The FA20 DI-T: A Testbed for the Future of Subaru Engines

Subaru has long been known for its commitment to innovation and performance, and their latest engine, the FA24, is no exception. The FA24 is built on the same platform as the FA20 DI-T, which was used as a testbed to develop and refine the new engine. This approach allowed Subaru to identify areas of improvement and make necessary adjustments before launching the FA24 in production.

One of the key areas of focus for the FA24 is the connecting rods. In the F82, these rods were prone to failure due to the immense pressure they were subjected to as the piston was pushed down by the combustion force. This pressure also pushed on the connecting rods, which are attached to the crankshaft off-center and connected to the piston on a pivoting pin. As the piston rotated, it would rotate the crankshaft, ultimately transferring linear motion into rotational motion that powers the wheels.

To address this issue, Subaru has upgraded the connecting rods in the FA24 to be almost twice as thick as those found in the F21. This significant increase in size and strength should provide a much-needed upgrade in terms of durability and reliability. However, it's not just the rods themselves that have been improved – the entire engine block has also undergone significant upgrades.

In addition to the strengthened connecting rods, the FA24 features new "beehive" valve springs. Traditional springs are shaped like a smooth cylinder, whereas beehive springs are small at the top and larger at the bottom. This unique design allows for a more progressive spring rate, which means they require less force to move at the same speed as traditional springs. As a result, the FA24's valve train is subjected to significantly less wear, which should lead to increased reliability and performance.

But just how much of an upgrade does the FA24 offer? To find out, let's take a look at some testing data from Prime Movering, who have been pushing their engine to its limits in various configurations. Mounted on a cross-track dyno, the FA24 was able to produce 500 horsepower to the wheels with nothing more than bolt-ons and a tune – and that was after just 50 dyno runs! This impressive performance is a testament to the FA24's potential for high horsepower output.

Of course, as we've seen time and time again, getting that kind of power requires significant modifications. Prime Movering ran their engine on the dyno with OEM turbocharger, cams, and ECU – but even these modest upgrades allowed them to coax an astonishing 800 horsepower from the FA24. This level of performance is exactly what fans of Subaru's STI series are hoping for: a reliable, high-horsepower platform that will allow tuners to push their cars to new heights.

For now, though, it seems that the FA24 is going to provide us with some serious competition in the world of rallycross and track racing. As we move forward into the future of Subaru engines, one thing is clear: the FA24 is the wave of the future – and we can't wait to see what it's capable of.

The Evolution of the EJ Engine

Subaru's EJ engine has long been a favorite among tuning enthusiasts, known for its exceptional reliability and potential for high horsepower output. But what makes this engine so special? To understand just how impressive the FA24 is, let's take a closer look at the evolution of the EJ engine.

In recent years, we've seen Subaru release several new engines under the EJ badge, each one building upon the last to become even more powerful and reliable. The F82, for example, features a number of upgrades over its predecessors, including a stronger block, improved connecting rods, and increased compression ratio.

One area where the EJ engine truly shines is in its ability to handle high-pressure combustion. This is due in part to the design of the engine's combustion chamber, which allows for a more efficient transfer of energy from the piston to the cylinder walls. As we discussed earlier, this results in a significant increase in power output – and when combined with the FA24's upgraded connecting rods and beehive valve springs, it becomes clear just how much potential this engine has.

But what about the STI series? How will the FA24 impact Subaru's iconic rallycross car? Fans of the STI have long known that the engine is the heart and soul of the car – and with the introduction of the FA24, it seems likely that we'll be seeing some significant upgrades in terms of performance.

The Future of Subaru Engines

As we look to the future of Subaru engines, one thing is clear: the FA24 is a major step forward for the company. With its upgraded connecting rods, beehive valve springs, and improved engine block, this new engine has all the makings of a powerhouse – and with the potential for high horsepower output, it's likely that we'll see some serious competition in the world of rallycross and track racing.

But what does this mean for fans of Subaru? In short, it means that we can expect to see even more impressive performance from Subaru cars in the years to come. Whether it's on the rally stage or on the road, the FA24 is a testament to Subaru's commitment to innovation and excellence – and as such, it's sure to be a fan favorite for years to come.

