98 LGT With EJ25 -> JDM EJ20 Swap

[ElijahHooper]

Hello everyone, I own a 1998 Legacy GT Limited Sedan which I love. However, it has the stock US EJ25 with its sad 4 spd transmission. It has 157,000 miles.

The car still runs pretty well  and looks amazing with little flaws as the previous owner garage kept it as a commuter. But you all can guess it’s SLOW, very SLOW (and the auto transmission is trash and on its way out anyway).

With all that said, I am a mechanic at a Subaru dealership (though I’m 18 and not extremely knowledgeable) and want to engine swap to the twin turbo ej20r.

I know that the ej20r came out of the GTB from Japan (I think?) of the same year so would that engine work best ? I know I could technically do like a ej257 wrx swap or something like that, but the EJ20R sounds cooler, is twin turbo, and I’ve heard is pretty strong (does it have forged internals?). I also know that a lot of sensors and everything would mate right up from my engine, although that might be the case with most EJ engines. 

What manual tranny mates up well for my car and for one of these engines? Would the manual off the GTB be the best option or maybe just the usdm 5 spd? Or is there any 6spd transmissions that would work?

I appreciate any help I can get I’m really excited of this being a possibility I just want to choose the best option for my car.

Any tips and tricks also would help, like what I need to know about using the Usdm computer and the usdm intake so that it’s still tunable and works fine with all the Egr and weird “eco-friendly” us requirements the original engine has. Thanks!

Edited April 11 by ElijahHooper

[KZJonny]

Haven’t got too many answers for you mate, but good luck on the swap!

Before you buy yourself a pile of headache, you may want to look into the reason why so many people that HAD the twin turbo EJ20s swapped them over to a single turbo. Lots of information out there on the topic.

An EJ20X is going to be a fraction of the cost/headache to make work, and is a known value these days.

Enjoy whichever option you choose!

[ElijahHooper]

Thanks @KZJonny,

From what I’ve gathered the EJ20x is open deck. Does this mean it couldn’t handle boost well? I mean the whole point of this project is to make more power. I don’t need anything crazy but boost would be necessary for a ej to be somewhat “fast”. 

[rhino6303]

I would recommend you reach out to iwire as they specialize in swaps. They could answer any questions and give good feedback on which motor would be easiest to swap. 

[KZJonny]

3 hours ago, ElijahHooper said:

Thanks @KZJonny,

From what I’ve gathered the EJ20x is open deck. Does this mean it couldn’t handle boost well? I mean the whole point of this project is to make more power. I don’t need anything crazy but boost would be necessary for a ej to be somewhat “fast”. 

Ej20X, EJ255, EJ257, all open deck blocks, or semi-open depending on how you call it. All come with factory turbos. Many make 350awhp when done up right....

That is plenty of power.

iwire will have great advice for sure.

I was mainly suggesting that there lots of known and documented ways of swapping to common engines that will make enough power for you. Anything twin turbo and JDM is going to be very expensive + a very small community of people who have done it, and are able to help. Not many of them here (if any). Probably 90+% of this forum is either EJ255/7 or some single turbo variant of that with a built block or a Type RA short block, which is the same thing.

Modern turbo technology means that twins aren't really a thing for small displacement engines like a 2.0/2.5L any longer.

 

LOTS of info out there on the argument, and tons here about the mainly USDM platform stuff. People here are happy to help, but I don't think many are going to have much to say about the twin turbo Legacy/Liberties.

I lived in New Zealand for a few years, and drove a TT Liberty that a friend owned. It was quick, but my EJ255 was faster when it was stock. Just sayin, more turbos isn't always better.

[KZJonny]

1 minute ago, KZJonny said:

boost would be necessary for a ej to be somewhat “fast”. 

@Febreze Mee....

I'm not so sure about that statement...

But my NA Legacy isn't at all fast.

[silverton]

If you wanna go fast you need more cylinders

[Febreze Mee]

Highlighted times were the best of our four morning runs. I came 6 out of 21.

