I did a search and couldnt find good info. Are they the same engine(clearly the internals would be different? So lets say I bought STI pistons and rods and slapped them in my Legacy 2.5l NA engine. would that make my legacy engine a "STI" engine? We are talking shortblock only. Question 2, Heads. I have DOHC heads is the valve train the same? could I just swap out the cams and call it a day?
Not even close to the same motor. I don't want to get into it, but go look around nasioc or rs25, as you aren't going to find a whole lot here.
battle of 2.5s? Basically open deck vs. semi closed deck. All about how much the cylinderwalls are reinforced inside the block. 2.5na with forged internals will be good for around 500whp, check rs25 for a refrence build. On an open deck there is reinforcement on both sides of the walls. There are 2 more points of reinforcement around the cylinder walls on the semi closed decks, one on the top of the cylinder wall and one on the bottom. So to answer your question, Unless you get a STI shortblock, your NA open deck wont ever physically be a sti shortblock. That does not mean you still cant throw forged internals in there and boost the hell out of it.
OK, Thank yo guys for your help so far. I am new to the subaru stuff and dont know of all the good websites yet. I will check out those 2 and see what I can do.
There is a lot more to it than that. There is extra ribbing on the outside of the block for reinforcement. The oiling system is different. The triggers are different. I could go on for hours.... The heads are pretty good, but still not the same. '96's were haudraulic. 97-98 were shim-over-bucket. I could go on and on again. I busting out the search stick again. This has been beaten to death on almost every Subaru forum in existence, except mnsubaru.
not to thread jack or anything but what is the difference between a closed deck, open deck and a semi closed deck? Doesn't it have to do with how the oil gets around the engine or something?
Mainly what Im trying to find out is if I put in STI rods and STI pistons and WRX/STI cams could I run a turbo safely. I realize I could do it now but I want lower comp pistons.
There is a sweet legacy forum out there somewhere... lol but i dont know the name. Yes, you culd lower the compression with sti rods/pistons and turbo it. But your going to need alot of supporting mods.
if you wantto turbo your Lego than find a franken turbo kit with a td04 and only run 8psi. Itll be a nice kick in the pants to beat around the ******* in the left lane doin 50 and also bring you fairly good reliability. How Many miles are on your car and have the headgaskets timing belt and cutch been changed? You may wantto think about doing those before you boost to eliminate future problems
because It already has a 2.5, why not just keep that? The car has 257000 miles on it HG, Tbelt, Water Pump, Radiator all that stuff is brand new. Its an auto. Im not making a race car here I just want it to not be the slowest car on the road. I mean this thing is SLOW! I also know that I will need probably a fuel pump and injectors and some way to tune it or maybe just an STI ecu or something. IDK.
If you want the 2.5, I would encourage you to buy a new ej257 block. The money you spend on buying the pistons/rods/bearings and having your block inspected/bored/honed and pistons/rods balanced is approaching $1300. Just pick up a ej257, great internals and you can be pretty certain that tolerances are correct.
Not really. Search for damn near anything on google and stuff shows up like this: nasioc nasioc sl-i nasioc rs25 i-club nasioc clubwrx nasioc ....... You see the trend here? There is so much out there, you just have to look for it. Unless you are trying to take the easy way out, and, unfortunately with Subaru's, rarely gets you anywhere. WRX/STi cams do not work in your heads, unless you happen to have a machine shop at your disposal. The thrust design is completely different. With all that said, I'll say this again, and a few people on here will attest to it including myself. Take whatever you think its going to cost, and double it. That might get you in the ballpark.
I would probably listen to Piddster... He has already done tons of research and reading. And putting the STi Pistons, crank, and rods in your 257,000 mile block wouldn't be the greatest of ideas either. Not to mention just trying to add a STi ECU into your legacy. You could add up everything you need, and triple it, and probably still need more money.
Hey now. I'm no internet mechanic. I've done my share of doing. Maybe not quite what you full time wrenches have but, enough
Never!! This is MY thread!!! lolz Your options are reliable or run with you have. Yes you can put in STi RODs and pistons. I wouldn't put in STi pistons (EJ257) though because of its type. I would go aftermarket like CP/JE etc. I would go STOCK compresion ratio for your engine build because of your heads you have. This would get you like a 8.5:1CR because your combustion chamber on YOUR head are not as much as the STi heads. Now that you have your shortblock semi-built, you need injectors. Finding the correct o-rings you're able to use the STi injectors with your fuel rails. Then you need a fuel pump upgrade so you have enough fuel when the injectors squirt away. Now that you have a stronger engine, and fuel, you need to be able to control them. Your factory ECU cannot run the setup to its full potential. The Factory ECU mapping was not intended for such a setup. It will not work. This is where you go aftermarket standalone ECU, or figure out if you can use the Apexi Power FC for your ECU plugs. You will have to have the ECU mapping tuned in so your car will run right and not blow up when you go full tilt. OR You can simply do a FULL USDM WRX/STi/Forester/LGT swap. This would mean you won't have to mess with any internal engine work. You'll just have to have your wires merged by some shop or someone. Install the engine and run simple mods with a simple ECU map to match them. This will give you reliability, driveability, and tune-ability. So awesome! BUT you're looking at spending at least $10,000. This is things from clamps, tubes, bolts, nuts, parts, engine, some labor and MORE parts, fluids, etc. I spent A bit over $17,000 to get my little wagon where it is now. But of course that's the WHOLE package.
^ +1 for what fuji said. In 99% of the thread and builds I have seen it is cheaper and more effective to do a swap (WRX/STi/LGT/FXT) than to turbo an NA motor. You get stock reliability, and alot more head room for future mods, not to mention it will cost you less in the end. I am working on my 3 version of a turbo kit for my NA motor, and let me tell you I could have easily afforded to do a 2.0L WRX swap, and saved alot of time in the process. I am just stubborn and like boosted 2.2ls.
