If there is a Turbo option available for the same year as you want to convert you can do it. Luckily Subaru being a small mfg, they dont have too many different engine variations. So if there was a turbo available for X year, that means that most likely the main bearings are all the same.
The problem with a non turbo year 2.5L is that the 2.5L was conceived to get every ounce of power out of the block that the engine could handle. The engine is already at its design limit. Its much easier to do a 2.2L then a 2.5L for this reason. The 2.2L is overbuilt and can easily handle a turbo, the 2.5 is a larger displacement 2.2 and modified to meet that.
Also it depends upon how long you want the engine to last. If i remeber correctly the issue is one of the thrust bearings in the "crankase".
Now if you want to do it from the bearings up, you can do it.
http://www.funco-motorsports.com/subaru_motor.htm
nipper
The problem with a non turbo year 2.5L is that the 2.5L was conceived to get every ounce of power out of the block that the engine could handle. The engine is already at its design limit. Its much easier to do a 2.2L then a 2.5L for this reason. The 2.2L is overbuilt and can easily handle a turbo, the 2.5 is a larger displacement 2.2 and modified to meet that.
Also it depends upon how long you want the engine to last. If i remeber correctly the issue is one of the thrust bearings in the "crankase".
Now if you want to do it from the bearings up, you can do it.
http://www.funco-motorsports.com/subaru_motor.htm
nipper
