(first posted 8/22/2014) Toyota knocked one out of the park with the introduction of the MR2 in 1984 (February, 1985 in the US)–the first mass-produced mid-engine car to come from a Japanese automaker. As one of the best contenders in an era where affordable sports cars were in abundant supply, it offered sharp handling, unbeatable quality and one of the best four-cylinders then on the market. As a package, it was hard to resist, but the company turned the dial up to “eleven” in 1988 with the US-market introduction of the MR2 Supercharged.
Powered by a Roots-blown and intercooled 4A-GZE engine that made ~30% more HP than the normally-aspirated car, the supercharged MR2 solved one of the few complaints which could’ve been leveled at the car as more powerful competition began to materialize. I was visiting my dad in Central Georgia earlier this summer when we caught this supercharged model and its owner, both of whom were eager to get off the hot asphalt parking lot. The owner confirmed this to be a 1989 model, to which he’s done some tweaking. He and his son are both MR2 enthusiasts, and his son drives a highly-modified MR2 that makes about 265hp (yikes!). If you zoom in on the photo, you can make out the “Supercharger” light on the tachometer gauge. The blower incorporated an electromagnetic clutch so it would only be active when needed (that would be all the time, right?) in order to preserve some modicum of fuel economy.
I was in the Industrial Design program at Georgia Tech when the MR2 was introduced, and it caused quite a buzz among my classmates (as well as the folks at Motor Trend, who awarded it “Import Car of the Year”). We were positive the angular styling was due to the car having been designed using CAD (easier to draw straight lines than curved, after all). As if to prove us wrong, the 1991 MkII (there was no 1990 model) went almost to the other extreme with its swoopy Ferrari-esque styling. Were I to choose a favorite MR2 model, it would be this one right here. The angular styling still looks good to my eye, and the throaty growl (and whine) of that supercharged engine would be too much to pass up.
What’s especially interesting about Toyota’s decision to supercharge the 4A-GE is that the company, along with most others, had been doing a lot with turbocharging during that period. By the tail end of the ’80s, however, forced induction was viewed more critically because of such obvious issues as lag, etcetera. Fitting a larger engine would’ve likely required an illogical degree of re-engineering of the MR2’s Corolla-based powertrain, however. Maintaining the linear power curve and instantaneous throttle response that were key parts of the MR2 experience, on the other hand, made supercharging a more obvious solution.
These days, turbocharging is back with a vengeance, with high compression ratios made possible by the cooling effect of direct injection’s spray of fuel directly into combustion chambers helping mitigate the effects of lag, along with a host of other improvements. But the ’90s and early ’00s seemed to represent a brief fling with the supercharger as an ideal path to extra power. At Toyota, they made an appearance in the 94-96 Previa, of course, and were more famously installed in a host Mercedes and Jaguar cars, in addition to the R53 Mini where, strapped to a 1.6-liter four, they sparkled. More obscure implementations include Mazda’s Miller-Cycle Millenia S and VW’s Corrado G60 and (Canada-only) Passat Synchro, along with the Thunderbird Supercoupe. And certainly, no one here at CC will forget GM’s excellent supercharged 3800-series. Overall, however, the list of factory supercharged cars is a short one. For the mid ’80s (it was introduced in Japan for 1986), the 4A-GZE was a very bold and clever solution. One could say it was slightly ahead of its time, despite being a low-volume curiosity, with no more than 2,000 likely sold on these shores over two years.
In Toyota speak, A refers to the engine family, 4 denoting the 1.6 liter displacement, with G referring to the wide valve angle head (the alternative, F, means narrow valve angle with the intake cam slaved to the exhaust cam, in some cases) and E, fuel-injection. Z, as we can guess, refers to supercharging; on other models, T is used to denote turbocharging. As seen in the MR2, 4A-GE the engine was boosted by 8 PSI, with compression lowered from 9.4:1 to 8.0:1, for a healthy 145 horsepower and 140 lb-ft of torque (at a lowish 4400 rpm, indicating a usefully broad powerband). Between the torque peak, the 6400 rpm power peak and 7500 rpm redline, the engine had a big enough sweet spot to move the now 2,600 pound MR2 with zest; no peaky delivery, no waiting. Mister Two now got to sixty in the high six-second range, with the quarter mile dispatched in 15.5 seconds, at about 90 mph.
Critical response to the turbocharged MR2 which followed was generally positive, but less enthusiastic. In addition to being a heavier car, the brawny new powerplant (more at home in the Celica AllTrac or GT4, for our overseas readers) did not have the same spunky and sharp characteristics as the wide valve angle A-block. The supercharged 1.6 went on to live in the Corolla and its derivatives until 1995 (if you’re a Japanese car buff, here’s yet another instance in which we’re denied the good stuff), where a smaller supercharger pulley and boosted compression netted a solid 160-ish horsepower (hard to exactly determine without SAE net measurements) and 150-ish lb-ft of torque.
Other variants of the 4A-GE with such unique details as individual throttle bodies and five-valves per cylinder would cement its legendary status, making the boosted 4A-GZE a footnote to history of one of Toyota’s most well-regarded engines. That the owner of this car managed to get his hands on one therefore makes him quite lucky, and we’re all fortunate that he gave me the opportunity to share it. Never a volume model, most of these cars are naturally aspirated models in red, white or black, making this more powerful yet subtle blue example one of my favorite recent finds.