be done with the 05 as well but one can not take the 04 ecu and stick it in an 05 or vice versa due to the immobilizer issue.

04 STIs fuel pump different than FXT. I understand that there are hardware differences with the ECUs as well even tho STI and MANUAL FXTs ECUs are interchangable.

I believe the 5spd in the FXT has the JDM RA gears and a stronger case. this has been debated before but it is def different than the WRX.


All 5 speeds share the same transmission. The only difference is the gears and final drive. The FXT is bullet proof compared to the WRX due to the 4.444 final drive and the fact that the owners are of a different breed than your typical WRX owner.

I am not sure how much of a different breed I am. I would actually say that I am the odd person in the Forester world really. But you say potatoe and I say potAtoe. None the less, I am not sure our tranny/gears can handle a TD06H/20g like and stock sti tranny/gears.

You'd be surprised. I spoke about this with Brett at MRT. Apparently years ago, Subaru had nightmare problems with another car over there with breaking gears. SOA's permanent solution? They only changed the final drive on the cars. A higher final drive adds a greater mechanical advantage and adds additional stress to the bigger/stouter ring and pinion gear than the transmission. While it seems ghetto, it works.

Oh and by different breed, I mean more mature. You don't hear about many FXT owners clutch dumping in the 7-11 parking lot like you do about some WRX/STi owners. ;)

WOW this thread I started realy took off. I thnk that every single question I asked and then some has been answered extensivly. I am a proud owner of a 02 340WHP wrx ( non 7-11 burn out type) but am going to be a new father soon, and am considering buying a new legacy gt outback. (realy like the way the hatch back looks for some reason) And I wanted it to be another fun 300-350whp project for me and you guys have been absolutly great on the info side of things.

THANKS AGAIN FOR ALL THE INPUT AND ANSWERS ALL, YOU GUYS ARE GREAT.

Scencirely Ryan T Crane.

I have an 04 Forester XT.
I just had an STi VF39, ECU and uppipe installed.
Having driven a stock STi i can say that my FXT now feels just as quick.
Can't wait to get her to the track.
Best $1000 i've ever spent on a car; complete transformed it.

edited

would the aftermarket turbo setups for an sti fit say a legacy gt ?
i am also looking for a 350whp setup (we'll say using dynojet cause they're the most common) and does anyone make a turbo-back exhaust for them
i am going to be living in an inspection free state soon and am looking forward to the possibilities

ALSO, any FMICS availible ?

if its easier i might just start with a wrx sti and de-wing/ hood scoop it and add an fmic, i just can't be looking like a kid when i show up to work... mainly because i am a kid but i work at an engineering firm so am trying to gain a little respect.

no
350 is very possible
yes several but they are expensive
ok
yes but only in japan .. differnt bumper beam perrin is rumored to be making one perrim makes a nice top mount

look at www.legacygt.com

Sorry, the Forester STi has the VF41.

The Legacy GT turbo is a VF40.

Correct, stock foresters put down more power than stock wrxs. There have been theories that it's because of gearing. But I don't buy that. How can you have a engine that is directly related to the STi engine (technology), same turbo as the WRX, more displacement and yield less power than the older tech 2.0?

ZuM

I think What he is trying to say is althought the forester is listed at 210 it makes closer to 240 or so

Correct, stock foresters put down more power than stock wrxs. There have been theories that it's because of gearing. But I don't buy that. How can you have a engine that is directly related to the STi engine (technology), same turbo as the WRX, more displacement and yield less power than the older tech 2.0?

ZuM

Well, only a lot of possible reasons...I'm not saying it doesn't make more power...but there are a number of ways it could make less. The most logical would be its timing and fuel curves. It's tuned to be more drivable. It could easily make less power than a WRX. And Its fatter torque curve may make for its faster acceleration times...not its HP. So, get them on the dyno and see.


John

why wouldnt sti turbo kits work with a legacy?

all kinds of fxt guys are replacing the stock turbo, ic, up-pipe/downpipe, and ecu to make basically an sti powered fxt; i dont see how a turbo kit designed for an sti wouldnt work.

something to do with the underhood space in the legacy vs sti or fxt?

No - not without changing TMIC and manifold.

elemental, its very possible to swap turbos... if you don't mind doing a custom intercooler.

Rotated mount turbo kits will be rare and likely long time from now thanks to a less "insane" ownerbase and the fact that subaru put the ABS block right in the path of the intake.