Subaru EJ20 Engine


  1. Specifications
  2. Overview, problems
  3. Performance tuning

Subaru EJ20 engine specs

Manufacturer Gunma Oizumi Plant
Also called Subaru EJ20
Production 1989-present
Cylinder block alloy Aluminum
Configuration Flat-4
Valvetrain SOHC
2 valves per cylinder
DOHC
4 valves per cylinder
Piston stroke, mm (inch) 75 (3.62)
Cylinder bore, mm (inch) 92 (3.86)
Compression ratio 8.0 (EJ205 WRX/EJ207/EJ20G/EJ20K)
8.5 (EJ205 Forester/EJ208)
9.0 (EJ205 WRX 2002+/EJ206/EJ208)
9.5 (EJ20X/EJ20Y)
9.7 (EJ20J)
10.0 (EJ204 Impreza II)
10.1 (EJ201/EJ202/EJ20D)
10.2 (EJ204 Impreza III)
Displacement 1994 cc (338.8 cu in)
Power output 224 kW (125 HP) at 5,500 rpm
239 kW (135 HP) at 5,600 rpm
298 kW (137 HP) at 5,600 rpm
300 kW (140 HP) at 5,600 rpm
224 kW (155 HP) at 6,400 rpm
239 kW (160 HP) at 6,400 rpm
298 kW (180 HP) at 6,800 rpm
300 kW (190 HP) at 7,100 rpm
224 kW (200 HP) at 6,000 rpm
239 kW (220 HP) at 6,400 rpm
298 kW (230 HP) at 5,600 rpm
300 kW (240 HP) at 6,000 rpm
224 kW (250 HP) at 6,000 rpm
239 kW (260 HP) at 6,000 rpm
298 kW (260 HP) at 6,500 rpm
300 kW (275 HP) at 6,500 rpm
224 kW (280 HP) at 6,500 rpm
239 kW (308 HP) at 6,400 rpm
298 kW (320 HP) at 6,400 rpm
300 kW (328 HP) at 7,200 rpm
Torque output 172 Nm (385 lb·ft) at 4,500 rpm
181 Nm (393 lb·ft) at 4,000 rpm
186 Nm (413 lb·ft) at 3,600 rpm
186 Nm (406 lb·ft) at 4,400 rpm
196 Nm (385 lb·ft) at 3,200 rpm
186 Nm (393 lb·ft) at 3,200 rpm
196 Nm (413 lb·ft) at 4,400 rpm
196 Nm (406 lb·ft) at 4,400 rpm
260 Nm (385 lb·ft) at 3,600 rpm
270 Nm (393 lb·ft) at 4,000 rpm
319 Nm (413 lb·ft) at 2,800 rpm
309 Nm (406 lb·ft) at 4,000 rpm
334 Nm (385 lb·ft) at 3,600 rpm
319 Nm (393 lb·ft) at 5,000 rpm
309 Nm (413 lb·ft) at 5,000 rpm
319 Nm (406 lb·ft) at 4,000 rpm
343 Nm (385 lb·ft) at 5,000 rpm
430 Nm (393 lb·ft) at 4,400 rpm
384 Nm (413 lb·ft) at 4,400 rpm
431 Nm (406 lb·ft) at 4,800 rpm
Redline
HP per liter 62.7
67.7
68.6
70.2
77.7
80.2
90.3
95.3
100.3
110.3
115.3
120.4
125.4
130.4
130.4
137.9
140.4
154.5
160.5
164.5
Fuel type Gasoline
Weight, kg (lbs) 147 (500) – EJ20G
Fuel consumption, L/100 km (mpg)
-City

-Highway
-Combined
for Impreza WRX STI GD
16.7 (11)
9.5 (21)

