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Old 06-29-2018, 08:00 PM   #1
Subaru_Freak
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Default Type RA vs STI Engine Internals

http://www.comeanddriveit.com/engine...-sti-internals

Worked with Jeff S. to create this article highlighting the differences between the RA and std STI
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Old 06-29-2018, 08:32 PM   #2
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Still amazes me that Subaru uses such a tight ring gap on these engines. I guess that's the cost of emissions compliance and efficiency demands.
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Old 06-29-2018, 10:02 PM   #3
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great reference thanks for sharing
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Old 06-29-2018, 11:44 PM   #4
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Quote:
Originally Posted by Blackfin View Post
Still amazes me that Subaru uses such a tight ring gap on these engines. I guess that's the cost of emissions compliance and efficiency demands.
It doesn't make a lot of sense to me either. Lots of popped motors and damage to the brand.
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Old 07-01-2018, 10:22 PM   #5
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Good info since i just ordered an RA short block. I was really hoping there would be more to the pistons. Oh well i needed a block anyway so why not.
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Old 07-09-2018, 08:39 PM   #6
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Great Read, Time for me to buy a '19
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Old 07-09-2018, 10:27 PM   #7
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Originally Posted by 07blksti View Post
Good info since i just ordered an RA short block. I was really hoping there would be more to the pistons. Oh well i needed a block anyway so why not.
Since it's a shortblock why not consider swapping the pistons with forged pieces and giving it reasonable ring gaps?
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Old 07-10-2018, 11:04 AM   #8
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The type RA shortblock is only ~$1.9k from my subie dealer. IAG block still a better choice for the extra couple hundos?
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Old 07-10-2018, 12:37 PM   #9
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Quote:
Originally Posted by Dick_fitswell View Post
The type RA shortblock is only ~$1.9k from my subie dealer. IAG block still a better choice for the extra couple hundos?
The RA short block is essentially a stock STI block... so if your goals involve anything beyond this, yes.
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Old 07-13-2018, 11:29 PM   #10
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I ordered the RA shortblock when they first came out. I opted to put in a Port and Polished VF48 with a 16g wheel with an 11 blade configuration from SoCal Porting. I'm hoping the shortblock will be able to hold the power. I wasn't expecting anything crazy but I figured I could be one of the first to see if it's able to hold more power. They're finally dropping it in. I could have opted for something from IAG but i figured why not test this out to see what happens.
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Old 07-16-2018, 06:10 PM   #11
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Originally Posted by ncsketch View Post
I ordered the RA shortblock when they first came out. I opted to put in a Port and Polished VF48 with a 16g wheel with an 11 blade configuration from SoCal Porting. I'm hoping the shortblock will be able to hold the power. I wasn't expecting anything crazy but I figured I could be one of the first to see if it's able to hold more power. They're finally dropping it in. I could have opted for something from IAG but i figured why not test this out to see what happens.
Have you had any prior experience with modified OEM turbos before? I am just asking because I have been looking into it and wondering how much quicker can the VF48 be made to spool. My only gripe with the power delivery of my RA is the turbo lag but I am not interested in big power. In fact I just want a tune and a quicker spool and then some reliability mods and call it good engine wise.

I have seen ball bearing conversions for these as well but they don't seem to utilize the coolant line for the turbo and just use the oil line so I lost interest in that and just wonder what can be done otherwise without going aftermarket turbo or downpipe. In other words I would love to improve the performance without any visible indications that the car has been modified.
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Old 07-17-2018, 01:23 AM   #12
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A VF48 can be made to spool faster by instead buying a VF53 and the associated exhaust parts. Ball bearing IHI turbos still use the coolant line.

Beyond that, you could add anti-lag.

When you get tired of blowing $3000 OEM turbos up, there's the GTX2860R which would be about as fast as you could reasonably spool while staying in the 300-325 whp range. I don't think I'd go smaller than this.
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Old 07-20-2018, 01:02 AM   #13
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Originally Posted by Lrn2Corner View Post
Have you had any prior experience with modified OEM turbos before? I am just asking because I have been looking into it and wondering how much quicker can the VF48 be made to spool. My only gripe with the power delivery of my RA is the turbo lag but I am not interested in big power. In fact I just want a tune and a quicker spool and then some reliability mods and call it good engine wise.

