USDM FA20 DIT Engine Specifications

The Subaru FA20F motor is a direct-injected turbo engine found in the 2015+ WRX. It features a four-cylinder horizontally-opposed "Boxer" layout with a twin-scroll turbocharger. The 2014+ Forester XT uses essentially the same engine, but with small changes and a different designation (FA20E).

Overview

Specification Standard Metric Engine Code FA20F FA20F Displacement 122ci 1998cc (2.0L) Layout H4 BOXER H4 BOXER Power 268 BHP @ 5600 RPM (WRX)

250 BHP @ 5600 RPM (XT) 197 kW @ 5600 RPM (WRX)

184 kW @ 5600 RPM (XT) Torque 258 Lb-Ft @ 2000 RPM (WRX / XT) 350 Nm @ 2000 RPM (WRX / XT) Rev Limit 6700 RPM 6700 RPM Assembly Oizumi, Japan Oizumi, Japan Firing Order 1-3-2-4 1-3-2-4 Spark Plug NGK ILKAR8H6 NGK ILKAR8H6 Fuel Pump Flow 40.4 Gallons (US)/Hr 153 L/Hr

FA20 Turbo Block Specs

Specification Standard Metric Block Material Cast Aluminum Cast Aluminum Block Design Open Deck Open Deck # of Cylinders 4 4 Bore Diameter 3.386" 86mm Bore Spacing 4.449" 113mm Cylinder Liners Cast-In Iron Cast-In Iron # of Main Bearings 5 5 Cylinder Block Height * 8.071" (R)

8.073" (L) 205.0mm (R)

205.05mm (L) Min. Cyl. Block Height 8.067" 204.9mm Cyl. Block Warpage Limit 0.00098" 0.025mm Cyl. Liner ID 3.3860 - 3.3864" (A)

3.3856 - 3.3860" (B) 86.005 - 86.015mm (A)

85.995 - 86.005mm (B) Cyl. Liner Cylindricality Limit 0.0012" 0.030mm Cyl. Liner Out-of-Roundness Limit 0.0012" 0.030mm Bore ID Limit 3.4057" 86.505mm

* - Difference in Cylinder Block Height is due to the water pump being placed on one side of the block and the resulting thermal expansion difference

Measuring for Cylindricality and Out-Of-Roundness

Take measurements in the thrust and pin directions (A + B) at the specified heights. Verify that the block is at 68°F (20°C) for all measurements.

$$Cylindricatlity =\dfrac {x_{\max }-x_{\min }}{2}$$

$$x_{\max } = \textrm{largest value of all the cylinder liner ID measurements}$$

$$x_{\min } = \textrm{smallest value of all the cylinder liner ID measurements}$$

Calculate the Out-Of-Roundness at each height measurement (H1 - H4).

$$OOR =\dfrac {x_{\max }-x_{\min }}{2}$$

$$x_{\max } = \textrm{larger measurement value at H1}$$

$$x_{\min } = \textrm{smaller measurement value at H1}$$

FA20 Turbo Piston Specs

The figures below are the OEM Subaru specifications for the stock OEM Subaru pistons. If you are rebuilding the engine using an aftermarket forged piston you will need to run considerably higher tolerances to accommodate the greater thermal expansion. Please consult your piston supplier for appropriate clearances.

Specification Standard Metric Piston Material Hypereutectic Cast Aluminum

with Anti-Friction Skirt Coating Hypereutectic Cast Aluminum

with Anti-Friction Skirt Coating Static Compression Ratio 10.6:1 10.6:1 Piston Weight 360g 360g Piston Wrist Pin Diameter

(Gudgeon Pin) 0.866" 22mm Piston Wrist Pin Offset 0.039" 1mm Piston Wrist Pin Weight 136g 136g Piston Crown Volume 0.8cc 0.8cc Compression Height 1.291" 32.8mm Piston Outer Diameter 3.3852 - 3.3856" (A)

3.3856 - 3.3860" (B)

3.3947 - 3.3955" (0.25mm OS)

3.4045 - 3.4053" (0.50mm OS) 85.985 - 85.995mm (A)

85.975 - 87.985mm (B)

86.225 - 86.245mm (0.25mm OS)