12.1 (16)
Turbocharger  Naturally aspirated
Mitsubishi TD04 (WRX)
Mitsubishi TD05H (WRX/STI)
Mitsubishi TF035 (WRX)
IHI RHF5HB (STI)
IHI VF28 (STI)
IHI VF30 (STI)
IHI VF34 (STi Spec C Type RA)
IHI VF35 (WRX Type RA)
IHI VF36 (STI Spec-C)
IHI VF37 (STI)
IHI VF42 (STI S203/S204)
2x VF13+VF14
2x VF18+VF19
2x VF25+VF27
2x VF25+VF26
2x VF31+VF32
2x VF32+VF33
Oil consumption , L/1000 km
(qt. per miles)
up to 1.0
(1 qt. per 600 miles)
Recommended engine oil 0W-30
5W-30
5W-40
10W-30
10W-40
Engine oil capacity, L (qt.) 4.0 1993-2007
4.2 2007+
4.5 WRX/STI 1993-2000
5.0 WRX/STI 2000-2007
Oil change interval, km (miles) 5,000-10,000
(3,000-6,000)
Normal engine operating temperature, °C (F)
Engine lifespan, km (miles)
-Official information
-Real


250,000+ (150,000)
Tuning, HP
-Max HP
-No life span loss

350+

The engine is installed in Subaru Impreza (WRX/STI)
Subaru Forester
Subaru Legacy
Isuzu Aska
SAAB 9-2X

Subaru EJ20 engine reliability, problems and repair

In 1989 Subaru Legacy introduced EJ20 engine which later became the basic for the whole brand. It was the first representative of the legendary EJ series. This 2-liter motor replaced 1.8 liter EA82. EJ20 engine has aluminum flat-four cylinder block, with cast-iron dry sleeves. Its cylinder block deck height is 201 mm. Inside of it crankshaft with a piston stroke of 75 mm is installed, connecting rods length is 130.5 mm, cylinder diameter is 92 mm, piston compression height is 32.7 mm.
On the block two aluminum heads are installed, one camshaft on each and 4 valves on the cylinder. Diameter of intake valves is 36 mm, exhaust valves is 32 mm, valve stem diameter is 6 mm. Camshafts are set in motion with the help of timing belt. The recommended interval of replacement of timing belt for EJ20 is for each 60,000 miles of mileage (100,000 km).

The first version of this engine was called EJ20E and it was installed on Subaru Legacy. It showed the power 125 HP at 5,500 rpm, and torque 172 Nm at 4,500 rpm.
Power of Legacy 2 and Subaru Impreza of the 1st generation was increased to 135 horsepower. 1998-2004 Legacy power was increased to 155 HP. And 2003-2009 Subaru Legacy BL became less powerful – 140 HP at 5,600 rpm.

Besides, 1989-1999 Legacy sometimes have EJ20D engines with DOHC heads. Their power is 150 HP at 6,800 rpm.

Since 1998 Subaru began to produce EJ201/EJ202 engines. These are Phase 2 engines with open deck block, new SOHC heads and lightweight pistons. Also EJ201 and EJ202 used the new intake manifold which is good at low and mid rpm. Such motors show 125 HP at 5,600 rpm. Specially for 2003-2009 Legacy (BL), EJ202 engine was improved: it uses lightweight cylinder block with lightweight sleeves, modified intake manifold and 4-2-1 headers. These improvements allowed to increase power to 138 HP at 5,600 rpm, and the torque increased up to 187 Nm at 4,400 rpm.

EJ203 motor differs in use of MAF-sensor and electronic throttle body.

EJ204 phase 2 engine differs in use of DOHC cylinder block heads. Also EJ204 used variable valve timing system AVCS on intake camshafts, adjustment range is 50 degrees. Power of EJ204 engine is 155 HP. You can find Subaru with EJ204 engine with 180 horsepower, this motor has AVCS system only on the intake cams, and also high compression pistons and modified ECU software.

