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Eunos 800 Miller cycle

Testing the prestige supercharged Mazda.

by Julian Edgar

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This article was first published as a New Car Test in May 1999. The Eunos 800M remains one of the most interesting cars of its class we've ever driven - and now they're available extraordinarily cheaply, many with unhappy superchargers.... (So much for the 'supremely reliable' comment!)

I push my foot flat to the floor and the trans kicks back to second. The car slingshots forward, supercharger whining faintly and the push in the back from the leather seats surprisingly strong. A shift at 5500 and the surge continues forward. The painted white line flashes by as the roadside greenery starts to become a vague blur. Apart from that faint but distinctive blower sound, only the soft sounds of air rushing by at 160 km/h disturbs the forward progress. At exactly 180 km/h and 6000 rpm, the trans slurs into fourth and only then does the acceleration start to taper away. Fourth is geared more for low cruising revs than maximum speed; the car only gradually inches its way faster after 200 has been reached.

It's an impressive performance, not so much for the outright speed but the way in which it is achieved. The car - featuring a 0.28 Cd - is incredibly stable on the road despite the gusting crosswind. The quietness and total lack of vibration from the 2.3 litre V6 is just exemplary, and then when you hit the centre pedal hard, the speed is washed off effortlessly, the nose dragged downwards and the speedo needle swinging back at a reassuring rate.

Sitting at 100, 120, 140 or 160 km/h - it doesn't make much difference which - the car is uncannily quiet, the cruise control imperceptible in its throttle movements, the CD sound from the Bose system clear and with depth. A couple of hours for a few hundred kilometres across narrow, windy and bumpy secondary roads is literally no task at all; 1000km across a state or country as natural as breathing.

Yes, we were impressed by the Eunos 800.....

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Developed in a time when Mazda saw a clear path forward for their luxo Eunos brand, the front wheel drive 800 was originally sold with two powerplants - a naturally aspirated 2.5 litre V6 and the unique Miller Cycle supercharged 2.3 litre V6. The facelift model tested here has just been released and is available only with the Miller cycle engine. Over the previous model it loses the M badge from the boot, picks up aggressive alloy wheels and a new grille, and receives some interior woodgrain and chrome tweaks. Oh, and chrome scuff plates that revealingly feature the Mazda logo.... Eunos? Mazda? Now one and the same it seems...

Costing A$74,150, the 800 is substantially cheaper than some previous models of the car; then it retailed for as high as A$85,165. One reason for the price drop might be the poor retained values of the 800 - more on that later. For your dollars you pick up in the Eunos 800 a luxuriously-appointed, medium/large sized car. About the only feature not included is a digital trip computer - you get full leather, tilt-and-slide sunroof, climate control, electric seats, Bose sound that includes single and six stack CD, remote central locking, electric windows and mirrors, four wheel steering, ABS, twin airbags - and that wonderful engine.

Opening the driver's door gives you a good indication of what is to follow. Firstly, the 'unlock' button on the remote doesn't cause the indicators to flash or the horn to toot - it just unobtrusively unlocks the doors and switches on the interior light. And it does so from many metres away - unlike some contemporary factory remotes that are pushing to work from 4 or 5 metres. The heavy door opens to reveal no less than three separate door rubbers - and when you shut the door you'll notice that the external seal fits flush with the outside architecture of the car. No wonder wind noise is quiet at speed. How quiet? At 110 km/h the driver can hear the rustle of a sleeve as a rear passenger moves their arm...

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Inside, the cabin is airy, helped by the standard sunroof. However, the all-black dash is a little sombre - its expanse needs to be broken up with some more of the woodgrain that's on the centre console or perhaps a strip of lighter vinyl. The electric seats are firm but supportive, though obviously designed more for large luxury bums than holding you tightly in place. The seat controls are intuitive, but don't include adjustable lumbar, and the steering wheel is adjustable only for reach, not height. With the seat and wheel in my preferred positions, the rim of the wheel hid the top numerals of the speedo and tacho.

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The leather wheel is a good size and gives excellent tactile feedback, the steering precise and well-weighted at all speeds. The initial gearing of the steering is nothing like the last Mazda that AutoSpeed sampled (the MX5/Miata!), but is probably pitched perfectly for this (up)market. At low speeds the four wheel steering turns the rear wheels in the opposite direction to the fronts, aiding manoeuvring. And it certainly works. Like many aspects of the car, initially you're surprised at its effectiveness but you soon take it for granted - until you get into another car. Over 47 km/h the rear wheels are steered in phase with the fronts. Like other 4WS Mazdas, this can be felt as a slight reduction in understeer when the car is being punted hard. The front tyres are being saved some of their turning duties, leaving more capacity for them to torque effectively.

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In really tight stuff (corners marked below 35 km/h, for example) the 800 isn't happy. The 215/55 Dunlop Windsor Luxe tyres wail, the understeer builds and builds. That's with the Traction Control System switched off; with it on, the power is knocked on the head before you can get that far out of shape. Having experienced this sort of cornering behaviour, you could figure that the handling is, well, pretty bad. But on more open corners - even those marked at 55 km/h - the 800 is very good indeed. Held in second, the strong torque of the supercharged six can be used to throttle steer the car through the bends at a speed which is surprising. It sits flat and feels unfussed, although again at times the TCS needs to be switched off to achieve really smooth progress. Front tuck-in is available when you get off the loud pedal; we never had the car's rear coming out. It ain't no jaw-dropper in the handling stakes, but it sure won't disappoint a keen driver who wants to punt the car hard now and again.

