The little engine that powers the Toyota GR Yaris and Corolla – the G16E-GTS, to give it its proper name – is something of a marvel of engineering. In countries where it’s not held back by emissions rules, it pushes 300bhp from just 1.6 litres and three cylinders.
Iconic Japanese tuning house HKS, however, reckons it’s got more to give. A lot more. It’s preparing a stroked-out, 1.7-litre version of the motor to sell as a crate engine, which will feature tricksy pre-chamber ignition to boost power, tech we’re more used to seeing on the F1 grid.
HKS G16E – crankshaft
To begin with, HKS is increasing the engine’s cylinder bore from 87.5 to 88mm, and massively upping the stroke from 89.7 to 95.7mm. This results in a new displacement of 1746cc, up from the original 1618cc.
It’s then beefing up the whole block, machining a new intake port for the cylinder head. The crankshaft and conrods are also fully machined, and the newly designed pistons get a two-layer, low-friction molybdenum coating. It’s also working on a high-capacity injection kit for even more powwwwerrrrr.
HKS G16E – piston head
Most impressive, though, is the pre-chamber ignition. This effectively utilises an extra little chamber adjacent to each cylinder, in which a fuel-air mixture is ignited prior to it being brought into the main combustion chamber. It’s not the easiest thing to engineer, but it not only allows an engine to make more power, but to do so more efficiently.
It’s a system that’s been used in Formula 1 for a while, but a version of it has only recently made its way onto road cars in Maserati’s Nettuno twin-turbo V6, found in the MC20 and Grecale Trofeo.
HKS G16E – ports
There’s no word yet on exactly how much power HKS’s G16 crate engine will make, how much it’ll cost, or when and where it’ll be available. One thing’s for certain, though – once it lands with customers, we’re expecting to see some properly unhinged GR Yaris builds appearing on track.