The Potential of the FA24

With its upgraded connecting rods, beehive valve springs, and improved engine block, the FA24 has all the makings of a powerhouse. But just how much potential does this new engine really have? To find out, let's take a closer look at some data from Prime Movering, who pushed their engine to its limits on the dyno.

Mounted on a cross-track dyno, the FA24 was able to produce an astonishing 500 horsepower to the wheels with nothing more than bolt-ons and a tune. This impressive performance is just the beginning – and when combined with the potential for high-horsepower output, it's clear that the FA24 has some serious competition in the world of rallycross and track racing.

Of course, as we've seen time and time again, getting that kind of power requires significant modifications. Prime Movering ran their engine on the dyno with OEM turbocharger, cams, and ECU – but even these modest upgrades allowed them to coax an astonishing 800 horsepower from the FA24. This level of performance is exactly what fans of Subaru's STI series are hoping for: a reliable, high-horsepower platform that will allow tuners to push their cars to new heights.

With the FA24 on the horizon, it seems clear that Subaru has big plans for its future engines. Whether it's the rally stage or the road, this new engine is sure to be a fan favorite – and with its impressive performance potential, it's likely that we'll see some serious competition in the years to come.

The Future of Rallycross

As we look to the future of rallycross, one thing is clear: Subaru's FA24 is going to play a major role. With its upgraded engine and improved performance capabilities, this new engine has all the makings of a powerhouse – and with the potential for high-horsepower output, it's likely that we'll see some serious competition on the rally stage.

In recent years, Subaru has been pushing hard to improve its STI series, introducing new engines and updated suspension designs to give the car an edge over its competitors. With the FA24 on the horizon, it seems clear that this will continue – and with its impressive performance potential, it's likely that we'll see some serious upgrades in terms of power output.

Whether it's on the rally stage or on the road, Subaru's FA24 is sure to be a fan favorite – and with its powerful engine and improved performance capabilities, it's likely that we'll see some serious competition from other manufacturers. As always, only time will tell – but for now, it seems clear that the FA24 is going to be a major force in the world of rallycross.

