Project 240SX – Part 1 – Buying The Right Nissan S13 Chassis

The Nissan 240SX has in recent years become synonymous only with drifting, and that’s a damn crying shame. There’s more to a S13 chassis than just burning rubber and sliding around (although that ability is appreciated from time to time). What many critics don’t realize is just how capable a 240SX can be on track and how much fun it is to drive. An engine swapped 240SX can easily make 300whp+, fit decently sized rubber underneath itself, has more parts available than you could ever imagine, is cheap to buy and weighs less than a Ford Mustang. Sounds good to us.

The first thing to do when building a project is to find the right starting platform. By now, everybody and their mother knows that the SR20DET engine is a 2.0-liter turbocharged four-cylinder power plant that can make some real power and was found in the Japanese-market Silvia. It drops right into the 240SX, is easily sourced, relatively light and will help us make more quick, simple power than we could by experimenting with a turbocharged version of the stock KA24DE engine.

In fact, the swap has become so popular that it’s actually cheaper to buy a pre-swapped project car that some schmuck has given up on than to go through the effort of buying a clean 240SX and a low-mileage SR. Blame that on the drifting craze, which has inflated the price of both the S13 chassis and the SR engine. The drifting craze also means that many of the cheap pre-swapped S13s on the market today will come “drift-ized” with any number of supposed drift-spec parts.

This particular 240SX, formerly an automatic, was picked with the SR20DET engine and five-speed manual already swapped in. We could have found one for less money but this S13-chassis Nissan came with highlights including a straight body, clean paint, a “only” semi-vague vehicle history, HKS Hi-Power exhaust, downpipe, front-mount intercooler, and air intake, Koyo radiator, custom Gram Lights wheels, TEIN drift coilovers, Nismo Power Brace, KAAZ two-way LSD, and a Rotora front big brake kit. It had some minor issues but seemed like a solid starting point. Drift days were the original intention for this 240SX, thus the two-way LSD and “drift” suspension, but now we need to un-drift zee auto. But first, we needed to make it run right.

Our starting point – SR20DET red top, HKS intercooler, Koyo radiator with electric fans, Nismo engine/trans mounts, stock turbo and 200whp

Cheap stamped steel control arms with beaten 200,000+ mile old bushings are due to be changed. We’d also like to pay attention to the roll center and bumpsteer issues that should be easy to fix

Like any real world Nissan 240SX, ours came dirty. A power steering leak soaked the front end of the car in grime and nearly 20 years of dirt covered the underside. There’s hope though, a S13 240SX has won a SCCA Solo autocross national championship

The first area tackled was the air filter. For some reason, there was a gaping hole in the dirty filter for the HKS intake. Maybe someone got hungry and couldn’t wait. We measured the diameter of the filter’s mounting side, the available under hood space and then gave K&N Engineering a call. With more filters applications than there seem to be cars on the road, they’d have one that fit. We got our universal filter with a carbon fiber cap, just to be special.

Next up was a complete refresh for Project 240SX. When picking up a used project car that doesn’t have a completely detailed vehicle maintenance and repair history, it’s a good idea to change out some vitals just to be safe. We headed over to Mavrik Motorsports in Buena Park, California for a new water pump, Nismo thermostat, engine belts, oil change, radiator hoses, and a new custom power steering line. While there we got “lucky” and the starter took a dump. If you own an old car like us, Ebay is your friend.

When purchased, Project 240SX had its stock clutch fan and a pair of electric fans but no fan shroud. Although supporters of both sides had arguments over which system worked better on track, we didn’t feel like sourcing a fan shroud and returning to the stock-style fan setup. A pair of SPAL electric fan relay kits were wired up to control the dual electric fans on the Koyo aluminum radiator. Combined with a Nismo thermostat and a manual on/off fan switch, Project 240SX runs a steady 70-degrees Celcius (as measured in the upper radiator hose) on the street, with the temperature reaching 80-degrees during stop-and-go traffic on hot days.

We tried a DME aluminum radiator diversion panel in order to keep incoming cool air from escaping upwards and over the radiator through the massive space in front of the radiator. At low traffic speeds, the panel does little and heat soak builds in the cooling system just the same as without it. But once you get moving, the DME panel proves its worth with the water temperature dropping faster and cooling quicker than stock. We’re really interested now in seeing how well the DME panel, and maybe some lower or side block-off panels, can help maintain a steady water temperature at the track.

Mavrik Motorsports gave the car a complete overhaul including a new thermostat, water pump, belts and lines

With D1GP and Formula Drift hopes floating through the air, Project 240SX was built by the previous owner with drifting in mind. This was the justification on why a sharp Exedy six-puck clutch, clunking KAAZ two-way limited-slip differential and TEIN Type HE drift suspension were installed. For the average street guy, this setup could work. The suspension isn’t the most compliant in the world and the KAAZ LSD, like most clutch-type LSDs, makes clattering noises as the clutches in the LSD engage and dis-engage during low speed turning maneuvers. Still, everything works much tighter and more responsive than stock.

