Adam's S13 Coupe: Silvias Do More Than Slide

Some might think that S13 coupes aren’t really suited to turning quick laps, but some know better. Adam Swan’s owned thirty-five different S-chassis cars, so he knows better than most. This particular car, bought before some of the JDM favorites were considered investments, only set him back a few grand. That would be a steal for a stock car nowadays, but this one had the running gear from an S15 Spec R.

That means an SR20DET, a six-speed transmission, and the viscous limited-slip differential in a body weighing around 2,750 pounds. It was immediately at home on canyon roads and shorter drift tracks, where Adam beat it mercilessly for the his first few years of ownership.

It even got the S15’s gauge cluster.

At the time, he was crewing for Valkryie Autosport/GOTO Racing, then running a Nissan R35 GT-R in various time attack series. Inspired by the challenge he was partaking in, he decided to take his recently acquired S13 and try the road course for himself.

Being light, moderately powerful, and rear wheel-drive, the S13 had the bones to become a track car. He called upon his experience and added some budget basics to free up a few horsepower and find some support.

For the power adders, he grabbed a trio of no-name budget bits: a 4” turboback, a front-mount intercooler, and a manual boost controller. Good enough for a healthy 220 horsepower at the driven wheels, which, after stripping the interior and stuffing a Joshua Sher half-cage in there, made for a pretty punchy machine. Great torque and a much wider powerband—one perk of the S15’s variant of the engine—propel this 2,600-pound car at a surprising rate. It’s not just about peak power, but mass, gear ratios, and available traction.

Forget Fancy Stuff

That last trait benefited from the first major handling improvement: 5Zigen FN01RC wheels wrapped in a staggered set of Toyo R888Rs—235s up front and 255 in the rear. To make the most of the wider footprint and improve support, he added Fortune Auto 500 coilovers, SPL tie rods, and a no-name front swaybar bought off eBay. Remember when an S13 was a budget sports car?

Even without primo parts, the package was enough for fast laps without any drama. However, it was nearly stock in other areas, and that became a problem when the factory S14 one-piston brakes would vary wildly from corner to corner, even with upgraded pads. Additionally, the VLSD’s tendency to peg-leg limited a lot of his corner-exit potential. Not perfect, but not too bad for what was essentially a stock car.

Life was stress-free a long time; going to track days without breaking the bank, running full laps without worrying, and putting in respectable times. As his confidence grew, Adam started to wonder if a few aero pieces might not make a massive difference. Adding an Alumalite splitter and an NRG rear wing spruced up the basic shape of the Silvia, but the aero change worsened his confidence.

Some inspection from the sidelines showed that the trunk was flexing under the pressure of the wing. This was due to a lack of trunk reinforcements, which, when added, made a huge difference. The balance went from being skittish at higher speeds to neutral with a hint of understeer in the fast stuff; something easier to lean on when learning the basics. It also helped cut about five seconds off his previous bests.

Adam recognized that what the car required was a little fine-tuning at this stage. Switching from Toyos to a set of Advan A052s proved to not only give him longer stints before the tires’ performance would dwindle, but after playing with pressures for a few lapping days, he found that he was getting much closer to that reassuring sort of balance he’d been after for some time.

By getting the preloads, ride height, and cambers correct, he was able to feel at ease while pushing. When the rear stepped out, his drifting experience came in handy. Even though the of the suspension wasn’t widely adjustable, he could get it to do what he wanted it to.

He took it to Global Time Attack twice, both times competing in the Limited Class—a best of 11th in 2020.

Resurrecting the Silvia

His business SwanSpeed has picked up in the last couple years, so the trusty Silvia has taken a spot in the back of his garage. Though the engine’s been plucked from the bay, it’s not a cause for dismay. The reason it’s gone is because he’s finally found the sponsorship needed to make the car a front-runner in Limited.

The body’s been widened with Origin overfenders to run wider tires; 275s at the rear—hopefully enough to harness the power the new motor will make. The heart of the new build, currently in progress, is a TEM Machine IndustriesM-built SR20 with forged internals, a quick-spooling turbo, E85 capability, and with any luck, a little over 500 horsepower.

The Silvia might not have the traction of some of its rivals, but it’s an underrated chassis in a grip setting. It doesn’t have much mass to push around, nor does it have many vices. Provided the brakes and differential are replaced for something a little stronger, Adam might be able to give his inconspicuous Silvia a fighting chance against the S2000s and GT-Rs. Not terrible for a car with less than ten grand invested.

A big thanks to Horsepower Industries for their endless support.

Seigo Ma's S2000: Grip and Reassurance

Photo credit: Jebin Huang

Seigo’s had a thing for lightweight Hondas since day one. His foray into track driving came through an RSX, and after about four years of that, he tried his hand at FR with an AP2 S2000.

With Gary Wong’s car in his reticle, Seigo started building this Silverstone Silver AP2 into a car that could run at the sharp end of S3. He began with a set of HKS Hipermax 4 SP coilovers, Stoptech ST40s at the front, and whatever inexpensive tires he could get his hands on. Cheap was the operative word with rubber choice; seat time was everything at this stage—especially if he wanted to get anywhere near Gary and his clean, measured, unruffled driving.

Photo credit: Jebin Huang

Despite it being his first FR, Seigo took to the S2000 quickly. Being an AP2, the rear is slightly more stable than its predecessor’s, but that doesn’t take away from the the accomplishment of adjusting so quickly to a very pointy car. Modeling his S2000 after Gary Wong’s car, he made some of the same changes to setup which help Gary drive quickly without taking in too many liberties.