EJ20 motors gained great popularity due to their turbocharged versions.
Turbocharged EJ20G was the first such engine. It used closed deck block and oil nozzles, low compression pistons (CR=8), two DOHC heads with two camshafts. The capacity of the EJ20G stock fuel injectors is 380 cc. This motor used Mitsubishi TD04 turbocharger, and the maximum boost pressure is 11 psi (0.75 bar).
You can find such motor on Subaru Legacy RS. Its power is 200 HP at 6,000 rpm, and its torque is 260 Nm at 3,600 rpm.
For Subaru Legacy GT, EJ20G engine produces 220 HP at 6,400 rpm, and torque is 270 Nm at 4,000 rpm.
1992-1996 Subaru Impreza WRX Wagon used EJ20G, but with air to air intercooler and lightweight valves .
EJ20G engine for Impreza WRX STI and WRX sedan used Mitsubishi TD05H turbocharger. Max boost pressure for Impreza WRX sedan is 11.5 psi (0.8 bar), and power is 240 HP at 6,000 rpm.
EJ20G motor for 1994-1995 WRX STI ver.1 differs in a kind of intercooler, but boost pressure is the same (11.5 psi / 0.8 bar). Its power is 250 HP at 6,000 rpm.
1994-1996 Impreza WRX Type-RA received the increased boost pressure to 12.5 psi (0.87 bar), and ECU was changed. Power increased up to 260 HP at 6,500 rpm.
EJ20G engine for 1995-1996 Subaru Impreza STI ver. 2 had max boost pressure 13.5 psi (0.93 bar), and power reached 275 HP at 6,500 rpm.

In 1996 EJ20G engine was replaced with new turbocharged EJ20K. Differences between EJ20K and EJ20G are the following: open deck block, TD04 turbocharger, modified intake manifold, increased intercooler, moly coated pistons (compression ratio = 8), new ignition coils and new ECU. EJ20K injector size is 505 cc.
EJ20K engine was installed on 1996-1998 Impreza WRX STI and used IHI RHF5HB turbocharger. The boost pressure was 15.5 psi (1.07 bar), and power reached 280 HP at 6,500 rpm, torque was 343 Nm at 4,000 rpm.

In 1998 they started to manufacture turbocharged Phase 2 engines: EJ205 for Impreza WRX and Forester, and also EJ207 for Impreza WRX STI.
EJ205 and EJ207 engines are equipped with new cylinder heads, the intake ports has been modified, Lightweight pistons were used and new ECU. Specs of camshafts are 256/256, lift 9.27/9.17 mm (8.25/8.61 mm for JDM)
Subaru Impreza WRX with EJ205 engine used Mitsubishi TD04 turbocharger, with max boost pressure 14.5 psi (1.0 bar). Subaru EJ205 engine for Forester had a compression ratio 8.5 and used Mitsubishi TF035 turbocharger. EJ205 engine for 2000-2007 Impreza WRX was equipped with variable valve timing system AVCS on intake camshafts. Also these motors used the intake manifold with TGV valves (Tumble generator valves) that improved ecological index and the increased compression ratio to 9.
EJ207 engine for 1998-2000 Impreza WRX STI has got the modified pistons (compression ratio 8), EJ205 camshafts, new ECU and IHI VF28 turbocharger with max boost pressure 1.1 bars.
2000-2003 Subaru WRX STI used IHI VF30 turbocharger (VF35 turbocharger for JDM WRX Type RA) which created charging pressure 16 psi (1.1 bar). Subaru Impreza WRX STi Spec C Type RA car used IHI VF34 turbocharger.
EJ207 engine for 2003+ Impreza WRX STI used VF37 twin scroll turbocharger. On WRX STI Spec-C versions you will find VF36 twin scroll turbocharger. And WRX STI S203 and S204, EJ207 were equipped with VF42 twin scroll turbocharger.
Besides, JDM Legacy also had twin turbo EJ20: EJ20H, EJ20R, EJ206 and EJ208.

