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Discussion Starter · #1 · (Edited)
Kia Ora from New Zealand!

Currently in the process of getting this thing fast(er), so before I go asking questions I thought a build thread would help!
Car is flex-fuel tuned with dyno sheet below (E85).

326kw on E85
303kw on 98 (RON)

Interior:
DAMD Flat-Bottom Steering Wheel
ATI Triple Gauge Holder
Defi Gauges
Full Carbon Fibre Interior
IDoing Android Headunit (Running DashCommand w/ Wifi OBD)
SSCO Shifter/Handbrake Boots w/ Red Stitch
SSCO Climate Rings
SSCO Reverse-Lockout
AliExpress Red Carbon Shift Knob
DMND Si-Drive Ring
KAP Industries Fire Extinguisher Mount + Generic Extinguisher

Chassis/Handling:
Enkei PF01 18x9 +35
Bridgestone Potenza Sport 265/35/18
DBA4000 Rotors Front/Rear
Hawk XP650 Brake Pads

Cusco Front Member Brace
Cusco Floor Center Brace
Cusco Lower Arm Brace
Cusco Rear Floor Brace
Cusco Front Strut Tower Brace
Cusco Rear Strut Tower Brace
Cusco Rear Member Side Brace
Cusco Rear Member Brace
Cusco Braided Clutch Line
Cusco Rear Diff Cradle/Brace
Cusco Adjustable Rear Lateral Links
Cusco Power Brace Rear End
Cusco Steering Rack Brace
Cusco Stainless Clutch Hose
Cusco Brake Cylinder Stopper

Grimmspeed FMIC Compatible Front Member Brace (Crashbar)
Grimmspeed Pitch Stop Mount
Whiteline Rear Diff Bushing Kit
Whiteline Rear Subframe Bushing Kit
Whiteline Front Gearbox Mount Bushings
Whiteline Front Sway Bar - 24mm 2 Point Adjustable
Whiteline Rear Sway Bar - 24mm 3 Point Adjustable
Whiteline Steering Rack Bushings
Whiteline Shifter Bushing Kit

Kartboy Short-Shifter Upgrade
Kartboy Endlinks Front/Rear
Group N Transmission Mount
Group N Engine Mounts

Block:
EJ207 W20C (Closed Deck S20C Block Replacement)
Subaru STI 2.5L Black Nitride Crank Shaft
JE Subaru EJ20 Forged Stroker Piston Set Bore Size: .5 oversize, Compression Ratio: 8.5:1
Manley Subaru WRX/STI (EJ18/20/22/25) H Beam Connecting Rod Set
ARP 625+ Custom Age Subaru EJ20/25 Head Stud
Subaru EJ20/EJ22/EJ25 (For Rear Thrust) (Size STD) Performance Main Bearing Set
Subaru EJ20/EJ22/EJ25 (Size STD) Tri-Metal Perf Rod Bearing Set
12mm Oil Pump
PBMS Oil Gallery Modification
PBMS Stage 1 Baffled Sump
IAG Timing Belt Guide
Fluidampr Subaru EJ Series Steel Internally Balanced Damper
Killer B Motorsport Ultimate Oil Pickup
Killer B Oil Baffle

Heads:
Performance Valve Seat Reface
PBMS Stage 1 Cylinder Head Porting
Heavy Duty Valve springs drop in
Kelford Cams 272 V11
IAG TGV Delete Kit

Turbo/Intake:
Blouch Dominator 1.5XTR Twin Scroll 10cm 3" inlet
Killer B EJ Cast Aluminum Turbo Inlet 3"
Process West Front Mount intercooler kit - Black
Turbosmart BOV Race Port GEN V Black
Radium Engineering Subaru STi Air Oil Separator Kit

Fuel:
ID1300X Injectors
Radium Surge Tank
Turbosmart Fuel Filter & Billet Bracket
Link Flex-Fuel Ethanol Content Sensor
Radium Fuel Rail / Line

Drivetrain:
Xtreme Extra Heavy Duty Organic Clutch kit with upgraded pressure plate

Other:
Killer B Upper Coolant Fill Tank

Engine Management:
Emtron KV8 ECU

Pics and stories here ADDCTV WRX STi (@addctv.wrx) • Instagram photos and videos

E85:


Pump Gas:



 

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Discussion Starter · #2 ·
(Sept '22)

Pretty happy with the cars performance. It's as responsive as it was with the original twin-scroll VF49 after the tune so am stoked to have picked up nearly 100kw with identical response.

