The Nissan 240SX is a Japanese-import sports car sold in the US. The 240SX coupe is also known as the Nissan Silvia and the fastback as the Nissan 180SX in Japan (and parts of Europe), as well as both models being known as the Nissan 200SX in Australia (and most of the rest of the world.) The 240SX is a mid-size sports car with a fairly low weight, good gas mileage, and excellent handling, while still remaining useful for knocking around town, commuting, or taking a trip, though I wouldn't exactly recommend traveling cross-country. As a sort of spiritual supercessor of the Datsun 240Z, especially in the form of the S13 fastback, it features a strong engine, great handling, and modern styling.

Overview

The 240SX is a front-engine, rear wheel drive car. It is a 2+2 seater, and comes in both coupe and fastback forms. The back seat is vestigal at best. It can be considered the descendant of both the (USDM) 200SX and the 240Z. While technically the design is an evolution of the 200SX, the design goals most closely matched those of the 240Z.

The fastback and coupe are basically identical except for weight and shape. The fastback weighs slightly more than the coupe, but the weight is in the back, so the weight distribution is better. In addition, there are two models of 240SX; The S13, and S14. Every fastback, and coupes made between 1989 and 1994, are S13s. All coupes made between 1995 and 1998, the last year of the 240SX in the US, are S14s. The S14 coupe has a significantly slicker body design than the S13 model, doing away with the pop-up headlights in favor of sleek, eye-shaped lenses. The big change in 1991, however, was the replacement of the KA24E 12-valve SOHC motor with the KA24DE 16-valve DOHC motor. There was a later model coupe called the S15 which was sold in Japan and Europe from 1999 to 2002, which is basically identical to the S14 except for some slightly revised styling and a more powerful version of the S14's engine with variable valve timing.

A convertible S13 240SX Coupe was available from 1992 to 1994 -- all 1994 240SXs were convertible. This car consisted of a standard S13 coupe which was then converted into a convertible by a third party, then sold through Nissan dealers as normal. A relatively small number of these cars were made. All of them came with an automatic transmission. They have non-power seatbelts, and a driver's side airbag. All non-convertible USDM 240SXs have power seatbelts. Canadian (and other) models were available with ordinary manual three-point belts.

Around the world

Confused yet? Here's the around-the-world summary: S13 From 1989 to 1994 Nissan produced the S13. In Japan the coupe ("Silvia") has first composite (1989,1990) and then composite projector (1991-1993) headlights and a 2 liter engine, while the fastback ("180SX", 1989-1993) has the 1.8 liter and pop-up lights. Europe (which for the purposes of discussing this car includes Australia) got much the same configuration as Japan, while the USA got a slightly different arrangement; all S13s are sold with a 2.4 liter engine and pop-up headlights. As above, all 1994s are convertible coupes, unique to the USA. S14 Everyone but the USA gets the S14 in 1993, while the US gets the convertible to keep us happy until 1994, probably to wait for the new 2.4 liter DOHC motor to be worked into the new car. The fastback is eliminated entirely. In 1996 the Japanese Silvia and European/Australian 200SX receive a styling bump and a new turbocharger, slightly increasing performance and making the car slightly more attractive. The styling cues don't come to the US until 1997; production of the S14 ends in 1998. No USDM S13 or S14 is offered with a turbocharger. All S13s, S14s, and indeed S15s are 2+2 seat models. S15 Only sold as a Silvia, never sold in the USA.

Engine

There are two engines used in the 240SX. The first is the KA24E, a 12 valve (3 per cylinder), Single OverHead Cam engine. This engine develops approximately 145bhp, except for some very early engines which had a 9.0:1 compression ratio, rather than later models, which ran 8.6:1. Those cars, made before February of 1989, are reputed to run 150-155bhp. This is an excellent, simple, sturdy motor, which features direct-fire fuel injection, pent-roof design, and electronic ignition, as well as having a host of aftermarket parts available, both from Nissan Motorsport and others. It is a strong performer, and very reliable.

The newer engine is the KA24DE, which is more or less the same design. Both engines have aluminum heads and iron blocks. The KA24DE, however, also has four valves per cylinder, and is a Dual OverHead Cam design. It runs about 155bhp, and features a knock sensor, top-firing spark plugs (like a hemi engine), and oil injection at the base of the pistons. This made for an even more robust and slightly more powerful engine. The KA24DE runs at 9.0:1 compression until 1994, where it becomes 9.6:1, but is detuned otherwise so that it develops similar peak horsepower, with a slightly broader power band.

