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posted on August 15th, 2016 at 10:27 PM
FA20 - New generation Subie motor
Hey guys, just posted an update of my buggy build with the FA20turbo in the Memebers Ride section, but thought I would post here a discussion on the
FA20 engines.
If anyone is thinking about doing a conversion with the new engines, do it!. I have only been on the road a few weeks, and not totally thrashing yet,
but the performance of it compared to the EJ20/EJ25 is awesome, particuarly the low down torque and quick turbo spooling.
The FA20 is now chain driven, variable intake and exhaust cams, higher compression and direct injection, the turbo model outputs 197kW standard and
the non turbo about 150kw. They are also more fuel efficient. It uses the same bellhousing and flywheel as the EJ20. It uses the same gearbox (but
with an extra gear), and the same engine mounts. I have thrown the tape measure over the FA20 and EJ20 quad cam, and they are pretty much the same
shape and size in every dimension. The main difference with the Turbo model is the turbo position. Instead of it being up near the gearbox to one
side, it is at the bottom middle of the engine. The bottom of the turbo is level with the bottom of the sump. It basically has no exhuast headers, the
twin scroll turbo pretty much bolts onto the engine, this is why it spools up a lot quicker. The catalytic converter then bolts directly onto the
turbo to one side, with the bottom of the cat also being same level as the sump.
The wiring of the FA20turbo is fairly different to the EJ's. The engine computer sits pretty much on the engine. It has 3 big plugs Two plugs are for
computer to the engine wiring, these do not need to be touched at all. The 3rd plug is the computer to chassis wiring, and includes the wiring for
power and grounds, accelerator pedal sensor, Canbus, and a few others. There is also a small plug on the engine for wiring that doesnt go to the
computer, such as the oil pressure lamp, battery charge lamp, as well as power and grounds.
This actually make modifying the loom somewhat easier, simpler and neater. Theres no need to remove the whole cars wiring to get to the engine/ecu
wiring.
Of course, this model is Canbus, and even more stuff is on canbus than previously, although this adds some complexity, it actually reduces wiring
(thats half the point of Canbus). Take the dash cluster for example, early model Subaru's had up to 30 odd wires going to it, one wire for every
warning light and function. The FA20 dash has about 10! 95% of it runs over Canbus (two wires). This means you pretty much have to run the dash,
otherwise you will need to install your own sensors. Also like previous Canbus models, the dash cluster is part of the immobiliser system so the
engine does not run unless it is present (or emulated with the Subatronics Canbus emulator).
Like older Subaru models with the immobiliser, the FA20 uses the body computer as its immobilser, so the key, key antenna, body computer and ECU need
to match to enable the engine to run.
The non turbo FA20s (in the BRZ and Toyota 86) are wired like the older EJs, where the engine computer is in the cabin.
The Canbus signals in the FA motors (and also the new generation FBs) are different to the EJ can signals However, the Subatronics Canbus Emulator
version 2.0 is used and emulates the canbus of the ABS, Traction Control, Air bag computer, Climate control system and headlight module. This allows
the engine to run in a VW without these systems connected without the engine going into limp mode. It also allows the vehicle speed to be transmitted
over Canbus from a VDO sensor connected to the VW speedo cable, or a Subaru gearbox speed sensor. This then allows cruise control to function.
There is a little driving clip towards the end of the following video
Andrew,that should drive like the Space Shuttle taking off.You make it all sound so easy.Good looking job.I have been asked to do a Suby conversion
into a Bus-guess there will be another loom coming your way.
lou0060
Wolfsburg Wizard
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posted on October 19th, 2016 at 07:34 PM
very nice!
I'm about to embark on another project and I was looking at an EZ3 but now I am thinking FA20T.... It just looks the part in a VW!!
