If someone told you they were doing an engine swap, you’d rattle off a list of cliche engine codes. “2JZ?” you’d ask. “RB? LS? K swap?” All great engines, all of which have grown more inaccessible due to their legendary status. But what if I told you that a Toyota Prius engine could give you naughty thrills on the cheap? What if Toyota’s other hybrids were packing engines with secret performance sauce hidden inside?
Enthusiasts have long chased engine swaps as a shortcut to cheap performance. Everyone knows that the right Honda four-banger or junkyard GM V8 can offer big ponies for pennies on the dollar. Of course, once a given engine becomes well known, the engines become popular. The junkyard finds start drying up, used engine prices go up, and what was once a low-buck solution becomes all too expensive.
The best engines in your local junkyard were plucked out long ago [Ed Note: Except for Chevy V8s and Hemis. Those remain plentiful. -DT], but there’s magic lurking where nobody else has looked. Head to the Toyota section. Hunt down a Prius or a Camry Hybrid. Get yourself a dull-as-dishwater economy engine and give it the high-RPM makeover that it’s always deserved. You might just get some surprising power out of the most humble engines on the market. I’ve been speaking to the guys that are doing just that.
Prius Power
To understand why you’d want to swap a Prius engine into your track car, we first need to understand what is special about these engines. Most desirable engine swaps have good power and torque in stock form, after all. The Prius engines simply do not. Instead, they were built and tuned for efficiency over all else. However, due to a quirk of their design, they actually have secret performance potential lurking inside. Let’s examine.
The original Toyota Prius came out in 1997. Under the hood was a small gasoline engine—a 1.5-liter inline-four known as the 1NZ-FXE. Paired with an electric motor for hybrid drive, the 1NZ-FXE was built for efficiency, first and foremost. To that end, the early models offered just 76 horsepower and 85 pound-feet of torque. A later version came out in 2012 and appeared in the Prius c, Aqua, and Yaris Hybrid. Amusingly, while more efficient, power and torque actually dropped to just 74 hp and 82 pound-feet in these later models.
To maximize efficiency, the 1NZ-FXE runs on the Atkinson cycle, instead of the traditional Otto cycle used by most gasoline engines. This involves the engine delaying the closing of the intake valve on the compression stroke. This dumps some of the intake charge, reducing the effective compression ratio of the engine. The result is that the engine has a shorter compression stroke than the expansion stroke. Thus, the engine spends less energy on compression, and thus able to gain more motive power out of each unit of fuel burned. Hanging that intake valve open for longer cuts total power output, of course, but the goal is efficiency in these vehicles, not big smoky burnouts.
Now, as we said, the engine is artificially dropping the compression ratio by leaving the intake valve open. That’s all well and good, but if you did that in a typical gas engine, you’d have an issue. With typical static compression of 10.0:1, say, you’d see the effective compression ratio drop as low as 6.0:1 with that little intake valve trick. That’d be far too low to make even mild amounts of power. To counteract this, an Atkinson cycle engine typically has quite a high static compression ratio. For example, in the 1NZ-FXE, if the intake valve closed normally, you’d have a compression ratio of 13.4:1 in the later models. That’s bonkers high. Most performance gasoline engines sit well below 11:1; even the highly-strung Honda S2000 only hit 11.1:1 with its F20 engine. However, because of the intake valve trick in the 1NZ-FXE, the effective compression ratio is just 9.5:1 in the later models.
“Wait a minute!” you shout. “High compression is a good thing! Could these engines make real power?” Indeed, you’re correct. If you could somehow modify the 1NZ-FXE with a different set of cams to close the intake valve at the right time, it it could be really good. You could buy an old Prius engine for a few hundred bucks, and you’d have a compact 1.5-liter high-compression engine ready to make big power.
“Why is nobody doing this?!” you scream. Don’t worry—somebody is. And they’re doing it damn well, too.
Did You Hear That Echo?!
Meet David van der Haas. He’s a car enthusiast based down in New Zealand. He’s also a man of somewhat unconventional tastes. Case in point? His track car is a heavily-modified Toyota Echo. Oh, and it’s got a tuned Prius donk under the hood.
“The Toyota Echo comes with a 2NZ engine [stock],” he explains. It’s a fine engine for an economy hatchback, but totally unexceptional. The 1.3-liter engine puts out 87 horsepower and doesn’t have a whole lot of tuning potential. However, it’s the same engine family as the 1NZ-FXE, which got David wondering. “The hybrid version of the engine sticks out because it has a very high compression ratio—13.4:1,” he says. Small, cheap, high-compression performance engines don’t come along every day, but the Prius engine is ripe for the picking.
