There’s a lot to be said for the combination of a big engine in a small car. Take a spin in this ‘big block’ Eunos 30X and you’ll be blown away - and not just by its outright acceleration. The repowered 30X offers astounding throttle response (the sort you can only dream of with a turbo engine), barrow-loads of torque at all revs and wonderfully useable performance. This is a tremendously easy car to drive - very different to a turbo car with on-off boost characteristics.
This Eunos 30X is an automotive orphan here in Australia. When Mazda’s luxury car division, Eunos, folded in 1996 it left the pretty little coupe out to dry - few people came to enjoy its contemporary styling and sweet 1.8-litre quad-cam V6.
But Mark George is one of the few.
Mark purchased his 30X brand new back in 1994 (which was the first year of Eunos sales in Australia). His motivation to buy the red coupe was its high quality, generous list of options (including airbags) and sheer good looks. At the time, the performance of the 100kW 1.8-litre V6 was pretty reasonable - it wasn’t in WRX territory but it was respectable within its class.
More than ten years on, Mark started searching for a replacement for his beloved 30X. The new Mazda RX-8 and Subaru WRX were high on his list, but the change-over cost was, well, more than a bit off-putting. And that’s when Mark decided transform ‘ol faithful into something new and completely different.
With a fair number of kilometers behind the original 1.8, Mark delivered the car to Brad’s Automotive in Rockhampton. This is where the 30X was reborn - the original 1.8-litre V6 bit the dust to make way for a 2.5-litre KL-ZE from a low kilometre Japanese-spec Mazda. We’re talking a substantial 39 percent swept capacity increase!
So what the heck is a KL-ZE engine, you ask?
Well, it’s a Japanese market high output version of the quad-cam, 24-valve, 2.5-litre V6 that appeared in the early/mid ‘90s Australian-spec Mazda 626. The Japanese KL-ZE version belts out an impressive 147kW and 224Nm at 6500 and 5500 rpm respectively – in comparison, the Australian 626-spec 2.5-litre (coded KL-03) generates just 121kW. We believe that a higher compression ratio and more aggressive camshafts are responsible for much of the KL-ZE’s extra power.
The KL-ZE conversion was a pretty straightforward process since the KL-series V6 shares the same architecture as the original K8 engine. This made it possible to retain the standard 30X 5-speed manual gearbox and driveshafts. The only change in this area is a heavy-duty single-plate clutch - Mark tried the standard clutch but it obviously wasn’t happy in its new role...
Rather than rely on the factory engine management system, Mark’s 2.5-litre 30X employs a piggy-back’d MicroTech programmable ECU. In its current configuration, the MicroTech unit controls fuel and ignition while the stockie system maintains control over ancillary systems such as thermo fan operation and idle speed control. ChipTorque on the Gold Coast has finessed the management system to provide excellent smoothness and drivability - we loaded the engine up in fourth gear at barely 1000 rpm and it accelerated without hiccup.
The tractability and on-demand torque of this car cannot be overstated. Accelerate in any gear and any rpm and the sweet V6 snaps your head back and whisks you down the road with real urgency. No need to change down a gear or two to find where the engine is punchiest.
And how much punch is there in this little package?
Well, after its recent ChipTorque tune the car has made around 115kW at the wheels (on a Dyno Dynamics chassis dyno). Obviously, we’re not talking about a horsepower hero but this is a massive 60 percent power gain over the original 72kW ATW output - more than enough to make an already sporty car very sporty! Fortunately, the progressive torque delivery of the KL-ZE means there are no problems with traction – sure you can get it to spin a tyre, but it’s far from rampant.
As we said, Mark has only recently decided to enhance his 30X so, for now, you’ll find the four-wheel-disc brakes and suspension are unaltered. There are plans to improve both of these areas but, when it comes to suspension, Mark is justifiably concerned he’ll sacrifice ride quality. He doesn’t want anything detracting from the car’s everyday comfort.
The 30X is a distinctive design with a very short, stubby appearance, smooth lines and Mazda/Eunos-esque headlights. Mark’s is also one of the best presented examples you’ll find - which is no surprise given it receives a wash at least once a week and is lightly polished every month... The only visual mod is a set of 17 inch Avanti rims wearing grippy 215/40 Yokohama A509s. These give the car a real cosmetic boost - and it’ll look even better when the suspension is brought down slightly.
Inside, the 30X has seating for four but it’s essentially a two seater with plus-two accommodation. Mark has added black sheepskin covers to protect the seats, a timber gear knob, Momo pedal covers and brought the sound system up to current standards. A Pioneer CD/tuner lives in the dash while full-range Pioneer speakers live front and rear. Mark didn’t want anything over-the-top that detracted from the car’s usability - there are no subs in the rear hatch area, just a CD stacker.
Mark says the big-cube Eunos 30X doesn’t need any more power than it currently has - and, realistically, a front LSD would probably be needed if the package was further developed. The last thing you’d want to do is bung on a turbocharger and fight a losing battle to get torque to the pavement.
It’s a case of leaving it as-is and having fun annihilating RX-8s!