I have seen ball bearing conversions for these as well but they don't seem to utilize the coolant line for the turbo and just use the oil line so I lost interest in that and just wonder what can be done otherwise without going aftermarket turbo or downpipe. In other words I would love to improve the performance without any visible indications that the car has been modified.
Give a pro-tune a shot before you go changing turbos

It's been years since I've had an AP on a car so I really can't recall, but at the very least AP marketing claims a quicker spool.
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Old 02-27-2021, 04:15 AM   #14
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Lightbulb For anyone looking for more recent news:

For anyone looking for more recent figures on the type RA shortblock's capacity, there have been several documened 500+whp builds on COMPLETELY stock internals. I believe a couple have even broken the 600whp mark. JR tuning, arguably one of the most knowlegable subie tuners out there said the block can hold about 550whp or something reliably.



There aren't any confirmed cases of spun bearings or ringland failure that I can find. A couple posts of people saying "I think I remember seeing a post somewhere..." or "I have a friend who talked to a subaru tech who said he saw a 2019 STI that spun a bearing" etc. But no one on forums that's saying "I spun a bearing on my 2019 STI with x power and x miles"


that being said, the engine has only been widely available for a couple years at this point, so it remains to be seen how long the stock block can hold the power. We also don't truly know the reliability of this engine. It'll be interesting to watch it play out.


My guess they changed the alloy the pistons are made out of, and maybe the 2mm thicker crowns actually helped a bit? It's the only reason I can think of that people have been hitting these crazy numbers. I think if the block is well taken care of, it can hold high power very nicely. If anyone wants to correct me or has found posts the disagree with me, I'd love to see them. Thinking about buying one of these blocks for my OBXT build.

Here's James's thread, whose pushing over 500 on his stock block 2019 STI: https://forums.nasioc.com/forums/sho....php?t=2913418

Last edited by Mymomsoutbackxt; 02-27-2021 at 04:16 AM. Reason: Added reference thread.
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Old 02-27-2021, 07:31 AM   #15
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Quote:
Originally Posted by Mymomsoutbackxt View Post
For anyone looking for more recent figures on the type RA shortblock's capacity, there have been several documened 500+whp builds on COMPLETELY stock internals. I believe a couple have even broken the 600whp mark. JR tuning, arguably one of the most knowlegable subie tuners out there said the block can hold about 550whp or something reliably.



There aren't any confirmed cases of spun bearings or ringland failure that I can find. A couple posts of people saying "I think I remember seeing a post somewhere..." or "I have a friend who talked to a subaru tech who said he saw a 2019 STI that spun a bearing" etc. But no one on forums that's saying "I spun a bearing on my 2019 STI with x power and x miles"


that being said, the engine has only been widely available for a couple years at this point, so it remains to be seen how long the stock block can hold the power. We also don't truly know the reliability of this engine. It'll be interesting to watch it play out.


My guess they changed the alloy the pistons are made out of, and maybe the 2mm thicker crowns actually helped a bit? It's the only reason I can think of that people have been hitting these crazy numbers. I think if the block is well taken care of, it can hold high power very nicely. If anyone wants to correct me or has found posts the disagree with me, I'd love to see them. Thinking about buying one of these blocks for my OBXT build.

Here's James's thread, whose pushing over 500 on his stock block 2019 STI: https://forums.nasioc.com/forums/sho....php?t=2913418
Not to throw shade at your response here but there are a couple of realistice things to note about this guys stock block 500whp sti. First, its not his daily driver. That fact alone can mean the car can last at this power level for a really long time. Especially if its just a weekend type of car. The car would be seeing a fraction of use comparped to a daily driven sti.

Another thing to consider is that a few stock block 500whp+ cars is not the same as a majority of modded cars. There will always be a few hp freaks or cars that just refuse to give up. Given the time and era, there were quite a few of those too back in the GR/GV days. Definitly back in the GD days.

