New '07 Spec B owner possible turbo failure.. need an education

Hello,

 

I recently bought an '07 Spec b with 150,000 miles. To my knowledge its all stock.

 

Shortly after buying it it developed a bit of a hesitation under acceleration. I wasn't sure what to make of it and was trying to work through the problem. I was still driving the car and was out on some back roads for a drive when I suddenly lost power and there was a "whirring" sound when I would try to accelerate. I stopped the car and the motor was running fine no sign of drivetrain issues I was sure the turbo had crapped out. I was out of cell service and out in the woods a ways so I had to limp it 10-15 miles to a safeway parking lot where I parked it for the night and got a ride home. I came back the next day with a flat bed and towed it home.

 

I'm going to start tearing into it today but need some direction. I've got moderate mechanic experience and plenty of aptitude but have not dealt with turbos much and feel a little daunted by what I've read in some of these threads regarding turbo failure and its possible engine failure consequences. I'm also a little overwhelmed with all the tuning options available and am not sure where to start with replacement parts. I also have no idea where to go to source particular parts.

 

I've done some reading up and I have searched here for information but would like some pointed advice. I know I don't want to go back to the stock turbo, I daily drive this thing and want it to be "streetable." I like driving fast but I don't need a race car or a drag racer, I like tinkering, when I have time, and enjoy upgrading to a degree so would like to have some future upgrade potential but at this time don't want to change fuel components or full exhaust if I don't need to. The car may need new headgaskets as I have been told by a mechanic that they are "weeping but not leaking" and to keep an eye on them. I have a budget of 2-3k but prefer 2k. My intent is to max out performance on stock fueling and clutch at some point but want to balance power upgrades with handling upgrades. Right now the main focus is using what budget I have to get the car running with some peace of mind that I did my due diligence to ensure as much future reliability as I can.

 

So I guess the question is....

Would it be wise to pull the motor now and go through it? All gaskets and seals, with part recco's.

How critical is it to replace the oil pan and cooler and flush the motor and how wild do people go in trying to see if turbo debris is in the motor?

What turbo would people recommend given my stated criteria? I have been looking at the BNR 16g with their in house oiling solution and would appreciate feedback on that particular turbo and suggestions of others.

What upgrades to turbo oiling are necessary and available?

What intake and exhaust mods are good at this point and what are the plus's to replacing them, with part recco's?

Should I replace the TMIC now and what are good parts?

If I just replace my turbo and nothing else do I need a "tune" and what does that entail?

Do I need a COBB access port or some other tuner or can the ECU be flashed?

Does anyone have tuner recco's for Spokane, Wa area? I hate just taking my stuff to someone I don't know.

 

Basically I need knowledgeable people who have experience with these things to tell me what to expect if in my situation and help steer me away from pitfalls and problems.

Welcome to the Forum.

 

You need a bigger budget.

 

http://people.csail.mit.edu/ilh/vacation/ that's the service manual.

 

You need to pull the downpipe and check the turbo for shaft play. If there's a lot, you most likely have put metal into the oil system.

 

A vf52 is a great turbo on stock fueling, it needs a 3" catted Dp, and Cobb AP with a custom tune. Those parts alone put you over $2000.

 

You'll need a clutch to hold the power, that's another $600.

TMIC can be "bulletproofed" the GS tmic is another $900 piece.

 

The vf52 is fine on the stock oil feed as mine has been on the stock oil feed for over 154,000 miles.

 

Keep your stock cold air intake, its good till your making over 350whp.

Read the first few threads in the Tech Forum and the sticky's up top.

 

Then ask more questions if you still have them.

Drained the oil and coolant today and this is what I found.... didn't have time for much more.

 

Oil from the filter. The pan oil looks similar but a bit less full of metal.

I've read through all the stickies and the tech thread. I read them all before I posted.

150K? Original engine?

 

With that much oil glitter I'd assume you probably just have a bad turbo, but it would be a very good idea to do a compression/leakdown test before you go forth with this. You may be in for a very expensive day. Our car's engines aren't exactly known to be their strong suit and the rings might be showing their age at 150K. YMMV but my car blew up at 214K.

 

If your block checks out fine then I'd rebuild the heads with a local machine shop that knows what they're doing. Resurface the heads, use the OEM Subaru head gaskets that come in later year Subarus. use ARP head studs so the heads get a good crush on the gaskets, and then rebuild the valvetrain as you see fit. Stock components are 100% fine but some upgrades to the valvetrain can make the car rev out more freely and last longer if you crank the power up. If you plan to crank the power up beyond the stock clutch, fueling, and shortblock capabilities (think 350 WHP+) then consider a stronger shortblock. It won't go as many miles, but a forged block can tolerate more knock events.

