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This thread was suggested a long time ago, before Covid this swap kind of made sense. Since Covid the prices for stuff has changed a lot, and i'm not really sure this swap makes sense.
There are a few advantages to the FD engine, but you can actually put most of them on an FC engine which would bolt right in the car, and thus be faster/easier. cost is basically the same too.
so then why this thread? i think after a lot of thinking there are about 3 scenarios where the FD engine makes sense. It also pretty much requires you to start with an NA as well, if you have a T2 you're way ahead just rebuilding the T2
First is if you have an NA, and manage to score a complete FD engine, and or live someplace like CA where you can do an engine swap legally, but it needs to be pretty complete.
so this is FD engine, turbos, ECU etc etc.
Second is basically the same, but you want to run a single turbo, also potentially emissions legal
and Scenario 3 is if you wanted to make the most power possible, 500+
the rest of the time the REW swap is a LOT of work, and since the REW part will usually bolt on the FC engine, its pointless.
there have been others like this Makers Racing one
these let you just bolt the engine in the car with stock FC mounts.
there are a couple of other ways, mine has a section added to the subframe so it uses stock FD mounts, but the engine is not in the right place, and it would be better if it used the spot in the frame designed to carry the load
you can also drill the REW center iron for the FC mount (and the left FC mount can be modified to fit the FD iron). drilling the FD iron though means you have a custom iron, and if you need to replace it you'd need to do the custom work again.
also the FC oil pan and FD front cover don't match up, so you need to fab something there too. its just too much work for too little gain.
for the clutch you can put the FC pressure plate right on the FD flywheel, and plop it in the car
ideally you want the FC Turbo transmission, although there is a kit to use the FD transmission in the FC from Supernow
Fuel System: this is the easiest part actually. the FC and FD fuel lines match, so its pick a fuel pump, and its plug and play.
the stock FD injectors are plenty for anything the stock FD turbos are good for, if you go with a different turbo, its about 320hp. and if you're going for a high power setup, you'd be replacing the injectors anyways.
the FD also has a bolt on fuel pressure regulator, so its pretty easy to add a regulator and bump pressure if its needed
The oil system is also pretty straightforward. the FD has a larger fitting on the front cover, which isn't a big deal, but they moved the rear hose to the oil filter base, so you need a completely different hose than if you had an FC
so you can either make some AN lines, or just buy the Banzai racing (your new best friend) kit
the REW cooler lines are a drop down, so make sure you pick the right one
The cooling system is where we get to the first hurdle. potentially. the FD twin turbos are longer than any other turbo, and its further enough forward that Mazda moved the lower hose on the FD to the center of the radiator instead of the side like the FC.
FC
FD
with a single turbo car you can just use this hose. i think it fits like a 95 dodge van?
on my car i modified the water pump housing, but if i knew about that hose i would have run it. this is all about working smarter, you want to spend the money/time fabricating stuff that makes the car better, and not to make something fit that already fit...
one of the FD upgrades was that it uses an electric fan so you need to as well. the Ford Taurus fan fits the FC radiator and works great. its nearly a bolt in.
the FD upper hose will actually fit with a little trimming
if you have the FD twins this is all a really tight fit, but i think it will.
the FC water pump housing could be used in theory but it actually hits the FD primary fuel rail (the FD water pump is further forward), and then to get all the pullies to line up would be kind of a PITA
Turbos: so this is one of the best things about the swap, you have more room for turbos than any other combo. the FC has more room to the shock tower, and the FD intake got moved up on the engine relative to the FC.
the FD twins fit, although its very tight lengthwise. any FD turbo kit will fit, the FC turbo will fit. really you can run anything.
HKS currently has a set up kit, which is the turbo kit minus turbo, i mention this because the T04S kit was CARB legal, so you can run this and be emissions legal.
The next hurdle is that the FD and FC exhaust systems are incompatible.
everything is different, diameters, flanges, where the flanges are etc....
if you're running the stock twin turbos, you will need a down pipe, and it will need to be modded a little, it bolts on, but it hits the floor of the FC
basically you can run an FD down pipe, and FC cat back, it need about an hour at a muffler shop to figure out the center
Intake/Intercooler. the FD engine leaves you no room for the T2 intercooler, so you need a front mount of some kind. if you're using the FD twin turbos, the hot side piping will need to be custom. no matter what turbo you run the hot side piping will need to be custom too.
the Greddy (or similar) intake elbows make this pretty easy,
however they will not fit with the FC power steering. the FD bracket has the PS and the AC lower, and it will fit.
actually the other issue is that even though you can put the FC v belt accessory pulleys on the FD engine, the belts do not line up very well. the PS is ok, but the ac isn't.
using the FD stuff is possible, but would need new hoses/lines. it is for sure easier to do manual steering and no ac here
for the intake, i've found that if you install the HKS kit upside down, so it goes to the fender, it fits quite nicely. (the apexi does not)
they come up used quite often, and its available new.
