Cars

Aoshima Savanna RX-7 FC3S ’89 [LSA Swap]

I never really planned to build an FC RX-7 since I tend to focus most of my builds on ’90’s and up tuner cars, but this Aoshima model just happened to land in my lap unexpectedly as a gift, so I figured it would make a good platform to try some unique things out on…like an LS swap.

A friend gifted this kit to me for some occasion or another, and what struck me first was how apparently new this kit was. You can tell right away from the box art and packaging that it’s one of Aoshima’s recent releases, though I figured they’d had already come out with an FC model like…two decades ago.

After some digging, it turns out this is a 2018 release, based on a mold from 2012. Aoshima did indeed also have an original model of the FC first released in 2005.

No lie, at first I was a little disappointed this was just a standard stock Savanna model, when the RX-7 has had so many aftermarket package models with unique body kits like the BN Sports, HPI, and RE Amemiya specifications.

After looking at the parts count I did however realize that Aoshima was nice enough to include neat GT-R-spec bumpers and ground effects, which do look nice with the extra lowered lips they offer.

LHD dash option included, which of course will be used since we’re building an American car.

Not super sure why we get two different rear subframe assemblies – I assume it must be because the sportier model uses the dual exhaust and there are mold accommodations in the subframe to make it happen?

Clear lights are actually colored clear – that’s usually how I judge how new kits are, since actual clear color plastic is a relatively recent luxury.

So…of course the big deal with this build is that it’s going to be a Mazda RX-7. LS swapped. The way RX-7’s should properly be built (fight me).

It was surprisingly difficult finding a 1/24 LS model engine, which I found extremely strange since you figure it would be one of the most popular “crate” engines to swap into just about any model car. But maybe because it’s so played out in real life no one really does it for kit cars?

Either way, at the time I was shopping for a motor there was no traditional LS1 or LS3 available, and I didn’t see any particularly well-detailed ones out of any Corvette model kits that I could poach. The only resin LS kit I could find was from a seller on eBay that was long sold out.

Eventually, I finally stumbled on my next-best option – a resin engine kit of the 6.2L supercharged V8 out of the ZL1 Camaro and CTS-V.

I’ve never heard of the LSA motor before this, and I suspect most other enthusiasts with only a passing interest in American freedom engines haven’t either. Apparently it’s most similar to the LS9? Supercharged making 580hp in the fifth-gen ZL1 Camaro and 556lb-ft. I really only got it as opposed to any number of other resin v8 engine kits available because I wanted the label privilege of saying my RX-7 was LS-swapped.

Aoshima doesn’t include a Wankel in this kit, but they do at least mold the radiator and bottom of the transmission into the chassis plate. Obviously if I’m going to be shoving my American abomination in, all those things will need to be removed via heat knife.

What a perfect fit. Almost like it belonged there from factory! (it did)

Put the body together with my choice of bumpers and skirts.

The transmission tunnel area needed a lot of smoothing and filling with Bondo since I was cutting out of it pretty aggressively to fit the LS tranny.

Subframe parts done satin black with silver accents.

At least Aoshima gave you some under-hood detail, even if they omitted the actual engine. You get some of the accessories up front and the strut towers are at least actual strut towers.

Maybe a tighter fit than I originally thought.

BNL Resin’s LSA “crate” motor included the motor, transmission, and intake assembly, but no exhaust manifolds or any portion of exhaust. Thus I had to source my own – thankfully V8 headers aren’t hard to find. This was just a random set I picked up at a scale model car show from a vendor.

This is awkward. The stock intake arm pretty much won’t fit since there’s not enough room in the bay before it hits the radiator support, but that’s not a big deal when I can just craft a smaller arm. The bigger problem here is that the headers make the motor so wide that it pretty much doesn’t fit where I cut the stock motor out from.

Of course the answer then is to go in with the heat knife and just cut more frame until it all fits.

The original RX-7’s angled radiator wasn’t going to work, so I went and sourced a random radiator online that looked to be about the right size (this one in particular apparently came from a 1963 Corvette grand sport).

Some 3D printed intakes from an aftermarket producer.

With the radiator in and the motor pushed as far back as possible, I still had very little room in front of the throttle body. At one point I considered running the intake arm straight up front and over the radiator support into the front accessory compartment (the way many LS swaps do it), but then the intake cone would’ve been hidden behind the front bumper. I paid for that piece and I want it visible, dammit.

I ended up lopping off the aftermarket intake arm and just kept the cone, with my own custom cut styrene pipe acting as the intake hose.

Cutting some of the subframe assembly now since the giant motor and transmission assembly will need all the room it can get.