I have a DAMD wheel on the way also, since they were on special at JapanParts and really give the car a more "race" feel given the diameter and D-shape.
Next mods will likely be a carbon driveshaft to smoothen out some of the jerk in the lower gears (typically 1st, 2nd have a bit of a tendency to "buck" on Sport / Sport # maps given the throttle maps are quite sharp).
In addition to the above, I'd likely go 2-piece (Girodisc) brake rotors and chromoly flywheel to give the car even more response. At a guess I could maybe reclaim 10hp from lightening the drivetrain/removing unsprung mass.

(Dec '22)
Have since fitted a carbon driveshaft and can feel the car is a bit peppier/more responsive but most importantly the "buck" has gone.
Also ordered a TSSFAB gearbox crossmember (7lb reduction), a race battery (17lb reduction) and a pair of race seats (56lb reduction).
Will remove the spare from boot too since I've not yet done that (26lb). Hoping to shave close to 100lb (45kg) and see how the car feels.

Plans next are to replace front LCA's with SuperPro items since the bushings are still OEM and the early ('08) STI's came with an inferior arm design. Will also fit a bump-steer kit as the car currently has a lot of it.

At this stage I'm thirsty for a bit more power. Car is built for it so am tossing up between an EFR 7163 and EFR 7670. Either option will see an SX-E style compressor cover upgrade as these net a 10% efficiency gain (spool/power).
7670 will be a bit laggier but I worry the 7163 just won't net enough power to warrant the fabrication costs involved in rotating the turbo and retaining twin scroll (currently stock location).

Wing extension, diffuser, APR mirrors and guard vents fitted:



 

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Discussion Starter · #3 ·
While the Dom 1.5 did really well as a well-performing, responsive turbo, the power levels just aren't high enough given the build on the engine.
🔥A twin scroll EFR 7670 .92 IWG has been selected for the next turbo for this car 🔥

I'm hoping that this takes me from 400hp on pump to somewhere just below 500hp.
Have been following Jeremy's GR build for a while and am intrigued to see how a 2.1L on a smaller A/R (.92) goes compared to a 2L with slightly larger (1.05) A/R.

Adding to this, an SX-E featureless compressor housing will also be added to make sure all possible gains are had.
I've seen a couple of guys fit these comp housings to the EFR 7163's now with 6-10% gains but nothing proven yet on the 7670's.
Internal wastegate will be upgraded to a Twin-Port Turbosmart IWG75 and turbine housing covered with a Funk Motorsport T4 Blanket.

I'm currently on the JDM twin scroll exhaust manifold with factory heat shields.
Tuner is suggesting we go to larger diameter exhaust headers but am not sure if that's absolutely necessary (or beneficial?) at this point. Would love some input around this

Intake manifold upgrade is also being considered, as well as the possible retention/deletion of A/C.

Would love some feedback!
 

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Beautiful hatch! Why must you show me light weight suspension/bracing bits when I don't want to spend any more money on the car right now?

You can do a NA intake manifold and still retain A/C while giving you more breathing room on the top end. Going from a ported stock manifold and a GS tmic to a ported NA manifold and a 4" ets fmic I gained just 100 rpms of spool time for something that pulls much harder up top. I'm not sure if it would really be beneficial without some upgraded valves/valvetrain though.
 

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Discussion Starter · #5 ·
Beautiful hatch! Why must you show me light weight suspension/bracing bits when I don't want to spend any more money on the car right now?

You can do a NA intake manifold and still retain A/C while giving you more breathing room on the top end. Going from a ported stock manifold and a GS tmic to a ported NA manifold and a 4" ets fmic I gained just 100 rpms of spool time for something that pulls much harder up top. I'm not sure if it would really be beneficial without some upgraded valves/valvetrain though.
Cheers! Someone's gotta do it...

