The EJ-series flat-four has ruled the Subaru universe since it debuted in the Legacy. Of course, those desiring more cylinders can have a 3. Known as the FB, the new engine looks pretty similar to its predecessor at first glance: 2.
While the displacement of both the EJ25 and the FB25 round to 2. This bump in size accounts for the 4 lb-ft increase in torque, to A 1-mpg improvement in city efficiency may not seem like much, but with the transmission and drivetrain staying the same, five percent is a fairly substantial gain. Subaru claims a percent reduction in friction losses within the engine, with the biggest contributors being lighter pistons and connecting rods, as well as a drop in piston-ring tension.
The less the engine has to work to keep spinning, the more efficient it can be. Going to chain-driven cams allows the valves to be placed at a narrower angle to each other. This let the engine designers shrink the bore, from The smaller-diameter cylinder and increased stroke now 90 mm, up 11 lets the FB suck air in more quickly, and the elongated cylinder also results in less unburned fuel during cold starts. Both intake and exhaust cams are equipped with variable valve timing.
Subaru achieved this by employing asymmetrical connecting rods like those it used to increase the stroke of the flat-six in the Tribeca without drastically changing the engine. The lamb-chop-shaped rods also ease assembly of the bottom end. By doing this, it was able to reduce NOx emissions. They look like half of a throttle valve and, through electronic control, manipulate the intake flow to maximize efficiency.
Doing a complete overhaul of an engine for a one-mpg boost in fuel economy might seem like a waste, but Subaru has its reasons. Performing these same upgrades to the EJ would have resulted in a much heavier engine; as it is, the FB is only marginally heavier than the old mill. Expect to see a hp, 2.
That engine will feature the same stroke as the 2. The car should bear a strong resemblance to the Impreza concept Subaru showed at the Los Angeles auto show this past year. The latter should get close to—if not achieve—40 mpg on the highway. Either way, greater efficiency and a looming hot-rod or two will keep Subaru showrooms busy.
Subaru soldcars in the U. Buyer's Guide. Type keyword s to search. Today's Top Stories. View Photos. Advertisement - Continue Reading Below. More From News.
Join the Conversation Show Comments LoadingThe quoted RDP is an estimate based on the postcode selected by you, and is not applicable to business or government buyers. Final on road costs may vary according to individual circumstances and actual driveaway price may vary between Retailers. Ask your Retailer for confirmation of their driveaway price. Price may vary between retailers and is based on a private purchaser with a good driving record and may be higher for other purchasers.
Excludes government buyers. While stocks last. Engineers make every endeavour to design engines that have high power output and exceptional fuel consumption.
Examining Subaru's New FB-series Flat-Four
The fact is, however, that power is derived from burning fuel, so the more fuel that can be converted into useful work through successful burning, the higher the net power output. The key to successful engine power output with good economy is to create optimal conditions for the most efficient burning of fuel with minimal energy losses.
There are a range of design options that have different attributes that produce better results in one direction or the other. The increase stroke length is achieved through the use of a new asymmetrical connecting rod design that allows the cylinders on the left and right banks to be moved closer together thereby avoiding any increase in engine width.
The emphasis of this engine is one of low fuel consumption and low CO 2 emissions in a vehicle that is ideally suited to short trips in an urban environment but at the same time is capable of longer distance cruising.
Maximum power is kW rpm and maximum torque is Nm rpm. Dual AVCS variable valve timing on both intake and exhaust improves volumetric efficiency breathing to further improve fuel consumption and exhaust gas emissions while maintaining low to mid speed range torque characteristics for ease of use in practical driving engine speed ranges.
Lower cost of ownership with small carbon footprint that also meets the needs for short and long distance travel.
The 2. Fuel consumption on the combined cycle is Its stroke x bore 90mm x 94mm ratio of 0. Variable valve timing AVCS is only applied to the intake camshaft.
Maximum power output is kW rpm and maximum torque is Nm rpm.In the successor of naturally aspirated EJ was presented. This motor has the same flat-4 boxer configuration, and its capacity is 2 liter.
