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STINick's S208 Twin Scroll VF58 Conversion

57K views 185 replies 23 participants last post by  Karlot 
#1 · (Edited)
I traded my '16 WRX in for a '19 STI a few weeks ago. I got a great deal on it and Subaru 1.9% financing so I couldn't pass it up. Even though the STI is slower than my flex fuel WRX was, it's better in almost every other aspect. The raw, mechanical, old school driving feel is what ultimately drew me to the STI. The Recaro seats certainly didn't hurt. The STI just suits me better minus the terrible fuel economy, but it's certainly better than my '95 RX-7 was.



2019 Subaru WRX STI CWP
MSRP: $41,622
Invoice: $38,802
Paid: $37,522

Factory Options:
  • Recaro Package (Recaro seats & keyless access/push-button start)
  • Popular Package #1 (Center armrest extension, wheel locks, auto dimming compass mirror w/ homelink, rear cargo tray, and rear bumper applique)
  • Shifter Package (STI shift knob & short throw shifter)
  • Rear splash guards
Some of my more notable previous cars:
  • '16 WRX - 330whp (E50 flex fuel tune, GS TMIC, GS EBCS, TGV/EGR delete, AOS, stock intake & exhaust). Plenty fast, but felt "numb" to me. Not the driving experience that I was looking for. I do miss getting 30+ mpg.
  • '11 Civic Si - slow, but I do miss the sound of vtec and revving to 9k rpm
  • '95 RX-7 - 330whp (intake, turboback exhaust, upgraded intercooler, etc.)
  • '05 AP2 S2000 - also slow, but handled amazingly, sounded great, and revved to 8.5k rpm
  • '01 Cobra - tried the American muscle thing for a while.. loved the torque & sound, but the handling & weight wasn't for me
  • '95 Civic w/ tuned K20 swap - stolen - light, fast, 220whp, 2300 lbs, 12 sec 1/4 mile, redline at 8.6k rpm
  • '93 Civic w/ LS/VTEC turbo swap - light, tons of power (~400whp), and no traction thanks to FWD.. even with the ITR trans w/ LSD
  • '93 RX-7 - 360whp ("FBO" with the stock turbos, street ported engine w/ ceramic apex seals)
The only cars that I really crossed shopped before the STI were the '19 ND2 Miata (the whole driving a slow car fast thing) and the '19 Mustang GT (gobs of power, fast, great exhaust sound, carb legal supercharger, etc.). But nothing beat the practicality of the 4 door, awd STI (wife approved - especially with a baby on the way). I think that it's a good balance of power, handling, driving feel, and practicality. Despite being a Honda guy at heart, I didn't really consider the CTR due to the looks and the dealer markups. I feel like Honda has really lost their way since the 90s & 00s. I'd rather Honda have made a lighter car w/ a high revving NA engine.
 

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#2 · (Edited)
Mod list:

Exterior
  • STEK Dynoshield PPF done by Detail Maniac ("Premium Full Frontal" - bumper, hood, fenders, headlights, a-pillars, front portion of roof, door mirrors, lower door/rocker panels). I learned from my WRX that Subaru's paint is way too thin. Rock chips make the front bumper look like swiss cheese.
  • CQuartz UK 3.0 ceramic coating
  • OEM JDM rear fog/brake light kit w/ pnp harness from SubieBros
  • OEM JDM LED DRL bezels ('20+) w/ SMYPerformance "pnp" harness (H4517VA437)
  • OEM JDM STI anti-glare sequential turn signal mirrors (ST91039ST050)
  • OEM STI front lip under spoiler (E2410VA030)
  • OEM Type RA black/cherry blossom fender emblem garnish (91123VA300 & 91123VA310)
  • OEM STI license plate frame (SOA342L126)
  • OEM JDM STI fuel cap
  • Diode Dynamics LED reverse & license plate lights
Interior
  • OEM JDM STI S207 shift knob (ST35022ST170)
  • OEM STI short throw shifter (C1010FG600)
  • OEM JDM coin holder/fuse box cover (66170VA010VH)
  • OEM JDM push button start - older, discontinued model w/ light-up STI logo (ST83031ST012)
  • OEM Kicker tweeters (H631SFJ101)
  • OEM windshield sunshade (SOA3991320)
  • OEM rear cargo tray (J501SFJ400)
  • Alcantara wrapped OEM extended armrest
  • Diode Dynamics LED interior lighting
Engine
  • COBB AP w/ my own custom tune (IG: STINickTuned)
Not yet installed
  • JDM S208 VF58 Twin Scroll, Ball Bearing Turbo Conversion w/ OEM TS ELH & Downpipe
  • STI Group N Competition Transmission Mount ST410224S040 (stiffest version)
  • STI Group N Competition Pitch Stop ST410404S000 (stiffest version)
  • STI Group N Competition Cross Member Bushings ST41022ZR000
  • STI Group N Rear Shifter Bushing B0220FG300
  • JDM Cusco Rubber Front Shift Linkage Bushing - similar to Group N rubber
  • Torque Solution Rear Diff Bushing Inserts
  • STI Red Silicone "Air Duct" Coupler ST2183066000 (TMIC > Throttle Body)
  • Killer B "Extreme Flow HARD Turbo Inlet"




