Japanese Domestic Market (JDM) modification is gaining steam in the U.S. with help from Japanese “takeout” engines. Japanese takeout (JTO) engines are removed from JDM vehicles through government mandated emission reduction programs. These programs demand that vehicle owners replace the engine in their vehicle at predetermined mileage intervals. Most of these engines are in good working order and many offer better performance that their United States Domestic Market (USDM) counterparts. Other engines are removed from high-performance vehicles that are not even sold on the North American market. Toyota, Nissan, Subaru, and Honda vehicles can all benefit from the import of these JTO engines. In this article, Nissan 240SX Offers Unlimited Potential – Part 2, we will examine some viable JTO solutions to the low output problems associated with the 240’s original KA24E and KA24DE engines.
In Part 1 of this segment on the Nissan 240sx, manufactured and sold in North America from 1989 until 1998, we took a look at its potential as a straight line drag racer capable of rapid acceleration and short bursts of power in said straight line. In this segment we will focus on creating a road racer.
Any decent tuner project will need to follow a plan of action. I have found that keeping a ledger for each car, or project, helps me to write down ideas and data that I would otherwise lose of forget. At some point in your ledger, write down a plan of action, goals for the car, purpose of the car, primary focus in building the car, and a list of priorities regarding the car. This will help you to stay on task and finish one task at a time (when possible), which will result in a higher level of quality and greater progress.
This car will need a dramatic increase in horsepower, more efficient shifting, enhanced handling, and better braking, therefore our plan of action will basically follow these requirements.
Our top priority will be improved horsepower. This means horsepower to the wheels, so we will discuss engine replacement, as well as transmission, and rear-differential upgrades. The light weight construction and rear-wheel drive configuration of the 240sx gives it a definite edge in building a road racer. The rear-wheel drivetrain yields superior handling and stability over front-wheel drive autos.
There are five primary engine options in keeping with a Nissan powertrain package. Since the 240Sx was originally equipped with a four-cylinder engine, a four-cylinder replacement engine will obviously be the easiest and most sensible route, despite ample space in the engine bay. If you decide to undertake one of the twin-turbocharged six-cylinder possibilities, then it will be more complicated and it will take more skill and effort to complete. However, once it is finished you will have something worth racing because there is no replacement for displacement.
The first engine option is also the smallest. The CA18DET can be found in the JDM Silva/180SX, Bluebird RNU12, Nissan Silva S12, and Nissan 200SX (European) models. Because the engine is built to be both turbocharged and intercooled it is capable of a very high RPM output. Although the 1.8-liter engine produced only 166-horsepower and 166 lb.-ft. of torque, the Garrett T25 turbocharger is upgradable along with the intercooler. Aftermarket companies like ATP offer high-quality turbocharger upgrade kits for an engine that is already known for rapid turbo spool with very little torque lag. Maximum output from this engine, turbocharger, and intercooler combination could reach as high as 500-horsepower.
One of the most popular engine upgrades for the 240sx is the SR20DET. It replaced the CA18DET in later model JDM Silva (1991 through 2002), 180SX (1991 through 1997), Bluebird (1989 through 1995) models, as well as the Pulsar GTI-R (1990 through 1994). Equipped with a turbocharger and intercooler, the 2.0-liter four-cylinder engine ranges in production from 201-horsepower to 245-horsepower, depending upon year and model. Output power variations are primarily contributed to differing turbocharger/intercooler combinations. The “Red Top” version, so called due to its red valve cover, was used in the S13 models. The first “Black Top” version came next with several other black valve cover equipped engines following. Certain S13 models used the black top engines, as did the S14, and S15 cars. The S14 featured a larger Garrett T28 turbocharger, replacing the T25 used in earlier models. The S15 was the most powerful setup, with 245-horsepower, although it also used the Garrett T28. In the S15 the turbocharger boost was raised to 11 psi. the S15 was also equipped with a much improved six-speed gearbox, as well. Numerous aftermarket turbocharger upgrades are available. AMS Performance offers top-of-the-line upgrade components and complete turbochargers. Larger intercoolers will increase engine performance, too. If you can find the highly sought after S15 variation, then choosing the complete drivetrain is the smart decision in this circumstance.
Both of the four-cylinder engines mentioned above will be more complimentary to the overall balance of the 240sx. If you plan to leave the suspension stock or make only minimal modifications, then you might consider going with the four-bangers.
The remaining three options are inline-6-cylinder engines that produce gross amounts of torque and have the capacity to generate extreme amounts of horsepower and very high RPMs, as well. If your plan of action includes major suspension enhancement, then you have the option of setting the car up to accept a larger engine with its accompaniment.
These highly sought after engines are JDM only, as the cars from which they are removed have never been sold in the U.S. The cars are called Nissan Skyline and the engines are in the RB series.
The R32 Nissan Skyline was equipped with the smallest of the I-6 engines; a 2.0-liter, with a 7,600 RPM redline, that produces 214-horsepower and 194 lb.-ft. of torque. This engine, which is designated as the RB20DET, is turbocharged with an intercooler and a five-speed manual transmission. APR turbocharger and intercooler upgrades can net incredible gains in engine performance.