FB20 cylinder block is aluminum and has open deck, with cast-iron sleeves, cylinder diameter is 84 mm, and piston stroke is 90 mm. Now it is undersquare engine. Also FB20 has got the improved cooling system, new lightweight pistons and asymmetric connecting rods.
On steel two-layer cylinder head gaskets there are two aluminum heads with two camshafts, 4 valves on the cylinder. These camshafts are put in action by means of timing chain, which is non-serviceable according to Subaru statement.
On the intake part there is plastic intake manifold with TGV valves, which improves ecological index. FB20 uses new headers and more straight exhaust system. This motor is usually called FB20B and it showed horsepower at 6, rpm, and torque Nm at 4, rpm.
Its difference is the use of an additional electric motor. Power of this motor together with electric motor reaches HP at 6, rpm, and torque to Nm at rpm. FB20 firing order is Also 2. High oil consumption. FB20 used to have this shortcoming till Most likely the problem is in piston rings or in the defective cylinder block.
Yes, there were such cases. If your cylinder block is curved, then you should buy a new one. You should replace piston rings or try to make decoking, it will help for some time. Besides, in order to enjoy long operating period of catalytic converter, you should use good gasoline and watch the level of engine oil, it is rather important for this engine.
Otherwise you will face problems with AVCS system, high oil consumption, connecting rod bearing failure and other troubles. It is also desirable to change engine oil more often, than it is recommended, for example every km. It will increase its resource. FB20 is the classical modern motor, it was created as the economic and eco-friendly motor. Besides, it has tendency to high consumption of engine oil and can work at high temperatures, therefore you should not dream of building powerful naturally aspirated FB You can adjust ECU more aggressively and install aftermarket exhaust system.
It will give additional horsepower and you will get pleasant Subaru sound. Mitsubishi 4G Honda K20A K20C. Honda K24A K24Z. Honda R18A. Honda R20A. Honda L15A L15B. Honda L13A L13B. Honda D15B D15A.Subaru introduced the FB20 in as a replacement for the very outdated EJ engine family. The FB20 was designed with economy in mind and features many technologies that allowed Subaru to improve their fuel efficiency. Just like many Subaru engines of the past, the FB20 is a flat four-cylinder engine.
The cylinder block and cylinder heads are made of cast aluminum to help save weight which also increases efficiency. The flat engine configuration helps keep the center of gravity low which inherently improves handling. Subaru focused on creating a very lightweight rotating assembly to help improves efficiency.
The connecting rods are asymmetrical and the pistons are extremely lightweight. Subaru also changed from a belt-driven valve train to a chain-driven valve train. This allowed them to decrease the angle on the valves allowing for a smaller cylinder bore. With that smaller bore came a slightly larger stroke which further increased efficiency.
The EJ engine family came in pretty much every Subaru produced after Although the FB series is fairly new, it will likely follow in the same footsteps of the EJ.
Since Subaru wanted this engine to achieve excellent efficiency they used a lightweight rotating assembly and a high compression ratio. Those lightweight pistons, however, are known are having poor oil rings. Poor oil rings results in excessive oil consumption as mileage increases. Other than the oil rings the FB20 is a pretty reliable little engine. For this reason modifying the FB20 engine is pretty much never done. A simple intake and exhaust may pick up a couple of horsepowers, but anything past that is a bad idea.
Unlike usual FB20, this motor uses new pistons, new crankshaft, and the compression ratio was increased to FA20 engines use new heads with direct injection system of Toyota D4S, and also variable valve timing system AVCS is used on intake and exhaust camshafts. Also headers are installed on this motor. This motor replaced EJ and EJ FA20DIT engine uses non-forged pistons with the decreased compression ratio On the intake part there is the plastic intake manifold with TGV valves, and new turbo manifold is also used.
The maximum boost pressure is Also, the over boost mode is available, at this mode boost pressure can increase to 22 psi 1.