Spotted a Type RA:
 
#3 ·
Nice start and quite refreshing to see someone who appreciates the merits of the STI over the WRX. I'm currently a little caught up in the power mods and seeing very little bang for the big bucks throw in, but as love my STI.

Looking back at the progression, I think I should have just stayed at getting a tune on the stock build + the Killer B ELH. I'm currently falling into the plan of getting a bigger turbo and it's a slippery slope.
 
#4 ·
Thanks! I've been fighting the urge to start modifying the engine. I would really like to do the Kill B ELH, but then figure that I should at least add a downpipe while I'm there and will need a tune anyways.. and then the slippery slope begins..

But I keep reminding myself that I should have just kept the WRX if I wanted to modify for power. The FA20 responds really well to ethanol. You can easily get 320 whp wiith only the $600 Cobb flex fuel kit & tune. The bang for your buck doesn't get much better than that. No need to upgrade the fuel system or add any other bolt-ons. The STI's EJ257 has a much higher potential once you start building the block, adding a larger turbo, etc., but that's honestly more than I want to spend at this point.. especially living in California and having to worry about carb regulations & smog down the road, but I'm sure you know how that goes :)
 
#5 ·
Yes, I understand the worries about smog. I actually don’t even get the 6 year exemption because I purchased my car new in Reno because I saved about $5K and when you bring a car in from out of state, you loose the exemption, so I’m sniffing every 2 years
 
#6 · (Edited)
Some minor OEM interior mods..

S207 shift knob w/ cherry blossom STI logo:


JDM STI push-button start w/ light-up logo (discontinued):




JDM coin holder/fuse box cover:


OEM Kicker tweeters - huge improvement for the base STI sound system for ~$90:
 
#7 · (Edited)
Some OEM exterior mods...

STI lip (sorry for the dirty car):


JDM LED bezels:


Wiring the LED to always come on with the DRL C lights was "fun"... They're far from plug-and-play with SMYPerformance's "pnp" harness. Comes with quick splice connectors & 0 instructions..


JDM rear brake/fog light (again, sorry for the dirty car):


 
#8 ·
OEM STI Type RA (black & cherry blossom) side emblems/garnish:




JDM STI anti-glare sequential turn signal mirrors:


Comparison of the mirrors - say good bye to blind spots & glare. The wider/zoomed out perspective does have a little adjustment period. This has been one of my favorite mods.



 
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#9 · (Edited)
Here's a quick write-up on the wiring that I did for the JDM LED bezels in case it's helpful for anyone else.. I know I was certainly lost when I received the kit.

I purchased the "plug and play" harness from SMY and was disappointed to find out that it's not truly pnp and requires splicing additional wires via quick taps. Their kit doesn't include any instructions :tdown:

I saw a lot of debate on tapping the side marker or the 3 wire plug directly below the headlight adjuster (which is essentially accessory power). But I wanted the LEDs to sync with the C-lights (both when the headlights are on & off). I read over the wiring diagrams in the FSM and thought I had it figured out, but I was missing one wire. I found that I needed to tap both wires 6 & 7 on the headlight harness connectors. I then ran the grounds to the existing grounding points on the frame.

