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Old 12-11-2020, 05:58 PM   #126
Scargod
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Quote:
Originally Posted by lidrew View Post
considering a build on my GR and deciding on using the RA block or IAG. I can save $3kish by going with the RA. Goal will be somewhere around 450 whp on flexfuel.

Anyone have any more experience with the RA block and how its holding up with high hp?
If you believe Mike Botti, I heard him say the RA's could do 500 all day long and 600+ for a while. Said that he had tuned cars for that. At 500 he said the engine was durable and went through a lot of hours being raced and was driven home...

I don't think 450 would be a big deal.

I think saying the stock rods can't take it is wrong. Perhaps not the best choice for 500 or a bit more but I have heard of people doing it. Look at "bragging rights".
If this is a street car I would do the RA SB. If you are going to be racing some and street mostly then I'd suggest buying the case, crank, bearings, rods of choice and Mahle pistons in 4032 aluminum alloy to allow for tighter cylinder to wall clearances and improved temperature stability.
I am building a DD engine this way and will make about 350. The thing is, it will be able to rev like crazy, safely. I will be cutting 30% (roughly) off the weight of the reciprocating parts.
It would be like an RA but with much lighter rods and pistons.
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Old 12-11-2020, 08:22 PM   #127
Homemade WRX
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Quote:
Originally Posted by lidrew View Post
considering a build on my GR and deciding on using the RA block or IAG. I can save $3kish by going with the RA. Goal will be somewhere around 450 whp on flexfuel.

Anyone have any more experience with the RA block and how its holding up with high hp?
I've always been a big proponent of DIY but if you don't feel up for working with your local machine shop to build an engine, there are numerous reputable builders that you can consult with.

Quote:
Originally Posted by cboggess View Post
I believe the rods have not changed. If I am correct in that regard then I would not run 450 on those rods. You're going to need something a bit beefier.
The rods (on page 1) do look a little different from the 08 but not notably.



OP:
1.) Guys have made big power on all years, and it's safe to say they're all time bombs.
2.) Then take into account "450 whp". Dyno's don't all read the same. For instance, we had a customer that was making 470 on a Dynopack and then made 360 whp on our Mustang. It was also notoriously a heart breaker with stock STi's making 205-210 whp.
3.) Is this a street car that might see 450 whp every once in a blue moon, or is this going to be raced? If raced, I would skip right to forged rods and pistons.

Just my $0.02.
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Old 01-15-2021, 07:34 AM   #128
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Does anyone know if 2019 STis with 2018 build dates will have the RA block too?
I’m looking at new 2020 or 2021 and some used 2020s and 2019s. Some of the 19s were built in 2018.
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Old 02-23-2021, 11:01 AM   #129
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Quote:
Originally Posted by lidrew View Post
Does anyone know if 2019 STis with 2018 build dates will have the RA block too?
I’m looking at new 2020 or 2021 and some used 2020s and 2019s. Some of the 19s were built in 2018.
Nobody knows if build date determines what cars get RA blocks? Is it all 2019s regardless of build date?
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Old 03-10-2021, 07:05 PM   #130
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As noted earlier PrimeMotoring tuned RA blocks to well above 500whp, and Botti tuning reported the RA block can handle 500whp safely, does it make RA block a perfect replacement for a daily driven STI?

Do other tuners /shops confirm this trend?
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Old 03-13-2021, 03:44 AM   #131
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Subbing to this thread. Very interested to see the results. Rebuilding my engine rn with a Type RA Block shooting for 400whp on meth and can't decide if I wanna split the block or not.
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Old 03-13-2021, 03:45 AM   #132
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I will say though, if you look at this thread, there have just recently been some people reporting spun bearings on the RA block at sub 400whp.
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Old 04-03-2021, 09:42 PM   #133
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I had a customer car (20 sti) come in for a shortblock replacement after he received 3 broken pistons from getting an e-tune from someone with no wideband. Was probably somewhere in the low 400ish range on ethanol.

They breaks/cracks were exactly the way they are on the usual 2.5 piston
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Old 05-05-2021, 12:53 PM   #134
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Originally Posted by sponaugle View Post
With the release of the 2018 STI RA, I was curious what changes were made to the internals of the engine. Subaru had indicated that new pistons were used, but didn’t specific much else in terms of internals.