WEBVTTKind: captionsLanguage: enboxer engines one of the most iconic automotive sounds out there is the rumble of that flat for VGA powering all four wheels of the Subaru WRX STI it's been the heart of the STI for 26 years and now Subaru is throwing it out and they're putting in an engine from an SUV yeah that burns your britches chaps your bun tans your hide it just plain ticks you off oh I have good news for you this engine is the best engine that SGI has ever had and today I'm gonna show you exactly why we're gonna look at this new fa20 4 engine and find out we're tiding all that buff boxer potential don't believe Subaru can turn a mom Mobil motor into a flat 14 up well I guess we just got to show you let's go a huge thanks once again to our friends over at keeps for sponsoring another episode of bumper to bumper I'm gonna be straight with you guys I have a weird-shaped head under this hat in all this hair so I need my hair without it I'd look something like this Shh the numbers are in and two out of three guys will experience some form of male pattern baldness by the time they're 35 and if you still have hair and you're worried about losing it prevention is key my friend keeps offers a full treatment to prevent hair loss almost as powerful as my RC 51 back there room so start your treatment today and keep your weird head hinted by all that lush beautiful hair just like I do how weird this head is you can even visit a doctor online and get hair loss medication delivered right to your door every three months you never need to leave your house which is pretty good right now aboard the dreaded comb-over and start your treatment today go to keeps calm slash b2b or click the link in the description to receive a special offer on keeps hair loss treatments that's K E PS comm / b2b thank you for supporting the companies that support us here at don't ask if you don't know the rumors are all but confirmed that the new Subaru WRX STI is coming in 2022 with the revised version of the FA 24 engine currently in the subaru ascend and supposedly the STI will make a total 400 horsepower to the wheels now to put that in quick perspective that's 90 more than the current STI 60 more than the most powerful STI and 140 more than what the assent makes right now now quick note before we get too deep we're gonna be saying FA + ej a lot today now if you don't know what those mean it's simply the engine code that Subaru uses to identify their box or power plants out ejs were the 2 liter and two and a half liter engines that came in the WRX and the STI all the way from the beginning and the fa engines are the new platform these engines don't have the same sube Rumble but it's theoretically got more power so where is that extra power coming from well let's take a look one of the main things that's new for the fa engines is direct fuel injection as opposed to the ejs pour injection a port injection is when your fuel injector is placed in the intake manifold upstream of the intake valve and the air and fuel mix there before they enter the cylinder now the upside of that is that the air if you'll have a longer time to mix before they enter into the cylinder but the downside is that it's less precise on the air fuel ratio because you're losing a little bit of fuel as it sticks to the intake valve now direct injection means that fuel is shot directly into the cylinder it's injected directly just like the spark is and the fuel is fired much later and much more precisely than port injection and it's fired in a much higher pressure and there are plenty of benefits from this now the system is more efficient meaning better fuel economy that's good and also it cools the cylinder because it sprays a nice mist of fuel on the cylinder walls and that lowers the temperature of the wall reducing the chance of pre-mission or engine knock that might occur from the combustion chambers heat think about that heat the cylinders get so hot that they can sometimes when you inject fuel in cause it to auto ignite it's not good it's creates not ping you don't want it you don't want it ultimately direct injection is better for fuel efficiency and engine health which overall lets the engine safely hold more power but there are some downsides to it as always as always good and bad direct injection needs the engine to be warm to atomize fast enough and mix with the air and to overcome that they need a lot more fuel on a cold start Oh trust me direct injection is the way to go but if you're not sold on it then I got some good news for you ok if you will please indulge me and take a quick trip over to the speculation zone on the current Subaru BRZ also the Toyota gt86 Toyota's fan cd4s fuel system uses both port and direct injection and it's actually a very simple system the direct injectors are strong enough to run the engine at high rpm but for a better start up the engine splits the work between the two sets of injectors at cold start literally the best of both worlds and this version of the d4 s system isn't in the FA 24 engine currently but it could be added assuming the STI isn't going to use the same intake manifold now our buddies over at prime motoring in New Jersey have been tuning Subarus for years and they took a closer look at the existing FA 24 and they've been tinkering with it just to see what the new STI is going to be capable of and with a new intake manifold the FA 24 could totally use this d-4s system from the BRZ but that's not the only promising thing they found in the new engine the block and head themselves has some hidden heft as well even though it's still a flat 4 and it's got about the same displacement as the old AJ 257 the FA 24 is a hundred percent new engine and subaru has had a lot of time to approve on how they make power the cylinder head on this new engine has more of a straight shot for airflow than the ej had with its more dogleg path for the air to go through you know what a dogleg eyes look like this looked like a bench ito and you may not think that these little angles could slow down free-flowing air but in an engine and especially in a turbocharged engine a free-flowing path is super duper important now if the pathway is causing air to bounce around creating turbulence and pressure pockets there can only go so fast and at high revs it can't get