The fuel economy of the American 240SX is also extremely significant. With the windows up, and the (optional) sunroof closed, all manual-transmission models of the car can easily get 30 miles per gallon of while running on the freeway at or near the top end of freeway speed, about 75 to 80 miles per hour. Even around town, the mileage is favorable. In the American form, it does not have a turbo, and the earlier (KA24E-based) cars can be run safely on 87 octane gas. The later models require mid-grade (89 octane) fuel. In fact, as other cars, using fuel with a higher octane level can actually result in decreased performance and engine life.

A word on other engines found in the S13 and S14 throughout the world: Early 180SXs (The S13 fastback in Japan) have a CA18DET 1.8 liter DOHC engine with a timing belt, coil on plug ignition (COP), direct-actuated valve, an iron block, and an aluminum head. Featuring a 8,000 RPM redline this motor develops 180hp in stock (turbo) form. It was also offered without a turbo (As the CA18DE.) Silvias (the coupe) were offered with the SR20DET 2.0 liter DOHC motor, which uses a timing chain, has rocker-actuated lifters, and produces 205 hp in stock form. It, too, was available without a turbo. The CA18DET was only used for a few years before the SR became the only engine found in non-US S13s and S14s. S14s have approximately 225hp (from an updated SR20DET) and S15s have the SR20VET engine with variable valve timing which develops 257hp (or 205hp with no turbo, SR20VE.) S15s were offered with a six-speed manual transmission coupled with a higher-geared rear differential (In the neighborhood of 3.73:1.) The final (road) gear ratio of the six speed silvia is identical to every other manual S13/S14/S15, however.

Suspension

The 240SX carries a McPherson Strut suspension in front, and a 5-link multilink independent suspension in the rear, where the power is. The car has a fairly high stance, probably to compensate for its long nose, which is easy to scrape on the ground. As a result, in stock form it lurches around a fair amount during aggressive cornering and braking. Steering is very neutral, with a touch of understeer when pushed. The turning radius is excellent. When coupled with the excellent suspension, the near-perfect weight distribution (Approximately 55% front) of the 240SX allows it to handle better than a Porsche 944 from the same year. The car is very "tossable", which translates into being able to lead it easily from corner to corner as long as you stay on it - the gas, that is. Other factors which make it a good handler include rack and pinion steering, and a low center of gravity (CG).

Four Wheel Steering

All models of 240SX were available with four wheel steering system. The rear wheels steer the same direction as the front at high speeds to improve lane changing, and the opposite direction at low speeds, to reduce turning radius. All models are equipped with the second-generation system HiCAS II, renamed Super HiCAS after minor revisions in 1990. Some USDM S13s were rumored to come with the original HiCAS. It is common in racing to disable this feature, with lockout kits available from numerous vendors.

Drivetrain

Nissan offered the 240SX both with both automatic and manual transmissions. The manual is a five speed with reverse, and with synchros on all gears except first and reverse. The automatic is a three speed with overdrive and uses the DUET-EA system to synchronize engine and transmission, for example to perform automatic rev matching on downshifts or to reduce engine output while the clutches are slipping. A similar and probably related system is featured on Subaru vehicles of the era.

Gear Ratios

    Manual

  • First: 3.321
  • Second: 1.902
  • Third: 1.308
  • Fourth: 1.000
  • Fifth/Overdrive; 0.759
  • Reverse: 3.382

    Automatic

  • First: 2.785
  • Second: 1.545
  • Top/"Drive": 1.000
  • Overdrive: 0.694
  • Reverse: 2.272

The driveshaft is a two-piece design, consisting of a front "propeller shaft" and a rear "drive shaft". It can be replaced with a single-piece driveshaft; Various companies will make them out of steel, aluminum, or carbon fiber for US$250-750.