But, for us, Project 240SX is supposed to go fast at the autocross course and on track. This means optimization for our needs and swapping out certain parts on the car. With who-knows-how-many drift events on it, the Exedy clutch had to go. We hooked up with Tomei USA, one of the only North American distributors of Nismo Competition Parts. This line differs from the Nismo products sold in the US, which comprise S-Tune and R-Tune aftermarket parts such as a Sentra SE-R exhaust or 350Z cold air intake. Nismo Competition Parts come from the same Tokyo headquarters where the Super GT teams are based and are hardcore tuning and racing parts. The line-up includes reinforced Silvia suspension arms, hardened rubber bushing kits, VQ35DE high comp heads and Coppermix clutch kits. The catalog alone is enough to blow the mind of any Nissan fan.

We went with a Nismo Super Coppermix single plate clutch, pressure plate, and lightened flywheel. For the SR20DET there are two push-type single-plate clutches available, the Super Coppermix Standard Spec (375bhp and 311 lb/ft of allowable torque) and the Super Coppermix High Power Spec (414bhp and 391 lb/ft of torque). Ours, the High Power Spec, obviously has a higher pedal effort but only pansies worry about how stiff their pedal will be versus the allowable torque capacity.

The Nismo clutch weighed in at 2.4-lbs (3.8-lbs for stock SR20DET), the pressure plate at 12.2-lbs (13.7-lbs for stock), and the flywheel at 16.4-lbs (19.7-lbs for stock) for a total reduction of 6.2-lbs. For those making even more power, a Nismo Super Coppermix twin-plate exists. The Nismo clutch kit includes all brand new hardware required for the install but there is no clutch alignment tool included. Nismo does sell a metal alignment tool separately and we assume that they expect your shop to have one at the ready. We ended up using a plastic Subaru one.

HKS Hi-Power exhaust. A good free-flowing design that’s actually very quiet. The turbocharger does a good job as well of muffling exhaust noise

TEIN Type HE “drift” coilovers. This design is a few years old and the newer designs from TEIN are light years ahead

For installation, we went to see Steve Rodgers at SR Motorcars in Gardena, California. A former A’PEXi engineer and Tomei-trained engine builder, Rodgers knows the 240SX, SR20DET, VQ35DE, and RB26DETT inside and out. When we visited, there was a RB26 sitting on an engine stand waiting for turbos and a white AE86 sitting on the dyno waiting for a tune. In comparison, our clutch job was a cinch. Once the old Exedy clutch was out, we found our timing couldn’t have been any better. There were hot spots on the backside of the flywheel and the clutch material was worn almost all the way down. We had maybe 1,000 miles left on the old disc. We get cold sweats just at the thought of the clutch disc grinding down during a hot lap.

After some minor adjustments to the engagement height of the clutch pedal by Rodgers, we went out for a test run with Project 240SX. There’s a reason why the Nismo clutch is the top seller in Japan and now we know why. Despite being rated to handle almost 400 lb/ft, the clutch features a very smooth engagement and light pedal pressure, both very close to factory. It’s noise-less, chatter-free, easy to drive, and all the components are lighter than stock. We’re rightfully impressed.

From here, we’ll be continuing our search for the winning setup that works well on the street, goes like stink on the track, and provides enjoyable driving feel. The latter is an important aspect to us that isn’t touched upon by many other tuning magazines. After driving cars like the Lotus Exige and the MX-5 Miata, we realize that a great deal of driving enjoyment can be derived from steering that isn’t squishy, a suspension that is balanced between stiffness and compliance, a proper seating position, a stiff brake pedal, and a shifter feel that is both smooth and precise. We know that 240SX owners can have all this; the parts exist, they’re just not the cheapest ones out there. So do yourself a favor, save up your cash, and buy the real stuff. You’ll never go back to knock-offs again.

Sources
K&N Engineering
(800) 858-3333
www.knfilters.com

Tomei USA
(949) 855-6577
www.tomei-usa.com

SR Motorcars
(310) 516-1003
www.srmotorcars.com

Mavrik Motorsports
(714) 523-1896
www.mavrikmotorsports.com

Project 240SX came originally equipped with custom Gram Lights wheels and a Rotora front big brake kit. We cleaned up the rotors and then bedded them in with new Carbotech XP8 brake pads

Tires are the foundation of any car. We swapped in a lightly used set of Michelin Pilot Sport Cup tires that we had left over. Then we promptly got a screw in one of the rears. Good thing they’re cheap. Wait, they’re the OE tire on the Porsche 911 GT3 RS? Actually, that doesn’t sound cheap

Apparently, someone forgot that the SR uses a MAF-based air metering system and that a blow-off valve which vents to atmosphere will dump excess fuel between shifts. Our rubber tube is a temporary fix to plumb that air back into the intake

DME’s radiator diverson panel keeps air from escaping through the empty space between the headlights. We want to further block off the sides and bottom, totaling sealing the radiator to airflow

Our electric seat belts had given up the ghost years ago so we ripped out all the rails and motors and replaced them with 3-point manual belts from an S14. They’re a direct bolt-in but will require a simple straight bracket for the reel and a hole to be drilled through the b-pillar plastic