Also for the guys taking the stock block to 500whp+ they are already aware that the engine can blow at anytime given this power level. If that engine blows up, you arent going to hear about those guys going to the dealer and having the engine warranty claim denied. You most likely wont hear a big fuss on the internet about it. You arent going to see bashing threads about how the engine blew up with minimal mods from these guys. They will just rebuild and or replace. They knew what they were getting into and were prepared to cross that bridge.

In terms of reliability, iduno a few guys with stock block 500+ cars wouldnt make me think its reliable. There are hundreds and or thousands of guys running stage 1 and 2 sti daily driven for over 10+ years without problems on stock oem block. Yes the type RA variant of the EJ has only been out for a couple of years but we would need ALOT more people making big power on stock block to say its "reliable" at power with that engine.

One last thing to mention, 500hp on one dyno may not be the same on another dyno. Just my 2 cents
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Old 02-27-2021, 08:06 PM   #16
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Good post. I agree mostly. When I said reliable, I didn't mean it would be roadtrip level reliability, I just meant it's not like these blocks would make 1 pull at a high HP level and then blow up like a lot of others. They seem to be able to hold this power level for numerous, numerous pulls. I doubt this engine will hold up like an IAG built block would, but the engines are taking the higher numbers like a champ, and I'd bet these guys aren't easy on their cars.

I also feel like they've taken it upon themselves to be the test rats of this new block. I would bet that when their engine does blow, they'll let everyone know. I have yet to hear of a type RA block failing at these higher powers, leading me to believe they can hold higher power atleast a little better than previous blocks. On previous blocks, while yes many would hold 500whp+ and take it like a champ, many also would have failed in the process of trying to reach that number. So I just feel like someone, somewhere would've blown up the engine trying to reach these higher levels and complain about it on a forum somewhere, letting us know that these crazy guys reaching 500, or even 600+ are just lucky guys who got an abnormally good engine, rather than it being a genuinely stronger engine.

In the past, people have been quick to post on forums and such when their low milage STIs, or even Ascents, blow up, and I doubt the case would be any different for these newer blocks. So I would bet if and when a 19+ STI blows up at low milage due to ring failure or a spun bearing, we'll hear about it.

EDIT: I don't wanna make it sound like I think these blocks are as good as built blocks with forged internals. I don't, and they're not. I just think there is some evidence that they're stronger than previous blocks. But we likely will have to wait years before there is enough evidence to judge where these engine's limits are. I just think it's an interesting topic and I'm interested to see how it plays out.

Last edited by Mymomsoutbackxt; 02-27-2021 at 08:42 PM.
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Old 03-01-2021, 05:43 PM   #17
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I'm rebuilding my 07 STI motor and was considering going with the type RA block. I can get it for about 2100-2200 and I can get an OEM 07 STI block for a couple hundred less. Is it worth the extra money? And the only modification it needs is a thicker headgasket right? I am only shooting for about ~280-300 whp with a TBE, CAI and tune. I'm looking to make it as reliable as I can as it will be a DD and not tracked or anything like that.
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Old 03-01-2021, 06:21 PM   #18
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For that level of hp a regular ol EJ257 will do just fine. But the type RA shortblock isnít any LESS reliable and doesnít hold any less power than a regular ej257. Itís just debatable if it actually can hold more. Personally, Iíd go with the type RA shortblock because even if it is just small changes, itís worth the couple extra hundred IMO. Thicker crown means slightly less susceptible to ringland failure, stronger pistons, etc.
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Old 03-05-2021, 01:54 PM   #19
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Quote:
Originally Posted by Mymomsoutbackxt View Post
For anyone looking for more recent figures on the type RA shortblock's capacity, there have been several documened 500+whp builds on COMPLETELY stock internals. I believe a couple have even broken the 600whp mark. JR tuning, arguably one of the most knowlegable subie tuners out there said the block can hold about 550whp or something reliably.



There aren't any confirmed cases of spun bearings or ringland failure that I can find. A couple posts of people saying "I think I remember seeing a post somewhere..." or "I have a friend who talked to a subaru tech who said he saw a 2019 STI that spun a bearing" etc. But no one on forums that's saying "I spun a bearing on my 2019 STI with x power and x miles"
Well, if my 2020 STI counts, which I believe has the RA pistons, my car had a spun main bearing in the first 1000 miles.

