Building_A_Legacy Posted August 27, 2022 Share Posted August 27, 2022 (edited) Good evening to all from the East Coast. My name is Derek, I've had a 5th Gen Legacy GT for about 2 years now. When I purchased this, it was at 19X,XXX miles with 1 owner and 11 pages of service history from a dealer. This has been a GREAT CAR! Super fun and love the challenges associated with having a unicorn. Recently I wanted to rebuild the suspension in the front from the ground up and replace absolutely everything. I also needed to do a timing belt which is what led me into this position I'm currently in. Look below at the waterpump I had to cut out with tin snips DISCLAIMER: I know this will be A LOT of work. I currently work as a mechanical engineer and design custom equipment for different industries and have automotive design experience. Also I know some of this may have been talked about before, information is kind of scattered everywhere so I apologize for that. If anything please just enjoy my struggle. ALSO: This car is actually really clean with no rust on the body and has limited rust everywhere I'm not removing parts lol. Since I've gutted a lot of stuff from my car to drop my turbo and remove the water pump, I discovered I need a rebuild on my turbo. I'm very temped to figure out a new setup with the turbo in a more "normal" location. I currently have a FMIC from my 04 WRX I was going to retrofit into the front of my car and create piping to route everything. I wouldn't mind running a down pipe from a typical WRX but I don't know that it would clear underneath the car (it looks like it would be TIGHT). Another concern of mine, and a large one at that, is the heads. I currently have STI heads from a 2011 as I know that the heads on our cars are special. Is there anything special that may be needed to just bolt the STI heads on my block? I know that it has a special blueprint according to IAG. As for the headers, what exactly would need to be changed? I have access to my own license of CAD software and can model pretty well. This very well could be worth not doing, that's why I figured I'd ask. It may just be worth slapping a rebuild kit in my turbo and putting everything back on and leaving it the way it is. I look forward to responses as I haven't heard or many if any people attempting this. Edited August 27, 2022 by Building_A_Legacy 1 Link to comment Share on other sites More sharing options...
FLlegacy Posted August 27, 2022 Share Posted August 27, 2022 (edited) Moving the turbo will take away the torque curve that makes this platform unique. There may be a header available but it will be costly and will only fit the stock turbo. The heads are "special" because they have the machined mounting point in the back of the passenger head for the oil scavenge pump that only this engine uses, otherwise they are pretty much like STI heads. The designation code is E25 for the heads, where the STI uses "D25" heads I believe. I have seen one other member change out the engine subframe for an older wrx one in order to mount an sti transmission and use the standard side mount turbo, personally I don't see the purpose in that but to each their own. Edited August 27, 2022 by FLlegacy Link to comment Share on other sites More sharing options...
Building_A_Legacy Posted August 27, 2022 Author Share Posted August 27, 2022 1 hour ago, FLlegacy said: Moving the turbo will take away the torque curve that makes this platform unique. There may be a header available but it will be costly and will only fit the stock turbo. The heads are "special" because they have the machined mounting point in the back of the passenger head for the oil scavenge pump that only this engine uses, otherwise they are pretty much like STI heads. The designation code is E25 for the heads, where the STI uses "D25" heads I believe. I have seen one other member change out the engine subframe for an older wrx one in order to mount an sti transmission and use the standard side mount turbo, personally I don't see the purpose in that but to each their own. Am I wrong in thinking I can correct that curve with a different trim? Also is that the only major difference on the heads? It would be nice to swap the exhaust cams. Maybe I'm wrong in thinking this but if I move the turbo and adapt the flange I'll have more room for different options. There are a lot of power limitations with these cars. I will say I was very irritated with Mitchell when it came to missing information on this thing which is a large driving factor for me wanting to change it. A lot of this and information came from removing the turbo and water pump themselves. Again maybe it's only worth slapping a rebuild in the turbo with a bigger billet wheel. Link to comment Share on other sites More sharing options...
FLlegacy Posted August 28, 2022 Share Posted August 28, 2022 1 hour ago, Building_A_Legacy said: Am I wrong in thinking I can correct that curve with a different trim? Also is that the only major difference on the heads? It would be nice to swap the exhaust cams. Maybe I'm wrong in thinking this but if I move the turbo and adapt the flange I'll have more room for different options. There are a lot of power limitations with these cars. I will say I was very irritated with Mitchell when it came to missing information on this thing which is a large driving factor for me wanting to change it. A lot of this and information came from removing the turbo and water pump themselves. Again maybe it's only worth slapping a rebuild in the turbo with a bigger billet wheel. It seems to me your trying to fix a problem which doesn't exist. There are options to upgrade the turbo and even with the stock manifold you will make more power than most any other Subaru. If you are willing to build a new manifold why not leave the turbo where it is and then use a different flange and upgraded turbo. The equal length setup has way more potential than moving it to a location which would need an unequal length header. Also, you can swap the sti dual avcs cams in for more lift and exhaust flow. They will fit in the stock heads with the proper shim buckets. The intake cam is what is machined to drive the scavenge pump and those are nearly identical to the STI intake cams anyway. 1 Link to comment Share on other sites More sharing options...
