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Super clean car my friend. This gallery/build actually helped me decide b/w CWP and the ice silver - I went with white on a '20 STI Limited. Couple of questions.
Where did you grab your side mirrors? I'm looking at some of the .jp sites and stateside sites, looking for any recommendations either way.
Second, your DRL bezels look very clean. I'm contemplating going with S4 DRL bezels and adding fogs w/ interior switch - did you come across any '18-20 STIs with that set up, or look into it at all? I'm assuming it's a pretty straight forward ordeal (after reading your DRL wiring write up and watching some subie bros videos), but not having seen anyone else do it makes me wonder if I've missed something in my assumptions. Thanks for the info and clean pics, i'm absolutely stealing some of your mods!
 

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Discussion Starter · #22 ·
Super clean car my friend. This gallery/build actually helped me decide b/w CWP and the ice silver - I went with white on a '20 STI Limited. Couple of questions.
Where did you grab your side mirrors? I'm looking at some of the .jp sites and stateside sites, looking for any recommendations either way.
Second, your DRL bezels look very clean. I'm contemplating going with S4 DRL bezels and adding fogs w/ interior switch - did you come across any '18-20 STIs with that set up, or look into it at all? I'm assuming it's a pretty straight forward ordeal (after reading your DRL wiring write up and watching some subie bros videos), but not having seen anyone else do it makes me wonder if I've missed something in my assumptions. Thanks for the info and clean pics, i'm absolutely stealing some of your mods!
Thanks! And congrats on your purchase!

I purchased the mirrors from JapanParts. Since you have the limited model, you would probably want the mirrors that include the blind spot detection (ST91039ST100):

Doing the S4 DRL bezels shouldn't be hard. I wired mine differently than most because people usually either wire them to the headlights on or to accessory power (so they would be on even if the DRL C lights aren't). I was OCD about it and wanted them to always be on at the same time as the DRL C lights. The fog lights should be pretty straight forward as long as you get the OEM switch and wiring.

FastWRX sells a kit, but you probably want other bezels and fog lights:

This thread should give you an idea of what parts are needed:

Good luck! Looking forward to seeing how it turns out.
 
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Discussion Starter · #23 · (Edited)
I received this rare gem in the mail today.. after searching for over a year. The VF58.. the "holy grail" of Subaru IHI turbos.

Twin scroll, ball bearing, titanium aluminide (TiAl) 9 blade turbine wheel & shaft, 6+6 straight blade compressor wheel, uprated wastegate actuator.. I plan to send it to Giorgio Provinciali @ ASEL for reconditioning with upgraded dual ceramic ball bearings & possibly a billet compressor wheel.

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I guess I have to sell the SwainTech coated Killer B header that I just purchased...
 

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Discussion Starter · #25 · (Edited)
I thought some may find this comparison interesting. Thanks to @dlheman 's VF56 EJ257 build, this is my primary motivation behind performing the VF58 twin scroll, ball bearing conversion on my '19 STI.. and why Giorgio & his team at Advanced Sports Engineering Lab are currently upgrading my VF58 :D

I extracted this data from the OEM power charts (provided by Subaru/STI) to create a torque curve comparison for various OEM EJ & FA engine/turbo setups.

Text Line Font Diagram Technology


Battle of the OEM Twin Scroll Subarus & the USDM STI EJ257.
  • JDM S208: EJ207 VF58 - twin scroll, ball bearing, TiAl
  • JDM STI: EJ207 VF49 - twin scroll, journal bearing
  • JDM WRX S4: FA20DIT MGT2259S - twin scroll, journal bearing
  • JDM Legacy S402: EJ257 VF51 - twin scroll, ball bearing
  • USDM STI: EJ257 VF48 - single scroll, journal bearing, UELH
Unfortunately, I wasn't able to find an OEM power chart for the S209 to include in this comparison. However, peak torque from the larger HKS turbo comes on ~1,000 RPM later than the VF48 equipped EJ257 (~4,700 RPM in the S209 vs ~3,700 RPM with the VF48).

