There has been a lot of buzz about the pair of alternative energy AE86s that Toyota unveiled at the Tokyo Auto Salon. However, even before Akio Toyoda‘s big reveal there’s been other efforts at making an environmentally friendly AE86. Specifically, the what creator Yoshinori Kamata calls the ECO-Hachi, which gets an astounding 42 mpg.
Kamata is the founder of Tec-Arts, a long time AE86 tuning shop in Japan. While most of his cars have been tuned with an eye toward performance, including cars for the D1GP, building the most efficient AE86 possible has long been a pet project of Kamata-san.
About two years ago, Kamata-san revisited the idea using modern parts. Its 4AG has been rebuilt with Kameari forged pistons, and AE111 crank and con-rods. The valve seats and surfaces were also polished to reduce friction. Key to the fuel efficiency is an electronic throttle and direct ignition via Bosch injectors, all governed by a Motec 800 ECU.
Kamata-san also removed parasitic drag from mechanical components. New accessory pulleys and bearings help keep the engine as smooth as possible. He also replaced the driveshaft itself with a brand-new unit from the Toyota Heritage Parts Program and sheathed it in new driveshaft bearings. Kamata-san also notes that the optimal operating temperature of the 4AG is 100 degrees Celsius, and is using coolant that keeps it there.
The result was an AE86 that gets about 40 mpg on average. Not only that, but it got a slight horsepower boost to 140. By comparison, a lightly tuned AE86 usually gets about 24 mpg. It’s an impressive feat, as we’re also certain that in addition to rivaling a Lexus UX hybrid in fuel economy, Kamata-san’s AE86 is also a perfectly dialed in touge runner.
These were incredibly neat little cars and the little twin cam motor was fantastic, I remember installing one of these engines and gearboxes in a Lotus Seven recreation years ago… what a delight it was.
Well all fine and good, but would it meet todays emission standards? And of course at what cost? Forged pistons? Custom porting? Special bearings and driveshaft? “Only” 140 hp?
Sure it’s great when you have the money and resources, but to the average Joe, not so much.
Almost certainly most of the fuel economy gains are from the better injectors, newer ECU with better fuel control/engine modeling, and the high coolant temps. If the tune is also running on the lean side at low load that probably helps too but will cause a big overshoot in emissions vs running at stoich. The WPC stuff while nice is probably almost irrelevant to fuel economy. DBW can really only help fuel economy in transient conditions in a manual car, automatics benefit more as you can silently open and close the throttle with gear changes to maintain constant acceleration while optimizing for more fuel economy.