86.475 - 86.495mm (0.50mm OS) Piston to Wall Clearance 0.00039” - 0.00118” 0.01mm – 0.03mm Piston Gauge Height 1.57" 40mm Piston Pin Clearance 0.0002 - 0.0003" 0.004 - 0.008mm Top Comp. Ring Axial Height 0.0394" 1.0mm Top Compression Ring Gap 0.0079 - 0.0098" 0.20 - 0.25mm Second Comp. Ring Axial Height 0.0472" 1.2mm Second Compression Ring Gap 0.0157 - 0.0197" 0.40 - 0.50mm Oil Control Ring Gap 0.0039 - 0.0138" 0.10 - 0.35mm Top Compression Ring Clearance 0.0016 - 0.0031" 0.040 - 0.080mm Second Compression Ring Clearance 0.0018 - 0.0033" 0.045 - 0.085mm Piston to Pin Clearance 0.0002 - 0.0003" 0.004 - 0.008mm Pin to Rod Bushing Clearance 0.0002 - 0.0010" 0.004 - 0.026mm

Piston Measuring

FA20 Turbo Rod Specs

The figures below are the OEM Subaru specifications for the stock OEM Subaru rods. If you are rebuilding the engine using an aftermarket forged rod you may need to run greater clearances for the power level.

Specification Standard Metric Con Rod Material Forged Steel Forged Steel Con Rod Design Asymmetrical I-Beam

with Cracked Caps

and Rod Bolts Asymmetrical I-Beam

with Cracked Caps

and Rod Bolts Con Rod Weight 492g 492g Con Rod Length 5.090" 129.29mm Big End Bore 2.087" 53.01mm Big End Width 0.843" 21.41mm Pin Bore 0.8671" 22.02mm Rod Bolt Torque 18.44 ft-lbs 25Nm

FA20 Turbo Crankshaft Specs

The figures below are the OEM Subaru specifications for the stock OEM Subaru crankshaft. If you are rebuilding the engine using an aftermarket crankshaft you may need to run different clearances.

Specification Standard Metric Design / Material 8CW Flat-Plane Nitrided Forged Steel 8CW Flat-Plane Nitrided Forged Steel Stroke 3.386" 86mm Rod Bearing Thickness

(Center) 0.0587 - 0.0594" (Std)

0.0595 - 0.0596" (0.0012" US)

0.0599 - 0.0600" (0.0020" US)

0.0638 - 0.0640" (0.0098" US) 1.492 - 1.508mm (Std)

1.511 - 1.515mm (0.03mm US)

1.521 - 1.525mm (0.05mm US)

1.621 - 1.625mm (0.25mm US) Crankshaft Pin OD

(Rod Bearing Journal) 1.9676 - 1.9685" (Std)

1.9664 - 1.9673" (0.0012" US)

1.9656 - 1.9665" (0.0020" US)

1.9577 - 1.9587" (0.0098" US) 49.976 - 50.000mm (Std)

49.946 - 49.970mm (0.03mm US)

49.926 - 49.950mm (0.05mm US)

49.726 - 49.750mm (0.25mm US) Crankshaft Pin

Cylindricality 0.0002" 0.006mm Crankshaft Pin

Out-of-Roundness 0.0002" 0.005mm Crankshaft Pin

Grinding Limit (dia.) 1.9577" 49.726mm Rod Bearing Oil Clearance 0.0010 - 0.0022" 0.025 - 0.055mm Main Bearing Thickness

Position #1 - 4

(Center) 0.0982 - 0.0989" (Std)

0.0992 - 0.0993" (0.0012" US)

0.0996 - 0.0997" (0.0020" US)

0.1035 - 0.1036" (0.0098" US) 2.495 - 2.513mm (Std)

2.519 - 2.522mm (0.03mm US)

2.529 - 2.532mm (0.05mm US)

2.629 - 2.632mm (0.25mm US) Main Bearing Thickness

Position #5 Only

(Center) 0.0981 - 0.0989" (Std)

0.0991 - 0.0992" (0.0012" US)

0.0995 - 0.0996" (0.0020" US)

0.1034 - 0.1035" (0.0098" US) 2.493 - 2.511mm (Std)

2.517 - 2.520mm (0.03mm US)

2.527 - 2.530mm (0.05mm US)

2.627 - 2.630mm (0.25mm US) Main Journal OD 2.6766 - 2.6775" (Std)

2.6754 - 2.6763" (0.0012" US)

