Bertin Posted October 28, 2018 Share Posted October 28, 2018 Quick little question for you guys. As you know I bought a 2005 LGT with blown turbo and questionable blown headgaskets. Well after tearing into the motor found the HG not blown, guess that is what I get for listening to others. Well gives me a chance to stud the heads and do some little things before it goes back together. Anyway, about the turbo, since I do have some power added plans was wondering if I put a td06sl2 18g or 20g turbo on with out any other mods as far as fuel or airflow at this time would it work? I am not able to get the Cobb Accessport at this time (this will be my next purchase). I feel that if I am not upping the boost or fuel or anything I would not need a tune, I know I will not be touching the potential of this turbo but plans in the future will bring it around. Would I be able to at least drive it with out a tune. Link to comment Share on other sites More sharing options...
Max Capacity Posted October 28, 2018 Share Posted October 28, 2018 YOU WILL NEED A TUNE for any turbo other then what came on the car. or may be a vf46. I have a VF52 with a proper tune on stock fueling, for the past 108,000 + miles. Have your head rebuilt by a good machine shop, install ARP head studs. Read my click here link in my sig. lots of good info there and pictures. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
mondtster Posted October 29, 2018 Share Posted October 29, 2018 I think you could run one of those turbos at a very low boost level and be ok for a while, but it would likely be a miserable experience. My advice would be to just hold off on putting it back together until you can afford to do the necessary supporting mods, then just do everything at once. Link to comment Share on other sites More sharing options...
Bertin Posted October 29, 2018 Author Share Posted October 29, 2018 Please explain to my why I would need a tune. I understand these cars do well with just an accessport and no other mods, it just trims it to work better on higher octane. But I am not changing any air or fuel set points. I also understand that the oil feed for these cars are a bit lacking, so I will address that, but as an auto technician I fail to see how I will need a tune to prevent engine damage by swapping a turbo. I know it could be a bit laggy and I will not reach full potential of the turbo without supporting mods and a tune. If I am correct a turbo will only flow more if boost is increased, and the small amount of increased flow through the turbo from going bigger should not hurt things, unless my thought process is all wrong Link to comment Share on other sites More sharing options...
rhino6303 Posted October 29, 2018 Share Posted October 29, 2018 Your car has its wastegate settings and boost tables for the turbo on the car. An alternate turbo will flow differently and the wastegate and target boost tables need to be changed accordingly. If you don't change these tables, your car may overboost and make the engine go kaboom. Link to comment Share on other sites More sharing options...
mondtster Posted October 29, 2018 Share Posted October 29, 2018 Your car has its wastegate settings and boost tables for the turbo on the car. An alternate turbo will flow differently and the wastegate and target boost tables need to be changed accordingly. If you don't change these tables, your car may overboost and make the engine go kaboom. How do you figure it’s going to overboost? Further, I’d expect only a slight variance in power at the same manifold pressure if the only thing changed was the turbo. Do I think it will run great? No, but I also don’t think it is going to blow up. Link to comment Share on other sites More sharing options...
fredrik94087 Posted October 29, 2018 Share Posted October 29, 2018 shaking my head... you better stay off boost or get a base map. it is very hard to stay off boost. unless you are sure that the wastegate setting of the new turbo is the same as your old one. even then, watch hour boost. not recommended to run a differrnt turbo than factory without a tune. "It's within spec" - SOA "Depth is only shallowness viewed from the side." - Fredism "So, how much did it cost for your car to be undriveable ." - Stephen (very close friend) "You have done so much it would be stupid to go back." - Sunny of Guru Electronics 2018Q50RS | 2015WrxThread | Shrek Link to comment Share on other sites More sharing options...
rhino6303 Posted October 29, 2018 Share Posted October 29, 2018 How do you figure it’s going to overboost? Further, I’d expect only a slight variance in power at the same manifold pressure if the only thing changed was the turbo. Do I think it will run great? No, but I also don’t think it is going to blow up.I didn't say it was going to happen, I said it may happen. The more probable result is that the car will knock even without overboosting. If he keeps the same tune with an 18g or 20g he's asking for trouble. The increase in volume of air from a larger turbo will most likely cause knock during spool and high rpm. Link to comment Share on other sites More sharing options...
