[jtsaip]

I've got a 1993 impreza L wagon that I'm currently deciding the fate for. I got the car for $700 a few months ago and since then it's been sitting on my driveway.

For someone who's done some oil changes, changed a few speedometer cables on a 91 nissan pickup, done spark plugs and wires, how out of reach is doing a FWD -> AWD conversion on my impreza, with the eventual goal of engine swapping a turboed 2.5 into it?

I have other vehicle(s) that are driveable, so this could theoretically take as long as I would want, but how much of this swap could I do by myself and how much do you think it would cost roughly? I have access to junkyards that have imprezas

 

[mike-tracy]

Just buy a wrecked AWD impreza, like a 93-95 for best compatibility, and swap everything over. If you can turn wrenches, you can swap it. It might take 6+ months to complete, but if time isn't a factor, then go for it. I live in Washington, and AWD cars are a dime a dozen, so I wouldn't bother buying a FWD one (fwd subies do exist in Washington).

 

[jtsaip]

I've decided I'm probably going to do a N/A ej22 swap from a legacy into it and keep it FWD for now.

If I go with a later year phase I (95-98) ej22 from a legacy those are single port exhaust correct? That won't fit with my dual port exhaust manifold so would I be able to take the exhaust manifold from the donor car and swap it for mine? Will an OBDII engine be a problem in the 93 impreza if i swap the intake manifold with wires from the ej18?

Also I realize that this should probably be in the swap forums 😅

 

[mike-tracy]

Many 95's had dual port heads, at least for Legacys. 95 Legacy "California emissions" motors were single port.
The single port ej22's aren't really a big deal, the single or dual port factory headers bolt up to the rest of your exhaust no prob.

If you find a 90-98 Legacy motor, you will be able to use your ej18 intake manifold and ej18 electronics & wiring and everything. 99 Legacy was the last year of that body style, but they updated the ej22 into something that is not compatible with your manifold and electronics.

If you do find an ej22 with single port heads, you could always slap your ej18 heads onto the short block. In addition to getting dual port heads, you will also gain a slight compression boost good for a couple more HP.

Before I forget, you will need to move the timing gears from the ej18 to the new engine, specificially the crank sproket and the driver's side cam gear. You might accidentially get the legacy engine that has the same exact timing regime and parts. But the chances of that happening, to a subi-newbie, are slim to none.

 

[jtsaip]

Do you know if the same thing would work but with an EJ25 from the same years?

 

[mike-tracy]

There's a lot of compromises in using complete ej25 engines.

But once again if you slapped your ej18 heads onto an ej25 shortblock irregardless of the year, that will work with 0 incompatibities.

 

[jtsaip]

What would the compromises be?

 

[mike-tracy]

It depends on the engine chosen.

But you might lose the ability to idle smoothly. Mileage in the teens. Needing to run premium fuel. You might end up earning your Bachelor's in Electrical Engineering just figuring out the wiring.

 

[jtsaip]

Not sure I can link posts to other forums but I found this in researching last night:

narg. my ej18->ej25 saga is complete - NASIOC

narg. my ej18->ej25 saga is complete Subaru Conversions

forums.nasioc.com

Looks like he didn't even switch the heads?

 

[mike-tracy]

You don't have to switch the heads. But look at his list of problems, and the potential compromises I wrote about above. His method only works with the 96-99 EJ25D engine.

If you put your ej18 heads on, there is no incompatibilities in any which way. You can use any ej25 shortblock Subaru had ever made, not limited to the 96-99 ej25D.

 

[jtsaip]

I was reading some stuff saying the 1.8 heads shouldn't go on 2.5 blocks since the bore is different.

I'm feeling like I'll probably go the phase I ej22. I feel like the only concern I have if I a pull a 21+ year old motor from a salvage yard is that it'll run worse than my existing ej18 and they're not even "that" cheap (~$300).

Would one of these require a ton of wiring?

MY97 Subaru Impreza WRX GC8 2.0L DOHC Turbo Engine Longblock JDM EJ20G

PARTS INCLUDED WITH PURCHASE : - CYLINDER HEADS- 2.0L BLOCK- INTAKE MANIFOLD- THROTTLE BODY- FUEL RAILS- INJECTORS- ALTERNATOR- TURBO MANIFOLD- TURBO- OEM TOP MOUNT INTERCOOLER- MAF (MASS AIR FLOW SENSOR) ** ACTUAL PHOTOS, THE ITEMS SHOWN IN THE PICTURES ARE THE ITEM(S) YOU WILL RECEIVE. **

www.lowmilejdm.com

 

[mike-tracy]

Guess what, the combustion chamber size for the 97-99 ej25 and later (not sure about the AVCS ones) are the same size and general shape as 2.0L Subaru heads.

The ej25 has a bore size of 99.5,
the ej22 is 96.9mm
The ej20 is 92mm
The ej18 is 87.9mm

What I'm getting at is Subaru mixed and matched their heads with different bore sizes, from the factory.



You don't have to take anyone's advice, because at the end of the day you'll be the one doing the wrenching. But I like the ej22 idea. It is subaru's most reliable engine to date. Just make sure you get one that's a 1998 and older.