The question of which engine to swap into Nissan S13’s is not an easy one- almost anything will work- if it has pistons and runs off pump fuel, there is a way to make it work. Consider the following list of candidates for a possible engine swaps: 2JZGTE, VQ35DE, RB20, RB25, RB26, among almost anything else (including rotary power), and the problem takes on a new dimension.
While all of the above engines have been successfully transplanted into S13’s, it must be borne in mind that some of them are not legal on the one hand, and that engines such as the 2JZGTE requires rather extensive modification to work, on the other. Engines not built for the US domestic market almost never conform to the law in terms of emissions- laws that are getting more stringent with each passing year- especially in California. However, the engines mentioned above represent only a small fraction of what is possible, which makes it impossible to provide detailed information on all possible engine swaps for all possible purposes.
Nonetheless, for a car intended to be a daily driver, the field of possible choices can be narrowed down considerably, especially given the fact that a stock S13 can be developed to deliver the same power that most transplantable engines can, which obviates the need for an engine swap in the first place- all without the penalties in terms of handling, and the costs associated with upgrading the suspensions to correct alterations in weight distribution- while remaining legal in terms of emission control. Which is where the LS- V8 engine series from General Motors comes into the picture.
The Good News.
Why good news? You may well ask. This engine series offers a bigger choice within the series than almost all other possibilities combined, but in addition, LS-series engines are the easiest to fit. With the exception of some minor modification to the transmission tunnel, the S13 chassis accepts the entire range LS, which consists of the L33, L59, L76, L92, LC9, LFA, LH6, LH8, LM4, LM7, LMG, LR4, LS1, LS2, LS3, LS6, LS7, LS9, LSA, LSX, LQ4, LQ9, LY2, LY5, LY6, and even the mighty LS7, an all-aluminum, 427 cubic inch powerhouse. However, for the purposes of simplicity, it might be more convenient to refer to the entire range as “LS”, since most of what follows applies to almost every engine in the range.
Why fit a LS-Series V8?
Although the LS1 first saw service in the 1997 Corvette, the engine soon became an available option in the 1998 models of the F-body cars, more commonly known as the Camaro and Firebird. These all-aluminum 5.7L V8 motors made 305-350 hp and 300-365 ft-lb of torque, but their biggest advantage lay in their low weight and small overall size. Nonetheless, there are many other advantages in using an LS series engine in a S13 over anything else, so we have compiled a short list that explains the issues in some detail.
It has a Favorable Power/Weight Ratio.
Official GM sources list the LS1 as weighing in at only 450 lbs- fully assembled and ready to start. By contrast, fully assembled KA24DE or RB series engines weigh in at 370 lbs, and 560 lbs respectively.
It's the Smallest V8.
Since LS engines use pushrods, they have single camshaft located in the valley between the cylinder banks. This translates into a lower height from oil pan to valve cover, and a smaller distance between the cylinder banks than would have been possible with overhead cams. Apart from compactness, this engine design also translates into a low centre of gravity, which goes a long way towards maintaining vehicle dynamics and handling.
It's Easy to Modify.
Depending on which camshaft is used with which engine, it is possible to gain as much as 60 or more horse power on the wheels simply by fitting a more aggressive camshaft. Even without resorting to forced induction, it is possible to develop in excess of 600 horsepower on the wheels with relatively minor modifications, and more than 1000 hp on the wheels by using forced induction in the form of turbo- and superchargers.
It Enjoys Established Aftermarket /OEM Support.
There is no comparison between the levels of both OEM and aftermarket support that is available for the LS series and that offered by any other manufacturer, including Nissan and Toyota. Moreover, there are hundreds, if not thousands of manufacturers and suppliers of performance parts and conversion kits for LS series engines, which makes it the easiest engine to modify and maintain out of all the possible choices for transplantation into a S13.
Is Has a Fully Reprogrammable Management System.
There is no need to mess around with aftermarket or piggy-back ECU’s for a LS1 engine. The computer is fully reprogrammable with software available to tune, adjust, or reset any aspect of the management system. In addition, there is hardly a tuning shop in the country that is not equipped to tune LS1’s, and as of late, many tuning shops have started offering email tuning solutions.