mondtster Posted October 29, 2018 Share Posted October 29, 2018 I didn't say it was going to happen, I said it may happen. The more probable result is that the car will knock even without overboosting. If he keeps the same tune with an 18g or 20g he's asking for trouble. The increase in volume of air from a larger turbo will most likely cause knock during spool and high rpm. The thing isn’t going to magically flow that much more air. For a given manifold pressure the VE should be close enough to the same that I don’t foresee major troubles. Besides, this is a mass airflow car so the air being ingested is actually being measured. Again, I don’t feel it is optimal but I don’t think it is going to blow up either as long as some discipline and common sense is used. Link to comment Share on other sites More sharing options...
xtea Posted October 29, 2018 Share Posted October 29, 2018 The thing isn’t going to magically flow that much more air. For a given manifold pressure the VE should be close enough to the same that I don’t foresee major troubles. Besides, this is a mass airflow car so the air being ingested is actually being measured. Again, I don’t feel it is optimal but I don’t think it is going to blow up either as long as some discipline and common sense is used. Do it! Swap turbos. I know you want to! Send it! Nobody here knows anything. Just stay off the internet and do what you think is right. If that doesn't work, eh, then maybe.... naw... If that doesn't work, just do it again. Link to comment Share on other sites More sharing options...
mondtster Posted October 29, 2018 Share Posted October 29, 2018 Do it! Swap turbos. I know you want to! Send it! Nobody here knows anything. Just stay off the internet and do what you think is right. If that doesn't work, eh, then maybe.... naw... If that doesn't work, just do it again. I’ve done it. Many times... Link to comment Share on other sites More sharing options...
rhino6303 Posted October 29, 2018 Share Posted October 29, 2018 You are absolutely right; if you install a new turbo without a tune and never get in boost and drive sensibly, you won't have a problem. However, if someone is installing a larger turbo without tuning and suffucient modifications for the turbo, they aren't using common sense. It only takes one full throttle event to blow an engine from being too lean. A larger turbo will flow more air at the same psi as the stock turbo. The car will require more fuel to account for this and will run out of fuel without injectors and a pump. We're not saying it will 100% happen. We're saying it is a BAD idea to do without the supporting modifications and a tune. Link to comment Share on other sites More sharing options...
xtea Posted October 29, 2018 Share Posted October 29, 2018 I’ve done it. Many times... Don't listen to these fools! Send it! 20g or GTFO Link to comment Share on other sites More sharing options...
mondtster Posted October 29, 2018 Share Posted October 29, 2018 You are absolutely right; if you install a new turbo without a tune and never get in boost and drive sensibly, you won't have a problem. However, if someone is installing a larger turbo without tuning and suffucient modifications for the turbo, they aren't using common sense. It only takes one full throttle event to blow an engine from being too lean. A larger turbo will flow more air at the same psi as the stock turbo. The car will require more fuel to account for this and will run out of fuel without injectors and a pump. We're not saying it will 100% happen. We're saying it is a BAD idea to do without the supporting modifications and a tune. And I’ve also said it isn’t the best idea but it will work. And it will work in boost too. You just can’t be a moron and beat on the thing relentlessly like many owners seem to do. Apparently I’m being a bit subtle here when trying to teach about what’s going on. A turbo capable of flowing more air efficiently will not flow that air unless there is a demand for it. You are not changing the VE of the engine appreciably if all that is changed is a turbo so the engine will be essentially flowing the same amount of air at the same manifold pressures. Will there be differences? Sure. Exhaust restriction will be less due to the larger turbine which should improve VE a bit. Also, the air coming out of the turbo should be cooler which will help things. These changes may cause a lean condition in open loop mode but my feeling is that the stock fueling is plenty rich at stock boost levels. Generally speaking, I’d be more concerned about ignition timing. Subaru seemed to have really aggressive timing tables to the point it seemed like they were relying on the knock sensor to pull it back. Stock turbo or big turbo, it will do the same thing to protect itself. Run low boost and get it tuned as soon as practical and I think it will be fine. Link to comment Share on other sites More sharing options...