The idea now is to attach the actual engine and transmission assembly to the lower front subframe and then drop it all into the body as one unit.

Lots of little pieces need to be trimmed by mere millimeters to achieve proper clearance. The oil pan on the LS needed to be carved up quite a bit since I planned to insert the subframe support in that area.

Motor painted up and ready to go

Of course, since Aoshima never intended for a motor in this car there was no firewall with the body frame. I cut my own out of a sheet of plastic.

Filling in some flat black in the wheel wells

So with the LSA’s engine cover, BNL Resin’s mold was actually so precise it actually had the lettering on the top of the cover raised and crisp, exactly like the real thing. The only problem with that is that each letter was about a hair’s width thin, making painting them in neatly next to impossible. At first my dumbass thought I could paint the whole thing red, then sand the letters on top gently to reveal the white underneath – which, to my credit, almost worked. The results are as shown. You can technically read it, but hell does it look sloppy.

I wanted that lettering on top of the engine cover no matter what (how else will people be able to tell it’s an LS if it doesn’t say LS?!) so my next option was to sand the raised lettering away completely and turn to some custom decal work.

With my custom Testors waterslide decal system, it really only works if you’re printing dark decals to go against a light surface. Because inkjet printers can’t print white, printing lighter color decals won’t really work. Case in point here: I tried the decals at first in a medium to light gray in order to replicate the silver they should be on the real engine cover, but once you slide the decals off you can barely make out the lettering against the red paint.

The solution then was to just print the decals in black, which ended up showing up fine against the bright red. It isn’t accurate to the real thing (the letters should really be silver), but at least it’s crisp and readable!

Intake cone done in dark red

Pulling out all the stops as far as detailing this motor goes. Red wire will be used for the spark plugs, pipe fittings will be used for the radiator and brake lines. Also picked up a nice pack of detailed resin batteries from Pegasus Hobbies.

Much more filled out. Probably not going to keep the braided lines for coolant since they fray super easy, but it’ll do for now.

That’s not a random scrap of plastic garbage. I actually sat down and carved an oil dipstick handle out of a piece of random scrap plastic garbage. It’s smaller than a quarter of your fingernail.

Thicker wire used for the actual dipstick tube itself routed to the oil pan with the scratch built handle glued on top. I’ve never built a dipstick before despite having done several detailed engine builds in the past – I guess I’ve just never had the luxury of checking oil before now.

Cut and removed the intake shroud or whatever it was that was in the front accessory compartment to make room for the battery.

Painted with a yellow top to add some color variety to the bay

Motor pretty much complete, will be mounted to the subframe next before it all goes into the actual body.

So, for the actual body I was really torn on how to approach it – I had just come out of building a white DC5-R so I didn’t really want to do another white car right away, but for me FC’s were just iconic in white. I knew I wanted some kind of livery, but I wasn’t sure exactly what – until I stumbled on this random “Tuner Decal Series” sheet from Scale Motorsports.

Apparently it was meant for Revell’s ITR model. I’ve never seen or heard of these decals outside of this random one-off I happened to stumble upon at my local hobby shop – even an online search didn’t turn anything up that Scale Motorsport had ever produced anything like this.

Anyway, what drew me was the unique purple/pink/red checkered pattern livery. I thought it was a unique look that would go well on a white body to add some spice, and it reminded me loosely of the BN Sports livery on their demo FC.

Unfortunately, it turns out the decals themselves were of rather low quality. In addition to being too stiff to really work around the body contours on the doors and front fender, they also tore extremely easily. Maybe it was a product of the decals being extremely old, but either way I couldn’t really make use of them.

At first I considered abandoning the checkered flag livery and turning around to using the leftover decals from my Revell Eclipse, but ultimately decided I still liked the purple/pink/red combo too much to just let it go.

I was printing decals with the engine anyway – I figured since everything was going on a white body anyway it wouldn’t hurt to try my luck at literally replicating the checkered flag livery on my own. To do this I literally took a picture of the original decal, vectored it in Illustrator, and sized it to print on my decal paper. I could’ve made any changes I wanted at this point to the livery to suit my own tastes or take any creative freedom with it since I was printing it bespoke anyway, but decided altering the design would take too much originality and brainpower that I didn’t have.

Took a while messing with the printer and color settings to get it looking right and crisp.

I don’t do this more often because self-printed decals will never be as crisp or vibrant as professionally-made ones, but in a pinch I think I got as close as possible. Keep in mind this particular situation also only works because the body of my car is white. Self-printed decals will always be slightly transparent because the ink doesn’t lay thick enough to create a solid, vibrant layer.