EJ20H engine differs in that it uses DOHC cylinder heads and two VF13 and VF14 turbochargers. Their boost pressure is 13 psi (0.9 bar), and power is 260 horsepower.
Since 1996, they began to produce twin turbo EJ20R which used IHI VF18 and VF19 turbochargers. Power of EJ20R reached 280 HP.

In 1998 twin turbo EJ20 received new heads and were renamed to EJ206, they were equipped with VF25 and VF27 turbochargers.

There was also twin turbo EJ208 engine which used VF25 and VF26 turbochargers in the first generation, then VF31 and VF32 turbochargers were used.
EJ208 rev D phase 3 engine uses VF33 and VF32 turbochargers, and their boost pressure is 13 psi (0.9 bar). Also it was equipped with a new intake manifold, 550 cc fuel injectors and other camshafts.

EJ20 firing order is 1-3-2-4.
Except EJ20, the EJ series included: EJ15, EJ16, EJ18, EJ22 and EJ25.
Since 2012 turbo EJ20 was being replaced by 2.0 liter FA20 engine while naturally aspirated EJ20 were replaced by FB20. 

Subaru EJ20 engine problems and malfunctions

Despite their fabulosity, EJ motors aren’t perfect and have some problems, so let’s discuss them.
1. EJ20 knocking sound. Very often we can hear knocking noise in the 4th cylinder. It is the hottest cylinder and it is cooled worst of all, therefore the piston begins to knock there. At first the engine knocks at cold start, and then all the time.
It is a bad sign, and you solve the problem only by means of overhaul.
2. EJ20 oil leak. Most often leaks appear in camshaft seals and valve cover gaskets. Check them.
3. High oil consumption. This often happens with turbo EJ20, don’t be surprised. Your piston rings failed. You have to change engine oil (each 7500 km) in time and to use what Subaru recommends.
Engine oil is very important for EJ20 turbocharged and even for naturally aspirated. Definitely you don’t want problems with the engine, so use high-quality original engine oil. If your country has problems with qualitative gasoline, then use the best of what it provides. Also you have to drive quietly, to the shop and back, no hard acceleration.
Of course you bought or want to buy Subaru Impreza WRX and STI for absolutely other purposes. Therefore, be ready to its low reliability and overhaul each 50,000-60,000 miles of mileage (100,000 km).
Owners of naturally aspirated EJ20 don’t need to worry, reliability and longevity of your motor is higher and can reach 150,000 mile of mileage (250,000 km) and more.

Subaru EJ20 engine tuning

Tuning guide

There is no sense to increase N/A EJ20 power. Everything we need to do is to buy EJ205 or EJ207 and to make swap. Or to sell the slow Subaru and to buy WRX STI.
Owners of turbocharged EJ205 need to buy only an aluminum 2-row Mishimoto radiator (or something similar), FMIC, STI intake system, VF30 turbocharger, BOV, WRX STI oil pump, new spark plugs, STI fuel injectors, Walbro 255 fuel pump, ACL bearings, boost controller, 3 inch performance exhaust system. After you install these aftermarket parts and will adjust ECU, your EJ205 will show about 300 horsepower.
It is possible to increase EJ20 capacity to 2,123 cc. Stroker kit includes EJ25 crank, H-beam rods, Mahle pistons, ARP head studs.
To get 350+ horsepower from EJ207 engine you need some performance upgrades. Buy a frontal intercooler, a 3-row Mishimoto radiator, Cusco engine mount set, sump baffle plate, TD05-18G turbocharger, HKS BOV, 800 cc fuel injectors, fuel lines, heavy duty timing belt, cold air intake, 12 mm oil pump, oil cooler, equal length headers and 3 inch aftermarket exhaust system. If ECU is adjusted correctly, then Subaru EJ207 will show more than 350+ horsepower. It is a reasonable limit for EJ207 stock internals.
To receive 450-500 horsepower on EJ207, you will be need forged pistons, head porting and all that is written in the article about EJ257 HERE.
Also you can make displacement 2.2 L (2,123 cc) on EJ207 as it is written above.

 

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