5 Engines Worth Swapping Into A Mazda RX-8

Car enthusiasts said their last goodbyes to the Mazda RX-8, as well as the rotary sports car as a whole, back in 2012 when Mazda discontinued it. While the RX-8 took a different approach to that formula, which is one of the reasons why so many enthusiasts were quick to shun it, it was still a sterling example of the breed and an excellent goodbye gift from Mazda. While the MX-5 would soldier on for a long time, Mazda's sports car stable wasn't ever quite the same without the rotary-powered 2+2 in the lineup.

As time went on, people found that the weakest link in the RX-8 is undoubtedly its 1.3-liter two-rotor 13B engine. While frequently revving it out and letting it breathe is one way to make the 13B rotary a more dependable powertrain, a lot of prospective RX-8 owners don't want to deal with the headaches of the spinning Dorito. RX-8 engine swaps are pretty popular, but only a few are actually worth it.

One great engine swap option if you want to keep it all Japanese while retaining some of the high-revving antics of the stock rotary is the good old K-series inline four from Honda. Featured in stuff like the Acura TSX, there are a few good reasons to choose the K-series.

Firstly, K-series are almost always readily available. Honda sold thousands of cars with a K20 or K24 throughout the years, so you shouldn't have any trouble sourcing a solid one. A higher-performance K20, say from a Civic Type R or Acura RSX, would be even better, as those can handle even more power. The K-series can also go for hundreds of thousands of miles, and that's not often the case with the rotary.

More importantly, the K-series RX-8 swap has gotten popular enough to warrant the existence of swap kits. This includes the clutch and flywheel, as well as the necessary ECU and flying lead to make sure the stock gauge cluster works with the new K-series under the hood. This is a slightly costly route, but the only thing you'd lose compared to the rotary is all the brap brap noises. It's definitely a trade-off worth considering.

Keeping it all Japanese is easy enough, but what if you want to keep your RX-8 project all Mazda? That's where Mazda's MZR engine comes in. Larger vehicles like the Mazda 6 used a 2.5-liter naturally aspirated version of the MZR, and it's a great fit in the RX-8 as well. Even though the stock rotary displaces 1.3 liters, would you believe, there's actually enough room for the MZR under the hood.

It would be a crime to suggest an MZR engine swap without mentioning the 2.3-liter turbo four from the Mazdaspeed3, in itself one of Mazda's most powerful sports cars. It was broadly the same across both generations of the underrated hot hatch, and it makes a lot of sense in the RX-8.

You will lose the high revs and the brap brap noises, but you'll gain excellent tunability and reliability, and more importantly, low-end torque. As you might be aware, the RX-8 totally lacks low-end torque. While there's a lot of fun in revving out an engine to get the absolute most out of it, for those enthusiasts who want a broader and more usable power band, this would be a great option. It helps, too, that it comes from the same manufacturer, which may alleviate some Frankenstein teething problems.

The MZR and the Honda K are all well and fine, but let's say you want a couple of extra cylinders, and even more bulletproof reliability. Fear not, the Toyota 1JZ is a great bet. Yes, really, the 1JZ six-cylinder fits under the hood of the RX-8, although you will have to hack away at the front crossmember a little bit.

Although this swap is very much possible, it's still a little fiddly. Yung Lee Auto over in Malaysia managed to successfully shoehorn a 1JZ under the hood of an RX-8, but it required some Frankenstein mods. From combining sensors and ECUs from both the 1JZ and the 13B, to swapping out the stock transmission with a Toyota W58, but making it all work with the stock RX-8 diff. If this sounds like a dream DIY project for you, maybe it's time to start browsing eBay for a 1JZ.

With a 1JZ under the hood, you'll gain a completely bulletproof powertrain that can take a beating when it comes to additional mods. Plus, you won't exactly lose out on excellent engine noises.

Staying in camp Toyota for just a little longer, for those who think six cylinders is still not exactly enough, how about the rather special 1UZ V8? This beacon of excellent engineering, first seen in the legendary Lexus LS400, is indeed a possible choice for an engine swap for your rotary coupe with half-size rear doors.

Fitting this engine into the RX-8 is no plug-and-play operation. Extensive work is required on motor mounts, wiring, gearbox plates, and much more. That being said, this is another one of those swaps that's popular enough to have conversion kits available, specifically clutch adapter plates that would allow the stock RX-8 manual transmission to work with the 1UZ.

Looking at the bigger picture, this engine is not really suitable for the RX-8 from a technical standpoint. It's designed for low-end torque, cruising, and smoothness. It can still pack a punch in terms of performance, though, and it can handle extra power mods. Plus, it's got enough Toyota reliability to reach seven figures on the odometer, as long as you stay on top of the maintenance.

Finally, we have the classic choice. If in doubt, just LS swap all the things. Putting a small block Chevy V8 under the hood of a rotary Mazda is nothing new, enthusiasts have been doing it for a while, and they've been upsetting rotary people for just as long.

LS-swapping an RX-8 isn't anything new either, lots of owners have done it, which means plenty of experiences to learn from, and also plenty of proof that going for a small block V8 not only works, once you sort everything out, but it's also a pretty fantastic idea.

This is one of the best possible engine swap options for your RX-8. Parts for the LS are readily available, the engines themselves are plentiful, both as crate motors, and as removed from the less fortunate Camaros and GTOs of the world, they can handle plenty of extra power, low-end torque is good, and they sound pretty excellent. As long as you can live with upsetting the rotary purists, General Motors' small block LS motor is a great and relatively affordable choice.