After he grew tired of the silver paint, he applied a metallic green wrap to help his car stand apart.

He made sure the car remained stable and predictable at the rear so he could push comfortably. “The OS Giken differential, man! After I rode in Gary’s car, I saw how much better the car could exit corners. He’d just stand on it and the rear would take it,” Seigo said.

While the pumpkin was off, he changed the final drive to the “happy medium” 4.3. This was just enough to keep the motor out of its lackluster mid-range more of the time without the inviting constant shifting a 4.44 would require.

And if he was going to get a more stable rear, it only made sense he’d find more composure everywhere. The addition of a set of JRZ RS Pro 3-ways, found secondhand for a steal, he could hustle this car over rough spots, berms, and undulations like never before. “After the JRZs, the dorito at Thunderhill West was just afterthought,” he laughed.

Further improving the stability of Seigo’s S2000, he went for a little aero. “I didn’t want to spend thousands and wait months for a real one, so I got an Voltex Type II replica that I eventually replaced with a swanneck-style replica.” Now, the S2000, which he’d just recently wrapped a metallic green, had much more stick at the rear than most in its league.

To help the aero balance, Seigo added a trick Racebred Components front splitter—the pretty one with tunnels. These help produce more downforce than the traditional flat splitter. In theory, the tunnels work with the fender vents to help reduce front end lift.

By that stage, he’d addressed the main aims regarding balance and grip, arguably the most important traits with a track-focused S2000, so a few power adders were in order. The list was short: a Blacktrax tune, a 70mm Ballade exhaust, Mugen header, and an AFe Performance intake. The total output wasn’t much on paper, but 230 horsepower at the rear wheels in a 2,700-pound car with the right gearing is a surprisingly quick thing.

Still, horsepower was never its thing and will likely never be. “Power adders are expensive, so I’m just going to focus on weight reduction for now,” Seigo added.

Never feeling torque-limited has payoffs—namely in corners where the tires are thrust into the pavement. With a flat underbody extending all the way from the splitter to the Spoon replica diffuser, he’s able to take some quick corners without much concern. With Thunderhill’s Turn 8, it’s just a matter of turning in and staying flat—all at around 108 miles an hour.

“It’s so easy to drive at the limit now! It does exactly what you want it to do, and although it doesn’t have that much power, it can catch more powerful cars—even at Thunderhill East. They walk away in the second half of the track, but I can close the gap in from Turn 1 through 8, though they’re still a little faster in Turn 7.”

Eventually, he had to address one of the S2000’s few shortcomings. With a kit consisting of RX-8 rear calipers and Mustang vented rotors, he got rid of the overheating problem which plagues the stock rear solid rotors. While at it, he decided to upgrade the rear hubs to Karcepts. He’d seen the way Gary Wong’s hubs had given up at Thunderhill West and had no desire to experience that himself.

For now, the desire to put him in contention with Gary Wong and not damage his bank balance has given him one route to follow: weight reduction. With a lighter Shorai battery, APR carbon mirrors, and a carbon fiber hardtop, he‘s trimmed a good hundred pounds from the car, but it’s still about a hundred away from his target weight. He hasn’t committed to the idea of turning this car into a rough, amenity-free track scalpel, but with the indecisive way he’s been casually removing interior panels, it’s not hard to guess where he’ll be in a year.

. With a little dieting, there’s a chance he could give Gary a good fight.

Exterior:
-Fender Roll/Pull
-Replica Voltex Type 7.5 1700mm
-K1 Style Ducktail
-Alumalite flat floor
-Voltex Style Fender Flares
-Racebred Components Splitter with tunnels
-CR Style Lip
-Fender Vents
-Mugen Style Hardtop
-DF Style Side Skirt
-APR Mirrors
-OEM Hood with Trackspec Hood Louvers
Wheel/Tire: Titan 7 17x9.5 with 255/40/17 Advan A052

Interior:
-Momo Mod 78 330mm
-NRG Short Hub
-Worksbell Rapfix GTC
-Recaro RSGE Bride/Cusco Zeta III Sport C with Bride Rails
-CR Shift Knob
-Cusco 6 Point
-Hard Dog Roll Bar
-Innovate Oil Pressure/Temp with SOS Gauge Mount
-Shorai Scorpion Lightweight LiFePO4 Battery (2.75lb)

Suspension:
-Hard Race RCA w/ Camber Offset
-Spoon Gusset Plates
-Origin Fab Front Offset Bushings
-Random Mix of Hardrace/Ballade/ESM spherical bushings
-Megan 32mm Front Swaybar - 2 Position
-Hardrace 30mm Rear Swaybar - 2 Position

Brakes:
-Stoptech ST40
-Raybestos ST45 Front and ST43 Rear Pads
-Reilly Racing RX8 rear caliper conversion kit with Mustang GT Rotor
-Project Mu G-Four Fluid

Engine/Drivetrain
-Ballade 70mm Exhaust
-70mm TP
-Mugen AP2 Header
-AFE Takeda Intake with Oiled Filter
-Flashpro Tune by Blacktrax Performance
-Vibratechnics Fast Road Engine Mounts
-Moroso Baffle with Trap Doors
-Schmuck Built Coolant Reservoir/Catchcan Combo
-Koyo Radiator
-Spoon Clutch Disk/ Ballade 10lb Flywheel
-4.3 Final Gear
-OS Giken 1.5way LSD
-Road Runner Fuel Tank Baffle

Best Laptimes:
Thunderhill East Bypass: 1'58.2
Thunderhill West:1'22.0
Laguna Seca: 1'40.07
Sonoma: 1'47.8
Buttonwillow CW13 - 1'55.5