air into the cylinder fast enough so we always want a freer flowing head to get us more air because we know our famous equation more air plus more fuel equals more power now we've already got more fuel from the direct injection and now we've got more air but for every engine there's a breaking point a point where if you put too much air in and you put too much fuel in you're gonna get too much combustion for the block to handle and the main thing about an engines block is that's got to be strong those cylinder walls have to be thick enough to withstand the pressure that the engine is gonna make or else well there's no easy way to say this your engine will blow up now let's say with a turbocharged engine you're making fifteen pounds of boost or fifteen psi of pressure that's pressurized air that goes into the cylinder on the intake stroke and when the piston is fully down as the most space available the intake valve closes and that air goes all the way back up and it gets compressed as the piston gets pushed back up again and an engine let's say with a ten to one compression ratio you're looking at roughly 150 psi that is a lot of pressure but that's not a lot of pressure compared to what happens next spark once that spark hits that compressed air & fuel mixture it ignites it creates a combustion and that pressure jumps to anywhere between 300 and a thousand psi forcing that piston all the way back down so the cylinder walls have to withstand that pressure right at the moment of combustion getting forced all the way down all the way up and that's happening thousands and thousands of times a minute so how does the fa 24 handle that well she's got thick cylinder walls and not only does he have thicker cylinder walls than its ej bro-bro it's got more cylinder support mold it into the casting and an engine that can take more pressure you could up the boost or up the compression to make more power but cylinder walls aren't the only thing that needs to be beefy to make power in an engine and lucky for us sube love and boxer boys at bay 24 just like our beef sandwiches it's got more beef inside has more beef it's okay stop it the FA engine has been around a little while and it's gotten its fair share of complaints but in a way that was kind of the point Subaru used the fa20 di t as a testbed for what the fa 24 would eventually become inside the SUV engine are some really over engineered parts it's almost as if they were designing this engine with something else in mind now the connecting rods were point of failure on the F 820 all that pressure that we talked about earlier pushing down on the piston well it also pushes on the connecting rods which connect the piston to the crankshaft now this is where the direction of our energy changes from the pushing force of the combustion to the rotational force now that connecting rod is attached to the crankshaft off-center and it's attached to the piston on a pivoting pin so as it gets pushed down it rotates the crankshaft thereby rotating your flywheel and eventually ro taking your wheels linear motion to rotational motion that's all an engine does can you do this can you guys do this I think that's like yeah that's like this thing is tough because that energy has to change direction and that puts a lot of stress on the connecting rod the more pressure there is the more likely you're going to bend or break a rod now it's not enough to just say the new engine has stronger rods so we'll show you instead now the new SP 24 rods are almost twice as thick as the old fa 21 these things are gonna be able to handle a lot more combustion pressure but the rods aren't the only thing that had an upgrade fa 24 has gone to the new beehive valve springs bud bud buzz a beehive refers to the shape of those Springs normal Springs look like this they're shaped like a normal spring now beehive Springs are small at the top and bigger at the bottom kind of like a beehive or maybe like one of those honey dripping tools that people use you know you dip it in honey I actually have one you let me go get it I can show them so what I do know is that these valve springs make a big difference they are designed to increase effective spring rate and combat valve flows as your engine revs higher and higher the camshaft spins faster and faster and the cams push those valves open and the bow Springs or it push the valve closed back again but what if your cam is spinning so fast that it pushes the valve open again before the spring can fully close it well this is called valve flow and to fix it you need stronger valve springs and you can go with thicker springs you can double or triple the strength of those Springs but that adds a lot of wear to your valve train now beehive Springs have a progressive spring rate and overall require less force to move them at the same speed as normal Springs so the upshot of this is that you get less wear on your valve train that's great and your Springs can also handle revs about 500 to 700 rpm higher than they could with a traditional spring so thanks beehive spring so all this new stuff is in theory gonna make the new STI a better platform than the old ej1 and even though Subaru hasn't pushed the EGA 340 horsepower I'm sure some of you are gonna point out that tuners have been able to push it way beyond 400 horsepower in fact we showed you an 800 horsepower one on this very show now most tuners will say to get 400 horsepower reliably it takes Forge Pistons boards rods new bearings new machining a bunch of new parts right I mean basically you're taking the whole engine apart and replacing half of it for the new FA 24 to get that same 400 horsepower it looks like it might take a lot less prime motoring has been putting these engines to the test here's their engine mounted in a cross track making 500 horsepower to the wheels with nothing but bolt ons and a tune and even the turbo and cams and ECU are just the OEM ones from a WRX and they've run it on the dyno over 50 times look ej engines are sick and if you want to know more information about them go watch this episode up to speed games is gonna gush all over them just really great episode but let me tell you the fa is the wave of the future and it's going to provide us with some super high horsepower reliable WR X's and Mann's there's nothing more