S-Chassis Engine Swap Options

The S-Chassis is a fantastic sports car platform. It is light, agile, and has huge aftermarket support. In many regions, the S-Chassis cars got delivered with 4 inline turbocharged engines, usually an SR20DET or in earlier models a CA18DET. Some regions were however less lucky (looking at you America). The American market received their S-chassis with a lackluster KA24, and even if you don’t have a USDM S-chassis, there is still the possibility that you got a naturally aspirated version of the car. No matter what your reason is, there is a good chance that you are reading this because you are ready for more power, a more potent engine with more potential. In this blog, we will take a look at some of the common engine swap options that we have for the S-chassis platform.

Nissan SR20DET: The OEM engine swap option for S-chassis cars

If you want the absolute easiest engine swap, or maybe you just like the OEM look and feel. The SR20DET is the way to go. The SR20DET was OEM for JDM S13s, EU & JDM S14s, and EU & JDM S15s. 

The SR20DET is by far the easiest engine swap. Because S-chassis cars came from the factory with an SR20 practically everything is a direct bolt-on. Everything will fit, you will have no clearance issues, and any aftermarket S-chassis aftermarket part you buy will most likely support the SR20 (especially if you buy JDM parts).

The SR20 is the more modern engine compared to other OEM Engines. It has an aluminum block and head. Despite it being fully aluminum it’s only about ~50lbs (~22kg) lighter than a KA24 and ~70lbs (~31kg) heavier than the CA18DET. 

One advantage of aluminum blocks is that they can be resleeved should the piston sleeves get damaged. On a cast iron block, the usual option is to bore the cylinder walls out to a larger diameter but this reduces wall thickness.

The SR20 has a strong following and tons of aftermarket support. They have good potential for power and are not too hard to get your hands on. The prices for SR20’s have been rising however and they are not that easy to find anymore.

Nissan RB20/25/26: 6 inline screamers

The turbocharged versions of the RB engine family are amazing engine swap options for an S-chassis. With this engine swap, you keep it in the Nissan family and gain some extra cylinders.

Everyone knows that the RB engines are the best-sounding inline 6 engines produced. They originally came in the Nissan Skylines, a platform that is surprisingly similar to the S-chassis. Because of many similarities, an RB swap is not that hard to pull off in an S-chassis. In fact, I performed this swap myself and wrote an article on how to swap an RB in an S-Chassis car. Many OEM parts can carry over, and there is a good amount of aftermarket support to make this swap a bolt-on affair if you have the cash.

You can expect the RB engines to be quite a bit heavier than your stock motor and it will sit quite close to your radiator shifting the center of gravity forward. Some people will say that the extra weight and center of gravity change will ruin the handling of your S-chassis. This seems more common on the S13 platform considering this chassis has the least front-end rigidity. If you are serious about motorsports staying with a 4-banger might be a better choice but if you just want a cool swap for everyday/weekend driving then the RB engines are a great choice.

Toyota 1/2JZ: 6 inline monster power for an s-chassis

The 1 and 2JZ engines from Toyota are an alternative to the RB engines. The 2JZ engine had a serious cult following and is known to hold incredible amounts of power with stock internals. When you decide to upgrade to forged internals, the sky is the limit.

Just like the RB the main downside to the 1 and 2JZ is that they are heavy cast iron blocks and will upset the balance of an S-chassis ever so slightly. They have similar dimensions as the RB engines so you will also run into clearance issues with your radiator fans, just like the RB’s. The 1JZ can sometimes still be found for a decent price but the current price of a 2JZ is just astronomical.

There are swap kits out there so swapping a 1JZ or 2JZ in your S-chassis should be relatively straightforward. When performing a swap like this you can make your life a whole lot easier by ordering a custom wiring harness so you don’t have to mess with the electronic side of things.

GM LS: Because there is no replacement for displacement

Of course, the classic LS swap can’t be missing from this list. The General Motors v8 LS engine is an American classic. There are many different versions of the LS and in a naturally aspirated setup, they make an easy 400 to 500hp without major modifications. The most popular LS engine is the LS1. 

The LS engines have decent aftermarket support so if you need anything to perform the swap you can most likely find an out-of-the-box solution. If you live in the USA finding an LS is easy and cheap. If you live outside of the states then there are better options.

The LS engines are a good choice if you don’t mind straying from the original ethos of the S-chassis. at 4 to 500 horsepower the LS engines are far less strained than an SR20 making similar power. The other massive advantage of a big V8 is the torque output. Despite what you might think, the LS engines are notoriously lightweight, being only slightly heavier than a KA24.

Honda K20/24: Cheap and bulletproof

The Honda K20 and K24 engines don’t need an introduction.  This is probably the second most popular engine swap in the world, just after the LS-swap. Honda K series motors are bulletproof, rev high, and take extremely well to a turbocharger.

The K-series engines are a good engine swap option for an s-chassis. Swapping a K-series in your s-chassis means that you don’t have to compromise much on handling. The K-series engines are a similar weight as the KA24 coming in somewhere around 400-415lbs (181-188kg).

Just like many other engine swaps, there are complete bolt-on kits available to swap a K series engine in your S13. TF Works for example makes a great bolt-on kit.

S-chassis engine swap conclusions

There are a ton of different engines that you can swap in your S-Chassis. You will have to consider the cost and (fabrication) skills required to perform the swap. Bolt-on swap kits make your life a whole lot easier, but the high-end well engineered ones are not cheap. To add to this, swap kits are seldom complete and you will very likely run into an issue that requires a custom solution. Think of custom piping, a power steering hose that doesn’t fit anymore, mating two wiring looms together, etc.

The engine swap options I mentioned in this article are all proven swaps with a lot of documentation around them. You can find almost anything you need to know with some little investigative work and scrolling through a lot of old forum posts.