The far end of the drivetrain is terminated by a differential with a 200mm ring gear. This is offered as a standard open differential, or a viscous limited slip differential, or VLSD. This viscous limited slip differential works on the same principle as the fluidic clutch in an automatic transmission, which is that as the fluid shears, it gets hot, and becomes less viscous. As the load on the output shaft decreases, the fluid in the differential cools, the fluid becomes less viscous, and the power to the slipping wheel is reduced, and given to the other wheel.

This accomplishes two things; One, it transfers power to the wheel which can use it, and two, as a result, going around corners is much smoother - The wheels are required to move at different speeds. While standard open differentials do allow for this, they are known to bind somewhat when making rapid sharp turns, something which is a lot of fun in a 240SX. This results in more even power while cornering, making the 240SX even more nimble.

Gear Ratios

  • Final: 4.083

Functionality

The 240SX is considered to be an excellent drift racing car, a sport popular on tracks and roads in Japan, and gaining popularity in the US, especially with the LSD. It has also seen some success in SCCA autocrossing. Versions of it have also been successful in GT Touring Car racing.

The 240SX has led a double life ever since its introduction. On the one hand, it is a fairly spry sports car, which while somewhat underpowered, is still extremely fun to drive even in purely stock form. This makes it attractive to underfunded street and track racers who have found it an inexpensive alternative to higher-priced sports cars such as Porsches. It is also a lightweight car with good fuel economy and a small turning radius, and as such it is enjoyed in the USA by many girls whose parents have purchased them for them so that they can get to and from school, as well as a large number of middle-aged women. It is relatively light in weight and has a fairly large four-cylinder engine, and as such is more difficult to stall with cars with less power (The powertrain has more rotational inertia and low-RPM torque.)

The aftermarket scene for the 240SX in the US is growing, as the cars become more inexpensive. The Japanese body kit manufacturer Veilside has opened an office in the USA and is selling body kits for the 240SX, including the kits which were previously not exported from Japan. Greddy, Whiteline, Suspension Techniques, Eibach Springs, Borla, and Brembo are among the companies who make products specifically for the 240SX.

Popular Modifications

Approximately since the release of The Fast and the Furious there has been a waxing of popular interest in the US over the 240SX. Many people have been getting into the import customization scene, and the 240SX has several compelling advantages; They are readily available for little money, they have rear wheel drive, and there is a large body of knowledge regarding improving their performance, as well as a large body of companies who can help you improve its appearance.

Performance Enhancements

There are four main methods used to improve the power of the 240SX. The first, and most common, is to swap an engine from a Japanese car. The S13 SR20DET is the most commonly swapped engine. It provides 205bhp stock, will output around 400rwhp on stock internals, and is the most readily available from a number of importers, usually for US$2500 in complete form. It is a direct drop-in provided you have the uncut engine wiring harness, and bolts up to the existing exhaust as well.

Less popular is the CA18DET, providing 180bhp stock and good to about 350rwhp on stock internals. It weighs the same amount as the SR, but is mounted further back, reducing the polar moment of inertia. Further, the CA has coil-on-plug ignition and direct-actuated rocker arms. The SR's rockers must be replaced for high-RPM use as they are known to break. It is less expensive, however, running about US$1800 complete.

There is also the extremely rare swap of the RB25DET or RB26DETT motor from the R34 and R35 skylines into the car. These are inline six cylinder motors which produce in the neighborhood of 300 horsepower stock and are known to commonly be upgraded to around 500. They require somewhat extensive modification to the car to fit into a 240SX, however, because of their additional length. They are also significantly more expensive; Around US$6000 for a RB26DETT.

It is not strictly necessary to swap engines to add more power to a 240SX, however. There are a couple of turbo kits available which will increase power to about 300rwhp on the original KA motor, mostly the KA24DE. They cost about the same as an SR, in the neighborhood of US$2500.

It is also possible to build an all-motor KA, meaning that you do not use forced induction but instead improve various engine internals to increase performance. This usually consists of balancing the rotating assembly -- The crankshaft, connecting rods and the pistons -- As well as increasing compression, going to larger fuel injectors, reprogramming the ECU, replacing the camshafts, and so on. Most of these steps are also performed when installing a turbo kit. Through this method it is possible to get about 200rwhp from either KA motor.