 

For the stock clutch, the VF52/16G is kinda it. Beyond that you're gonna be looking at shorter clutch longevity and potentially day-to-day slipping. I'd recommend you get a VF52 from our local forum guy, Jmp. For stock fueling, some say a VF52 can take it but my 200K fuel pump started really showing its age with a maxxed-out VF46 until I put in an AEM pump recently. My sidefeed injectors were at 90% duty with a maxed VF46. I now have OEM STi topfeeds and they're still within a margin of error of that load. Upgrading to topfeeds while you have the engine out and heads off while be thousands cheaper in terms of labor, if that's something you'd care to upgrade. I would recommend that and some Injector Dynamics units. Oh, and while that whole intake manifold is off, TGV deletes are also recommended. I can't remember if it works the same way on your car as it does on my '05, but you can remove the butterfly valves from the TGVs or you can use spacers from IAG. I have the latter after the topfeed conversion. A larger turbo will also necessitate a 3-port boost controller.

 

For intake and exhaust, any upgrade to the turbo will necessitate a downpipe with no cat or a freer-flowing one. I have an Invidia catted and it's been good to me. Leave the intake alone as they're pretty good on our cars.

 

I would replace the oil pan and pickup tube for sure. I cleaned my pan out during my engine rebuild and reused it, but the pickup tube was clogged way up. Killer B. sells a better unit not made of the plastic ours use from Subaru. If your car still has the in-line oil filters throughout the VVT system ("banjo bolt filters") then those need out pronto in your situation. Just discard the filters and call it good.

 

If your TMIC works fine then cool, but it'll leak at higher boost levels. I have an older Perrin unit and it works fine. No complaints. The Grimmspeed one requires a minor modification to the hood scoop with included parts for that, but I assume more air gets in with that than with my setup.

 

You should get a protune after an engine rebuild regardless if your car has been tuned relatively recently. Your car will produce more boost with a new engine. You may also spring some boost leaks during the engine and turbo surgery, as I did. Surgeline went through my car and found like three boost leaks after my rebuild, if I recall correctly. But no, technically, if all you do is swap in a new turbo and nothing else then you're fine.

 

Your tuner (preferably local to you) will have their own preferences for tuning software. Mine uses Cobb and requires an Accessport. Some won't and will tune using open-source software. I've heard from many tuners who tune both that they prefer using an Accessport. Your mileage may vary. If your local tuner can open-source tune then that'll save ya some cash for now.

 

Since you're in Spokane, you're just out of my realm. I use Surgeline here in Portland. I highly recommend them, but you're a little far to limp a car to them for tuning. I've heard Dom is pretty good. https://www.getadomtune.com/contactus.html

Oh man classic oil pan glitter bomb Hate to say it but that’s a full rebuild now that you’ve got metal in the system. Too much risk to go 90% of the way and then that last 10% cause your new motor to fail. This happened to me in my ‘08 Outback XT, (while on the dyno at Surgeline getting tuned for stg 2 with a custom JMP VF52). In my case it was a spun rod bearing so the turbo was spared. Either way, I had a glitter bomb. Short of rebuilding it myself, which I wasn’t capable of doing, I opted for a new factory shortblock from Heubergers Subaru in CO, $1900 shipped to your door (they are widely known for the best pricing). Surgeline rebuilt the heads to factory spec along with new pan, pick up, etc. All in think it was about $8k. I know... . You’re definitely at a crossroads here and depending on how much and what condition your Spec B is in, you’ve got some hard choices to make. For me I’ve been drinking the Suby Kool-aid for too long to jump ship yet and when it comes manual tranny wagons with over 250HP, your options are next to none. That’s why I went long haul and if your gonna do that then I’d put a vote in for Surgeline. It will cost going rate to be sure but it will get done right.

 

If you go this route, VF52, even tuned for stock fueling, with stock injectors is a well matched kit for this car. Really the way it should have come from the factory. Significant bump in power from your VF-46 but similar spool characteristics. Add a pump and injectors if you like to get every last bit out of it and a bit more power. Still running my stock TMIC for now, (it’s been about 3 years). The end tanks will eventually blow but I have an old Perrin top mount laying around that was pulled from my track car so will swap that in eventually. A bulletproofed OEM one should be fine long term as well.