Last edited by ntg44; 03-12-2021 at 08:49 AM.
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Old 03-05-2021, 02:52 PM   #20
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Oh yikes. Thatís kinda terrifying since I just bought a type RA block that wonít be warrantied since Iím putting it in my OBXT. Ima hope yours was a lemon haha. Or maybe Iíll replace rods pistons and bearing before I put the engine in. Canít decide.
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Old 03-06-2021, 12:57 PM   #21
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Quote:
Originally Posted by Mymomsoutbackxt View Post
Oh yikes. Thatís kinda terrifying since I just bought a type RA block that wonít be warrantied since Iím putting it in my OBXT. Ima hope yours was a lemon haha. Or maybe Iíll replace rods pistons and bearing before I put the engine in. Canít decide.
If I were you, I'd call Dave at https://www.cryotuneperformance.com/

And ask his advice, he's also who you want to use as your Tuner.
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Old 03-06-2021, 05:51 PM   #22
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Quote:
Originally Posted by Mymomsoutbackxt View Post
For anyone looking for more recent figures on the type RA shortblock's capacity, there have been several documened 500+whp builds on COMPLETELY stock internals. I believe a couple have even broken the 600whp mark. JR tuning, arguably one of the most knowlegable subie tuners out there said the block can hold about 550whp or something reliably.



There aren't any confirmed cases of spun bearings or ringland failure that I can find. A couple posts of people saying "I think I remember seeing a post somewhere..." or "I have a friend who talked to a subaru tech who said he saw a 2019 STI that spun a bearing" etc. But no one on forums that's saying "I spun a bearing on my 2019 STI with x power and x miles"


that being said, the engine has only been widely available for a couple years at this point, so it remains to be seen how long the stock block can hold the power. We also don't truly know the reliability of this engine. It'll be interesting to watch it play out.


My guess they changed the alloy the pistons are made out of, and maybe the 2mm thicker crowns actually helped a bit? It's the only reason I can think of that people have been hitting these crazy numbers. I think if the block is well taken care of, it can hold high power very nicely. If anyone wants to correct me or has found posts the disagree with me, I'd love to see them. Thinking about buying one of these blocks for my OBXT build.

Here's James's thread, whose pushing over 500 on his stock block 2019 STI: https://forums.nasioc.com/forums/sho....php?t=2913418
Great timing. 2019 STI 30K and 5K at 380whp on a Dynojet. Spun a rod bearing, wasn't even during a pull. Last three oil changes at 3k had perfect Blackstone oil analysis's. My conservative tune had the torque coming in past 3500. Although the car had a good compression test and the break in was in accordance with the mfrs recommendations I was never comfortable with the motor consuming 1qt per 3K. This despite having an IAG aos. Once I pull the motor and split the case I should have more insight on the cause of the bearing failure.
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Old 03-06-2021, 06:09 PM   #23
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Quote:
Originally Posted by undyjr View Post
Great timing. 2019 STI 30K and 5K at 380whp on a Dynojet. Spun a rod bearing, wasn't even during a pull. Last three oil changes at 3k had perfect Blackstone oil analysis's. My conservative tune had the torque coming in past 3500. Although the car had a good compression test and the break in was in accordance with the mfrs recommendations I was never comfortable with the motor consuming 1qt per 3K. This despite having an IAG aos. Once I pull the motor and split the case I should have more insight on the cause of the bearing failure.
Keep us posted. I'm interested in seeing/hearing the cause.
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Old 03-06-2021, 07:57 PM   #24
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Quote:
Originally Posted by undyjr View Post
Great timing. 2019 STI 30K and 5K at 380whp on a Dynojet. Spun a rod bearing, wasn't even during a pull. Last three oil changes at 3k had perfect Blackstone oil analysis's. My conservative tune had the torque coming in past 3500. Although the car had a good compression test and the break in was in accordance with the mfrs recommendations I was never comfortable with the motor consuming 1qt per 3K. This despite having an IAG aos. Once I pull the motor and split the case I should have more insight on the cause of the bearing failure.
yes please keep us updated!
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Old 03-07-2021, 09:59 AM   #25
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High res pics of both main and rod bearings please.
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