It's Available Everywhere.
The chances of not finding at least several LS series engines at your local junkyard are vanishingly small. In cases where the engine is still in a car, it is possible to run a check on the car’s Vin history, unlike JDM engines, where there are no records as to the history, or provenance of the engine. Sourcing an engine from a local yard is also the better choice since the vendor is much more likely to warrant the engine beyond the initial start-up warranty.
It's Emission Legal.
Since the LS series was developed for the US market, it means that every engine in the series is emission-legal, and they will pass all emission tests without trouble. In contrast, imported engines can seldom be made to conform to the law in this regard, and where they can be made legal, the costs involved are often more than the trouble is worth.
It's Relatively Inexpensive.
Admittedly, this is true only up to a point. Depending on the level of modification and the purpose of the engine swap, a LS1 conversion can be as expensive as you want to make it; however, by using a stock 5.7L or 6.0L the costs can be kept down to anything between six and eight thousand dollars, which is about the same as what a conversion to run a stock SR20DET costs.
Nonetheless, to this must be added the costs of developing the SR20DET to produce the same power as the LS engine (350-400hp) in stock trim. Seen from this perspective, the high price tag of a LS conversion suddenly does not seem as high anymore, especially in view of the fact that the legendary reliability of the LS engine is not compromised by extensive modifications or possible sloppy rebuilding.
Some Practical Considerations.
There is no doubt that from a practical stand point, the LS series engines makes the most sense as an engine replacement for a 240 SX. All the engines in the series are identical on the exterior, which means that just about anything is possible in terms of the ease with which ancillary equipment can be swapped out between different engines in the series.
All equipment on all engines attach in the same way- which means that anything from any engine will fit on any other engine without the need to modify anything, although some members of the LS family are better suited to fitment into a S13 than others because of clearance issues with some ancillary equipment on the truck engines.
Although the iron block truck engines can be had for well under a thousand dollars, you will face clearance issues with the intake ducting, throttle body, and other equipment. Conversion kits for these engines are available, so if you plan on using forced induction, the iron block engines are the way to go, since they are better able to withstand the forces that go with forced induction than the aluminum versions.
Most Powerful Option?
This is much like asking how long a piece of string is, since the options are almost unlimited. However, if you need lots of power from the get-go without having to modify anything, the 427 c/in LS 7 or supercharged 378 c/in LS 9 is the way to go. These engines deliver 500+, and 600 hp respectively, which should be enough for anyone.
However, even smaller, cheaper versions can dwarf these numbers with only relatively minor modifications, but on the other end of the scale are LS engines built by any of several dozen performance specialists that deliver in excess of 1000 hp. The bad news of course is that this kid of power comes at a price, so be prepared to fork out anything up to $20 000 for one of these powerhouses.
The Best Option?
The “best” option means different thing to different people, but it lays somewhere between the cheapest iron block truck engines, and the top-of-the-range pre-built engines. Nonetheless, the most popular engine and transmission set is that from the first GTO’s, as well as those from F-bodied Corvettes. Expect to pay up to $3000 for an engine set in this case, but the ease with which it fits into The engine bay of a S13, more than justifies the price.
For about $1000 more, you can get an engine set from later model GTO’s, Pontiac G8’s, diverse SUV’s, Trailblazer SS’s, SSR’s, and CTS-V’s. These variations deliver anything between 350bhp and 400 ft/lb, depending on the engine variant and the vehicle it is pulled from.
Although accessories from LS series engines are interchangeable, some parts like the intake and throttle body from truck engines do not fit into a S13, because they sit too high, thus preventing the hood from closing. However, these parts from Corvette and GTO engines fit without trouble. Other fitment issues are listed below.
All oil pans except that from a GTO will interfere with the cross member on a S13. However, even when using this oil pan, a small notch must be cut from the cross member to provide sufficient clearance. On the other hand, some, if not most conversion kits include oil pans that obviates the need to modify the S13 cross member.
C6 Corvette manifolds fit without trouble; however, C5 manifolds need a special flange to adapt from the non-standard oval tubing to standard round tubes, but again, several conversion kits include bolt-on manifolds that fit without trouble.