 

Also with your other questions: Cobb Accessport -yes need it. Oiling - lots of debate on this. I run the oiling set up that comes from the factory on both my Outback and my track car. Needless to say the track car gets wrung out and I have had zero issues. Same with my daily. Forum member JMP who built both my custom VF52 and my EVO16g for the track car, knows a hell of a lot more about it than me, has stated that a properly working OEM set up is fine at these power levels, (other than removing the banjo filters). I’ve seen nothing in both of my cars to dis-prove that.

Edited May 23, 2021 by shralp

Couple questions:

 

What is a TGV delete?

Would you guys mind posting part links or numbers?

Pleides, when your car crapped out what extent did you go to in the rebuild with the rods bearings and cams?

From what you guys say VF52 is the ticket but I've read that people are unsatisfied with the boost taper at higher revs. I've read that the BNR turbos hold boost longer and have similar low range response. The 16G is supposed to be a bit milder but have good low rpm uptake and holds boost to higher revs. I'm wondering if anyone can speak to the differences and weigh the pros and cons here.

The reason I think I don't want a new stock turbo is because I've read that it is undersized for the potential of the motor and mostly because its a poor design that's prone to failure. Is that an accurate statement?

 

Just to clarify, I'm not looking to make a bunch of power here, and based on what you guys are telling me my options are dwindling. I really didn't mind how the car drove stock. I don't race around town, I'm too old for that, and I'm not going to the track with this car. I primarily bought it for a daily and for long road trips. My primary concerns are a reliable fun car that I can wring out on some windy backroads when I find them. I'd like to find a little more power over stock and have maybe the potential to amp it up one day when the wife wrath over the rebuild subsides. Again, I'm not interested in doing fuel upgrades right now, I want to stay with TMIC indefinitely as it seems the cheaper option long terms and horse power limitations are satisfactory to me. I also don't want to have to upgrade clutch at this time and won't dial the car up to a point I would need to do that until sometime in the future, if at all.

 

My car supposedly has a catless UP and I'm wondering if I have to replace that because of something to do with mating to the VF52 turbo or if its just to wring the most out of the turbo.

 

I guess to sum it up you guys are telling me that at minimum I replace the turbo, clean out the motor, roll the dice on the cams and rod bearings. Since the motor is at 150k maybe I need rings soon. Or, maybe it spins a rod bearing, the cams bearing surfaces fail or the turbo blows up and I'm back here where I started but really only out the cost of the turbo replacement and the motor flush? The downside being I'm gambling that it won't all go up in smoke in 10k miles.

 

Or, I go all in and rebuild or replace the bottom end, reman the heads and valve train, replace the turbo and have peace of mind knowing that everything is basically new and not gonna fail for a few thousand miles.

 

Am I off base or does that sound accurate?

 

Also, again if anyone has tuner and mechanic recommendations in the Spokane, Wa area that would be helpful. I might be willing to pull the motor and bring it to Portland though if I can't find anyone reputable around here.

Sorry for the pain. Turbo wise, sure could put a 16G and it would move your power band to the right slightly compared to a VF52 but if you want to stay OEM fueling, (and I would based on what you've said you want out of the car), you won't really be able to optimize the turbo with your current injectors and pump anyway. The VF52 is a good choice for stock fueling because of this, (and really, its not that much smaller than a 16G anyway). I really love my VF52 / stock fueling stage 2 Outback for a daily so I can only imagine how it would be on a Spec B with a better road suspension. Again, would really stay away from a half step rebuild based on the pics you've posted. In a lot of ways, if you're paying to rebuild your block by a reputable builder, by the time you've paid labor to do it you've pretty much bought a factory fresh short block that has been assembled to factory spec. Again based on what you want to do with the car, a factory short block is fine. It won't be cheap but would still recommend getting the car to a place like Surgeline, have Heubergers drop ship a short block to them and they will R&R the heads, re-assemble, and tune the car with your turbo of choice. Don't worry about TGV deletes, not a big deal at your power levels so not worth the cash to put them in if you're on a budget.

What is a TGV delete?

 

http://www.circuitmotorsports-blog.com/2015/06/subaru-tgv-delete-port-and-polish.html (found this link first, but the one below is another excellent, very detailed write up by covertrussian)

 

https://legacygt.com/forums/showthread.php/build-install-tgv-deletes-263724.html

Couple questions:

 

What is a TGV delete?

Would you guys mind posting part links or numbers?