“Usually you’d need to rebuild a motor and fit higher compression pistons, but this was much simpler to just swap the motor in,” he says. He got himself a 1NZ-FXE yanked from a 2014 Prius Type C. He left all the hybrid stuff behind—he had no need for the batteries or the electric motor. He just wanted to make the most out of that glorious high-compression long block.
Of course, the 1NZ-FXE isn’t exactly race-ready out of the box. The biggest thing to change is the cams, which in stock form are optimized for an efficiency-focused Atkinson cycle. Appropriate performance-focused cams from the non-hybrid 1NZ-FE were sourced from JUN Auto, but that’s just part of the build. A few other well-selected mods are necessary to make the most of those gloriously cheap high-compression internals. “The intake manifold absolutely kills this motor, then second-most important is upgraded valve springs so you can rev past 7000 rpm,” explains David. Add injectors to flow enough fuel, individual throttle bodies (ITBs in tuner parlance), and an ECU to run the show, and you’ve got a properly performance-sorted 1NZ-FXE. Naturally, you’ll need premium gas to avoid detonation at such a high compression ratio, too.
Sound up, you’ve gotta listen to this thing scream at 9,000 RPM.
The results speak for themselves. With the featherweight 2005 Toyota Echo stripped down to just 1741 pounds, it was woken up significantly with its tuned Prius heart. “It ended up around 150 wheel horsepower at 8,000 to 8,500 rpm,” says David. Redline? A spine-tingling 9,000 rpm. “This car ran a 13.4-second quarter mile, still with the factory exhaust,” says David. “The factory exhaust is the absolute last place to spend money or effort on.” He’s also had the car out on track, and it sounded beautiful thrashing down the straight at Pukekohe.
Those are solid numbers for what started as a $400 engine with under 19,000 miles on it. However, it’s worth noting that David does have a fair bit of investment in the vehicle over and above that. “I used the C56 gearbox from a Vitz RS for better ratios, a Link G4+ ECU, and some BMW S1000RR e-throttle quad throttles,” he explains. It’s a few thousand dollars worth of gear on top of the Prius engine, but few engine swaps get away without requiring you to make similar investments.
It’s also worth noting that, as it was originally a hybrid engine, the 1NZ-FXE wasn’t designed to run a typical alternator or accessories. In the Prius, all that was handled by the electric hybrid motor. David thus had to fab up some brackets and sort out an alternator himself. Having gone down this path, he’s got some advice for others looking to do the same. “Start with an early 1NZ-FXE that still has the mechanical water pump, then the swap is a lot easier,” he says. “You just need to set the intake cam back 1 tooth, then the big cams clear the pistons and you’re good to go.”
It’s not going to make 600 horsepower with an eBay turbo kit, nor will it win you a burnout competition at a muscle car meet, but the value of this 1NZ-FXE build is obvious to anyone looking to build a fun racecar on the cheap with a seriously rad high-RPM screamer of an engine. It’s an accessible modern option for smaller builds, as David explained well in a forum post last year. “A lot of the classic cheap and cheerful engines like the 1JZ, 13B, 4AGE, 4G63, B18C … almost everything from that era, you’re paying an ever-increasing amount for an ever- increasing pile of clapped-out shit,” he says. “There are a few modern-day gems I think, [and the] 1NZ was one of them I reckon.”
For A Few Hybrids More
The 1NZ-FXE was perhaps the first of Toyota’s Atkinson-cycle engines to go into mainstream production. However, since then, the technology has rolled out across the Toyota fleet. You can get hybrid engines in everything from a Camry to a Sienna these days, so there’s plenty out there ripe for the picking. Thus far, seldom few have ended up in performance builds, until I happened across one guy hacking away in Indiana.
You might have heard the name Marc Labranche before. He’s an engineer who shot to fame in the car world for building an MR2 with an aircraft radial engine hanging out the back, as featured by Car and Driver in 2014. These days, he’s hard at work running his business, Frankenstein Motorworks, which specializes in supplying parts for MR2 engine swaps. “The name of my company comes from a history of just Frankensteining stuff together to make it work without just throwing a crap ton of money at the problem,” he explains. It’s that ethos that drew him towards Toyota’s hybrid engines.
Marc’s fascination began with the Toyota 2AR-FE, a non-hybrid Otto cycle engine. The 2.5-liter inline-four was used in the Toyota Camry and RAV4, and put out around 176 horsepower and 172 pound-feet of torque. “I’ve spent over a decade racing the 2AR-FE,” explains Marc. “It’s been stupid reliable and I wanted to bring it to other people, but I needed to come up with some recipes that make for high-power cheap builds.” This is where the hybrid version—the 2AR-FXE—came in.
