FB is the new EJ

[Nick Koan]

Car and Driver had a write up on the new FB motors, and the differences from their EJ predecessors

http://www.caranddriver.com/news/car...-four-car_news

[Nick Koan]

Also, in earlier writeups and pictures I'd seen, I never noticed where the oil filter was moved to the top of the engine.

I also heard that Subaru is requiring the new motors to run their special synthetic 0w20 oil.

[sperry]

Why did the serpentine belt have to get so crazy? Is that really better than just having two belts on a wider crank pulley? Also, is that the water pump getting driven by the serp belt now too? I guess it would if the motor's gone over to a timing chain.

Oh, and F that oil filter location. I hope that cup it sits in is deep enough to act like a drain, or oil changes are going to be messy. At least the filter isn't wrapped by exhaust headers anymore.

Seems like a lot of changes not to have included direct injection. I guess it's supposed to be coming still, but why bother with an interim version? This thing only gets 1mpg better mileage than the motor it replaces due to the sloppy drivetrain, no? They should have waited a year and released a DI version of this motor in conjunction with the switch to all CVT or 6MT gearboxes. Something tells me, 2011 Forester owners are basically going to be beta testing this motor for reliability.

Aside from all my negativity, it's nice to see Subaru finally got around to building a modern flat 4.

[sybir]

Best comment I've seen so far:
"Man, I've made a couple of new-style rods already."

[Street Pirate]

the crazy serp belt is all about lower resistance, the whole motor is about lower resistance. some cool things though, no more pulling wrist pins to get pistons it comes apart like a normal V motor piston and rod. also the alt, compressor and pwr str pump all come off as a unit. it also has permanent tumble generators. subaru is also going to be very aware of service history if the motor has a problem. first time a motor has be sent to the US before Japan or Europe.

[knucklesplitter]

Originally Posted by Street Pirate

the crazy serp belt is all about lower resistance, the whole motor is about lower resistance. some cool things though, no more pulling wrist pins to get pistons it comes apart like a normal V motor piston and rod. also the alt, compressor and pwr str pump all come off as a unit. it also has permanent tumble generators. subaru is also going to be very aware of service history if the motor has a problem. first time a motor has be sent to the US before Japan or Europe.

I think the very serpentinish serpentine belt configuration has more to do with the fact that it is single belt driving everything, the water pump is now driven by it, and the overall tighter packaging of accessories on the front of the new engine.

The whole motor is not all about lower resistance though. If that were the case they would have stuck with a timing belt instead of dual chains driving the cams. That was obviously a compromise to eliminate the need to replace the timing belt (up to twice) during the engine's lifespan. In general a timing belt is more efficient and more accurate than a chain. Whereas chains are generally cheaper and lower in maintenance than timing belts.

An interesting change is that the injectors are now in the head instead on the intake manifold. Maybe this is a step toward direct injection?

Also the tighter valve configuration may result in a smaller combustion chamber. This combined with the smaller bore would result in lower minimum best timing. This would be a good thing for turbo engines, as it reduces the tendency to knock.

The rocker arms in place of cam "buckets" are also interesting. It looks like they may be going for ECU-adjustable active valve lift with this configuration.

[sperry]

Originally Posted by knucklesplitter

I think the very serpentinish serpentine belt configuration has more to do with the fact that it is single belt driving everything, the water pump is now driven by it, and the overall tighter packaging of accessories on the front of the new engine.

The whole motor is not all about lower resistance though. If that were the case they would have stuck with a timing belt instead of dual chains driving the cams. That was obviously a compromise to eliminate the need to replace the timing belt (up to twice) during the engine's lifespan. In general a timing belt is more efficient and more accurate than a chain. Whereas chains are generally cheaper and lower in maintenance than timing belts.

An interesting change is that the injectors are now in the head instead on the intake manifold. Maybe this is a step toward direct injection?

Also the tighter valve configuration may result in a smaller combustion chamber. This combined with the smaller bore would result in lower minimum best timing. This would be a good thing for turbo engines, as it reduces the tendency to knock.

The rocker arms in place of cam "buckets" are also interesting. It looks like they may be going for ECU-adjustable active valve lift with this configuration.

Yeah, I don't know how a longer belt, plus additional idler pulleys would result in lower resistance.

An article I read explicitly said this motor appears to be a step towards DI. And I think there appear to be solenoids or something on the non-valve side of those roller(?) rockers, which would create variable lift.

I bet the STi version of this motor will be turbo, DI, variable timing, variable lift, and probably put out 350hp. Which is really needed, ever since the WRX got 265.