Pleides, when your car crapped out what extent did you go to in the rebuild with the rods bearings and cams?

From what you guys say VF52 is the ticket but I've read that people are unsatisfied with the boost taper at higher revs. I've read that the BNR turbos hold boost longer and have similar low range response. The 16G is supposed to be a bit milder but have good low rpm uptake and holds boost to higher revs. I'm wondering if anyone can speak to the differences and weigh the pros and cons here.

The reason I think I don't want a new stock turbo is because I've read that it is undersized for the potential of the motor and mostly because its a poor design that's prone to failure. Is that an accurate statement?

 

Just to clarify, I'm not looking to make a bunch of power here, and based on what you guys are telling me my options are dwindling. I really didn't mind how the car drove stock. I don't race around town, I'm too old for that, and I'm not going to the track with this car. I primarily bought it for a daily and for long road trips. My primary concerns are a reliable fun car that I can wring out on some windy backroads when I find them. I'd like to find a little more power over stock and have maybe the potential to amp it up one day when the wife wrath over the rebuild subsides. Again, I'm not interested in doing fuel upgrades right now, I want to stay with TMIC indefinitely as it seems the cheaper option long terms and horse power limitations are satisfactory to me. I also don't want to have to upgrade clutch at this time and won't dial the car up to a point I would need to do that until sometime in the future, if at all.

 

My car supposedly has a catless UP and I'm wondering if I have to replace that because of something to do with mating to the VF52 turbo or if its just to wring the most out of the turbo.

 

I guess to sum it up you guys are telling me that at minimum I replace the turbo, clean out the motor, roll the dice on the cams and rod bearings. Since the motor is at 150k maybe I need rings soon. Or, maybe it spins a rod bearing, the cams bearing surfaces fail or the turbo blows up and I'm back here where I started but really only out the cost of the turbo replacement and the motor flush? The downside being I'm gambling that it won't all go up in smoke in 10k miles.

 

Or, I go all in and rebuild or replace the bottom end, reman the heads and valve train, replace the turbo and have peace of mind knowing that everything is basically new and not gonna fail for a few thousand miles.

 

Am I off base or does that sound accurate?

 

Also, again if anyone has tuner and mechanic recommendations in the Spokane, Wa area that would be helpful. I might be willing to pull the motor and bring it to Portland though if I can't find anyone reputable around here.

TGVs (tumble generator valves) are an emissions device used in our cars. They're closed on cold starts and then they open when the cats are up to temperature. They very slightly rob power (not much) but they're mainly a nuisance to get at if they fail as it's a good 6-hour job to remove and reinstall the intake manifold to get at them, so you might as well remove them now. You can do so by removing the butterfly openings or by using a part from IAG such as this to replace the TGV housings entirely.

 

My car went up in a smoky haze one day on startup. It was already burning oil at a quart every 500 miles before I bought a beater and saved up for a rebuild. The car ended up having a clogged pickup tube. The rod bearings were suspect by sound alone, but we never tore the block down entirely. My oil pan looked about like yours, but we were able to re-use my cams, somehow. I think the car ran for maybe 20 seconds total the way it was before the engine came out. I'd recommend new cams if you've driven the car any length of time with the oil looking like this. I used an OEM Subaru shortblock and rebuilt the heads with a local rebuilder to me. I bought some valvetrain stuff from Surgeline (intake and exhaust valves, valve springs, and ARP head studs) and called it a day on engine internals. I used Felpro head gaskets, but have heard the OEM Subaru ones are better. BTW I'm fairly certain those links I gave were exact parts I used but it's better to check with an engine builder before buying those for your car.

 

As for the turbo, the VF52 spools very similarly to the VF46 as it's only slightly larger of a turbo. The factory turbo in your car is in my car and they're perfectly reliable. Yours went at 150K, right? That's pretty normal. Lots of failure stories are from the uppipe cat failing (not an issue for an 07 with a factory catless one) and the banjo bolt filters getting clogged. As for boost taper, the laws of physics sadly apply and a turbo as small as the factory IHI turbos on Subarus are gonna have a harder time at higher RPMs. JMP can help out with special turbo internals, however, if that's to your liking. He even rebuilds upgraded VF52s for less than the cost of a new stock one from IHI.

 

Your uppipe is fine. If it's catless then it's good to go, OEM or otherwise.

 

With that much oil in your filter, I'd play it safe and tear everything apart. Being a turbo EJ engine, it probably wasn't long for the world with 150K on it anyways.