Just like the 1NZ-FXE, the 2AR-FXE is an Atkinson cycle engine, with a lovely high static compression ratio of 12.5:1. Stock, it’s a 2.5-liter engine that puts out 154 horsepower and 153 pound-feet of torque. It was used in a wide range of vehicles, like the Camry Hybrid, RAV4 Hybrid, and the Lexus NX 300h. Marc figured it could make a lot more power if it was reconfigured for performance over efficiency. “It’s all over the place and it’s cheap as heck,” he said in his first video on the topic.
From there, he looked to other mods that would support additional power. “Beyond using the high compression pistons and the long duration intake cams this engine also needs a nice free-breathing exhaust,” he explains. “From there, I ran into the limit of the stock 2AR-FXE intake cams, and I wanted really badly to cross over the 250 wheel horsepower mark [on natural aspiration],” he explains. Naturally, he set about designing some custom cams and having them manufactured. He’s currently working to bring them into production for sale at his store.
“Using the high compression pistons from the 2AR-FXE and bigger camshafts, I managed to do this while still retaining the stock intake manifold,” he says, laying out another dyno sheet with a peak power of 252 hp.
He reckons the 2AR-FXE could go even further armed with big cams. “The advantage with those [cams] is that they are big enough now to take advantage of the velocity stack intake I make,” he explains. He’s seen typical 2AR-FE engines with bigger cams gain 30 horsepower from his upgraded intake design, and he hopes for similar results with the high-compression 2AR-FXE. “I’m expecting 270-280whp from that FXE bottom end with these new cams,” he says.
Even on an early test drive, the engine pulled well.
Tonya runs hard out on track.
Marc runs his 2AR-FXE in a third-generation Toyota MR2 Spyder. He’s paired the engine with an EB60 transmission from the Scion tC, a six-speed manual that holds up much better than the stock unit. He’s had great success with it on the track, as borne out on his YouTube channel. His team actually set the fastest lap at the 2021 Rust Belt GP, though it didn’t finish the Lemons race due to a brake line issue.
Frankenstein Motorworks currently sells engine mounts to put the 2AR engine family in the second- and third-generation MR2s. That includes the 2AR-FXE, for other fans of high-compression four-cylinder engines. However, Marc notes that the engine needn’t just end up in Toyota’s mid-engine cars. “As for which platforms can this be applied to, there’s no reason this stuff can’t be applied to the normal applications,” he says. “There is at least one Scion tC out there that has done it, but my jam is the MR2s and it’s generally where I stay.”
Moving Forward
In the world of cars, nothing stays the same for long. Once upon a time, long before I was born, Chevy small blocks and Ford 302s were the hot business for swaps. Technology eventually moved on and made them obsolete. Fast forward to my youth, and people were dropping in SR20s and 13Bs, until they got expensive and thin on the ground. These days, it’s Barra this and K-swap that, but the junkyard stocks of those engines won’t last forever. Enthusiasts seeking power will need to move on.
These Toyota hybrid engines won’t be everything to all enthusiasts. If you want big turbo power figures, you’d be advised to look elsewhere. If you’re building something a little out of the ordinary, though, and you’re chasing an exciting naturally-aspirated engine on the cheap? Look at Toyota, and the junkyards overflowing with ex-Uber cars and grandma’s old supermarket sled. Those humdrum hybrid engines are wearing some awfully sexy lingerie under their boring work clothes. Don’t be afraid to take them for a dance.
Image credits: Marc Labranche, David van der Haas, Toyota
Wonder if you could fit one of these re-cammed 1NZ-FXE’s in a Scion IQ? That would be a professionally bonkers ride.
This was an excellent article. Well done.
Frankenstein Motorworks also has made 400hp on an N/A 2GR-FE v6 from Toyota.
Bananas power from such small displacement, on a budget no less.
I’ve often wondered about the potential of converting Atkinsons to Ottos. It’s about what I thought, but I didn’t realize the compression would be quite so high. None of these are DI, are they? That seems like a lot of compression to trust to MPFI and the fuel quality of gas stations for a street car. For a racer, though…
That Echo sounds really nice.
This is probably a case where Ethanol is your friend.
I’m curious what jacking up the compression on an engine designed to run much lower would do to its longevity, but these are known for being pretty bombproof in stock form (as long as you keep oil in them, since they basically all burn it after 100k or so) so I can see where they might be overbuilt enough to tolerate some tuning.
I love NA 4 bangers pushed to their limits. 100hp/liter small engines always make me happy. Owning a car with individual throttle bodies is definitely on my bucket list.
I want to see this in a Super 7
Never messed with Toyotas, but the potential sounds interesting
Finally… the 1NZ get’s it’s day in the sun. Had one in my Toyota Echo, and the thing was dang near bulletproof. 40mpg all day long. Went to over 200K miles with no issues. Cool to see them modded. Best I’ve seen was the Scion guys supercharging their first gen XBs.