I was able to compile this... a "stage 1" comparison (protune w/ stock hardware) of the S209, S208 & USDM STI (EJ257 w/ VF48). There's a clear winner in terms of area under the curve.. and it's not either engine with the extra 463cc of displacement. As you can see, peak power numbers are great for marketing, bench racing, and bragging rights on forums & social media, but they're often meaningless and fail to depict the actual powerband.

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Text Line Font Plot Diagram

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Area under the curve:
Text Line Font Slope Design


This is why I'm harsh on the S209 and am disappointed that it didn't receive an equal length, twin scroll, ball bearing turbo configuration like the S208. The S208 makes significantly more "area under the curve" (~19%) despite its nearly 0.5L smaller engine. I look forward to being able to add my EJ257 VF58 build to this comparison in the future.

For those interested, illustrations courtesy of my Instagram page @STINickTuned.

And just for laughs while we're on the topic of "horsepower" 🤣

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If you like this kind of technical content & rare Subaru/STI parts, come join our Subaru Motorsports community at Advanced Sports Engineering Lab:

And follow us on Instagram @advancedsportsengineeringlab & @STINickTuned
Or on Facebook: Advanced Sports Engineering Lab
 
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Discussion Starter · #27 ·
Why would I go down such an atypical modification path? Many will think that I'm crazy for spending the time & money when I could have just went with an [INSERT Brand] ELH & turbo (Cobb 20G, Dom 1.5XT-R, FP XR Blue, BCP X500, etc.).

My goal is to maximize efficiency, responsiveness and area under the curve. I have no desire for crazy peak power, but rather creating the ultimate OEM-ish EJ257 that Subaru of Japan never made for the US.. the setup that the S209 should have received. I also have an obsession for the OEM+ theme (S-series, Group N, etc.). Previously owning a very responsive, flex fuel tuned, twin scroll FA20DIT also inspired this build. The only somewhat similar documented build that I've seen is the EJ257 + VF56 build by @dlheman (Corsa catback + IHI VF56 twinscroll setup = superior sound).

Advanced Sports Engineering Lab is in the process of rebuilding my VF58 and are one of the only companies in the world that I trust with such a rare turbo. I contacted at least 10 of the most well known turbo re-builders in the US and all said they couldn't and/or wouldn't rebuild it.. I'm not sure they had even heard of this turbo before.

ASEL is rebuilding the turbo with ceramic dual ball bearings, a forged billet aluminum compressor wheel with extended tips (reducing rotational mass while also improving strength & flow), porting the compressor inlet & turbine housing inlet scrolls, ceramic coating the turbine housing, and most importantly, retaining the rare, lightweight TiAL (aka Gamma-Ti) turbine wheel & shaft. Essentially modernizing the turbo with similar features as EFR turbos and the IHI turbos supplied to Ferrari.

I'm hoping that this will make for a virtually zero lag setup when combined with the EJ257's extra displacement, longer stroke, and slight compression bump. The only aftermarket setup that I believe could provide comparable levels of power & responsiveness would likely be a @killerbmotorsport ELH & EFR 6258. I'm just trying to keep up with the FA platform and future FA24DIT STI.. it's a torque monster when combined with a flex fuel tune!

ASEL has been amazing to work with.. sending pictures & videos of the entire process with balancing on their Schenck machine and machining/assembly on the TurboClinic workbench. They clean the parts via sandblasting, ultrasound & solvents.. finishing with a protective coating to prevent rusting. They X-ray, laser & pressure check the components to verify their integrity prior to reusing anything.

The compressor housing is currently in their 5 axis CAD/CNC lab awaiting machining to match the extended tip wing profile of the new billet aluminium compressor wheel. Unfortunately, the lab is busy working on some billet racing short blocks at the moment. ASEL primarily specializes in S-series, RA-R & WRC cars and has a direct relationship to STI. They are a true engineering company.. that happens to also have a strong passion for Subaru Motorsports ;)

I will update once I've received the final pictures, balancing report, etc. Some teasers in the meantime...