2.6746 - 2.6755" (0.0020" US)

2.6667 - 2.6677" (0.0098" US) 67.985 - 68.009mm (Std)

67.955 - 67.979mm (0.03mm US)

67.935 - 67.959mm (0.05mm US)

67.735 - 67.759mm (0.25mm US) Crankshaft Bending Limit 0.0014" 0.035mm Crankshaft Main Journal

Cylindricality 0.0002" 0.006mm Crankshaft Main Journal

Out-of-Roundness 0.0002" 0.005mm Crankshaft Main Journal

Grinding Limit (dia.) 2.6667" 67.735mm Thrust Clearance 0.00512 - 0.01213" 0.130 - 0.308mm Main Oil Clearance 0.00051 - 0.00122" 0.013 - 0.031mm

FA20 Turbo Head Specs

Specification Standard Metric Head Design DOHC 16-Valve

with Dual AVCS DOHC 16-Valve

with Dual AVCS Combustion Chamber Volume 40.3cc 40.3cc Rocker Type Roller Rocker (INT/EXH) Roller Rocker (INT/EXH) Rocker Ratio 1.59:1 (INT/EXH) 1.59:1 (INT/EXH) Spring Retainer Material Hi-Strength Steel Hi-Strength Steel Spring Retainer Weight 11.38g 11.38g Intake Camshaft Clearance

(Note: Measure at 68° F / 20° C) 0.0051" (Std)

0.0039" (Min) - 0.0059" (Max) 0.13mm (Std)

0.10mm (Min) - 0.15mm (Max) Exhaust Camshaft Clearance

(Note: Measure at 68° F / 20° C) 0.0087" (Std)

0.0079" (Min) - 0.0095" (Max) 0.22mm (Std)

0.20mm (Min) - 0.24mm (Max) Cylinder Head Warp Limit 0.00079" 0.020mm Grinding / Surfacing Limit 3.874" Height

0.004" Removed 98.4mm Height

0.1mm Removed Cylinder Head Height 3.878" 98.5mm Valve Length 4.132" (INT)

3.854" (EXH) 104.95mm (INT)

97.9mm (EXH) Valve Angle 14° (INT/EXH)

28° Included 14° (INT/EXH)

28° Included Intake Valve Specs 1.38" (Face Diameter)

0.217" (Stem Diameter)

45.5g (Weight) 35mm (Face Diameter)

5.5mm (Stem Diameter)

45.5g (Weight) Exhaust Valve Specs 1.14" (Face Diameter)

0.217" (Stem Diameter)

37.0g (Weight) 29mm (Face Diameter)

5.5mm (Stem Diameter)

37.0g (Weight) Valve Head Edge / Margin Thickness 0.031 - 0.047" (INT)

0.039 - 0.055" (EXH) 0.8 - 1.2mm (INT)

1.0 - 1.4mm (EXH) Valve Stem Diameter 0.2148 - 0.2154" (INT)

0.2144 - 0.2150" (EXH) 5.455 - 5.470 (INT)

5.445 - 5.460mm (EXH) Valve Guide ID 0.2165 - 0.2170" (INT/EXH) 5.500 - 5.512mm (INT/EXH) Valve Stem to Guide Clearance 0.0012 - 0.0022" (INT)

0.0016 - 0.0026" (EXH) 0.030 - 0.057mm (INT)

0.040 - 0.067mm (EXH) Valve Guide Protrusion Limit 0.449 - 0.465" 11.4 - 11.8mm Valve Shim ID 0.2165 - 0.2189" 5.500 - 5.560mm Valve Spring Type Single-Coil Steel Single-Coil Steel Valve Spring Dims

6-Speed Trans 1.617" (Free Length)

1.299" (Set Length)

0.866" (Comp. Height) 41.06mm (Free Length)

33.0mm (Set Length)

22.0mm (Comp. Height) Valve Spring Dims

CVT Trans 1.641" (Free Length)

1.299" (Set Length)

0.866" (Comp. Height) 41.68mm (Free Length)

33.0mm (Set Length)

22.0mm (Comp. Height) Valve Spring Tension

6-Speed Trans 40.92 - 47.22 Lbs (Set)

124.11 - 137.15 Lbs (Comp) 18.56 - 21.41 kgf (Set)

56.29 - 62.20 kgf (Comp)

182 - 210 N (Set)