 

I had help from mechanics at my work (I work at a stealership) and still probably spent 6500 or so all in. My quote from Surgeline still ended up in the high 8K range with the basics all taken care of, and that was before an Accessport was added so they could tune it.

 

I mentioned GetADomeTune because he's local to you. I've heard great things about his tuning and his shop Tier One in Liberty Lake is close to you. Surgeline is very good as both shralp and I have pointed out, if you're good with the road trip/tow.

Edited May 24, 2021 by Pleides

 

Also, again if anyone has tuner and mechanic recommendations in the Spokane, Wa area that would be helpful. I might be willing to pull the motor and bring it to Portland though if I can't find anyone reputable around here.

 

He was mentioned before, but Dom (https://www.getadomtune.com/) is a really good tuner. I think he only does Accessport for subarus now. I'd also suggest following getadomtune on facebook and reading back some posts before messaging him. He's gotten pretty intolerant of customer BS. He works out of Tier One, which I've heard is a good performance-oriented mechanic/shop. (https://tieroneimports.com/) They're out in the valley, pretty close to the ID border.

 

Personally I've taken my LGT to Hopkins Subaru when it needed work I didn't want to do (timing belt).

Thanks guys, I appreciate you taking time to reply, you've given me a bit to chew on and I enough to at least start in a direction. I'm more of the "play it safe" type and will most likely head in that direction. I have a good mechanic here in town that I have used for years and talked to him today about the head work and short block. When I hear back from him I'll have a little more to go on. I think my upgrade aspirations may need to be shelved a bit for the moment budget depending. Like I said though its not too much of a letdown as I don't have that high of ones to begin with.

Does anyone know any other TMIC offerings than grimmspeed?

Does anyone know any other TMIC offerings than grimmspeed?

 

https://www.google.com/search?q=tmic+05-09+subaru+legacy+gt&rlz=1C1OKWM_enUS906US906&sxsrf=ALeKk02zL0cuKZyaoWMp_ygpsxACHCw_aw%3A1622480014467&ei=jhS1YPyDHKiJggfevY-gBA&oq=tmic+05-09+subaru+legacy+gt&gs_lcp=Cgdnd3Mtd2l6EAwyBQgAEM0COgcIABBHELADOgYIABANEB46CAgAEAgQDRAeUIqsAViswwFg5dIBaAFwAngAgAHNAYgBlgWSAQU2LjAuMZgBAKABAaoBB2d3cy13aXrIAQjAAQE&sclient=gws-wiz&ved=0ahUKEwj8gquHsfTwAhWohOAKHd7eA0QQ4dUDCA4

 

IMO as most, the GS is the best upgrade for a tmic. The ones in the link above are good but they can be a PITA ti get lined up and the TB hose on.

 

I had one of these styles years ago but gave it away to a friend and both my cars have the GS tmic now.

 

You can help justify the GS by rationalizing the cost of one of those towards putting the money into a GS tmic.

 

Maybe you'll get lucky and find one in the for sale forum.

 

You should click on my "click here" link and see what's involved in replacing the short block and doing it right the first time.

Found one for you, this person has one for $750.

 

https://legacygt.com/forums/showthread.php/id-oem-ps-pump-madrig-cf-scoop-gs-tmic-3port-286065.html

Found one for you, this person has one for $750.

 

https://legacygt.com/forums/showthread.php/id-oem-ps-pump-madrig-cf-scoop-gs-tmic-3port-286065.html

It's in the sold section, to me [emoji16].

 

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^what he said Honestly, I gotta say that I had no issues with my Perrin TMIC for the years that I owned it, (and that was a lot of years...). Don't doubt there are fitment issues because everyone certainly bitches about it to some degree or another. That said, it was purchased and installed thru Cobb Surgeline here in Portland and pretty much stayed on the car for 6 years with no issues. If the car needed work or i was upgrading my turbo, they were wrenching on it so I guess I never experienced the pain. Strangely, when I brought up everyone's issues with install of the Perrin they said that it really hasn't been an issue for them. Maybe its because they were taking off/on tons of them each week and got good at it. So yeah, can't bash the Perrin performance wise, I still have my take off and will put it on my VF52 daily driver Outback when the stocker eventually blows out. Edited June 1, 2021 by shralp

Thanks for that I messaged him,

 

I'm wondering what the difference between the ej255 and ej257 are?

 

In the limited time I have, I've got the motor just about ready to pull out and it's about time to start ordering parts.

 

I tried searching for a perrin version but couldn't find anything.