The only modification required is the hammering out of the radius that marks the entrance to the transmission tunnel. Hammering this radius back by as little as 1.5 inches provides sufficient clearance for a T56 transmission.
The sway bar interferes with most oil pans, so either fit spacer kits, get a sway bar with enough clearance, or buy a kit that includes both a sway bar and an oil pan to suit.
The best transmission to use in this conversion is a T56 from an F-body Corvette, or a late model (2004 onwards) GTO. Other T56’s require some modification to linkages, but the exact amount of modification depends on the origin of the transmission. Nonetheless, transmissions from GTO’s are good choices because of their better gearing as compared to those from Corvettes. Prices vary from about $2000 new, and anything between $850 - $1600 used.
The 6-speed Tremek T-6060 manual transmission is reputed to have been mated to LS engines, but the issues revolving fitment to a S13 is not clear. Because of the rarity of these transmissions in the used market, it is recommended that you do extensive research on the issues, especially in view of the $4000+ price tag of a new unit.
Other manual transmissions.
No manual transmission other than a T56 will mate to LS engine without modification, which could be more expensive that a T56 from a Corvette that will bolt straight on.
GM 4L60-E (4-Speed automatic transmission)
Automatic transmissions such as the GM 4L60-E can be fitted; however, doing so requires a lot more modification to the S13 transmission tunnel, apart from the fact that some types of exhaust system have clearance troubles with this transmission’s oil pan.
Rear axle and final drive.
Although the stock rear axle of a S13 is robust enough to withstand anything a LS engine can throw at it, it must be borne in mind that the 4.083 : 1 ratio of a stock 240 SX might not give the best results. Some Infinity models from the early 1990’s have final drive ratios of 3.54 : 1, which is as close to the 3.46 : 1 ratio of a GTO as to make almost no difference. By contrast, an F-body Corvette has a final drive ratio of 3.27 : 1 which might be acceptable, but since you are going the whole hog, it might be worth the extra cost and trouble to get the final drive ratios as close to what your Ls series engine is used to.
In addition to gear ratios, it might be worth getting a limited slip differential from a S15 Silva as new LS engine is used to as possible. well, since you are going to need a means of controlling the torque from a LS engine. If a S15 diff is unavailable, you can use bolt-on units from Nismo and KAAZ instead.
Manual to automatic to manual conversion.
All that is required here is the replacement of the flex plate with a flywheel or vice versa. Wiring changes involves the mere replacement of on type of connector with another, and the simple reprogramming of the engine management system to accommodate the automatic transmission, or vice versa.
The list of required parts will be different from one level of conversion and modification to another, but the golden rule here is to purchase an engine set that does not need anything to start. There should be no missing wiring, sensors, accessories, brackets, or any other item(s) that will prevent the engine from starting or running smoothly.
It is impossible to provide guidance here on fuel pump capacity, injector delivery rates, or ECU programming since these issues are engine dependent. The best thing to do is to get a complete engine, install it, get it running satisfactorily, and only then take tuning tweaks and adjustments from there.
Some More Points To Ponder.
There seems little point in swapping a perfectly good engine with something from a junk yard, and that goes for any conversion. If you are going to replace the engine in your S13, use a new, or at least a rebuilt engine, so be prepared to spend anything up to several thousand dollars on an engine alone, but also;
Consider the Whole Process.
Don’t get hung up on the cost of only the engine and transmission. Consider all the bits and pieces that go into a successful conversion- fuel pumps, custom radiators, custom exhaust systems, engine management systems and wiring harnesses, suspension and brake modifications, chassis strengthening, and a host of other issues that could make the conversion several times more expensive than what the car is worth in stock form.
Decide What You Want.
If money is no object, you can build anything you want; however, for those on limited budgets it is crucially important to decide what the car is going to be used for. For street racers and daily drivers, driveability and safety is as important as performance, so choose an engine that will not upset dynamics and handling, which in the case of the LS series, does not upset anything. In fact, fitting a LS series engine will actually IMPROVE the weight distribution of a S13!