FA20 firing order is FA20 rough idle. The problem is caused by ECU software. You need the new modified software for your ECU. FA20 stalls. The problem with cam gear, which leads to the loss of pressure of engine oil. For this engine it is necessary to use the best quality gasoline, and also to use original high-quality engine oil and change it twice more often than it is recommended.
It will allow to keep reliability and will increase an engine resource. For this purpose you need to buy only 3-inch aftermarket cat-back exhaust system, cold air intake, boost controller and adjust ECU. For cars with an automatic transmission it is desirable to have transmission cooler. It will give you WHP. It will be excellent if you install aftermarket radiator and a frontal intercooler.
Owners of BRZ and 86 are not so lucky as they need a turbo kit at once.
Examining Subaru's New FB-series Flat-Four
It is possible to install cold air intake, straight exhaust system, to adjust ECU and to receive additionally HP. The best choice for your Toyota 86 is supercharger kit, you should install it on FA20 stock internals. Such kits have max boost pressure psi 0. It is simple and optimal variant to receive great power.
Mitsubishi 4G Honda K20A K20C. Honda K24A K24Z. Honda R18A. Honda R20A. Honda L15A L15B. Honda L13A L13B. Honda D15B D15A. Honda D17A.But the Subaru Impreza gets a complete remodeland the newly developed next-generation 2. It gets two new upgrades over the old powerplant that will improve fuel-efficiency and overall performance.
Without getting too technical, Subaru engineers nearly gave the 2. Subaru says 80 percent of the parts in the new 2. This was the theme when engineers went to work on the new engine.
Consumers will feel a difference in the smooth acceleration due to improved balance in the internals. The reborn engine also has improved fuel-efficiency because of less weight.
Shirasaka Nobu says the new 2. Subaru says engineers expanded the ratio coverage speed range in the automatic transmission that will improve acceleration performance, and fuel economy will be improved at higher speeds. Engineers also reduced the weight of the transmission case by 7.
The Subaru Impreza gets a complete remodel and the newly developed next-generation 2. The upgrades over the old power plant will improve fuel-efficiency and overall driving performance. Skip to main content. The new Subaru Impreza gets a complete remodel and important engine upgrades.
What will it mean for consumers? What it means for consumers Visit Torque News homepage for more stories. Latest Automotive News. Subaru News, Pricing and Reviews. Subscribe to Torque News on YouTube. Notify me when new comments are posted. All comments. Replies to my comment.
New Impreza. Impreza Interior.The 2. The FB20 is the entirely new flat-four third generation engine. Subaru announced the FB-series engine in The engine looks pretty similar to its predecessor at first glance, but it has a lot of changes inside. This engine has the new cylinder aluminum block with decreased piston bore. The same displacement is achieved by increasing piston stroke this change gave a little more torque at low revs also. There are asymmetrical connecting rods to keep exterior dimensions of the engine are unchanged compared to EJ-series engine.
Subaru's new 2.0-liter boxer: It's better, but does it matter?
New cylinder heads are DOHC 4-valve per cylinder heads. The angle between intake and exhaust valves was reduced to 27 deg EJ angle was 41 deg. The distance between camshafts are smaller - mm instead mm. That was made possible by moving to chain-driven camshafts EJ used timing belt.
The narrow valve angle and smaller bore provide less unburned fuel during cold start, thereby reducing emissions. The intake manifold is made of plastic material. It has four tumble-generation valves, which manipulating the intake flow to maximize efficiency through electronic control. As a result, the engine is more environment-friendly with the same power, and a broader band of torque compared to the EJ The engine consumes oil.
It is necessary using only Subaru recommended engine oil and always checking oil level. Home Subaru FB20 2. Subaru FB20 2.Mod Overview (Updated) - Subaru Impreza 2.0i (FB20)
Engine Specs Manufacturer. Production years. Cylinder block material. Cylinder head material. Fuel type. Number of cylinders. Valves per cylinder.