Subaru debuts 3rd gen Boxer

[Dimman]

Originally Posted by cyde01

the fb series is said to eventually replace all ej series motors in subaru's lineup, so it's a given that aside from the 140hp version, there will be other higher output versions as well. we already know that toyota is designing the heads, so i think it's safe to assume that if the ft-86 comes with the fb20, it will not be the base 140hp version. as far as how much performance potential is in this engine? i think that's anybody's guess at this point. the n/a ej20 was also 140hp but i think there was a n/a version in japan that did 190hp..

here's an interesting blog post about the engine if you can read japanese.

http://golf4.blog65.fc2.com/blog-entry-201.html

based on the pics it does look like the intake port has a less straight, more curved path due to the narrow angle, but i'm no airflow dynamics expert so what do i know?

the engine's gonna be a lot wider than the ej so the engine bay's gonna have to be pretty wide to fit d-4s and anything else toyota builds into the heads. the plus side will be that while the engine is wider it will be shorter front to back, so it will possible to place it even further behind the front wheels.

Had to stick with only the pics. Damn it!

I was most interested in this one:



Like you said, the new motor's intake ports look more curved than the old EJ. Especially where I marked it with 'C'. This is not what I think of when I think of performance ports. Air doesn't like to make sudden volume or direction changes, and compared to the old one (The section 'A') the EJ's intake looks much better. But I'm not an engineer either.

One issue that confuses me is the step right before the valve ('B'). I don't know what this is. I though it was maybe where the valve seat is supposed to go but all the other components are there, so maybe not. It could be there to introduce more turbulence as the air enters the chamber. A reason for this could be the EJ's larger than usual bore. This leads to a big flat pancake-shaped combustion chamber which means the burning fuel has farther to travel. This can make for less efficient combustion but having the intake charge swirling around more can help improve that.

It also shows that they went from buckets and shims to finger-followers which are lighter and have less friction.

Nice find. Now to wait for Ichitaka to maybe, perhaps, do some translating...?

[Siriusly.Andrew]

nah that bum is in Japan enjoying himself, he won't be doing much translation work till he gets back I betcha. Which sucks. Great diagram though, I am learning!

[70NYD]

hi dimman i think that the recess B is for valve seats, since they arent actually shown anywhere.. this looks like a solidworks model.. SOMEONE GET ME A FUCKIGN COPY PLEASE

[nate89]

Taa DAa!

・ New generation of Subaru horizontally opposed four-cylinder engine Part 3



↑ FB20 type. Oirufira, level gauge, note the location of the oil cartridge



Technical description is made of a new generation of Subaru engines recently, almost the whole picture became clear. Engine type name first, FB announcement type. Therefore, the FB25 2.5L North American type, as in Japan, the main type 2.0L will be FB20.

FB20 ・ bore stroke, 84.0 × 90.0mm, FB25 is 94.0 × 90.0mm. The bore pitch is 98.4mm, EZ system (cylinder 6), EE system (turbo diesel) is seen to be played on the same production line. However, FB skeleton type engine parts are new designs.






The concept of development, characterized by a boxer engine revs up to high revs rise, but will remain stress-free, that aimed to improve environmental performance and ease of use can increase combustion efficiency.

"What? Is trying to high speed until the age now?" But not even I do not feel that it is actually 6000 + rpm maximum allowable rotation alpha.

The specific aim of developing efficient combustion (burning rate) and up, the main increase in mean effective pressure-reducing the frictional resistance by increasing the manageability of a low-speed torque and response, enhance the drivability thing.


Select a stroke of 90mm Sono Tame, FB20 in long strokes, FB25 has become slightly over-square. The purpose of the stroke itself, rather than long, of course, smaller than the diameter of the combustion chamber, combustion chamber to narrow the angle and ultra Konpakutopentorufu pinch valve together, but they get to increase the burning rate.