Yeah have looked into the NA manifolds but I think I'll likely bite the bullet and go with a Process West manifold ..if anything.
I'll pair that with a Bosch 74mm throttle body and let that be it.

Deleting/retaining the AC will solely be based on the choice to either forward or rear-face the manifold. At this stage I'm leaning towards ditching the AC to recoup some response out of the turbo.
 

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Cheers! Someone's gotta do it...

Yeah have looked into the NA manifolds but I think I'll likely bite the bullet and go with a Process West manifold ..if anything.
I'll pair that with a Bosch 74mm throttle body and let that be it.

Deleting/retaining the AC will solely be based on the choice to either forward or rear-face the manifold. At this stage I'm leaning towards ditching the AC to recoup some response out of the turbo.
Beautiful car.

im Like 99.999% sure you can keep the ac even if you flip the manifold…..
 

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Cheers! Someone's gotta do it...

Yeah have looked into the NA manifolds but I think I'll likely bite the bullet and go with a Process West manifold ..if anything.
I'll pair that with a Bosch 74mm throttle body and let that be it.

Deleting/retaining the AC will solely be based on the choice to either forward or rear-face the manifold. At this stage I'm leaning towards ditching the AC to recoup some response out of the turbo.
You can keep a with a cosworth manifold, even flipped. But good luck finding one for a reasonable price. Pretty sure the ams manifold can retain ac in the stock position. Same with the street version by pw. What exactly are you building the car for? It seems odd to me that after building something that was so focused on responsiveness and lower end tq you'd put something on that leans entirely the other way in the power band. Especially when you consider that to really take advantage of of a manifold that flows up top more you'll have to do cams and probably should upgrade the valve train depending on how high you want to rev. The general consensus I've seen is that you really don't even need to look into a different manifold until 500+ whp range. Though I'm sure a 7670 can get you there.

Also I run the IAG bolt on 74mm throttle body. It requires a spacer plate that still necks down to the factory inlet size. It would take some modification to the manifold to be 74mm straight through.
 

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Discussion Starter · #8 ·
You can keep a with a cosworth manifold, even flipped. But good luck finding one for a reasonable price. Pretty sure the ams manifold can retain ac in the stock position. Same with the street version by pw. What exactly are you building the car for? It seems odd to me that after building something that was so focused on responsiveness and lower end tq you'd put something on that leans entirely the other way in the power band. Especially when you consider that to really take advantage of of a manifold that flows up top more you'll have to do cams and probably should upgrade the valve train depending on how high you want to rev. The general consensus I've seen is that you really don't even need to look into a different manifold until 500+ whp range. Though I'm sure a 7670 can get you there.

Also I run the IAG bolt on 74mm throttle body. It requires a spacer plate that still necks down to the factory inlet size. It would take some modification to the manifold to be 74mm straight through.
Yeah I believe all aftermarket manifolds should allow retention of AC in stock orientation.
Sorry, to clarify I've only been deliberating over whether I should A: Upgrade the manifold and/or B: Flip the manifold or not and potentially lose AC.
The other drive to lose AC is the added airflow into the radiator with the removal of the AC condenser radiator which sits again behind the FMIC.
I'll look to be adding an oil cooler soon as I will need to get serious about keeping temps in check.

Car was built for street & track (over a year ago.. new thread but old(ish) build sorry should have also stated - only just gearing up now for next turbo upgrade).
I might drive it on the street say once a week in the weekends. Reading this back to myself, I should really just ditch AC

Also probably worth pointing out that the car has 272 cams, valvetrain and head porting done already.
It's a stroked 2.1L with closed-deck with 625 studs, we should be able to reach 750hp+ (eventually).

The car was always going to be a two-part build. At the time it died, we were already at the limits of the factory turbo so it made sense to put something a bit larger in the factory position while the engine was out. The Dom 1.5 XTR is admittedly a bit too small for this build as it does appear to choke up top especially when fed with E85.
Sourcing an EFR turbo out of the USA, intake/exhaust manifolds and additional fabrication were costs and delays I didn't want to undertake at the time.
Due to covid and operating restrictions on businesses here in NZ during lockdowns, the car had also been in the shop for close to 9 months already.