 

Anyone have any recommendations on injectors? not sure I'm gonna do them but It seems a pita to get them out later and if I am I may as well now.

 

Also I'm gonna look the clutch over but suggestions on clutch would be helpful as well. Like I said I'm not looking for crazy power but want that door to be open. Correct me If I'm wrong but stock can do fine up to 300is whp? Not really shooting for that just wondering the threshold, or if there is a reasonable upgrade what might it be?

Edited June 1, 2021 by Bobsyouruncl

There is no real difference worth worrying about between the ej255 and ej257, we all go ej257. That topic has been talked about for years...When I bought mine the ej257 was less money.

 

Order the ej257 and the engine gasket set for your year car & ARP head studs.

There is no real difference worth worrying about between the ej255 and ej257, we all go ej257. That topic has been talked about for years...When I bought mine the ej257 was less money.

 

Order the ej257 and the engine gasket set for your year car & ARP head studs.

 

This is what you need to go with. max is correct. I followed his thread and parts guide, then added ARP head studs, 1000 cc injectors, pump, FPR, full fuel system, custom lines, TVG deletes, fluid crank, blah, blah, tons of performance and OEM parts, and went over board. I did get the 257, and gasket kit. The car has 3458 miles on the build and has been running solid.

 

It does sit in my garage a lot now cause I have a daily driver. I try not to drive in in the rain or snow. I am over 300 AWHP on conservative tune. My trans is limiting my power, but that is fun. I really want a R35 So I will not do anything but keep the in tip top shape.

Okay... Having read this, and with a my car at 124k miles (200k kms). I bring it home from the dealership tomorrow and if she wants to self destruct, I hope it happens on the way home... Still don't regret buying her lol. Definitely gonna pull the turbo and see if there is any shaft play and go from there. (Thank you lemon law for hopefully getting this project started for me!)

Wait...

I thought the 257 was just fine for '05-06 as they actually had the STi engine.

https://legacygt.com/forums/showthread.php/05-06-lgts-255-04-06-stis-257-once-and-264989.html

 

But the '07 Spec B/GT actually have a 255 which has different pistons due to the D25 (vs B25) heads.

I don't know what it does to the compression ratio, but I think I remember reading that it changes it if you go 257 for an '07+ Spec B/GT.

 

If I'm wrong and/or not remembering something correctly, someone please chime in.

While everything is torn apart if you do want to upgrade fueling, might as well put in 1050cc top feeds, either from Cobb or Injector Dynamics,(they are the same ID makes Cobbs). More than enough for your turbo upgrade with no downsides. I saved money by swapping in OEM top feed fuel rails from an older WRX that Surgeline had from the many aftermarket fuel rail swaps they do. I’m running an ACT stage 1 clutch with a WRX flywheel in my track car and an OEM clutch in my Stg2 daily, (VF52 on stock fueling). It’s holding fine but I wouldn’t trust doing 4K stoplight clutch dumps. Luckily that’s not my jam... I’d suggest keeping your OEM TMIC for now and just bulletproof it if you’re on a tighter budget. I love my Grimmspeed for sure but at your power levels you’ll be fine until you’re ready to upgrade your kit. Edited June 1, 2021 by shralp

Wait...

I thought the 257 was just fine for '05-06 as they actually had the STi engine.

https://legacygt.com/forums/showthread.php/05-06-lgts-255-04-06-stis-257-once-and-264989.html

 

But the '07 Spec B/GT actually have a 255 which has different pistons due to the D25 (vs B25) heads.

I don't know what it does to the compression ratio, but I think I remember reading that it changes it if you go 257 for an '07+ Spec B/GT.

 

If I'm wrong and/or not remembering something correctly, someone please chime in.

 

 

Can anyone speak to this definitively? The ej257 is generally $1000 cheaper but I don't want fitment or compression/pre ignition issues from getting the wrong short block.

 

Seems to me from what shralp says, on stock fueling and mostly stock bolt ons stock clutch should be ok?

 

Does anyone know what model years wrx and STI have direct fitment with legacy gt and spec b of my model year? Is there a wiki of direct crossover"upgrades"? I ask because, shralp, you mention having a WRX flywheel. Makes me wonder where you can save some cost over aftermarket by going oem of a different model?

Whatever small compression ratio difference there is, it really is not a big deal. The custom tune will be able to handle any changes.

 

There has been lots of discussions about it.

 

Here's one, short one, see post 2.

https://forums.nasioc.com/forums/showthread.php?t=2721214