Pinch-type valve is the final corner EJ20 (DOHC) and significantly reduced time compared with 27 → 41 degrees. The distance between the core 126mm → 104mm intake and exhaust cams are the limits to attack. The earliest way EJ20 is the engine and sports aimed at the class output angle clamp valve is large and 52 degrees and deliberately pursued a straight port and the area expansion valve assumption Big Bore, high output full-scale - was a high speed engine. FB have a sense of the type than just poles apart.




The structurally-cylinder unit and the cam carrier is separated expressions, productivity has been increased maintainability.

The cam drive chain and expression, the auxiliary machine belt driven by one. And chain drive for most Enjinfurontokaba made of aluminum casting has become.
The chain lubrication is an integral oil pan.

FB20 specifications for regular gasoline, 10.5 compression ratio. The piston head shape is a shallow dish. Valve is to reduce friction, the equation changes Rorarokkaamu direct expression of art.




The combustion chamber configuration and the narrow valve angle is sandwiched between a good shape compact and increasingly difficult while the intake port shape. If racing straight port, Sutoretointekumanihorudo It is possible, in the engine room of passenger cars is limited to the width and height can not help 曲Gezaru ports, including at a large angle.

In order to achieve both high power and low-speed torque port shape is a major issue, or how the intake variable valve lift mechanism is the solution of one of them. But FB is the proven engine selected using conventional TGV. As shown the port side or the port TGV provided a partition wall for, at low speed TGV closed, increasing inspiratory flow rate by playing the top wall a small volume of the intake vortex to match the shape of the piston head yet generated, so that they can make a uniform mixture.








When running a large number of low load than conventional EGR (exhaust gas recirculation) to introduce, but also for enhancing ignition TGV will be adopted. The introduction of high EGR, increase the throttle when driving low load, it aims to reduce the pumping loss.

Unique to that EGR volumetric efficiency of a diesel engine as an EGR cooler provided. The gasoline engine would probably not see the other cases. For the diesel but EGR cooler is often system intercooler in earnest with a core cooling if the horizontally opposed engine in order to equip and flow that connects the cylinder block left and right upper back of the engine, FB type within this cooled by water-cooled EGR pipe to flow through EGR cooler and it has been.





Each of the intake and exhaust cam AVCS (variable valve timing) is equipped. Equipped with both conventional exhaust from the intake side was only this can be done with an expansion ratio operation. Therefore, as hydraulic AVCS intake side of the midpoint of the first and locking. Conventional hydraulic Upon stopping the engine had become the rock on one side, by locking the intermediate stop at an intermediate position during engine shutdown, on restart becomes possible to operate with the retarded according to the situation, closing early, None of that can be closed slowly.

[nate89]

Reduce the volume of the set of equal length exhaust manifold and exhaust manifold is also new design, put it more directly under the catalyst, which accelerate the activation of the catalyst to reduce heat loss during startup. Due to the small amount of hazardous materials generated by the improved combustion The amount of the precious metal catalyst is 30% lower that the catalyst cost by half.


In terms of cooling, while the portion of the cylinder block around the combustion chamber is cooled enough to adopt two cooling systems to maintain temperature. Hakatsu to reduce both the friction reduction and cooling loss of the cylinder to balance the promotion of new warm air can even bypass passage bottom.

To reduce friction, circular bore machining, drilling bore when assembled dummy head that has worked to make the axial force on the stud. But the European luxury car engine approach, more recent years to reduce friction, which is also used for the engine Nissan March.

Piston, connecting rod about 20% of the conventional level of weight reduction. Rorarokkaamu expression and the valve drive also has to reduce friction and also by lowering the two-stage pressure relief oil pump relief.

The engine weight, cast aluminum front cover, AVCS conventional equipment due to the four types from the EJ20 is a little heavy.


FB-type performance, fuel economy of about 10%, about 3% acceleration, with low acceleration accelerator opening, the response acceleration in the range of practical means to achieve a better acceleration feel.