Interior will be fairly basic – I’m not going too crazy with this one

Nice that a LHD dash is included. In retrospect I went with a very JDM street style culture look for this car, as a deliberate counter to the freedom-maker under the hood. Maybe I should’ve stuck to RHD after all.

I also bought a set of aftermarket resin steering wheels from an online seller – it came with some neat variants, but I was really just in it to get the heart wheel.

Went with a gunship gray interior instead of a boring black. Almost actually did burgandy, but decided I really didn’t want to buy burgandy carpet flock.

Flocked the cabin carpet light gray and the trunk compartment black. I don’t plan to tint any of the windows so all this flocking work can actually be on full display.

Going with a pair of Recaro buckets from Hobby Design, though no harnesses or roll cage for once.

Probably the most thorough seat kit I’ve ever had – comes with photo etched parts for the brackets and harness pass-throughs, along with its own dedicated decal sheet

Painted matte black

The heart wheel is hilariously small, as it should be. I didn’t really stop to consider the logistics of how you’d view the gauges with that thing – I just built a custom hub for it out of styrene, slapped it with some pink, and sent it onto the dash.

Interior done. Has some character despite no fancy roll bars or harness straps.

Aoshima includes masking stickers for the front and rear windshields, making painting a breeze

I’ve been doing slotted rotors up until now, but figured it was time to finally try some strictly drilled variants.

For the wheels, I figured this would be the perfect opportunity to make use of some Super Advans, sourced from Fugu Garage. They’re definitely a classic wheel choice for RX-7’s because my wheels are triangles so you can tell it’s a R O T A R Y, which brings me great ironic joy because we have an alpha LS under the hood instead.

Lips done in Motolow chrome

The Super Advans came with some standard separate lug nuts which are always nice, but I opted to go with some open-ended short lugs from Fugu Garage just for a bit more style

So…maybe such tiny 16″ wheels shouldn’t have been the play here. See that giant wheel gap up front? That’s happening because the front subframe is literally on the ground, and with the way it mounts, the body will be quite a ways in the air. Therefore, for proper fitment you either take the L with a massive wheel gap up front or go with larger wheels that’ll give you more ground clearance while filling out the wheel wells.

Look at that. The subframe with the motor is literally riding lower than the front bumper. If I push the motor up too far, the supercharger will get in the way of the hood closing all the way up top. It’s almost like this motor wasn’t designed to fit in this car.

Of course going with different wheels isn’t an option at this point, so the only route left to us is to push the subframe and motor/transmission assembly as high as possible to give us more ground clearance. To achieve that step one is to cut the struts.

Cutting the struts creates a butterfly effect where everything else around it suddenly needs to be modified – the upper control arms need to be hollowed out larger so the shorter struts with the springs can fit through them. The entire independent suspension assembly also needs to be bent upwards to get some negative camber out of the wheel hubs, which then requires the subframe to be trimmed so the steering axle still has room to move after it’s bent upwards.

Is this the kind of shit real swappers have to work around? I’m sick of just doing a model swap, I’d have zero patience to do a real one if this is the kind of roadblocks they run into.

Pulling together a few more miscellaneous engine accessories. This brake booster I stole from a Revell Civic Si.

Connecting the master cylinder to an ABS module, modeled after the actual module from the Camaro ZL1. Built entirely from scratch with pla-plate and styrene.

Metal fittings glued in so we can easily run some wire as brake lines once they drop into the bay

I won’t claim to know exactly how brake systems work. This makes sense to me. It’s probably missing a lot of other connections, but this is enough to get that extra bit of detail under the hood and on the firewall.

I’m kind of impressed Aoshima even included the option for open headlights. They only include one set of covers so unfortunately they aren’t even parts-swapping functional – they obviously don’t go up and down on their own but you’re basically stuck with open or closed depending on which you choose.

I normally don’t mind pop-ups, but the FC’s lights seem egregiously large. And what’s with them being angled so far down at the outside ends?! No one’s going to take my LS seriously with the car looking so sad all the time.

Solution: cut the headlight housings in half to make sleepy eyes.

I’m reusing most of the stock exhaust since I’m lazy and really don’t want to custom pipe the entire thing and craft new mufflers. The tiny stock quad tips will at least be replaced by some megaphone tips though.

Cutting the catalytic converter off and routing custom piping there to the headers next to the transmission.

Stock mufflers drilled to fit my megaphones

The hood has been one of the toughest parts of this build – only because all I’m trying to do is make it a very basic carbon fiber hood. Keep in mind I’ve pretty much never done this successfully. I’ve tried many times over, but somehow I just can’t get a smooth glossy carbon finish out of my hoods. I’ve done it countless times on smaller parts like wings, splitters, and lip kits, but to this day I’ve yet to achieve a nice looking carbon hood.