Finally, there are some bolt-on parts which can be used to modestly improve the KA's response. An aftermarket air intake can be purchased for $10 to $500 depending on type, brand, and features, which will add somewhere in the neighborhood of 1 to 5 horsepower depending on the type. An aftermarket "cat-back" (from the catalytic converter back) exhaust system (which runs US$400-750 or so) will add perhaps 7-10 hp, and a header (a high-flow welded exhaust manifold) will also produce similar gains. It is possible to reach 180rwhp from a KA24DE by using a header and exhaust (With no catalytic converter), a timing advance, reprogramming/chipping the ECU, and modifying the stock airbox by the simple expedient of adding holes.

There are two free things which can be done to the 240SX to slightly improve performance. One of them is to remove the intake resonator box which sits in the driver's side fender well. This box restricts airflow and reduces the sound of the intake. Removing it will add 1-2 horsepower due to colder and more free-flowing intake air; from the fender well instead of from behind the driver's side headlight. You can also install a K&N air filter which flows more freely, which should also give you 1-2 hp. Finally, on DOHC engines (KA24DE) you can remove a butterfly valve (which does require removing the intake manifold] which is supposed to net 2-3hp but which probably increases undesirable emissions.

Appearance/Aerodynamics

A number of companies, many of them based in Japan, make body kits which fit the 240SX. Perhaps the best known is Veilside, which company makes some of the most vivacious designs. Perhaps the next most common kits, at least in the US, are from Blitz, Bomex, and Erebuni. Erebuni is the lowest-quality of the above, and they essentially are known for making cheap knock-offs of kits by Veilside and Bomex. A french company Jacquemonde makes a widebody kit for the 240SX which features styling similar to the most recent models of Ferrari.

Also quite popular is the practice of buying JDM (Japanese Domestic Market) S13 and S14 parts (And sometimes S15 parts) and grafting them onto the USDM (US Domestic Market) 240SXs. Putting the fenders, bumper cover, and lights from the Silvia on the S13s (both coupe and fastback) are extremely popular. Putting it on the fastback is extremely popular as this produces the US equivalent of the Sileighty, a modification which became popular in Japan due to drift racers running their 180SXs into hills and replacing the front end with the cheaper equipment from the Silvia, or coupe. This became so popular for purely cosmetic reasons that Nissan actually sold an official Sileighty. The reverse, the 180SX front end on the Silvia, is known as the One-Via. This is the default appearance of the USDM 240SX S13 Coupe. A very small production run of such cars is rumored to have been produced in Japan.

Various other parts from JDM 180SXs and Silvias come here and get put on cars as well. The S15 Silvia (the last model made even in Japan, discontinued in 2002) has a very distinctive front end which can be swapped onto USDM S13s and S14s with varying degrees of difficulty. There was a 180SX Type X which has slick-looking taillights, which can be simply bolted onto the 240SX Fastback.

Like other imports, another common modification is to make or purchase clear turn signals, tailights, and so on. These lights are generally equipped with a colored bulb to make them light up in the proper color. Another popular modification is to make your headlights open only half-way, for the "sleepy" look. Finally, one Japanese tuner company, East Bear, makes non-popup headlight replacements for the 240SX which supposedly have poor light output and cost US$1200!

Handling/Suspension

Power without handling is useless for anything other than drag racing. While the stock 240SX is still one of the best-handling cars ever sold in the US (.98 lateral Gs stock) due to the suspension setup and weight distribution, as well as fairly beefy stock sway bars front and rear on all models of S13 and on S14 SEs (Non-SE S14s lack the rear sway bar), anything can be made better. A number of companies including KYB make replacement adjustable shock absorbers for the 240SX, and a number of companies including Tokico and Stillen make sets of springs. Finally, you can install adjustable-height coil-over setups from Ground Control, OBX or others in order to increase suspension customizability. The most common setup for the 240SX is the use of the KYB AGX adjustable gas shocks with Eibach Pro-Set or Sportline springs.

Also very common is the use of a strut tower brace which makes the chassis more rigid. You can also get a rear ladder brace which stiffens the chassis by running a member across the floor in the passenger footwell area. There is also a bar called a triangle bar or brace which is like a rear strut tower brace which is triangulated to the floor of the car, significantly enhancing rear rigidity.

Finally, the common practice of replacing bushings with polyethylene or polypropylene rather than the gel-filled rubber which is typically found stock is in full swing on the 240SX. Some people actually run soft metal bushings in the rear frame of the vehicle. Bearings with an offset hole in them can be used to correct changes in camber incurred when lowering the car.