Passenger headlight:
  • Tap wires 6 (black/blue) & 7 (red/green) and Y the connection to the red power wire on the harness. It's recommended to use diodes on each pin.
  • Run the black ground wire on the harness to the existing ground point on the frame.
Driver side headlight:
  • Tap wires 6 (black/green) & 7 (red/green) and Y the connection to the red power wire on the harness. It's recommend to use diodes on each pin.
  • Run the black ground wire on the harness to the existing ground point on the frame.
These are the diodes that I used:
https://www.amazon.com/gp/product/B071YWNBVM

The only downside is that the LEDs don't dim with the C lights, but that's not a big deal to me.

Someone else made a super helpful video and wiring schematic that I can't take credit for. Just passing along the information.

2018 WRX STI - JDM S4 Bezel LED Running Light CLight Wiring - YouTube

Wiring schematic:
 
#11 ·
Went to the dealership today for my 1st free oil change (5,300 miles). I had changed the oil on my own at around 1,200 miles with Pennzoil Platinum 5W-30 (got it for $10 with rebate).

Unfortunately, after driving home the car smells like burnt oil. I don't see any leaks, but it just leads me to believe they were probably a bit careless. I plan on checking the oil level in the morning, but this just reminds me why I do all of my own maintenance.

Not sure if I'll take it back for the 2nd free oil change.
 
#12 ·
Went to the dealership today for my 1st free oil change (5,300 miles). I had changed the oil on my own at around 1,200 miles with Pennzoil Platinum 5W-30 (got it for $10 with rebate).



Unfortunately, after driving home the car smells like burnt oil. I don't see any leaks, but it just leads me to believe they were probably a bit careless. I plan on checking the oil level in the morning, but this just reminds me why I do all of my own maintenance.



Not sure if I'll take it back for the 2nd free oil change.
Always do your own work. And switch to 5w-40. I use Pennzoil Platinum Euro. It quiets down the valve train noise quite a bit and reduces blow by. Car is much happier with it. Use the OEM blue filters.

Sent from my SM-G960U using Tapatalk
 
#14 ·
Thanks! I look forward to seeing your build thread.

I preferred wingless, but didn't want the sunroof. Maybe I'll do a trunk swap some day.
 
#15 ·
Finally, a new part! It should have come like this from the factory...

Alcantara Extended Armrest:







Not a perfect match color-wise for my OCD, but it's close enough. I'm sure it'll get closer as it gets dirty and wears some :)
 
#16 ·
Hi Nick,
When you install the JDM rear fog/brake light, did you put the wires through the opening that is truly intended for it and the clips to hold the wiring or did you just use the same plug that most if not all aftermarket vendors recommended ? If so, did you remove the rear bumper to get to the plug or was it accessible just by removing the bottom clips?

I just bought the complete SubiBro kit with PnP harness and dual intensity harness plus LED bulb, is this the same setup you have on your car? I will be installing it during the holidays so any words of wisdom will be greatly appreciated.
 
#17 ·
Hi Nick,
When you install the JDM rear fog/brake light, did you put the wires through the opening that is truly intended for it and the clips to hold the wiring or did you just use the same plug that most if not all aftermarket vendors recommended ? If so, did you remove the rear bumper to get to the plug or was it accessible just by removing the bottom clips?

I just bought the complete SubiBro kit with PnP harness and dual intensity harness plus LED bulb, is this the same setup you have on your car? I will be installing it during the holidays so any words of wisdom will be greatly appreciated.
I bought the SubiBro PnP kit as well, but with the OEM light. It was a pretty easy & straightforward install once you get in there. Everything was plug and play for me. There was no need to remove the bumper.

I used the trunk plug that was already there. I ran the wiring behind the top of the plug rather than putting a slit in it as I didn't want to risk slicing the existing wiring. I did use the included clips to hold the wiring in place just to make it look a bit cleaner. Here's a pic from inside the trunk.

 
#21 ·
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!
 
#22 ·
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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#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...
 
#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.

59833

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" 🤣

59837


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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#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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#29 ·
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 ;)
 
#30 ·
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.
 
#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:

60625


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

60626


More OEM S208 goodness:

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#32 ·
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

View attachment 60624


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!
 
#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.
 
#38 · (Edited)
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 😁
 
#40 · (Edited)
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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