I will never claim my EJ253 is fast, but since @KZJonny brought it up lol, this was my standing at one of the AutoX events last summer. Not exactly an apples-to-apples comparison. And although the ppl I drive with don't time our uphill/downhill runs in the mountains, I'm still successfully punching above my weight.

OP please yield to everything said in this thread. 90's JDM twin turbos are expensive to keep up with, and high maintenance. Add the headache and expense of swapping, and not a lot of ppl want to invest the effort that you're discussing. 

However, if you pull it off, I'm here to see it!

[KZJonny]

26 minutes ago, Febreze Mee said:

Highlighted times were the best of our four morning runs. I came 6 out of 21.

I will never claim my EJ253 is fast, but since @KZJonny brought it up lol, this was my standing at one of the AutoX events last summer. Not exactly an apples-to-apples comparison. And although the ppl I drive with don't time our uphill/downhill runs in the mountains, I'm still successfully punching above my weight.

OP please yield to everything said in this thread. 90's JDM twin turbos are expensive to keep up with, and high maintenance. Add the headache and expense of swapping, and not a lot of ppl want to invest the effort that you're discussing. 

However, if you pull it off, I'm here to see it!

Torque solves a lot of problems… I would genuinely like to find a NA bugeye wagon and give it the proper suspension/tire/engine once over.

Top speed and hill climbing. The EJ253 isn’t gonna take down a well trimmed GT, but driver skill counts for a lot.

Plus not having to upkeep a garage queen turbo car means you have more money to spend shredding tires and filling the tank. (Which you well know….)

[silverton]

Way back before my GC was turbocharged I went out and played in the twisties with someone who had a GC with an ez30 swap.  My car was auto, his manual, and he claimed he had a difficult time keeping up with me in some sections, even having more power.

Knowing how to drive and to use your car efficiently has a lot to do with it. It's a shame you can't go out and play like this anymore, way too many people.

Edited April 13 by silverton

[Febreze Mee]

7 hours ago, silverton said:

Way back before my GC was turbocharged I went out and played in the twisties with someone who had a GC with an ez30 swap.  My car was auto, his manual, and he claimed he had a difficult time keeping up with me in some sections, even having more power.

Knowing how to drive and to use your car efficiently has a lot to do with it. It's a shame you can't go out and play like this anymore, way too many people.

Someone who gets it!

Btw we play like that every single weekend, and more in the summers. Specifically, on that very road. I know I've sent the invite to you too. Shoot, I was driving that road every night in November of 2023. And even had @Captain Redbeard, @boxkita, and a bunch of the cars throughout my build thread there for a few runs before taking off on vacation in December. 
 

Come out next time!

[silverton]

Oh yeah, I know you've invited me a ton of times and i just haven't been able to make it due to whatever.  I believe we've even exchanged numbers. I know that one time I was on my way to join you but I was way too late and the ferry was very backed up so I just went home, lmao.  I'll definitely try harder to meet up with yall in the coming weeks if you extend the invite.

[boxkita]

1 hour ago, silverton said:

Oh yeah, I know you've invited me a ton of times and i just haven't been able to make it due to whatever.  I believe we've even exchanged numbers. I know that one time I was on my way to join you but I was way too late and the ferry was very backed up so I just went home, lmao.  I'll definitely try harder to meet up with yall in the coming weeks if you extend the invite.

Ferry? are you on the pennisula? or the islands?

I can attest to @Febreze Mee driving his "turbo look" non turbo wagon like it was meant to be driven. After a couple days hooning the backroads I started looking for a replacement for my wagon that I sold.

[boxkita]

@ElijahHooper - depending on the dealership you work at, there will be a master engine tech who can tell you everything you never wanted to know about swaps. Make friends with them. They have every tool you'll ever need. And knowledge you can't afford to buy. The master tech at the dealership I worked at had built 1000's of engines. More of a testament to the quality problems of Subaru...