Jeremy's reaching over 500hp in his EJ207 with 7670 on E85. 28psi at 4250rpm on pump gas also seems pretty streetable.
It's a large turbo, yes but I am opting for the smaller .92 AR turbine housing and do have the added displacement with the stroker (and potentially the improved exhaust manifold).
 

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Discussion Starter · #9 ·
MotoIQ do a write-up on the Process West Manifold here
"On a stock engine, Process West has reported a 9% gain across the powerband.
IAG has reported gains of over 40 hp across the board with this manifold on more heavily modded engines."


While the price is high it does seem to provide some decent gains, though not yet documented/proven at a consumer level.
I'm surprised that nobody has done a back-to-back dyno comparison with the stock manifold, however the PW manifold does actually relocate the factory throttle body slightly so there is some fabrication involved even in stock orientation which would make it a costly exercise.
 

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MotoIQ do a write-up on the Process West Manifold here
"On a stock engine, Process West has reported a 9% gain across the powerband.
IAG has reported gains of over 40 hp across the board with this manifold on more heavily modded engines."


While the price is high it does seem to provide some decent gains, though not yet documented/proven at a consumer level.
I'm surprised that nobody has done a back-to-back dyno comparison with the stock manifold, however the PW manifold does actually relocate the factory throttle body slightly so there is some fabrication involved even in stock orientation which would make it a costly exercise.
I've seen that article before but what i've been told from both my tuner and others on the internet (so take this part as you will) is that the PW intake manifold will kill your bottom end. My tuner was specifically comparing the NA & AMS manifolds to the PW race version. With how huge that plenum is on the race version is and how short the runners are i'd be surprised if it didn't have a negative effect on the low rpm range/spool times. The AMS manifold does have a pretty large plenum, though not compared to the PW race version, and has some pretty long runners which help keep velocity up at lower rpms. Short/fat runners are great for top end flow at the expense of low end velocity.

On the old jdm 4g63's out of the Galant vr4 Mitsu made a dual runner intake manifold. It had 4 short/fat runners that were typically closed with butterfly valves and 4 long/skinny runners that stayed open all the time. The valves were operated off a an internal wastegate mounted to the side of the manifold that would open once a set boost level at which point all 8 runners would be open. Over the factory single runner manifolds we got in the US they would drop 300-500 rpms in spool time and pick up around 50 wtq more on the low end. I'd love to see something along those lines made for us but it would be a costly endeavor for something that would have a really small market.
 

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Discussion Starter · #11 · (Edited)
I've seen that article before but what i've been told from both my tuner and others on the internet (so take this part as you will) is that the PW intake manifold will kill your bottom end. My tuner was specifically comparing the NA & AMS manifolds to the PW race version. With how huge that plenum is on the race version is and how short the runners are i'd be surprised if it didn't have a negative effect on the low rpm range/spool times. The AMS manifold does have a pretty large plenum, though not compared to the PW race version, and has some pretty long runners which help keep velocity up at lower rpms. Short/fat runners are great for top end flow at the expense of low end velocity.
Yes 100%, that's all been in line with what I've found so far also regarding low-end. PW would be a great top-end manifold while the AMS is going to lose a bit less down low.
Looking at availability for a short-runner 2.5i NA manifold (I already have TGV deletes and don't want to run phenolic spacers to clear AVCS on a long-runner version since the injectors get lifted away from the back of the valves if spaced up), seems like a good upgrade without much sacrifice (if any). Maybe a mild port and slightly larger TB and it could be a really good option to save some $$ also.
 

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Yes 100%, that's all been in line with what I've found so far also regarding low-end. PW would be a great top-end manifold while the AMS is going to lose a bit less down low.
Looking at availability for a short-runner 2.5i NA manifold (I already have TGV deletes and don't want to run phenolic spacers to clear AVCS on a long-runner version since the injectors get lifted away from the back of the valves if spaced up), seems like a good upgrade without much sacrifice (if any). Maybe a mild port and slightly larger TB and it could be a really good option to save some $$ also.
That's exactly what I ended up going with. Picked up a NA short runner for maybe 200, got it port matched to the radium tgv deletes I already had, paid for powder coating. Finally since I was going from a tmic to a fmic at the same time I added one of the 74mm IAG throttle bodies since I was getting custom intercooler piping made at the same time. I betting most of the cause of the additional 100 rpm spool time is due to the increase in piping and intercooler size rather than the manifold. On the street I don't even notice. I only know because you could see it when comparing dyno logs.