Max Capacity Posted October 29, 2018 Share Posted October 29, 2018 Just saying, if someone is putting on, even a slightly bigger turbo, the likely hood of that person staying out of mid to higher boost levels for a long time is slim. That's not why we buy these cars. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
m sprank Posted October 29, 2018 Share Posted October 29, 2018 Yes it can be done. Is it safe? NO. Especially when you consider the weaknesses of an EJ255/257 engine. It is not a cast iron block and heads. It is not an EVO VI. Turbo dynamics (at a minimum) should be adjusted. Do not trust the ECM to self correct. You do not have a true wide band afr sensor. The stock tune leaves a lot to be desired and the areas that run lean specifically for EPA regulators can get scary with a larger turbo and no adjustments. Car goes boom in cruise (closed loop) due to excessively lean condition. Link to comment Share on other sites More sharing options...
Bertin Posted October 31, 2018 Author Share Posted October 31, 2018 Thank you guys for the info, I am not trying to beat on this poor thing, just driving it from one shop to another, and maybe to get a few things here and there. It is winter time here so I cant get into boost now anyway, if I do I will end up in a ditch or something. The accessport will be here in a month or two, so I will be covered soon there. I didn't want to try and move it without a trailer if I thought it would blow up, i have done many turbo swaps before without a tune, yeah it ran like crap, or better yet was laggy as hell, but never blew. I just dont know how these blocks handle things stock-wise. Also, decided on a 16g, that will cover all the power potential in the future that I will get, my future plans are just turbo back exhaust, cobb accessport, cobb intake, larger injectors (dont know what size yet, probably not too big) and a fuel pump. But, to get things rolling I have to move it to a better equipped shop. Link to comment Share on other sites More sharing options...
Max Capacity Posted October 31, 2018 Share Posted October 31, 2018 Didn't we tell you, you don't need a intake. Or was that someone else, The stock one is the best up till over 350whp. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
DaveWaters Posted October 31, 2018 Share Posted October 31, 2018 I’m currently breaking in my new build with no boost (16g). It’s not easy. I’ve accidentally boosted to ~1.5 psi and ~3psi and both times i have feedback knock of 5 reported. This is on an etune that was netting me ~18psi (vf40) with no knock before the build. Bigger turbo = more volume of air. The ecm needs to add more fuel to the mix and isn’t programmed to do so. Link to comment Share on other sites More sharing options...
Bertin Posted October 31, 2018 Author Share Posted October 31, 2018 My intake tube is dry rotted cracked and split I will be replacing it, just cant find a stock one Link to comment Share on other sites More sharing options...
Max Capacity Posted October 31, 2018 Share Posted October 31, 2018 Any dealership, Parts Dept should be able to get one for about $90. That's the one from the air box to the turbo inlet ? Here's my local dealership parts link. https://parts.suburbansubaru.com/p/Subaru_2005_Legacy-GT-Limited-Sedan-25L-TURBO-5MT-4WD/DUCT-ASSEMBLY-AIR-INTAKE/49226946/14459AA340.html 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
Bertin Posted March 2, 2019 Author Share Posted March 2, 2019 Quick little update on the turbo. I ended up going with a customized Kinugawa 16g, so far so good, haven't got into the throttle at all, but I can drive it and it does seem to be doing fine, no lights no knock at cruising according to my scan tool. Getting the car ready for summer, Access Port is on the way along with a fuel pump. Not sure if I should do injectors or not, only looking to get about 350-400hp out of it. If I do go with injectors should I stick with side feed or convert to top feed? Full Invidia exhaust will be in the works as well. Any other suggestions would be greatly appreciated. Thanks Link to comment Share on other sites More sharing options...
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