Nobody ever expected Toyota to offer a snarling turbo, all-wheel-drive version of their ultra-compact people mover, the humble Toyota Yaris. And even fewer expected that the spicy GR performance variant would be powered by a little three-cylinder power plant. And while it won’t make its way to the U.S., the heart of the GR Yaris can be found in the U.S. Toyota GR Corolla.
At just over 2,800 pounds and transferring 257 horsepower to all four corners, the GR Yaris is a three-door demon right out of the box, but it didn’t come without some doubts from the masses, specifically about Toyota’s engine choice. The four-cylinder that you’d expect under the hood is instead the G16E-GTS—a 1.6L, inline-three direct-port injected turbo engine with 10.5:1 compression. Those that shook their head at the G16 were quick to point out that it was probably “maxed out” and wouldn’t take kindly to aftermarket prodding for those in search of more power. Powertune Australia, however, was hearing none of that.
Highly respected in the motorsports world and well known for their custom firmware solutions, advanced tuning services, and essentially anything else that involves go-fast goods for a variety of chassis, Powertune Australia has quite a bit of experience with Toyota’s new platform having tuned multiple versions from their Sydney headquarters. For the past 12 months, the group has dissected, researched, and developed higher performance options for the hyperactive three-cylinder.
This project, dubbed the “Rodent,” is the property of Peter Freedman, owner of Rode Microphones. If you’re a video creator, producer, engineer, etc., then you’re already very familiar with their array of high-quality microphones and audio equipment. His stable of cars is vast and the GR Yaris might not seem a likely fit among the sports cars and exotics, but Powertune tells us he loves this car and drives it almost every day.
The mod list you’d expect would be full of bottom end enhancements from the aftermarket, like rods, pistons, and a custom crankshaft, but, this GR Yaris retains all of its factory internals on the lower end, and has only received upgraded head studs and a head gasket. You’ll find Kelford cams, valve springs, and retainers inside its head, but that’s the extent of the internal upgrades.
Externally, a Garrett G30-770 turbo and Turbo Smart 45 mm wastegate are now on duty and mounted using a Golebys Parts turbo manifold with dump pipe which leads to an Akropovic cat-back exhaust. Bosch 2,200 cc secondary injectors and an Elixr brushless fuel pump increase fuel delivery while a Plazmaman intercooler with Golebys piping keeps pace with the additional boost introduced.
MoTeC offers a Yaris plug-in ECU that oversees the entire operation and after a substantial number of dyno sessions, the result is 740 hp at the hubs, which equates to a mind blowing 246 hp-per-liter! So, where’s the weak link in all of this? Powertune tells us, “The factory bottom end is very fragile when it comes to detonation. We have seen many engines destroyed (particularly in places where E85 isn’t available) from detonation at much lower power levels. Thankfully, E85 is readily available here in Sydney, which means we benefit from the increased knock resistance and cylinder cooling.”
That sort of power transferred through a factory transmission reliably, even one as well-built as the GR Yaris, would be a very tall order. For this build, an X-shift 6-speed sequential gearbox was brought in and joined by an ATS triple carbon clutch to take advantage of that huge power increase.
Powertune says the next big test for this project is longevity. It’s currently racking up street miles (spirited street miles, that is) and has well over 30 dyno runs under its belt with no issues so far. “We still haven’t broken the bottom end yet, so it’s anyone’s guess how far this bottom end will go,” they add. “We would like to think with everything else perfect—bigger turbo, maybe some nitrous—it may even be capable of making four-digit power levels. Again, this is only a guess as we haven’t reached the limit yet.”
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