A limited slip differential is an absolute must for a rear wheel drive sports car, and some 240SXs did come with them. The 240SX uses a 200mm ring gear, and the stock open differential is referred to as the "R200". There is also an "R200V" which is a viscous limited slip. Viscous LSDs use the same principle as automatic transmissions, which is to say that when the fluid in them shears, it heats up, and when it heats up, it becomes more stiff. Thus, when one side is turning faster than the other, the other side shears and locks up and both wheels turn together. This is a good general-purpose limited slip which while very slightly sluggish, will distribute force during both braking and acceleration. There are also gear-type and clutch-type limited slip differentials, which I will not go into here, except to say that there is no better limited slip than a well-adjusted clutch-type, and that their only down side is that they must occasionally be rebuilt. The R200V differential is generally available for about $500 and it's a simple bolt-on swap. You can sometimes identify the R200V in a junkyard by an orange sticker somewhere on the differential, but on many cars that sticker is long gone. A finned rear case is sometimes said to also be a sign, but that is not reliable. Differentials can be swapped between S13 and S14 but the rear case must be changed when this is done. All Super-HiCAS equipped 240SXs have a limited slip, and it is believed that all ABS-equipped vehicles do also.

You can also get a VLSD200 from a non-turbo Z32 (90-96) 300ZX, but it has different output yokes and you will need axles from a 1991-1994 Infiniti J30 to match it. Those axles bolt-on to the 240SX with the non-turbo Z32 diff. Turbo Z32s have a 220mm ring gear and the differential will not fit.

Brakes

Many companies make upgraded brake calipers (usually with correspondingly larger brake rotors) to improve stopping power. However, by far the easiest, cheapest, and probably best method is to use 300ZX brakes on the 240SX. For five-lug vehicles this is a simple bolt-on, with the exception that the brake fittings on the 240SX are banjo types that will not work with the 300ZX calipers. Four-lug vehicles need conversion hubs (and then, of course, new wheels et cetera) or for the rotors to be drilled out to a four lug pattern. As the four and five lug wheels have the same bolt circle this is a relatively trivial process and some internet retailers sell pre-drilled rotors.

The calipers come in two sizes, to accomodate 26mm and 30mm thick rotors. The 26mm types will fit inside of stock S14 SE wheels (the spoked kind) but will not fit with the "teardrop" pattern alloy wheels. They will not fit with the steel wheels, either. 30mm calipers are very difficult to fit, and will likely require a 17" wheel with plenty of offset to clear them. The swap can be made with or without the 300ZX brake master cylinder, which is little larger than the one on the 240SX.

If you plan to make significant engine upgrades, changing to 300ZX brakes is a must.

Maintenance

As with any car, the 240SX will eventually need certain maintenance items. Some of them are definitely more common than others, and should be well-considered. Aside from regular scheduled routine maintenance there are several items which are known to go out after a decade or so, and some sooner.

Timing Chain Guides

Probably the most serious failure in the 240SX's design is in the engine, and thus shared with a number of other USDM Nissans - the timing chain guides. Both single and dual cam engines have timing chain guide issues of some description, but the SOHC engine by far has the more serious problem. These guides are made of plastic and must occasionally be replaced, but this is a symptom of the chain tensioner wearing out or freezing in place. Amusingly, the timing chain itself is not considered a service item, and should last the lifetime of the engine. The timing chain guides will eventually be destroyed by the chain, ending up as many small bits of plastic in your oil pan. Once they are gone, the chain will eventually saw through the timing chain cover and you'll need another one. Get them replaced before this happens. The KA24DE DOHC engine also has a timing chain guide issue, and it has both metal and plastic guides. The metal guides stay (they'll be fine) and the plastic guide can be removed without ill effect.

Suspension

An extremely common part of the 240SX to fail is the tension control (or T/C) rod bushings. The T/C rods tie the lower control arms of the front MacPherson strut suspension to the front of the car such that they maintain a fixed arc pivoting around a point far to the fore. This system is the same on both S13 and S14 240SX. The stock bushing is rubber and filled with silicone gel. When the bushing fails it will squirt out this gel (which is harmful to automotive paint) and then become sloppy, and the car will make a "clunk" noise when going between forward and reverse, especially while turning, and your car will likely pick up a "shimmy" in the steering wheel which cannot be aligned away and is not caused by warped brake rotors.