we can ask forboxer engines one of the most iconic automotive sounds out there is the rumble of that flat for VGA powering all four wheels of the Subaru WRX STI it's been the heart of the STI for 26 years and now Subaru is throwing it out and they're putting in an engine from an SUV yeah that burns your britches chaps your bun tans your hide it just plain ticks you off oh I have good news for you this engine is the best engine that SGI has ever had and today I'm gonna show you exactly why we're gonna look at this new fa20 4 engine and find out we're tiding all that buff boxer potential don't believe Subaru can turn a mom Mobil motor into a flat 14 up well I guess we just got to show you let's go a huge thanks once again to our friends over at keeps for sponsoring another episode of bumper to bumper I'm gonna be straight with you guys I have a weird-shaped head under this hat in all this hair so I need my hair without it I'd look something like this Shh the numbers are in and two out of three guys will experience some form of male pattern baldness by the time they're 35 and if you still have hair and you're worried about losing it prevention is key my friend keeps offers a full treatment to prevent hair loss almost as powerful as my RC 51 back there room so start your treatment today and keep your weird head hinted by all that lush beautiful hair just like I do how weird this head is you can even visit a doctor online and get hair loss medication delivered right to your door every three months you never need to leave your house which is pretty good right now aboard the dreaded comb-over and start your treatment today go to keeps calm slash b2b or click the link in the description to receive a special offer on keeps hair loss treatments that's K E PS comm / b2b thank you for supporting the companies that support us here at don't ask if you don't know the rumors are all but confirmed that the new Subaru WRX STI is coming in 2022 with the revised version of the FA 24 engine currently in the subaru ascend and supposedly the STI will make a total 400 horsepower to the wheels now to put that in quick perspective that's 90 more than the current STI 60 more than the most powerful STI and 140 more than what the assent makes right now now quick note before we get too deep we're gonna be saying FA + ej a lot today now if you don't know what those mean it's simply the engine code that Subaru uses to identify their box or power plants out ejs were the 2 liter and two and a half liter engines that came in the WRX and the STI all the way from the beginning and the fa engines are the new platform these engines don't have the same sube Rumble but it's theoretically got more power so where is that extra power coming from well let's take a look one of the main things that's new for the fa engines is direct fuel injection as opposed to the ejs pour injection a port injection is when your fuel injector is placed in the intake manifold upstream of the intake valve and the air and fuel mix there before they enter the cylinder now the upside of that is that the air if you'll have a longer time to mix before they enter into the cylinder but the downside is that it's less precise on the air fuel ratio because you're losing a little bit of fuel as it sticks to the intake valve now direct injection means that fuel is shot directly into the cylinder it's injected directly just like the spark is and the fuel is fired much later and much more precisely than port injection and it's fired in a much higher pressure and there are plenty of benefits from this now the system is more efficient meaning better fuel economy that's good and also it cools the cylinder because it sprays a nice mist of fuel on the cylinder walls and that lowers the temperature of the wall reducing the chance of pre-mission or engine knock that might occur from the combustion chambers heat think about that heat the cylinders get so hot that they can sometimes when you inject fuel in cause it to auto ignite it's not good it's creates not ping you don't want it you don't want it ultimately direct injection is better for fuel efficiency and engine health which overall lets the engine safely hold more power but there are some downsides to it as always as always good and bad direct injection needs the engine to be warm to atomize fast enough and mix with the air and to overcome that they need a lot more fuel on a cold start Oh trust me direct injection is the way to go but if you're not sold on it then I got some good news for you ok if you will please indulge me and take a quick trip over to the speculation zone on the current Subaru BRZ also the Toyota gt86 Toyota's fan cd4s fuel system uses both port and direct injection and it's actually a very simple system the direct injectors are strong enough to run the engine at high rpm but for a better start up the engine splits the work between the two sets of injectors at cold start literally the best of both worlds and this version of the d4 s system isn't in the FA 24 engine currently but it could be added assuming the STI isn't going to use the same intake manifold now our buddies over at prime motoring in New Jersey have been tuning Subarus for years and they took a closer look at the existing FA 24 and they've been tinkering with it just to see what the new STI is going to be capable of and with a new intake manifold the FA 24 could totally use this d-4s system from the BRZ but that's not the only promising thing they found in the new engine the block and head themselves has some hidden heft as well even though it's still a flat 4 and it's got about the same displacement as the old AJ 257 the FA 24 is a hundred percent new engine and subaru has had a lot of time to approve on how they make power the cylinder head on this new engine has more of a straight shot for airflow than the ej had with its more dogleg path for the air to go through you know what a dogleg eyes look like this looked like a bench ito and you may not think that these little angles could slow down free-flowing air but in an engine and especially in a turbocharged engine a free-flowing path is super duper important now if the pathway is causing air to bounce around creating turbulence and pressure pockets there can only go so fast and at high revs it can't get air into the