Equipped with the Garrett T28 turbocharger, the next engine option was frequently used in the R33 Skyline that began production in 1993. It is a 2.5-liter inline-six-cylinder engine that is capable of withstanding very high RPM levels. While the RB25DET can offer a tremendous performance upgrade and the Garrett T28 turbocharger is easily upgradeable with aftermarket parts from Turbonetics, the difficulty level of installing this engine instead of the four-cylinder engines is much greater. Some would say that it rivals the level of difficulty that installing the RB26TT would require. So, why not just use the twin-turbocharged motor – affectionately known as “Godzilla”?
Our final engine in this segment is capable of achieving over 1,000-horsepower. This is the optimum in JDM power upgrades. Without any internal engine modification the RB26DETT can handle approximately 600-horsepower with only tuning, turbocharger, and intercooler upgrades. Greddy offers cutting edge turbocharger upgrade kits, components, and complete turbochargers, as well as larger intercoolers and piping, wastegates, blow-off valves, etc. The 2.6-liter engine utilized twin-turbochargers and six individual throttle bodies to produce 277-horsepower and 293 lb.-ft. of torque. The R32, 33, and 34 GT-R models were equipped with this engine. The GT-R is known by sports car enthusiasts as Godzilla.
As a rule, the more open the exhaust system is the better the engine performs. There is certainly nothing wrong with quiet exhaust, if that is what you desire, but a certain amount of horsepower will be lost with it. Engine exhaust noise is created by exhaust gases “tumbling” from the engine to the point of exit. Factory exhaust systems that reduce engine noise do so by interrupting the tumbling exhaust, thus causing it to flow more slowly through mufflers and resonators. The harder that the engine is required to work, in order to push the exhaust from the tailpipes, the more horsepower is robbed in the process. Several reputable exhaust systems are available aftermarket. Borla, Corsa, and many others offer free flowing high-performance exhaust systems for virtually any level of performance.
Once you decide whether you want an automatic transmission or a manual transmission, you will need to explore your options. In my opinion a manual transmission works well for road racing (especially in turbocharged cars) because of the driver’s ability to select the gear ratio according to driving conditions. If you decide to go with a manual gearbox, then a dual clutch system offers a pedal effort level that is comparable with stock but yields increased clamp load capacity to handle the increased horsepower of the highly modified engine. Most aftermarket clutch kits, lightweight billet aluminum flywheels, and dual-disc clutch kit systems are compatible with factory hydraulic clutch parts. If you have some strong legs, or you would like to have some strong legs, then you can also go with a conventional paddle-style or aggressive carbon-fiber high-performance clutch kit that will provide increased clamping pressure but will be harder to depress and hold. On the other hand, this is an easy and sure method for keeping the girlfriend or daughter away from your ride. Either way, I would recommend a short throw shifter manufactured from billet aluminum, freshening up all of the clutch pedal linkage bushings and hydraulic parts, additional bracing for the transmission (for highly modified applications), and a driveshaft loop for added safety. Automatic transmissions are the best bet for drag racers but can perform sluggishly in turbocharged road racers. Cars with lower final drive gear ratios can benefit from the smooth shifting of the electronically controlled automatic transmission provided it has been built with road racing in mind. Again, selecting a complete drivetrain from a JDM car can have great benefits if you are able to get the complete wiring harness and computerized controllers.
Unlike the drag racer, the factory independent rear differential and suspension in the 240sx should be sufficient for most applications. If you plan to modify the engine to produce in excess of 300-hp, then a rear-differential upgrade may be in order. This can be accomplished in one of two ways; either you can use aftermarket parts to fortify the OEM differential or you may opt for a differential and suspension setup from a more powerful car, such as an Infiniti or a 300ZX, etc. Ideally, if you plan to radically increase horsepower in your 240sx the purchase the entire driveline from the JDM vehicle (wiring harness, engine/transmission controllers, and all) is the best possible solution.
The level of suspension modification should depend upon the type of powertrain that you will employ, the size and type wheels that you prefer, and what (if any) competitive driving in which you plan to engage. As a safe bet you can’t go wrong with fully adjustable coil over struts. They allow you to adjust ride height and spring rate according to driving circumstances. Front and rear anti-sway bars, lightweight aftermarket high-performance control arms, tie rod end links, chassis stabilizers, neoprene bushings, and pan hard bars will help to increase stability in the curves. Inside the cabin and under the hood, adjustable strut tower tie bars and lateral links can tighten the body up and reduce roll during high speed maneuvering.
With the added stress of greater horsepower, there is a need for increased braking efficiency. Brembo Brakes are on the cutting edge of oversized cross-drilled and ventilated brake rotors, multi-piston brake calipers, and temperature resistant steel braided brake flex hoses. Most of these aftermarket brake upgrades are compatible with your factory brake master cylinder and booster assembly making the brakes one of the least expensive systems to upgrade.
Wheels & Tires
Your style of driving, choice of competitive activities (if any), and personal tastes will factor into your choice in aftermarket tires and wheels. Usually, wider tires are used with high-performance vehicles that will demand a higher level of track adhesion. The degree of wheel offset along with wheel composition and color are a matter of preference but speed rated tires should always be used for competitive driving purposes.
Because of the rear-wheel drive configuration of the 240sx, it is a very popular drifting car. Any of the engine choices above are viable options for drifting. Small domestic V8 and V6 engine and transmission arrangements work well, too. The basic powertrain setup will not change with the drifting car with the exception of a locking differential and possibly a lower gear ratio.
Like the road racer, the drifting car performs better with a manual transmission. An aggressive racing clutch or dual disc setup works well for the drifting car, as well.