The FB type is announced today but have been tuned specifically for the naturally aspirated, with regular gasoline specifications, however, feel that the output is somewhat unsatisfactory. You did not have lingering than if converted to suppress the reverse.

As a future development course, cylinder head, special design of the turbo by pistons and connecting rods, etc., can be considered as direct.

This engine is considered the prototype of the underlying engine in the Subaru and span the next 10 years. In the future, but seems to have been downsizing also consider the concept, to realize it is expected to take some time.

I really like the oil filter location, but the 10.5 compression ratio. Thats good for N/A power, but not if you're planning on adding a turbo.

[cyde01]

Originally Posted by Dimman

Nice find. Now to wait for Ichitaka to maybe, perhaps, do some translating...?

i can translate but i'm also very busy and that's a lot of text. maybe if you can pick a paragraph or two that you're especially interested in and i can translate it for you. it includes a lot of stuff about TGVs and EGR valves. i'm not too familiar with subaru so it's kind of over my head, especially the stuff about the egr valve. both tgv and egr seem completely unnecessary to me.

[nate89]

I just translated the whole article above. It's a little rough but it gets the point across.

[Siriusly.Andrew]

looks like you ran it through Google Translate. I mean as far as free translators go its sufficient but I hate how literal they are. They just translate word for word. Guess I shouldn't expect so much lol

[nate89]

Yeah you caught me lol. I figured I'd give some of the guys on here a break from translating everything for us.

[Dimman]

Originally Posted by 70NYD

hi dimman i think that the recess B is for valve seats, since they arent actually shown anywhere.. this looks like a solidworks model.. SOMEONE GET ME A FUCKIGN COPY PLEASE

That's what I thought at first, and would make the most sense. But I then thought it was weird that they wouldn't put them in the model when they did the whole rest of the valvetrain.

I'm picking up a couple EJ22T heads sometime this week and will see for myself then. I do think you're right though.

And what exactly could you do with a Solidworks model of it? Get one CNC machined out of billet?

[70NYD]

Of the new one?? Find a whole bunch of flow related shit for it, from that find (theoretical) maximum power, find what the extremities would be for boring out (subsequent power increase etc)

[cyde01]

the latest best car (japanese car mag) had a comparison between the ej20 and fb20 and review, but the reviews were mixed at best. one reviewer was impressed with the improvement in low and mid-range torque and smoothness, while the other complained of valvetrain noise after 2000 rpm and poorer engine feeling at wide open throttle than the ej20. this is in stark contrast to the absolute rave reviews the mazda sky-g engine got a page later.

[Dimman]

Originally Posted by cyde01

the latest best car (japanese car mag) had a comparison between the ej20 and fb20 and review, but the reviews were mixed at best. one reviewer was impressed with the improvement in low and mid-range torque and smoothness, while the other complained of valvetrain noise after 2000 rpm and poorer engine feeling at wide open throttle than the ej20. this is in stark contrast to the absolute rave reviews the mazda sky-g engine got a page later.

Interesting.

The valvetrain noise is likely from the switch to finger followers instead of the old shim and buckets.

Did they go anymore in-depth on the poorer feeling at WOT? If it's from mashing the gas I wonder if maybe they have a non-linear E-throttle. (Hated it on my buddy's Yaris...)

If it was an acceleration 'feeling' or something, it could have to do with maybe the new motor not having as much peak airflow (from what I was talking about before from the port shapes), and power could be falling off at high revs faster than the old motor (even though the HP peak numbers are the same). Same thing could relate to the improved mid-range too.

Motivation for me to study Japanese a little harder... (Yomimasen...)

[cyde01]

nothing in depth. it was just a very preliminary first impression based on a first drive. and the two reviewers kinda contradicted each other, one wasn't pleased with the engine feel at wide open throttle while the other had no problems with it and thought it revved to 6500rpm quite nicely.

although there's no way to tell, your theory of it having to do with the intake heads makes sense. that would explain why despite all the improvements, the fb20 only makes the same amount of peak hp as the ej20 rather than more hp.