Nissan 240sx Offers Unlimited Potential – Part 1

Posted by

240 tire smokeRegardless of whether you are into getting the hole-shot on your opponent and blazing through the quarter mile, cutting through the curves in your local canyon, or gliding on the edge of chaos in a drift car, the rear-wheel configuration of the Nissan 240sx offers plenty of potential. Even if you want to restore an older car to factory specs, you can’t go wrong with a 240. Why? Because of its unique body design and drivetrain configuration. During an era when Japanese import cars were virtually all front-wheel driven, the 240 brought the benefits of lightweight import construction and rear-wheel drive to bear.

500hp LS6 240sx
500hp LS6 240sx

The 240sx was manufactured from 1989 until 1998. It offered the handling advantages of rear-wheel drive with a lighter gross-vehicle weight than most domestic rear-wheel drive cars. The sporty looking coupe went unnoticed by driving enthusiasts of that generation, primarily because it was grossly underpowered from the factory, leaving a whole new generation of today’s modified car enthusiasts poised to reap the benefits.

240 drag racer 2

In this segment on the 240sx, we will discuss how to build a car that is best suited for Drag Racing. Be on the lookout for Part 2, where we will examine what it takes to build a road racer using a potent Japanese Domestic Market SR20DET engine with an upgraded turbocharger/s, a bigger intercooler, and possibly even some skillfully placed nitrous or methanol injections and later, Part 3 will likely deal with a 240 that is modified with competitive drifting as its primary purpose.

240 drag racer 3As a lover of drag racing and street racing, one of my guiding fundamentals has been that there is no replacement for displacement. The Nissan 240 is designed with an abnormally large (by today’s standards) engine compartment. Why would I want to waste space by putting a dinky little import mill underneath there, when I can load it out with a giant V8? The 240’s OEM rear-wheel drivetrain configuration makes it the perfect candidate for a domestic powertrain upgrade.

240 engineI know all about your four-banger with your little turbo and how many ponies you can make with a big intercooler, and blah, blah, blah. Wrap your head around this; I can lay a big hog of a naturally aspirated V8 in there that will produce horsepower at a level comparable to the baddest turbocharged import on the street. Are you following, so far? Then I can outfit the big V8 with a turbocharger, supercharger, or both. If that is not enough I can throw in a splash of nitrous oxide. There truly is no replacement for displacement.

Another alternative to the carbureted strategy is electronic fuel injection. A V8 from a Corvette or Camaro, even a pickup or SUV, complete with the wiring harness and computer can provide an economical solution to radically increased horsepower.

1991 Nissan 240sx w/ GM LS1 EFI 5.7-liter
1991 Nissan 240sx w/ GM LS1 EFI 5.7-liter

The big V8 will demand more fuel than the standard 240 electric pump can supply. While you could opt for a mechanical pump on a carbureted engine, for the sake of horsepower conservation, a high-quality inline electric fuel pump could be just the ticket. For fuel injected engines, a high-pressure/high volume electric fuel pump will be required. Also take into account any forced air induction with which you plan to equip the engine. Added forced air and/or nitrous will demand increased amounts of fuel. Frame rail mounted, inline electric fuel pumps are easily installed with a flaring tool, some fuel hose, hose clamps, and a little common sense. You can re-use the fuel tank. Just remove the factory fuel pump housing from the fuel tank and discard the pump. Place a section of fuel line that is the approximate length of the pump on the housing in place of the pump and put a new “sock” on the end of the hose to trap debris. Make sure that the fuel sending unit float arm is unencumbered by the new apparatus. Now place the fuel sending unit housing back in the tank being careful to make sure that it forms a tight seal. Don’t forget an additional in-line fuel filter between the pump and the engine, along with an adjustable fuel pressure regulator.

240 radiatorThe engine cooling system will also need attention. An all aluminum radiator with multiple rows is just the ticket. The bad news is that you are looking at a custom-made radiator; the good news is that a lot of hot-rodders have travelled this way before you. Aftermarket companies like Griffin Performance Radiator can build you a radiator that will last forever and really keep your engine cool. Never, ever think about using the radiator from the four-cylinder. It will definitely not work; been there — done that — long ago.

240 transYou will need the right transmission. Some guys choose manual and that is alright but I can beat them with an electronically controlled automatic. You will need heavy-duty clutch packs and some hydraulic modification, as well as a stall converter depending upon how radical of a camshaft that you choose, but a good transmission shop can help you with that. With the 5.7 Bowtie motor, I would use a 4L60E or 4L80E transmission, depending upon the horsepower rating. I also like steering wheel mounted paddle shifters in conjunction with a programmable controller of some sort. In lieu of that a heavy-duty hydraulic unit with a reliable ratchet shifter will work; think Turbo-Hydramatic 400 or better. A heavy-duty auxiliary cooler is also a grand idea.

The Nissan rear differential is not going to work anymore. We will need to have a driveshaft and differential fabricated. I know that sounds horrifying but it is really not terribly complicated. A perfect case scenario would entail a narrowed Ford nine-inch differential with a set of 4.10:1 or possibly 4:56:1 gears along with some massive tubs in the trunk to accommodate a large set of racing slicks. In this scenario you would never require a differential upgrade.

240 diff 2There are those who will tell you that a rear differential from an Infiniti or a Z-Car is the solution. Don’t you believe it; for this kind of muscle you want a domestic rear differential. At a minimum you will need a solid differential from a rear-wheel drive, V8 powered auto or truck. Something with a ring gear that exceeds 8.5-inches, preferably positive traction, but you can always upgrade to a locking carrier later without removing the differential.

rear diffA trailing arm style differential, with coil springs, will work well with the multi-link setup of the 240sx. The differential will need to be customized to fit under the car using aftermarket suspension components. That means that it must be shortened and, in most cases, have the original brackets removed and the 240 brackets installed. Once you have removed the factory diff. from the car, roll the adjustable trailing armsnew one under it and mark the tubes at the length you desire. Take into account the size and the degree of offset of the tires and wheels you will use. Temporarily secure the differential to a point near where it needs to be mounted and mark the new aftermarket rear lower control armslocation of the  brackets. Depending upon the amount of horsepower that the engine will produce, you may want to consider additional traction control solutions, such as ladder bars and/or pan-hard bars. Now, either cut the brackets loose and re-weld them onto the domestic housing or have a qualified welding shop do so. I like to remove all of the factory brackets from the domestic differential, unless I can utilize them to gain added stability from an additional link to the body or chassis. Don’t take chances with these welds. They need to be very secure.

240 DIFFThere are also a number of aftermarket firms (DIY Auto Tune .com, for one) that can hook you up with a differential to meet your specific requirements if you have the loot.

axlesYou will need new axles and a custom fabricated driveshaft, as well. Any driveshaft or driveline specialty shop should be able to accomplish this for you. If their sign says “Spicer” or “Dana” then it will be a fine place to start. Obviously, the differential will need to be firmly mounted in place before measurements for the driveshaft can be taken. Don’t forget to account for the slip yoke, making sure that it is adequately inserted into the transmission.

Check the Blue Collar Blog regularly for Nissan 240 SX Offers Unlimited Potential – Part 2 and Part 3 as we look at the possibilities of a JDM upgraded road racer with a completely different transmission and suspension setup and a competitive drifting car.

S.M. Darby

S.M. Darby

I am a freelance author with over 25 years of experience as a professional, ASE certified automotive technician and shop owner, muscle car enthusiast, avid street racer, and classic car restoration specialist.