New Donor 2.5 l Legacy convert to turbo ??

[willy]

Do not know that much about subarus so have done some reading, Read that they had a 2.5 twin turbo (not inported to the USA) legacy. I was thinking how hard would it be to fab a set of manifolds (2cyd to one turbo) on a 2.5 for twin tubos? second would it do any good ie. spooling-up faster ? and thirdly I know they are have a lot of interchagable parts but if I got a 2.5 Leagacy would the supenion parts be the same as a WRX ?? just thinking of some possibitys I can get a 2.5 Legacy fairly easy and cheaper than a WRX and How knows, may work really good.

[Steve91T]

Usually it's cheaper to just get a factory turbo'd car. The price of manifolds, turbo's, tuning is going to cost a lot. Plus, you'll probably have to lower the compression ratio. I'm sure an aftermarket, fairly small turbo will spool very fast, yet still make good power.

That being said, I've seen video's on youtube of people turbo'ing the 2.5 n/a.

Steve

[2KWIK4U]

Usually it's cheaper to just get a factory turbo'd car. The price of manifolds, turbo's, tuning is going to cost a lot. Plus, you'll probably have to lower the compression ratio. I'm sure an aftermarket, fairly small turbo will spool very fast, yet still make good power.

That being said, I've seen video's on youtube of people turbo'ing the 2.5 n/a.

Steve

Willy,

Steve is right, it will be cheaper to start with a turbo car. I have been looking into doing the same as you but what Steve said is what I found out.

[Ks2]

putting most any forced induction system onto a N/A motor isn't a great idea, you wont get much boost for the money without re-building the internals and/or swapping the heads

[Steve91T]

Something else to think about, if you are planning on rebuilding anyway, starting out with a worn out n/a will give you 2.5 liters. A built 2.5 turbo would be pretty mean.

I'm sure the pros will know what most people are doing.

Steve

[StatGSR]

Do not know that much about subarus so have done some reading, Read that they had a 2.5 twin turbo (not inported to the USA) legacy. I was thinking how hard would it be to fab a set of manifolds (2cyd to one turbo) on a 2.5 for twin tubos? second would it do any good ie. spooling-up faster ? and thirdly I know they are have a lot of interchagable parts but if I got a 2.5 Leagacy would the supenion parts be the same as a WRX ?? just thinking of some possibitys I can get a 2.5 Legacy fairly easy and cheaper than a WRX and How knows, may work really good.


Actually i dont believe there were any twin turbo 2.5s, i think they were all 2.0's but really that's besides the point. Unless you were thinking of purchasing and using the JDM TT set up in it's entirety, there is no good reason to try and replicate it as it has a very awkward powerband from my understanding that is usually remedied by switching to a single turbo.

As for exchangeable between legacy and impreza wrx. Yes there are a lot of things, but i wouldn't guarantee that all things required from the donor for the 818 would match well enough to work, im sure alot of it could be figured out by asking the questions in the right places and comparing part numbers and even then, just because the part numbers don't match doesn't mean the parts wouldn't work either.

As for turbocharging an NA 2.5 it can be done fairly easily by using the oem parts off of the turbo vehicles (or building your own setup), but without ripping into the motor you wouldn't really be able to get past stock wrx power and even then the life of the engine may be questionable, really if i was trying to that to save some money i would start with an NA EJ22 and turbo it, then keep a spare in my garage. On that note, the 818 may be an amazing candidate for Supercharger (roots blower) Build with a NA 2.5/2.2 depending on what the engine compartment looks like when it all comes together.... i kinda like that idea... i kinda like it alot.... means i could actually reuse the 2.2 i pulled outa my legacy, heck, depending on what other parts are going to be used on the 818 i may rip them out 97 legacy before i scrap it, this could all turn out pretty good for me...:D

[PhyrraM]

The twin turbo Legacies were only 2.0. It was a sequential turbo system and suffered from a hoorible response gap in the middle of the powerband (Subaru peeps call it the "Valley of Death"). The plumbing for the second turbo does not fit left hand drive cars (steering shaft and brake booster), but should fit the 818. They are cheap in the USA (full motors only have longblock value) because of this fact.

The longblocks are basically the same as single turbo WRX stuff (slightly higer compression), and are a good base if your going donorless and are not planning a full rebuild. All the single turbo stuff will bolt on. You just need to plug oil and coolant lines for the missing second turbo.

[willy]

Thanks for the info. was just an idea I had due to the probley added room behind the engine ( seeing there will be no fire wall behind the engine with the mid engine set up ) who knows it may have worked. guess will stick to the pros at subaru and find a stock WRX and go from there.