cylinder fast enough so we always want a freer flowing head to get us more air because we know our famous equation more air plus more fuel equals more power now we've already got more fuel from the direct injection and now we've got more air but for every engine there's a breaking point a point where if you put too much air in and you put too much fuel in you're gonna get too much combustion for the block to handle and the main thing about an engines block is that's got to be strong those cylinder walls have to be thick enough to withstand the pressure that the engine is gonna make or else well there's no easy way to say this your engine will blow up now let's say with a turbocharged engine you're making fifteen pounds of boost or fifteen psi of pressure that's pressurized air that goes into the cylinder on the intake stroke and when the piston is fully down as the most space available the intake valve closes and that air goes all the way back up and it gets compressed as the piston gets pushed back up again and an engine let's say with a ten to one compression ratio you're looking at roughly 150 psi that is a lot of pressure but that's not a lot of pressure compared to what happens next spark once that spark hits that compressed air & fuel mixture it ignites it creates a combustion and that pressure jumps to anywhere between 300 and a thousand psi forcing that piston all the way back down so the cylinder walls have to withstand that pressure right at the moment of combustion getting forced all the way down all the way up and that's happening thousands and thousands of times a minute so how does the fa 24 handle that well she's got thick cylinder walls and not only does he have thicker cylinder walls than its ej bro-bro it's got more cylinder support mold it into the casting and an engine that can take more pressure you could up the boost or up the compression to make more power but cylinder walls aren't the only thing that needs to be beefy to make power in an engine and lucky for us sube love and boxer boys at bay 24 just like our beef sandwiches it's got more beef inside has more beef it's okay stop it the FA engine has been around a little while and it's gotten its fair share of complaints but in a way that was kind of the point Subaru used the fa20 di t as a testbed for what the fa 24 would eventually become inside the SUV engine are some really over engineered parts it's almost as if they were designing this engine with something else in mind now the connecting rods were point of failure on the F 820 all that pressure that we talked about earlier pushing down on the piston well it also pushes on the connecting rods which connect the piston to the crankshaft now this is where the direction of our energy changes from the pushing force of the combustion to the rotational force now that connecting rod is attached to the crankshaft off-center and it's attached to the piston on a pivoting pin so as it gets pushed down it rotates the crankshaft thereby rotating your flywheel and eventually ro taking your wheels linear motion to rotational motion that's all an engine does can you do this can you guys do this I think that's like yeah that's like this thing is tough because that energy has to change direction and that puts a lot of stress on the connecting rod the more pressure there is the more likely you're going to bend or break a rod now it's not enough to just say the new engine has stronger rods so we'll show you instead now the new SP 24 rods are almost twice as thick as the old fa 21 these things are gonna be able to handle a lot more combustion pressure but the rods aren't the only thing that had an upgrade fa 24 has gone to the new beehive valve springs bud bud buzz a beehive refers to the shape of those Springs normal Springs look like this they're shaped like a normal spring now beehive Springs are small at the top and bigger at the bottom kind of like a beehive or maybe like one of those honey dripping tools that people use you know you dip it in honey I actually have one you let me go get it I can show them so what I do know is that these valve springs make a big difference they are designed to increase effective spring rate and combat valve flows as your engine revs higher and higher the camshaft spins faster and faster and the cams push those valves open and the bow Springs or it push the valve closed back again but what if your cam is spinning so fast that it pushes the valve open again before the spring can fully close it well this is called valve flow and to fix it you need stronger valve springs and you can go with thicker springs you can double or triple the strength of those Springs but that adds a lot of wear to your valve train now beehive Springs have a progressive spring rate and overall require less force to move them at the same speed as normal Springs so the upshot of this is that you get less wear on your valve train that's great and your Springs can also handle revs about 500 to 700 rpm higher than they could with a traditional spring so thanks beehive spring so all this new stuff is in theory gonna make the new STI a better platform than the old ej1 and even though Subaru hasn't pushed the EGA 340 horsepower I'm sure some of you are gonna point out that tuners have been able to push it way beyond 400 horsepower in fact we showed you an 800 horsepower one on this very show now most tuners will say to get 400 horsepower reliably it takes Forge Pistons boards rods new bearings new machining a bunch of new parts right I mean basically you're taking the whole engine apart and replacing half of it for the new FA 24 to get that same 400 horsepower it looks like it might take a lot less prime motoring has been putting these engines to the test here's their engine mounted in a cross track making 500 horsepower to the wheels with nothing but bolt ons and a tune and even the turbo and cams and ECU are just the OEM ones from a WRX and they've run it on the dyno over 50 times look ej engines are sick and if you want to know more information about them go watch this episode up to speed games is gonna gush all over them just really great episode but let me tell you the fa is the wave of the future and it's going to provide us with some super high horsepower reliable WR X's and Mann's there's nothing more we can ask for