552 - 610 N (Comp) Valve Spring Tension

CVT Trans 40.92 - 47.22 Lbs (Set)

112.87 - 124.56 Lbs (Comp) 18.56 - 21.41 kgf (Set)

51.19 - 56.49 kgf (Comp)

182 - 210 N (Set)

502 - 554 N (Comp) Valve Seating Width 0.031 - 0.063" (INT)

0.043" - 0.067" (EXH) 0.8 - 1.6mm (INT)

1.1 - 1.7mm (EXH) Valve Seating Angle 45° 45°

Intake Valve Shim Thickness Formula

$$R = A + 1.69 × (B – 0.13mm (0.0051"))$$

A = Current Valve Shim Thickness

B = Measured Cam Clearance

R = Required Valve Shim Thickness

Exhaust Valve Shim Thickness Formula

$$R = A + 1.87 × (B – 0.22mm (0.0087"))$$

A = Current Valve Shim Thickness

B = Measured Cam Clearance

R = Required Valve Shim Thickness

FA20 Turbo Camshaft Specs

Specification Standard Metric Camshaft Duration

Seat-to-Seat 236° (INT)

246° (EXH) 236° (INT)

246° (EXH) Camshaft Lift 0.403" (INT)

0.399" (EXH) 10.24mm (INT)

10.14mm (EXH) AVCS Cam Phasing Range 68° (INT)

54° (EXH) 68° (INT)

54° (EXH) Intake Valve Timing

(Open) 42° BTDC - 26° ATDC 42° BTDC - 26° ATDC Intake Valve Timing

(Close) 14° ABDC - 82° ABDC 14° ABDC - 82° ABDC Exhaust Valve Timing

(Open) 66° BBDC - 11° BBDC 66° BBDC - 11° BBDC Exhaust Valve Timing

(Close) 0° ATDC - 55° ATDC 0° ATDC - 55° ATDC Base Circle Diameter 1.339" 34mm Camshaft Journal OD 1.0215 - 1.0222" 25.946 - 25.963mm Thrust Clearance 0.0027 - 0.0047" 0.068 - 0.116mm Oil Clearance 0.0015 - 0.0028" 0.037 - 0.072mm Lobe Height 1.588 - 1.592" (Std. INT)

1.652 - 1.656" (Fuel Pump Drive INT)

1.583 - 1.587" (EXH) 40.34 - 40.44mm (Std. INT)

41.95 - 42.05mm (Fuel Pump Drive INT)

40.20 - 40.30mm (EXH)

FA20 Turbo Cooling System Specs

Specification Standard Metric Water Pump Flow Rate 65.5 Gal(US)/min 248 L/min Thermostat Open Temp 187 - 194 °F 86 - 90 °C Radiator Cap Pressure 14 - 18 PSI 93 - 123 kPa

0.95 - 1.25 kg/cm²

FA20 Turbo Oil System Specs

Specification Standard Metric Oil Pump Dimensions

Diameter x Thickness 3.03" x 0.55" 77mm x 14mm Oil Pressure

at 248 °F / 120°C 5.1 PSI (600 RPM)

46.6 PSI (6700 RPM) 35 kPa / 0.4 kg/cm² (600 RPM)

321 kPa / 3.3 kg/cm² (6700 RPM) Oil Flow Volume

at 248 °F / 120°C 7.8 Qt/min (US) (600 RPM)

63.6 Qt/min (US) (6700 RPM) 7.4 L/min (600 RPM)

60.2 L/min (6700 RPM) Relief Valve Pressure 102 PSI 700 kPa

7.1 kg/cm² Oil Viscosity 5W30 Synthetic 5W30 Synthetic

FA20 Diagnostics + Misc. Specs

Specification Standard Metric Base Ignition Timing 10°±10° at 700 RPM 10°±10° at 700 RPM Idle Speed 700±100 RPM (A/C OFF)

700 - 865±50 RPM (A/C ON) 700±100 RPM (A/C OFF)

700 - 865±50 RPM (A/C ON) Compression Pressure

200 - 300 RPM (Cranking) 196 - 254 PSI 1350 - 1750 kPa

14 - 18 kg/cm² Intake Manifold Vacuum at Idle -17.72 inHg (A/C OFF) -60.0 kPa (A/C OFF)

-450 mmHg (A/C OFF)

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