Building_A_Legacy Posted August 28, 2022 Author Share Posted August 28, 2022 46 minutes ago, FLlegacy said: It seems to me your trying to fix a problem which doesn't exist. There are options to upgrade the turbo and even with the stock manifold you will make more power than most any other Subaru. If you are willing to build a new manifold why not leave the turbo where it is and then use a different flange and upgraded turbo. The equal length setup has way more potential than moving it to a location which would need an unequal length header. Also, you can swap the sti dual avcs cams in for more lift and exhaust flow. They will fit in the stock heads with the proper shim buckets. The intake cam is what is machined to drive the scavenge pump and those are nearly identical to the STI intake cams anyway. I just came across something on eBay to convert the header to a V band. I will go down this route instead. Do you know which shim buckets would be needed? I have both a set from my STI heads and the ones in the car unless I would need to buy some sort of after market deal? Link to comment Share on other sites More sharing options...
FLlegacy Posted August 28, 2022 Share Posted August 28, 2022 Shim buckets size depends completely on measuring the clearance between your shim buckets and cam lobes. You may not need to buy any. You will need to get a set of feeler gauges and measure the clearance. Link to comment Share on other sites More sharing options...
FLlegacy Posted August 28, 2022 Share Posted August 28, 2022 https://youtu.be/mDuvTHrPbdM Link to comment Share on other sites More sharing options...
Building_A_Legacy Posted August 28, 2022 Author Share Posted August 28, 2022 24 minutes ago, FLlegacy said: https://youtu.be/mDuvTHrPbdM Thank you so much! And seriously thank you so much for walking through everything with me. This car physically pains me sometimes to work on but you are correct in saying I'm trying to fix a problem that doesn't exist. I believe I found a turbo that should fit my application, I just have one more question regarding this. I would have to transfer that pan underneath correct? And in regards to oil pressure to the new turbo, since it's being pumped from the head already the pressure should be fine I would imagine right? I know it changes from turbo to turbo but I can't imagine this thing needing to have an orifice. Link to comment Share on other sites More sharing options...
FLlegacy Posted August 28, 2022 Share Posted August 28, 2022 You would need to contact the manufacturer for that information, I wouldn't want to take a chance on wiping out a turbo and subsequently the rest of the engine with bearing material. Some turbos don't need a flow restrictor and some do. Link to comment Share on other sites More sharing options...
moral hazard Posted September 3, 2022 Share Posted September 3, 2022 On 8/28/2022 at 12:23 PM, Building_A_Legacy said: I would have to transfer that pan underneath correct? And in regards to oil pressure to the new turbo, since it's being pumped from the head already the pressure should be fine I would imagine right? I know it changes from turbo to turbo but I can't imagine this thing needing to have an orifice. You'll notice that the banjo bolt on the oil feed line to your existing turbo has an orifice. That does need to be set correctly. I've compared banjo bolts between our VF54 and the low mount WRX MGT2259s, they have a different size orifice. The good news is, the latest G series of turbo from Garrett have the oil restrictor built into the turbo so you'd not need to worry in that case. You will need to transfer the oil pan over to the new turbo, unless you buy an aftermarket one or make a custom one. https://m.youtube.com/watch%3Fv%3DzJchCTVvjgQ&ved=2ahUKEwjPqdKeuPf5AhWoR2wGHac0AoAQtwJ6BAgJEAI&usg=AOvVaw2vDThG0TdGoiBZrnIDeMW8 Link to comment Share on other sites More sharing options...
Building_A_Legacy Posted September 3, 2022 Author Share Posted September 3, 2022 2 hours ago, moral hazard said: You'll notice that the banjo bolt on the oil feed line to your existing turbo has an orifice. That does need to be set correctly. I've compared banjo bolts between our VF54 and the low mount WRX MGT2259s, they have a different size orifice. The good news is, the latest G series of turbo from Garrett have the oil restrictor built into the turbo so you'd not need to worry in that case. You will need to transfer the oil pan over to the new turbo, unless you buy an aftermarket one or make a custom one. https://m.youtube.com/watch%3Fv%3DzJchCTVvjgQ&ved=2ahUKEwjPqdKeuPf5AhWoR2wGHac0AoAQtwJ6BAgJEAI&usg=AOvVaw2vDThG0TdGoiBZrnIDeMW8 I wasn't able to get that link to work, it had a problem with traffic. That is good to know though that I will have to transfer the pan. Link to comment Share on other sites More sharing options...
moral hazard Posted September 3, 2022 Share Posted September 3, 2022 Sorry about that, here's a link that works. I found it interesting when considering what to do with my low mount turbo. 1 Link to comment Share on other sites More sharing options...
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