I really do like how the NA manifold looks like its a factory piece under the hood. I have a pocket ported set of heads, bc 272's and bc/gsv valve train. It seems like my motor can outflow what my turbo can do up top. It's a 66 lb/min turbo. I've seen other guys with stock ported heads and stock intake manifolds run fp greens, which are 61 lb/min) out to 7500+ without as much drop off in power as I get up passed the stock redline. If you're sure you want to trade low end for top end make sure.you have a turbo that's going to be able to breathe enough for your engine in that range. I've seen a few people break 500 whp with a 7163. But that's about the same size as a green. Idk how much bigger the 7670 is but if you're set on a Borg Warner turbo I'd lean towards the bigger one with the size compressor cover.

Is there a reason you aren't considering something newer? The new g series turbos seem to have some great performance and responsiveness. Even gen 2 3576r should spool by mids 4000s, hold boost well passed redline and have enough low end to still make it enjoyable to drive on the street. Killer b has a comparison dyno chart comparing a gen 2 3576r and a gen 2 3071r floating around the internet. The low end was nearly identical. But where the 3071 started to level off on power the 3576 just kept building power. I'd bet that the newer g30-770, g30-900 or even a g35-900 would be even more responsive in comparison.
 

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Discussion Starter · #13 · (Edited)
That's exactly what I ended up going with. Picked up a NA short runner for maybe 200, got it port matched to the radium tgv deletes I already had, paid for powder coating. Finally since I was going from a tmic to a fmic at the same time I added one of the 74mm IAG throttle bodies since I was getting custom intercooler piping made at the same time. I betting most of the cause of the additional 100 rpm spool time is due to the increase in piping and intercooler size rather than the manifold. On the street I don't even notice. I only know because you could see it when comparing dyno logs.

I really do like how the NA manifold looks like its a factory piece under the hood. I have a pocket ported set of heads, bc 272's and bc/gsv valve train. It seems like my motor can outflow what my turbo can do up top. It's a 66 lb/min turbo. I've seen other guys with stock ported heads and stock intake manifolds run fp greens, which are 61 lb/min) out to 7500+ without as much drop off in power as I get up passed the stock redline. If you're sure you want to trade low end for top end make sure.you have a turbo that's going to be able to breathe enough for your engine in that range. I've seen a few people break 500 whp with a 7163. But that's about the same size as a green. Idk how much bigger the 7670 is but if you're set on a Borg Warner turbo I'd lean towards the bigger one with the size compressor cover.

Is there a reason you aren't considering something newer? The new g series turbos seem to have some great performance and responsiveness. Even gen 2 3576r should spool by mids 4000s, hold boost well passed redline and have enough low end to still make it enjoyable to drive on the street. Killer b has a comparison dyno chart comparing a gen 2 3576r and a gen 2 3071r floating around the internet. The low end was nearly identical. But where the 3071 started to level off on power the 3576 just kept building power. I'd bet that the newer g30-770, g30-900 or even a g35-900 would be even more responsive in comparison.
Just have had a look at your build thread too, nice build! We've similar mods (have updated my list with the handling/chassis stuff).

All of the comparisons have been made with GTX series turbos and not the G30 & G35's.
I had read in this thread, that even the new G30/35 turbos lack the response that the EFR turbos provide.

Even the smaller G25-660 proved very lackluster results on an EJ207, full boost at over 5,000rpm. Video Here

Below is an excerpt from the list of turbos I've compiled. Note: There are also still characteristics of each turbo (wheel design, wheel material, twin scroll etc) to consider.
For example, the EFR turbine wheels are made from Titanium aluminide (Gamma-Ti) with dual-row ceramic bearings and generally have a better spool/transient response than their Garrett counterparts. Garretts on the other hand, seem to make a little more power up top, likely due to a newer design.
However, when factoring in the addition of one of EFR's new SX series compressor housing upgrades, I would go as far to say the EFR trumps the Garretts.





