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.