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2.5 N/A to Turbo
Posted: Fri Feb 16, 2007 5:33 am
by TdotSubie
Im in the process of buying a new car, and I'm trying to decide between a 94 SS auto, or a 97 GT 5spd (legacys obviously). My question is if anybody knows wether or not the 2.5 N/A motor can be boosted easily, and if so how much is safe? I had a 93 SS auto and the only thing I didn't like about it was that was an auto, so this time around I really want a 5spd. Another option is maybe a 5spd swap in the SS. Thoughts?
Posted: Fri Feb 16, 2007 5:49 am
by gto7419
The 2.5 can be boosted just as easily as any other n/a motor. the problem you will run into though, is the rods/crank are not forged, you have a higher compression motor, your ecu will have advanced timing where as a boosted application may need the timing retarded.
Basically, the stock rods in the 2.5 n/a cannot handle the extra torque a turbo adds. On top of that, you will have to deal with adding fuel and retarding the ignition. You might also want to get a set of pistons made for a turbo as the n/a pistons are higher compression.
I would personally do the tranny swap and upgrade the turbo on the ss....
Danny
Posted: Fri Feb 16, 2007 6:23 am
by 555BCTurbo
Actually, all Subie EJ cranks are forged...and most of the rods too...
Many people have turbocharged the EJ25's, but I honestly don't see the reason you would want one over an EJ22T...
An auto to manual swap is very straight forward, much less time and money than a turbo EJ25 project
Posted: Fri Feb 16, 2007 7:05 am
by Kelly
NA22s turboed suck.
Posted: Fri Feb 16, 2007 7:11 am
by 555BCTurbo
He is talkin NA 2.5's Kelly...
But I am sure that's what you meant
(Kelly has expressed his disdain for turboed EJ25's to me in the past lol)
Posted: Fri Feb 16, 2007 7:27 am
by gto7419
555BCTurbo wrote:Actually, all Subie EJ cranks are forged...and most of the rods too...
Many people have turbocharged the EJ25's, but I honestly don't see the reason you would want one over an EJ22T...
An auto to manual swap is very straight forward, much less time and money than a turbo EJ25 project
Hmmm - I thought we were the only lucky ones!!! Are the rods in the 2.5 n/a forged also?
Posted: Fri Feb 16, 2007 7:39 am
by douglas vincent
Kelly is currently "in a snit"
But I still love him.
Posted: Fri Feb 16, 2007 7:56 am
by azn2nr
pistons are the difference betwenn 22t and 25x. they all use the same rods which can withstand the power.
turboed subie na's hardly make power off the shelf turbo style. their very finiky when it comes to this sort of thing
Posted: Fri Feb 16, 2007 9:05 am
by Kelly
Wow, I was so blinded by rage about my dog eating my pizza.
NA25's are grunty when done correctlly, but grenades when not.
NA22's suck.
Neither are fast.
And yes, I'm a bit "snitty"
Posted: Fri Feb 16, 2007 11:05 am
by 92ss satinsvoice
get some stock turbo pistions, rods and call it good on the bottom end.
for a n/a 22 that is..
Posted: Thu Mar 29, 2007 4:53 am
by justin the subie
my '92 touring wagon was an automatic... i think many people in this forum already have had this convo with "laurel the queen" when she was getting it done.... the swap looks and works very very good... i just hooked up the neutral safety switch to the alarm and remote start and it works sweet as well... kudos to whoever did my AUTO2MANUAL swap!!!
[img]C:\Users\User\Pictures\2007-03-27\IMGP0239.JPG[/img]
Posted: Thu Mar 29, 2007 7:22 am
by 555BCTurbo
Pacific Import Auto did your auto > manual swap...
Posted: Fri Mar 30, 2007 5:41 am
by justin the subie
hey thanks man!!

im tryn to get as much info on this car as possible.. do u know the previous owner(s)??? i have many questions about my car, like what is this wire harness all tucked up behind my radio??? it looks like a computer monitor plug... what turbo ive got... neway thanks for the info.. much appreciate
Posted: Sat Mar 31, 2007 12:04 am
by 555BCTurbo
I knew Laurel, before she decided to go totally apeshit on me and not be my friend...
I don't know a whole lot about the car, but I rode in it when it was Auto, and I know it has a TD05 Turbo and an AWIC...and it was REALLY slow!!
It's a nice car, take good care of it...
and no big hood scoops!!!
Oh...that computer monitor plug is most likely a select monitor cable...search to find out about what that is

Posted: Sat Mar 31, 2007 1:40 am
by justin the subie
Posted: Sat Mar 31, 2007 2:36 am
by gto7419
That is a damn nice downpipe...
Posted: Mon Apr 09, 2007 9:14 pm
by MY99 2.5GT
VF39 is the stock STI turbo but it isn't ball bearing.
The VF34 is an older JDM stock STI turbo and is ball bearing. I was just reading about someone that did VF34 swap into their ss.
You will definitely need to swap injectors. I would think the STI side feeds would work. I bought a set of 740cc sidefeeds from a good seller on ebay for under $300.
Brad