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Calipers Tool Measuring instrument Metal


An example of their twin scroll conversion "wake up kit" (not my turbo pictured):

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Discussion Starter · #29 ·
You make me wanna send my VF56 to ASEL for optimization and enhancement.

I can't wait to see how your VF58 goes.
I can't either haha I'm waiting for the Cobb Redline CF intake release to decide whether to go with that or the S209 intake. Then I just need to decide what I'm going to do about fueling.. whether or not to upgrade to the Cobb/ID 1050cc injectors & E85 flex fuel kit. The main issue is the strict emissions/visual "smog" inspection that we have in California. All non-OEM modifications/part replacements must be "CARB" certified.. which means that I would likely have to revert the fuel system back to stock and then re-install it every time which would be a huge hassle.

Once everything is ready, I plan to do before & after dynos as well as some road "lag testing" to measure the time that it takes to reach full boost & peak torque in various gears. I would also love to find a local S209 that I could do a dyno comparison with.

Let me know if you decide to send your VF56 to ASEL and I'll see what kind of deal I can get worked out for you ;)
 

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I am sure you will like the TS VF58 on EJ257 and the extra top end above the VF56 is a welcome addition.

Perhaps you can ask ASEL to calibrate your ECU since they have a lot of experience with this turbo.

I myself is currently about to get a new ECU calibration since I am relocating the IAT to the intake manifold using Spec C IAT sensor and re-purposing the rear 02 sensor for wideband. This time by a German tuner. And this time Aquamist will be utilized as part of the tune.
 

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Discussion Starter · #31 · (Edited)
Sorry, it's been a while since I last posted.. so here's a quick sneak peak..

A huge thanks to Giorgio @ Advanced Sports Engineering for this rare, beautiful, engineering masterpiece.. I almost feel that it belongs in a museum glass case rather than under the hood of my STI.

JDM STI S208 IHI VF58 turbocharger.. twin scroll, ceramic ball bearing, billet compressor wheel, TiAl (titanium aluminide aka Gamma-Ti) turbine wheel & shaft, and custom CAD/CNC machining & porting. I will also be using the OEM S208 turbo manifold (header & uppipe) due to its excellent build quality & impressive heat shield. Now, I just need to find the perfect downpipe to pair with my setup.

The legendary VF58 that few know exists.. let alone have ever seen.

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Custom profile 6+6 billet compressor wheel w/ extended tips:

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The TiAl (titanium aluminide) 9-blade turbine wheel & shaft:

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More OEM S208 goodness:

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Sorry, it's been a while since I last posted.. so here's a quick sneak peak..

A huge thanks to Giorgio @ Advanced Sports Engineering for this rare, beautiful, engineering masterpiece.. I almost feel that it better belongs in a museum glass case rather than under the hood of my STI.

JDM STI S208 IHI VF58 turbocharger.. twin scroll, ceramic ball bearing, billet compressor wheel, TiAl (titanium aluminide aka Gamma-Ti) turbine wheel & shaft, and custom CAD/CNC machining & porting.

The legendary VF58 that few know exists.. let alone have ever seen.

View attachment 60623

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Custom profile 6+6 billet compressor wheel w/ extended tips:

View attachment 60625

The TiAl (titanium aluminide) 9-blade turbine wheel & shaft:

View attachment 60626

Optional big port (gasket matched) twin scroll turbine housings available:

View attachment 60627

More OEM S208 goodness:

View attachment 60628

View attachment 60629
I look forward for your review!
 

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Discussion Starter · #33 ·
Me too 😁 Thanks for your inspiration for this build!

I've yet to decide on a downpipe.. I'm leaning towards the HKS or Moore Power TruDivorce downpipe. I'd love to find a high flow R205 downpipe that's not $1500-2000+ USD 🤣

I wish I could just use COBB's new GESi catted downpipe.
 

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Me too 😁 Thanks for your inspiration for this build!