Digital HUD Gauge Cluster

Another frequently-failing part is the dash cluster. In cars equipped with a digital dash, the HUD may go bad. This is usually a result of solder connections on the HUD unit PC (printed circuit) board failing over time. Some of them are surface mount connections and unless you are fairly skilled with a soldering iron (and have a decent iron!) you will want to simply replace the unit.

Fuel Injectors

After several years, many 240SXs will experience a loss of power due to damaged fuel injectors. Frequent replacement of your fuel filter and occasionally running fuel injector cleaner through your engine may help prolong their life. This is a pretty straightforward job which involves depressurizing the fuel system, unbolting the fuel rail, and replacing injectors one at a time. There will be fuel in the rail, and removing two injectors at once results in a fair amount of fuel pouring onto the top of your motor. (This is not typically serious if it's not hot at the time, however.) In order to do this, remove both the fuel filler cap and then the fuel pump relay which should be in a box on the passenger side of the car under the hood, and turn the car over until it runs and then dies, plus a few seconds. Now you can replace your injectors with impunity. Just remember that there's gasoline in that fuel rail, and that the stuff is dangerous in a broad variety of ways.

You can test injectors by somehow tying them firmly to the fuel rail (with zip ties or baling wire, most likely) and then having someone hold them up and point them at a piece of cardboard at just a few inches distance and examining the resulting pattern. It should be a perfect circle (assuming they are held perpendicular to the cardboard) with no large spots or runs. It is mandatory that you tie the injectors into the rail when doing this, because the fuel system is under considerable pressure. (Note that you can't do this with the fuel pump relay removed.) It would be very bad to do this carelessly, especially if you have electrical "leaks" in your spark plug wires. For safety, please do not do this with the injectors pointed toward the engine.

1989 240SXs use a slightly different connector on their fuel injectors than other models. The connector has an offset key on the 1989 model, while on later vehicles the key on the connector is centered. Finding the injectors won't be difficult, though replacing the connectors can be a pain. If your connectors are corroded, you might think about going to the 1990 injectors, for which connectors are readily available. Installing them is a simple matter of soldering them into the harness and sealing them down with heat shrink tubing, then taping the harness sealed again. The wiring is only about 16 gauge and so you could do this job with a $5 soldering iron from radio shack. My fuel injector connectors were corroded, and I had a bear of a time finding replacements, but I did so and the engine behaves much better now.

Note that 1989 240SXs had a safety recall against the injectors for seal failure that resulted in fuel leakage on top of the engine.

I would like to amend drinkypoo's excellent write up with one correction and a couple other facts.

The KA24E had 12 valves total, or 3 per cylinder, not 12 valves per cylinder.

The 1989-1993 240sx fastback as it is found in the US is identical superficially to the Japanese 180sx that was produced with the CA18DET engine for 89-90 and the SR20DET engine for 91+ (I believe production stopped in 98).

The 1989-1993 240sx coupe is unique to the US (and other countries that receive the same USDM model). As it has the 180sx front end but a s13 Silvia tail. So in effect it is already a one-via.

The convertible model, which I believe was only--and the only model--offered for 1994, is also unique for the same reason as above.

In 95-98 the 240sx switched from half-unique/half-borrowed styling and adopted completely the styling of the S14 Silvia, although in 98 the front changed a bit more to S15 styling.

As for modifications, a popular thing to do is swap the KA24 for a CA18DET, SR20DET, or rarely an RB series engine from the Nissan Skyline.

Amendment:

The KA24DE has an iron block instead of aluminum. The DOHC cylinder heads are however, aluminum. The engine was also producted in Aguascalientes, Mexico.

Automatic models also feature Nissan's "DUET-EA" system. A electronic link between the engine control module (ECM) and the transmission to facilitate smoother, more controlled shifts.

Additional Information: - http://www.nissannews.com/site_library/nissan/1998vehicles/240sx/index.shtml

Detailed Specfications (1997 and 1998 models): - http://www.nissannews.com/site_library/nissan/1998vehicles/240sx/specs.shtml

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