The ride is firm but supple; those expecting a luxo boulevard cushion will be disappointed. However, over really broken bitumen the firmness never degenerates into harshness - if anything the car seems to ride better as the road surface deteriorates! You get the feeling that the Mazda test track has a particularly bad piece of road that was never allowed to disturb a full glass of water sitting on the dash...

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The controls work well, with all easily accessible and clear in their function. However, the piano key buttons of the climate control are slightly dorky - Dep Ed Michael Knowling suggested that they looked like they were from a child's toy - and are also angled more towards the passenger than driver. Ironically - considering that the Eunos brochure makes a major deal of the "ergonomic switches and controls that have a uniform stroke" - one of the annoying aspects is that the switches to the right of the steering column operate in a different way to the switches on the left, although looking nearly identical. With one lot, you push to turn on and push to turn off. With the other set, you push on one side of the switch to turn on and the opposite end of the switch to turn off.... Can't imagine BMW doing something like that!

But without that superb engine all that you'd have is a nicely-appointed, competent luxury sedan. The Miller cycle engine is unique in that it closes the intake valves much later than in a conventional Otto engine. In fact, for the first 20 per cent of the compression stroke, the inlet valves (two per cylinder) are left open. The valve timing of the intakes is from 2 degrees before TDC until a mammoth 70 degrees after BDC, with the exhaust duration from 47 degrees BBDC to 5 degrees ATDC. Thus the intake valves remain open for another 30 degrees of crankshaft rotation beyond "normal". So, why do Mazda do that?

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Firstly, pumping losses are reduced. Power is required to squeeze the mixture on the compression stroke, power that is robbed from the crankshaft output. Reducing the amount of compression that occurs therefore frees-up power. But won't the intake mixture be pushed out of the open inlet valves on the compression stroke? Well it would - but there's a twin-intercooled Lysholm screw-type supercharger using no less than 14 psi boost (we measured it!) to push that mixture back in. The supercharger absorbs less power than is released by reducing the pumping losses, giving an overall benefit. The late closing of the intake valves also reduces the effective compression, dropping it from the nominal ratio of 10:1 to just under 8:1. This drop in CR reduces frictional loadings, also releasing power, with the blower then boosting the dynamic comp ratio.

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The result is 149kW at 5500 rpm (87hp per litre) and a peak torque of 282Nm at 4000 rpm, accompanied by a claimed 10 - 15 per cent less fuel consumption than an equivalent 3 litre engine. The quoted torque curve is also high and flat - more than 275Nm is available from 2000 - 5500 rpm. On the road you simply can't argue that the engine is a Good Thing. Smooth, sweet and powerful, it feels not like a 2.3 litre V6 or even a 3 litre V6. In fact, it feels quite unique. But while we admire the technology, we can't help but wonder - even with an economy sacrifice - whether conventional valve timing, bigger intercoolers and the 2.5 litre engine couldn't have been used to get 170 or 180kW - that would make a very good car even better!

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We put the Eunos on Awesome Automotive's chassis dyno and found that the wheel power peaks at 111kW, pretty much what is expected with a flywheel power of 149kW. Incidentally, the sudden drop in power is caused by hitting the rev limiter at 6000 rpm - the curve is still heading upwards before that brick wall is met! Tractive effort peaks in the midrange, falling away fairly quickly after that. However, on the road, the engine doesn't feel much like this in the torque delivery. While the car was on the dyno we placed a thermocouple on the 'cool' side of one of the two tiny intercoolers. After 10 or so seconds at 5000 rpm full load, this showed an inlet air temp a horrendous 75 degrees C.... ouch.

The four speed auto works unobtrusively and well. It also possesses a feature that is simple but effective. An electronic 'hold' button is placed on the side of the gear lever. When pressed, first, second and third gears become manually selected - the engine will bounce off the rev limiter rather than change up when in Hold mode! The only auto change that occurs is if you manually select third gear and come to a standstill, in which case the trans will select second so that you can still drive away. However, one downside of the hold function is that the button returns to its original position whether in or out. That means that you can't tell by feel alone whether you're in hold or not - you have to take your eyes from the road to look at the dash indicator.

Against the clock the Euno reaches 100 km/h in 9.0 seconds and does the rolling 60-90 km/h sprint in 3.0 seconds. Over a wide ranging test (full speed, urban and 110 km/h cruise) the Eunos returned 12.4 litres/100 km, better than we expected.

Under the bonnet the view is not quite up to the levels that you expect in a car of this type. The Miller Cycle Engine sticker looks like a cheapy run up as the local sign shop, while the welding of the two air/air intercoolers and their location appear to be cost-cutting measures. The intercoolers are fed via underbonnet ducts from the grille between the headlights; at times the intercoolers are too hot to touch, even on a cool day with the car not driven hard... The wiring loom looks haphazard - there are relays sprinkled here, there and everywhere with multicoloured wires revealed when the loom tape runs short. The fuse box lid is flimsy and difficult to remove, while we're told that the engine - while supremely reliable - is not at all cheap to fix if something does go wrong.

And perhaps that explains the resale. You can pick up a 1996 model for around A$40,000 - a stunning price reduction over buying this current model. If you're looking at a lease, these sorts of resales might also want to be kept in mind when picking the residual.

The Eunos 800 is a damn good car using innovative technology in a time when more and more car companies are playing follow-the-leader rather than creating something new and interesting. If you are looking at spending in the high Seventies, put it on your shopping list. And if you have a lot less dough, have a look on the secondhand market!

Contact:

www.mazda.com.au

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