I've yet to decide on a downpipe.. I'm leaning towards the HKS or Moore Power TruDivorce downpipe. I'd love to find a high flow R205 downpipe that's not $1500-2000+ USD 🤣

I wish I could just use COBB's new GESi catted downpipe.
The only reason I bought the HKS is the dual cats. Don’t bother with oem downpipe.
 

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Discussion Starter · #36 ·
Forgive my deer in the headlights look, but why not?
The JDM twin scroll turbos have a different turbine housing (TS P25 on the VF58 vs SS P18 on the VF48). The V49, VF53, VF56, V58, etc. thus have a different downpipe flange preventing compatibility with the USDM downpipes. While it's technically possible to have a shop cut of the USDM flange and weld on a JDM flange.. it would just be wasting money to hack up the beautiful one-piece, cast bellmouth of the COBB downpipe. I have yet to find any JDM downpipe that have as nice of a bellmouth design as COBB's nor as high quality of a catalytic converter as the GESi catalyzer.
 

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Discussion Starter · #38 · (Edited)
Off topic, but I would love to see you post a to do list for a "stage 2" street build that you would drive... and then answer all my questions!
I'm always happy to answer any questions! That one is pretty easy because I recently posted the same topic on Instagram because I get asked this same question quite frequently haha

I'll preface with saying that I've never been a COBB "fanboy", but I'm very impressed their recent re-designs of their products..

What are the "BEST" bolt-ons?
This is a highly subjective & controversial topic that depends on how you define "best", but below are the parts that I personally recommend based on the criteria most valuable to me: Engineering, Performance, Quality & Support (of both the product & Subaru community). The modification must improve volumetric efficiency without compromising reliability or being obnoxiously loud. You'll also see that I'm a big proponent for thermal management.

*Killer B Motorsport 4-1 Holy Header w/ SwainTech Coating
@killerbmotorsport symmetrical, equal length header (ELH). There are so many reasons that this is the "best" header in my book.. from the engineering, design, materials, coating & lifetime warranty.. I actually purchased this header before deciding to go with the VF58 twin scroll conversion. This header is my #1 recommendation.. along with SwainTech's White Lightning coating being my #1 recommended ceramic coating.

*NEW COBB GESi Catted 3" Downpipe + Ceramic Coating (SwainTech or Cerakote coating)
COBB has stepped up their Subaru game recently. From an aesthetic and engineering standpoint, I appreciate COBB's cast bellmouth design. Now that they've added a GESi catalyzer, it's earned the #1 spot on my downpipe list. I also like that their downpipe has the option to retain the OEM donut gasket & spring bolts. I do wish that they offered a ceramic coating option. Of course, I'd recommend SwainTech's White Lightning coating.

If you're not familiar with high flow GESi catalytic converters, they're one of the very best on the market in terms of performance and reducing emissions. COBB's new downpipe features a 3" high flow, 300 cell catalytic converter that's rated for over 500 HP while still being EPA certified (reducing up to 99% of harmful emissions). The catalytic converter core itself is ~$400. Almost every other downpipe on the market goes with an undisclosed, lower quality "high flow" cat.. often with a lower cell count. It's funny because I posted a few months ago that my ideal downpipe would have their bellmouth design combined with a GESi cat towards the rear.. coincidence or just that great minds think alike?! 🤣

Why do I recommend a catted downpipe? Simple, a quality catalytic convert will keep the setup legal (in most states except California), it's environmentally friendly, and prevent boost creep (improving safety/reliability) while having a negligible impact to performance.

*COBB Titanium 3" Catback Exhaust
This is HIGHLY subjective. But COBB offers one of the best catbacks on the market IMO... a lightweight, dual muffler, quad-tip, titanium exhaust that comes in at 24 lbs (~50% lighter than the stainless steel alternatives). This will shave ~20 lbs +/- compared to the factory exhaust while producing a relatively mild, but unique exhaust note due to its titanium construction. I'd personally add a Vibrant Performance titanium resonator to keep things extra quiet and ensure a drone-free experience (I guess I'm getting old haha). I'd also like to see COBB offer an option for a set of more mature rolled, brushed titanium exhaust tips (similar in design to the tips on their stainless steel catback).