if you have a single turbo, basically any 45 degree pipe and pod filter works.
the FD throttle cable also will fit the FC, you will need to adjust the FC pedal to get WOT, but it fits
so if you follow most of this, engine is in the car and pretty lose to working.
the next bit is the ECU and harness. this is one of the big rabbit holes of the whole thing.
if you're running the stock twin turbos and stock injectors it is really hard to beat the Power FC, although stock ECU is also possible
you will still need some sort of wiring adaptor to go between the FD harness and the FC body. the FD harness fits the FC pretty well.
if you're single turbo, you can run the FC harness and some adaptors (works best with an S5)
again Banzai Racing has PFC swap kits
and then obviously you can go link/haltech/motec (cheaper than haltech these days), etc etc
lets see other stuff i forgot, the S5 battery harness plugs right into the FD alternator, water temp sensor, and oil level sensor, which is really nice
and that is it, from me. any questions? please fire away!
Nice comprehensive list on what is needed to do this swap. I did this swap myself a little over 5 years ago and there was only a few documented swaps. In my case my car started as a S5 GXL, and I had been contemplating doing a TII swap. I also have a FD and I had a complete spare JDM auto REW along with a bunch of FD parts that I could use for this swap.
I ended up going through a similar process that you outlined above. Off the top of my head I used:
-Motive fab mounts
-Banzai harness with PFC
-FD Greddy front mount
-CX Racing FD vmount radiator w/ RX8 fans
-Stock sequential twins
-FD fuel pump
-Complete S5 TII drivetrain
Took a few months to complete, but I am just a weekend hobbyist working in my garage. Wiring wasn't too difficult, just had to look through schematics for the FC and JDM auto FD. I think I only had to wire up about 10 wires. Hardest part was fabing up the intercooler and radiator setup. One negative was in order to mount the intercooler, I had to cut out the factory radiator mounts. But I also don't plan on going back to stock or selling the car. The stock FD downpipe actually fit without hitting the floor, although I did have to bend the heat shield. It also had to be lengthened about 5 inches for my setup.
So in my case it was a more reasonable swap since I had most the parts, and back then any additional parts I needed were more readily available and cheaper. The car has been running great the past few years and it is just a weekend car and occasional track car, just need to fab up the a/c lines and maybe redo the end tanks for the intercooler.
Yes I moved the battery because of the intercooler. I thought about relocating to the rear bin, but for now it was a easier location to put the battery.
You're right, I recently just redid both the brake booster and master cylinder to a mid 90's Subaru legacy from the info from one of the threads on here.
... although stock ECU is also possible
you will still need some sort of wiring adaptor to go between the FD harness and the FC body. the FD harness fits the FC pretty well.
what's the dumbed-down version for getting this done? i've heard a couple of people say the stock ECU won't let you do things if it doesn't "see" the car, so you need to incorporate circuits from the car (similar to the Rx-8 PCM). however, i did start to suspect it wasn't true when i saw your build thread.
what's the dumbed-down version for getting this done? i've heard a couple of people say the stock ECU won't let you do things if it doesn't "see" the car, so you need to incorporate circuits from the car (similar to the Rx-8 PCM). however, i did start to suspect it wasn't true when i saw your build thread.
ok the stock ecu needs to see most of the inputs to work correctly, it will set codes if you don't. the output side it cares less about, and we would use most if not all of it.
the S5 and JDM FD are actually pretty close, which is nice
if you wanted to run the twin turbos, you pretty much have to run the FD wiring harness, and make some adaptors to plug into the FC.
if you went single turbo, you have the option of running the FC harness with some adaptation to plug into the FD engine.
i notice when the JDM tuners do the FD upgrades to their FC's they usually end up with like an expansion harness, so its like FC ecu, FC harness, HKS F Con V, and then they can add whatever wiring they want
the only two systems you need to add to the FC, are the cooling fans, as the FC was mechanical, and the relay for the Air Pump. the fuel pump speed uses a different polarity relay between FD and FC, but that is easy to deal with
everything else actually works the same, or just lives on the engine. things like the clutch switch, fuel pump, etc
pics from someone parting out a car in Japan.
Engine, only real deviation from stock is that the OMP is the FC one, which lets it plug into the FC harness, not sure what they did with the CAS, its using the FD one, but i don't see the plugs on the harness
engine is sitting on a cradle like this one, which uses the FC mounts in the subframe, it makes the engine a bolt in
The emissions were removed, but they kept the metering pump and the thermal wax, you can also see the FC metering pump connectors. the FD vacuum rack is modular, so the coolant pipe may have come from that
all the vacuum hoses go to the modified throttle elbow, it looks like it could have had power steering, although its not for sale, so i can't say
Turbo is/was a T04S on an HKS manifold, FD turbo fits an FD engine....
07-03-23, 12:04 PM
