Ken's 240SX: Twenty Years in the Making

A student of motorcycles, Ken Yu spent his formative years tracking two-wheeled vehicles at Thunderhill, Laguna, and Sonoma. Eventually, he grew tired of taking spills and started looking for a four-wheeled way to get his fix. Specifically, he wanted something easily modified and cost-effective. Back in 2001, 240SXs could be found for nearly nothing — especially ones with blown motors.

A Zilvia.net posting led him to this 1989 hatch, which had been sitting for some time and needed a little love. Well, a lot of love. Aside from the blown motor, there were some serious issues contributing to the low cost of the car. “Someone left a burger in the back. There were maggots everywhere!” Still, $1,500 was a steal.

He started with a basic set of suspension upgrades. Whiteline sway bars, Megan Racing track coilovers, SPL lower arms and tension rods.

Out came the interior and in went the vinegar solutions. Then came a stock SR20, Z32 brakes, Tokico shocks, 5Zigen wheels, and Federal tires for plenty of fun in those halcyon post-college years. And this first round of modifications didn’t break the bank; many youngsters could swing these back then — no pun intended. When a full S13 front clip only cost $2,500, it was not too hard to put a quick 240SX together.

Rather than take the typical drifting route, he decided to make his 240SX corner. At 2,600 pounds with ~200 to the tires, the 240SX could graze 100 at the end of Thunderhill East’s front straight. It was nimble enough to get around many autocross courses, too.

By transplanting the motor without replacing the coolant hoses, Ken blew a pinhole leak in a coolant line at Thunderhill in the middle of July. Three of the ringlands broke, sending shrapnel into the head. He managed to limp the car all the way home to Hayward with regular coolant top-ups, but the SR was toast. He rolled it into the back of his garage with hopes to quickly replace the motor, but he didn’t bet on the next chapter of life taking him down a very different path than he’d pictured.

Ken got married, had two kids, a dog, and bought a house, so the track toy no longer took precedence. However, he kept the dream alive over the next five years by amassing a small stockpile of go-fast parts and tools.

Starting seven years ago, from ten to midnight — after the kids had gone to sleep, Ken would sift through his parts pile and make small steps towards rebuilding the car. Megan Racing coilovers with Swift springs, a pair of Sparco seats, an extensive cooling package, and a bolt-in cage set the tone: it was going to become a full-on track car built on years of forum trawling.

With his new CD009 on the floor, Ken spent a couple nights fitting Jun Flares and GarageMak overfenders.

Lots of research was needed to find out all the desired suspension settings for the 240SX — no darling of the track day community. With relatively scant information available for track-oriented S-chassis, he had to consult some of the video library he’d amassed over the years. “I’ve been watching Video Option since Volume 12.”

As this would be a fat-tired track car with a need to put power down better than what a stock S13 ever could, he had to identify the flaws of the suspension setup.

Up front, he added a set of Geomaster knuckles to lower the roll center for improved camber and toe curves. Along with that, he threw on most of the S13 parts in the SPL catalog, Techno Toy Tuning’s lower front arms, and even an S14 rear subframe for slightly better geometry and a wider track. Thankfully, retrofitting the older car with this S14 part only required a set of conversion bushings.

It would have to stop well, too. There were the two-piston rear Brembos sourced from a 2004 Subaru STI and mated to two-piece Girodisc rotors with Carbotech XP12s. Installing them was a cinch, too — almost a bolt-on affair.

At the front, the Core4 Motorsports Wilwood six-piston with Carbotech XP16s fulfilled the same need for easy modification, while offering far more reassurance than any hodgepodge of other car’s parts. Any track rat loves knowing that the kit on their car has been used by Core4 on their Silvia build for AER endurance races.

“Collecting all those parts was what kept the dream alive.”

When the ball was officially running, he called on two respected old school shops to help him rebuild the one piece he didn’t replace himself. Lonnie Jenson Co increased the SR’s bore to 86.5 mm and assembled the bottom end with Eagle rods and CP pistons. Performance Options rebuilt the head, while Ken added HKS Step 3 camshafts and dual shim rocker guides to keep the head from vibrating itself to bits at higher revs.

With a whole new fuel system and a Link G4X standalone ECU to decide on the right blend, Ken knew that he’d be stretching the stock gearbox to its limit. A Mazworx conversion kit, a CD009, and an ORC twin-clutch disk made up the the beefy new drivetrain — more than strong enough to handle 360 horsepower at 310 lb-ft at 5,500 rpm. That was sent back to an S15 helical differential with a 4.3 final drive. The combination of this gearbox and rear end resulted in explosive acceleration.

Getting tuned at Blacktrax.

After bolting in and tuning the new powertrain, the car would hook when pointed directly ahead, but the lack of compliance over surface variations caused Ken a few spins. At first, Ken struggled to find much grip coming through Turn 3 and 3A at Sonoma. “The inside wheels kept losing contact due to the lack of droop and suspension compliance. The solution was to ensure 30% of the suspension travel was reserved for droop through the helper springs,” Ken noted.

With more toe-in at the rear and a TCS Sportline rear wing, the car’s stability improved at higher speeds and under heavy braking. Being heavier in the front than the rear, it still gets a little light over the crest of Laguna’s Turn 1, but it’s less than vicious. The wingless iteration felt like it might bite his head off.

To expect much more from the projet would be unfair. December 30th was the first time he had this car on track in over a decade. And, wisely, Ken wanted to study the ways to get a dependable car out on track first.

Clearly, Ken’s done his homework. The engine manages temperatures well for a turbo car — admittedly, only cold-weather testing has been done so far, but it’s likely cooling won’t be a problem except perhaps on the warmest days.

The geometry is improved, the drivetrain handles the horsepower well, and the maintenance it requires is relatively low for an old Nissan. There’s also little tweaks that show an attention to detail and an emphasis on presentation, like how the ISR exhaust extends far enough to avoid blackening the bumper. It’s pretty — and that’s not always a great descriptor for a 240SX with bolt-on over fenders.

The attention to detail and insistence on putting reliability first will make the car’s issues easier to diagnose. However, half the car’s ancillaries are OEM SR20, so time will tell how well they’ve weathered the elements.

It’s clear Ken’s laid the right sort of foundation. Coilover testing, adding a front splitter, and increasing body rigidity are the main items on the agenda. Seam welding around the hatch and the doors — two massive apertures for such a small body — should make another massive step forward in making this middleweight handle well. Buttoning it up will take time, but Ken’s already sunk two decades into this car and his enthusiasm for tuning the 240SX hasn’t diminished one iota since the start. In the grand scheme of things, what’s another year?