And the video RE: EFR SX Compressor Cover Gains:


Twin scroll was a "must-have" for this build in order to keep responsiveness. Having looked at comparisons between the SS and TS versions of say the 7670 and it is an absolute no-brainer, especially on the EJ207. The single-scroll 7670 examples I've found (and even the GTX3576R's) are horrible performers RE: response.

Garrett GTX3576R is the closest match to the EFR 7670 below:

BrandTurboCmpIndCmpExdTrbIndTrbExdFlowCHRA BearingNotesMounting Location
BlouchDom 1.5 XT-R537156.551.749Ball BearingXStock
BlouchDom 2.5 XT-R53716054.949Ball BearingStock
Forced PerfFP 71HTA51.271655551Journal BearingStock
BorgWarnerEFR 71635771635660Ball BearingXRotated
GarrettGTX 3071R54.171.46054.956Ball BearingXBoth
SteamSTX 7154.171.46154.159Journal BearingStock
BlouchDom 3.0 XT-R57766054.955Ball BearingStock
BlouchDom 3.5 XT-R57766458.658Ball BearingStock
BorgWarnerBW 76705676706158Journal BearingRotated
Forced PerfFP HTA 3076R54.8766054.959Ball BearingRotated
Forced PerfFP Green HTA54.876675959Journal BearingStock
Forced PerfFP Red 76HTA58766054.960Ball BearingStock
MHITD06H 60-159.5766758.861Journal BearingStock
BorgWarnerEFR 767057.276706264Ball BearingXRotated
PrecisionSubaru 553054.976.256.551.7852.5Ball BearingStock
GarrettGT 3076R5776.26054.952.5Ball BearingBoth
PrecisionPTE 555854.976.264.957.9159EitherXRotated
PrecisionPTE 58585876.264.957.9162EitherXRotated
PrecisionPTE 58625876.27161.964EitherRotated
GarrettGTX 3076R5876.66054.964Ball BearingXBoth
GarrettGTX 3576R5876.66862.265Ball BearingXBoth
Forced PerfFP Red61.2181.79675965Journal BearingStock
PrecisionPTE 626262.2381.997161.970.5EitherRotated
PrecisionPTE 62666281.9974.176673.5EitherRotated

Some 7670 Examples on E10 (Pump gas):

Version 8 STI w/ 7670 .92 A/R and IWG
Closed deck 2ltr W block
Bigger valve seats and springs
Pistons, rods
2200cc injectors
3 fuel pumps
Standard intake and exhaust manifold
(Camshafts unknown)



Jeremy's GR (1.05 A/R EWG) :
V11 Heads with Porting
Kelford 282 Race D-Shaped Cams
Ferrea 1mm Oversize Valves
Kelford 282 Cams
Standard intake and exhaust manifold



Approx a 16hp difference and nearly identical spool between both cars.
While these are the only two real examples of the 7670 I can find on an EJ207, I'm pretty confident I should land somewhere close to those.

I'm hoping that with the addition of the SX housing, I can see slightly higher numbers, 6% would be great 10% would be unreal.
I also have the stroker (2.14L) as an advantage over and a slightly-less duration (272) shaft than Jeremy's.

I've also added my pump gas dyno for the Dom 1.5 to my first post, for an apples-to-apples comparison.
You'll see that full spool is around 4,000rpm, about 250rpm later than E85.

So from the Dom on pump, a ~250/300 rpm penalty for at least 115hp is a pretty reasonable trade-off I would have thought, expecting more with the SX cover.
The gap between E85 and pump should also be greater (Currently I have about 33kw difference so there's little tempation to buy a 200L drum of it since we can't get it at the pump anymore - thanks to Covid and our ethanol reserves now being used for hand sanitizer).

And finally, here is the same version 8 STi (7670 .92 IWG) from above on E85 :



620hp and 773Nm of torque.... That's gotta be testing the axles!
 

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I kept thinking you were on a 2.5l even though i had read through the thread. I also didn't realize that the 7670 was ball bearing. That was really what i was thinking when suggesting some of the other turbo. All of Killerb's testing was on a 2.5l.

That tq drop off on the second dyno sheet is brutal.
 
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