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Guest Message by DevFuse

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How do you get engine compatibility/swap info?

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5 replies to this topic

#1 swc7916


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Posted 21 September 2006 - 02:15 PM

I'm sure that this subject has been beaten to death somewhere, but here's my situation and what I think that I would like to do about it:

I'm not satisfied with the engine/transmission/suspension in my 2004 Outback. It has the 2.5 liter 4 with the automatic transmission. The Baja has the same vehicle configuration, so why wouldn't a Baja turbo engine/transmission just drop right into my Outback? I could replace the hood with a Baja turbo hood and the car would look like it came that way from the factory.

The things that I would like to know are:

Does the Baja turbo have the same basic engine as my 2004 or is there something different about it? (i.e. can I add the turbo components from a Baja or Forester XT to my engine, or would I have to replace the entire engine?) I don't know about this, but since the Baja and Forester turbos put out 210 hp vs. the 250 hp of the turbo Legacies, it seems to me that there is something different about these engines. Does anyone know anything about this? I also own a Baja and it seems to have a firmer ride and to have more ground clearance. Is the suspension in the Baja different from the Outback?

If you don't know any or all of this, could you point me somewhere to start my research?


#2 torxxx


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Posted 21 September 2006 - 11:55 PM

as for adding a turbo to a N/A motor, waste of time. the heads have oil and coolant ports built into the heads. Not to mention the pistons in the block and the dome of the heads are set for a lower compression. Turbo engines run 7.5 to 8:1 compression, where as a N/A (Naturally Aspirated) run 9:1 to 11:1 compression. You could use a high compression block with a turbo, but right there you've just lost reliability.

Yes you can put a turbo engine in your outback, but you are gonna be looking at swapping wiring harnesses. As for baja 210hp vs legacy 250 hp, you are looking at different spec engines, ecu and all that. the baja is most likely detuned some because of the lack of weigh in the rear.. turbo forresters are putting out 230+ hp and can be easily made into over 250 with just flashing the ecu

The baja has stiffer suspension because its lacking a buttload of weight over the rear end. Subaru has made their cars heavier and heavier over the years.

You want more power, go for the EZ30 (6 cylinder) or get a WRX wagon

#3 Numbchux


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Posted 22 September 2006 - 01:36 AM

well, the EZ30 is going to be at least as much work as any other engine swap, and probably more, because it's physically a biger motor. and doesn't have that much potential unless you're doing a full-on build, and still....

the automatic tranny is you're #1 problem. they rob horsepower, and even more torque, like nothing else. if it's even remotely a possibility for you, I'd be looking at a 5-speed swap first.

N/A motors can easily take some boost. there's a local guy who just slapped (as much as you can say that) a WRX turbo/intercooler on his impreza. the OBDII factory engine management system can easily compensate. now, running the full 8psi of boost that the WRX turbo can put out in stock form, he's sacrificing some reliability, and he knows that. but that turbo can be modified to put out about 4-5psi. which should be good for about 50hp at the wheels, and won't sacrifice your reliability much at all (depending on how you drive it)

#4 idosubaru


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Posted 22 September 2006 - 07:28 AM

there is a board member who put a turbo on his Impreza OBS. it was originally non-turbo and has the higher compression non-turbo pistons. he had excellent results and it was fairly easy to do considering. i think there was even an easily accessible oil supply line someone on the EJ22 that he used, but i don't know much about turbo's except that it's been done. it would be my guess that there's information on this board about this kind of stuff, if he didn't write about his own set up at least. the computer didn't even need upgraded, it handled the boost quite well. he actually removed all the turbo stuff and has been driving the car for a long time, it's still in great shape and he drive it in stock form now, back to non-turbo.

a 2.5 turbo will definitely drop in without a problem, i just don't know what issues you may encounter. i bet it plugs right in. the engine will be identical, it'll just have different pistons and a few other items, but the basic layout, size, motor mounts are the same. one issue with turbo motors is that the engine cross members on the older subarus are different. the turbo's require some clearance for the exhaust so you have to have a turbo crossmember on some older subaru's to get the swap to work right or customize your exhaust (not a good option). you'd think Subaru would find a way to make them all the same by now though...cheaper manufacturing costs.

so...i really don't know any specifics to this swap, it's a relatively new vehicle. but it shouldn't have any problems fitting, but i'd suspect some minor issues to creep up. i'd guess NASIOC guys have more info on these specifics.

you'll want an entire engine, engine wiring harness, complete intake, and exhaust. and an ECU might be nice as well.

#5 Numbchux


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Posted 22 September 2006 - 05:34 PM

yep, the crossmember is different, however a custom up-pipe could be bade to go behind the crossmember and passenger side axle.

a buddy of mine and I put a turbo on his 2.2l impreza. we used a t-fitting on the oil pressure sending unit, and bent a custom line up over the intake manifold to the turbo. and had an inlet welded onto the oil pan for the return line. the coolant lines can be tapped into the heater core lines. we also had a custom up-pipe made so the stock crossmember could be left.

if you're doing a full engine swap, I'd recommend swapping the crossmember aswell. it's virtually the same amount of work. I'm also fairly certain you'll need the wiring, but I'm not sure on that.

you're best bet for information on this sort of swap, is www.nasioc.com or www.rs25.com lots of information on either site about swapping EJ motors and what works best and how to do it.

#6 torxxx


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Posted 22 September 2006 - 11:01 PM

heres a better idea.. sell the outback and buy the right car.

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