I ordered a 2018 RA engine block about 2 months ago, and at that time there were no spare engine blocks in the US. It was eventually ordered from Japan and arrive at the end of last week. The price was the same as the regular STI short block.

On first glance, the block looks almost identical to the existing EJ257 motor. The cases is the newest 705 case, the crankshaft has the nitride black finish, and the piston tops look very familiar.





I disassembled the engine and first took a look at the pistons, since that is something documented as being ‘improved’.



RA piston on the left (BV), 2004-2006 STI piston on the right (A5)/

The pistons are very similar, and both appear to be machined cast parts.





The most obvious difference is the construction of the bottom of the piston. The older EJ257 piston does not fully enclose the pin boss, while the new construction has significantly more material around both of the pin sides of the piston. RA piston on the left above, STI on the right.



From the side, you can see the difference in material around the pin area. Construction and dimensions of the ring and ring area looks the same, with the exception that the upper ring area is fully coated on the older ones.

While not easy to see in these pictures, on the bottom side the depression right at the center of the piston is less, and the material is thicker. I would estimate the piston is between 1 and 2mm thicker going from the top to the bottom surface.

Other dimensions appear to be the same. Compression height, ring position, etc are all the same.

The new piston is heavier - 424 vs 414 grams (10 grams heavier).

I did a quick CC measurement and they appear to be pretty close. I’ll do a more complete measurement in the next few days.





The crankshaft appears identical to the 2016/2017 crankshaft, with no special oil modifications.



The rod also looks to be the standard previous year EJ257 rod. You can see the slight difference in design between the original EJ207 rod, the early EJ257 (2004), later EJ257 (2008), and the 2018 STI/RA rod.


How do we measure the 1 or 2 or mm of additional material. Do you measure from the top of the piston to the little carved out recess for the wrist pin? Curious what these 2 measurements are...
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Old 02-20-2022, 10:23 PM   #135
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Default Piston material

Anyone know if the RA pistons are made with a different metal than that used in the older STI pistons?
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Old 02-21-2022, 07:21 AM   #136
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Originally Posted by idntvpe View Post
Anyone know if the RA pistons are made with a different metal than that used in the older STI pistons?
I don't know of anyone that has sent one to a lab for material analysis. Manufacturing techniques appear similar, but that isn't helpful here.
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Old 02-24-2022, 10:10 AM   #137
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Default Cost of RA pistons

Quote:
Originally Posted by KillerBMotorsport View Post
I don't know of anyone that has sent one to a lab for material analysis. Manufacturing techniques appear similar, but that isn't helpful here.
KillerB, who sells the most affordable RA pistons and do you know of a reputable company that can do the metallurgic analysis? I’m considering sending one for analysis. I understand if you don't know but, it doesn’t hurt to ask. Thanks
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Old 02-24-2022, 04:04 PM   #138
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KillerB, who sells the most affordable RA pistons and do you know of a reputable company that can do the metallurgic analysis? I’m considering sending one for analysis. I understand if you don't know but, it doesn’t hurt to ask. Thanks
I would google 'materials lab', search out one local to you that does Spectrometry, and give them a call.

For something like that, I'd just try to find a spent on either here or Ebay so you don't have to spend money on new.
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Old 02-28-2022, 05:09 PM   #139
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Originally Posted by KillerBMotorsport View Post
I would google 'materials lab', search out one local to you that does Spectrometry, and give them a call.

For something like that, I'd just try to find a spent on either here or Ebay so you don't have to spend money on new.
Cool thanks
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Old 12-26-2022, 06:40 AM   #140
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i saw some pics about new type ra block

did casting change again ? something like 706?
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Old 12-26-2022, 06:40 AM   #141
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...........

Last edited by turbosenna; 12-26-2022 at 06:43 AM. Reason: same post
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Old 12-27-2022, 06:10 PM   #142
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Originally Posted by redrexmeister View Post
As noted earlier PrimeMotoring tuned RA blocks to well above 500whp, and Botti tuning reported the RA block can handle 500whp safely, does it make RA block a perfect replacement for a daily driven STI?

Do other tuners /shops confirm this trend?
Badder has tuned several stock block ej to 6-7-800hp.

All this and prime is on E85 and they still die shortly. Everyone stop being cheap and throw some bearings and pistons in your RA now or later.
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