I didn’t realize until this kit that the FC’s intake scoop is actually off-center. At first I thought it was Aoshima being dumb with their mold and messing it up, but after some further research it looks like the Turbo II’s top-mount intercooler was actually off-center, and the hood scoop routed directly to it so of course it had to be off-center. The more you know.

Anyway, like I was saying, I must’ve decal’d, cleared, and stripped this hood over 7 times over the course of this build. The problem was always with the final clear coat over the decal – no matter what I tried, it always came out messed up. Either the clear lacquer would bubble and texturize, or it would go on too heavy and literally melt the decal. At first I suspected it was because I cleared it too early and there was still moisture trapped under the decal – Scale Motorsports’ carbon decal instructions warn of this happening after all.

So I heed the instructions and let the decal’d hood sit for around 2 weeks in order to completely dry out – even running it in the oven just to be sure during this time! I go to clear it after 2 weeks and it still shows texture after the clear! I tried everything from blow-drying the decal so it’s absolutely dry to switching to an acrylic-based clear coat – nothing worked.

I burned through an entire sheet of 1/24 carbon weave decal trying to make this damn hood work. Eventually after I ran out I was forced to use a 1/12 scale weave, since it was all my local hobby shop had in stock. I don’t particularly mind – the 1/12 weave is huge, but I like that it looks more distinctly carbon fiber, even if it isn’t as realistic. Actual 1/24 weave is super-fine, you really don’t even notice it’s carbon until you really get up close with a magnifying glass.

Good lord after maybe the tenth attempt we finally made it. With the 1/12 weave no less. The secret? No spray clear at all. It ended up being good old fashioned Future Floor Finish, fire-baked in the oven immediately after application so it retained its shine. A coat of actual automotive wax afterwards cleaned up any potential dull spots for the most even shine I’ve ever achieved on a carbon hood. I’ve gotten better shines out of splitters and spoilers before when I used actual lacquer spray, but for some god-forsaken reason I guess that technique just doesn’t work on hoods?!

You get your choice of pre-facelift or facelift taillights, made up of multiple clear pieces which is a nice touch to add detail.

Finishing off the exterior with a big wang. I didn’t realize Tamiya produced aftermarket parts sets for 1/24 cars like this, so it was nice to come across this ings+1 set with 3 universal GT wings.

It’s actually a very impressively comprehensive package, including seat belt harnesses, complete carbon fiber decals for each wing, and a photo-etched set of seat belt clips and hood pins.

My main challenge here would be figuring out the wing stands, since the FC has such a tiny short rear deck that most GT wings I’ve seen mounted have a special L bracket that connects to the back of the hatch lid. The standard wing stands alone included in the INGS kit wouldn’t quite cut it.

The solution was to trim the actual stands shorter at the base so they would fit on the FC’s short deck lid behind the rear window, then scratch-build my own L-bracket extensions that would glue to the back of the hatch.

Wing deck was body color-matched with the endplates in carbon. I’ve been wanting to do this look for a while.

Last touches were the front side markers right behind the bumpers. I decided that I really didn’t like the look – the markers were giant and I felt like they interrupted the front end way too much (normally these things don’t really bother me, but it felt egregious in this instance), so I opted to just sand the parts flat and paint the trim pieces completely white, deleting them.

Done. This is the first time I’m finally making use of a slap decal pack I got from a local vendor almost two years ago.

There’s no crack or blemish or anything on the front driver side lip or anything – a slap decal there just seemed appropriate.

All told I’m kind of incredibly shocked I got the fitment dialed in and all four wheels flat on the ground. Normally when things get as hairy as they did with the engine swap being too low I have to constantly adjust the wheels so it’s corner balanced correctly, but miraculously on the first try when I glued the wheel hubs on it happened to lay flat.

That’s not to say the oil pan and subframe isn’t literally touching the ground along with the wheels though. It totally is.

It’s really hard to see because of my shitty printer quality, but I did actually self-print my own ZL1 badge to stick on the rear bumper next to the wing stand. I was tempted to slap a ROTARY POWER decal on the bottom of the wing too just to rile the purebreds even more.

Anyway, overall I’m happy with the swap. It turned out to be a lot more work than expected (especially when there was no motor in this model to begin with), but it looks clean and I think(?) you can generally tell what it is.

I really didn’t realize until later how hilariously big the battery is. When I put it in it felt like a normal size, but when you really think about it it’s like over half the size of the motor.

Nothing short of a miracle that the hood actually closes flush. During the early stages when I was test fitting the motor I was honestly prepared to cut a hole for the engine cover to stick out of since it didn’t seem like I was going to get enough under-hood clearance.

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