*Intake: COBB Redline Carbon Fiber Intake OR the OEM S209 Intake w/ a DryFlow Filter
COBB recently released what I consider to be one of the best (and only) aftermarket intakes that I recommend. A true cold air intake constructed of stylish, lightweight carbon fiber that will better resist heat soak (compared to a metal intake box). It should also produce a more mild, mature induction noise and shave a bit of weight compared to the stock airbox. If not for this intake, I would choose the OEM S209 intake.

*Boost Controller: GrimmSpeed or COBB 3-Port EBCS
A 3-Port EBCS is a no brainer before getting a protune. We'll want it in order to more precisely control boost now that we've significantly reduce backpressure increasing the intake & exhaust flow, thus improving volumetric efficiency.

Thermal Management (Reducing radiant heat transfer to the TMIC and lowering IATs & post turbo manifold temps):

*GrimmSpeed's V2 Turbo Heat Shield (Ceramic Thermal Coating & DEI Reflect-A-Gold Foil

*PTP Lava Turbo Blanket

*Protune

At this point you've maxed out the stock fuel injectors in 4th gear at higher RPMs. Skip the intake if you're worried and/or have your tuner dial the boost back in 4th gear and higher to be more conservative to lower IDCs a bit... I mean how much time do you really spend at ~100+ mph anyways?

If you do truly track your car and want to maximize reliability, you should look into upgrading the Fuel System to go "Stage 3".

Fuel System:
  • COBB/ID 1050x Fuel Injectors
  • AEM 340lph Fuel Pump (E85 compatible)
  • COBB/IAP FPR "fuel stumble" kit
  • COBB Flex Fuel Kit (E85 should offer ~ +50 whp/wtq while more importantly reducing knock tendency)
Now you've maxed out the stock VF48 turbo (probably around ~350-360 whp or so with well over 400 wtq). Luckily there's a great, reliable, budget OEM turbo upgrade option:

*IHI Turbo Performance's VF48 HF (Hi Flow) Turbo
Thanks to IHI installing a larger & lighter billet aluminum compressor wheel, the OEM+ VF48HF is capable of supporting over 400 whp for ~$1,000 USD while appearing completely factory. I'd also recommend having a reputable turbocharger porting company (like SoCal Porting or Turbo Parts Canada) Port the Turbine Housing (Turbine inlet & wastegate) to maximize the potential of the restrictive single scroll turbine housing and reduce boost creep. The setup above should produce ~400-420 whp while spooling (reaching boost threshold) as fast, or faster, than the OEM VF48.

This is the setup that I would do on my personal car if I hadn't went down the twin scroll conversion route. This would make for a perfect daily driven, high performance street car with occasional track use. Of course, I'd spend the extra money and have my great friends at Advanced Sports Engineering Lab perform a ball bearing conversion on the VF48 Hi Flow.. because I believe in having everything overengineered 😁
 

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For the downpipe, you could go with a Tomioka Racing divorced twin-scroll, and have a GESi cat welded in. That is my initial plan for a potential twin-scroll build. The TR downpipes are USDM length as well, dual bung for AFR/O2 sensors.
 

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Discussion Starter · #40 · (Edited)
For the downpipe, you could go with a Tomioka Racing divorced twin-scroll, and have a GESi cat welded in. That is my initial plan for a potential twin-scroll build. The TR downpipes are USDM length as well, dual bung for AFR/O2 sensors.
I've considered that option several times, but I'm not a fan of their bellmouth design for the price.

I'm going to reach out to Moore Power to get an estimate and see if they can do a GESi cat. I've yet to see a better twin scroll downpipe design. Their downpipe takes advantage of the "true" divorced wastegate design of the the OEM twin scroll housing, has nice smooth transitions and recirculates the wastegate gasses back into the downpipe further downstream.

The VF58 turbine outlet:

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The Moore Power "TruDivorce" twin scroll downpipe flange:

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I think it'll be another nice piece of functional artwork to add to my build 😁
 

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