A twin turbo subie is a money pit. Even more than a single turbo. There's a reason so many ended up in junkyards. 

you can buy a wrx full drivetrain for less than it will cost to get the twin turbo working 

[silverton]

47 minutes ago, boxkita said:

Ferry? are you on the pennisula? or the islands?

I can attest to @Febreze Mee driving his "turbo look" non turbo wagon like it was meant to be driven. After a couple days hooning the backroads I started looking for a replacement for my wagon that I sold.

I'm in north seattle, they were driving around the peninsula iirc but were starting in tacoma so I was going to meet up somewhere in the middle

[boxkita]

1 hour ago, silverton said:

I'm in north seattle, they were driving around the peninsula iirc but were starting in tacoma so I was going to meet up somewhere in the middle

Hmm wonder if that was the trip I did.

A gr86 doesn't fare well when the road you used to flog your turbo wagon on turns into a gravel pit for miles.

[Febreze Mee]

5 hours ago, boxkita said:

Hmm wonder if that was the trip I did.

A gr86 doesn't fare well when the road you used to flog your turbo wagon on turns into a gravel pit for miles.

This was that very drive. It's when we went with Corey up to Crescent Lake bc Hurricane Ridge was closed.

 

@ElijahHooper we have completely thread jacked this, and I am sorry for that. 

Edited April 14 by Febreze Mee

[KZJonny]

Back to OP:

Some good info here on ‘other’ turbo engine choices.

Even back in 2011, the TT swap wasn’t well liked apparently. At that was when a TD04 wasn’t considered an outdated dinosaur of a turbo.

[silverton]

On 4/10/2024 at 9:13 PM, ElijahHooper said:

Hello everyone, I own a 1998 Legacy GT Limited Sedan which I love. However, it has the stock US EJ25 with its sad 4 spd transmission. It has 157,000 miles.

The car still runs pretty well  and looks amazing with little flaws as the previous owner garage kept it as a commuter. But you all can guess it’s SLOW, very SLOW (and the auto transmission is trash and on its way out anyway).

With all that said, I am a mechanic at a Subaru dealership (though I’m 18 and not extremely knowledgeable) and want to engine swap to the twin turbo ej20r.

I know that the ej20r came out of the GTB from Japan (I think?) of the same year so would that engine work best ? I know I could technically do like a ej257 wrx swap or something like that, but the EJ20R sounds cooler, is twin turbo, and I’ve heard is pretty strong (does it have forged internals?). I also know that a lot of sensors and everything would mate right up from my engine, although that might be the case with most EJ engines. 

What manual tranny mates up well for my car and for one of these engines? Would the manual off the GTB be the best option or maybe just the usdm 5 spd? Or is there any 6spd transmissions that would work?

I appreciate any help I can get I’m really excited of this being a possibility I just want to choose the best option for my car.

Any tips and tricks also would help, like what I need to know about using the Usdm computer and the usdm intake so that it’s still tunable and works fine with all the Egr and weird “eco-friendly” us requirements the original engine has. Thanks!

To get back on topic and from someone who's also done a thing to be different with their Subaru (GC-RS+t)....  do you own another car? If this is your only form of transportation I highly recommend NOT turbocharging your car.  My RS spent more time on jack stands than it did its own rubber... tires did last a long time though. The best thing you can do for this car is locate a used EJ25D, completely refresh it, and put a manual transmission behind it.  From there start doing tire and suspension mods. Absolutely do not cheap out on anything.  Do it right, or do it twice...or thrice.  That doesn't mean you have to buy top of the line everything, what it means is to do your research make sure the stuff works and dont buy anything knock off from ebay/amazon.

The best advice I can give anyone wanting to turbocharge their Subaru is this, buy a factory turbo Subaru.  Those twin turbo legacy's are getting to the point we can import them now if you really want to play with one, but as others have said... they really aren't all that exciting.  They have one tiny turbo to help in the lower rpm range, and one medium turbo to help in the upper range and from what I've read the transition is not smooth while out bending the twisties and makes for a not good driving experience.