No one thought that Toyota would make a version of their tiny Toyota Yaris with all-wheel drive and a turbocharger. Fewer still believed that the hot GR performance version would have a small engine with only three cylinders. The engine in the GR Corolla sold in the US is the same as in the GR Yaris. The GR Yaris is a three-door monster right out of the box. It weighs just over 2,800 pounds and sends 257 horsepower to all four wheels. However, the general public wasn’t happy about it, especially Toyota’s engine choice. The G16E-GTS engine is not a four-cylinder. Instead, it is a 1.6L inline-three turbo engine with a 10.5:1 compression ratio. People who made fun of the G16 quickly pointed out that it was probably “maxed out” and wouldn’t be easy to create more potent with extra parts. On the other hand, Powertune Australia didn’t hear any of that. Powertune Australia is well-known in the racing industry for its custom firmware solutions, advanced tuning services, and just about anything else that helps different cars go faster. They have changed different versions of Toyota’s new platform at their offices in Sydney. The crew has spent the last year looking at, studying, and developing better ways to replace the engine’s three cylinders. Peter Freedman, who owns Rode Microphones, made the “Rodent.” People who work as video directors, engineers, and so on are already familiar with their top microphones and other audio gear. Even though the GR Yaris doesn’t look like it fits in with his vast collection of foreign and sports cars, Powertune says he loves it and drives it daily. On the other hand, the bottom end of this GR Yaris still has all of the original parts. Only the head studs and head gasket have been updated. You might think that the change list would include bottom-end upgrades like rods, pistons, and a different crankshaft. The only improvements inside the head are the Kelford cams, valve springs, and retainers. A Garrett G30-770 turbo and a Turbo Smart 45 mm wastegate are all housed in a Golebys Parts turbo manifold with a dump pipe. A cat-back exhaust from Akropovic is connected to the turbo. Bosch 2,200 cc secondary injectors and an Elixr brushless fuel pump improve fuel delivery, and a Plazmaman intercooler with Golebys pipes keeps up with the extra boost. After multiple test runs, MoTeC’s Yaris plug-in ECU controls the whole process. The result is 740 horsepower at the hubs, an astonishing 246 horsepower per liter! So, where is the weak link in this situation? Powertune says that the original bottom end is likely to blow up. We’ve seen engines get blown up at much lower power levels, especially in places where E85 isn’t always easy to find. Since E85 is easy to get in Sydney, we may get better protection against knocks and more excellent cylinders. Even in a well-built car like the GR Yaris, moving that much power with the stock gear would be hard. For this job, a 6-speed sequential X-shift gearbox was paired with an ATS triple carbon clutch to maximize the power gain. Powertune says the next big test will be how long the project will last. It’s been on the dynamometer more than 30 times and is now putting on street miles (excited street miles, that is). So far, everything has gone smoothly. “We haven’t broken the bottom end yet,” they say, “so who knows how far this bottom end will go.” “We’d like to think that if everything else was perfect, it could make four-digit power levels with a bigger turbo and maybe some nitrous.” Again, this is a guess because we haven’t hit the limit yet.
