Press Kit Mazda MX-3 1991
Mazda MX-3 (European Version)
www.mazda-press.com
1 / 33
Press Kit Mazda MX-3 1991
Table of Contents
1. Introduction .............................................................................................................. 3 INTRODUCTION ...................................................................................................... 3 MAZDA MX-3 IN BRIEF ......................................................................................... 6 2. Technical Information ............................................................................................. 8 PACKAGING AND DIMENSIONS.......................................................................... 8 EXTERIOR DESIGN AND AERODYNAMICS ...................................................... 9 INTERIOR................................................................................................................ 11 ENGINES ................................................................................................................. 12 DRIVETRAIN .......................................................................................................... 19 CHASSIS .................................................................................................................. 22 BODY ....................................................................................................................... 27 SPECIFICATIONS................................................................................................... 30
www.mazda-press.com
2 / 33
Press Kit Mazda MX-3 1991
1 Introduction INTRODUCTION Mazda Motor Corporation is proud to introduce the Mazda MX-3. The Mazda MX-3 was conceived, designed and developed to be unique and expressive. No conventional wisdom dictated its character or specifications. The MX3 product planning and design team set out to redefine and revolutionalize the compact speciality car, as their colleagues had successfully done to the affordable sports car concept in the MX-5. The Mazda MX-3 defies ready classification. It has great looks -sleek, smoothly contoured and animated- a sporting Mazda through and through in the direct lineage of the RX- 7 and MX-5. Yet the car accommodates four adults in comfort and carries ample luggage, and has the versatility of a hatchback. The interior surrounds the driver and passengers in comfort and inspires by its sporty environment. The MX-3 incorporates the latest in exciting technological features. Its performance and dynamics are an irresistible invitation to grand touring at its best, yet the car turns the shortest of commuting and errands into pure joy. The compact and aerodynamic MX-3 is endowed with Mazda's established quality that assures reliability and longevity. Mazda MX-3 Attributes Dramatic and emotional new looks The MX-3 is one of the most extraordinarily beautiful automobiles. It encompasses all the essential elements that make up a great design, fulfilling contradictory requirements. It is thoroughly modern, yet has a tint of romantic classicism. In fact, the planning and designing team’s goal was to create a classic beauty in decades to come. It has an eloquent visual expression of vehicle dynamics, yet radiates with elegance when standing still. www.mazda-press.com
3 / 33
Press Kit Mazda MX-3 1991
Four-seater that looks as dashing as a two-seat sports car The MX-3 is a coupe that accommodates four adults in comfort and has a versatile luggage space. The large doors and one-piece hatch make entry /exit and loading/unloading easy. Velvet - smooth Ligbt-Six With the MX-3, Mazda resurrects the compact grand touring car, as it has redefined the light-weight sports car with the MX-5. The premier engine is the type K8D 1.8-litre V6, the only one of its kind in the displacement class. The dualcamshafts-per-bank, four-valves-per-cylinder fuel-injected engine is powerful, torquey and willing, whose velvet-smooth power delivery and sweet sounds are matched only by Mazda's own rotary engine. This is the modem version of the Light-Six that once propelled a number of fine European compact grand tourers in the bygone romantic area. Superb dynamic - StaGility Mazda's chassis designers and development engineers have a canny way to describe the MX-3's superb road manner; "Spa-Pita." No such words are found in the Japanese dictionary, or any other language for that matter. They are phonetic expressions of the driver's action and the car's responsive behaviors. The driver flicks the steering wheel, more by wrists than arms, and the car instantly responds, turning into a bend, corner or an adjacent lane with minimal change in its posture. That's "Spa," the sound of a sharp knife cutting through an object. Flick it back, or into a new line, the MX-3 immediately stabilizes itself, with hardly noticeable roll, no undesired residual sway, which is the phonetic "Pita." Agility and Stability in unparalleled harmony. To coin a new word, "StaGility." Mazda' s renowned all independent suspension system for the front-wheel drive MX-3 is combined with one of the largest footprints in the class, a very quick and precise rack and pinion steering and ultra-wide low-profile tyres (V6-powered series) to elevate the art of automobile dynamics.
www.mazda-press.com
4 / 33
Press Kit Mazda MX-3 1991
Comfort The Mazda MX-3 offers a comprehensively equipped and well thought-out passenger environment. The design and materials chosen for the interior upholstery are sporty and tasteful. The car has an efficient heating and ventilation system.
www.mazda-press.com
5 / 33
Press Kit Mazda MX-3 1991
MAZDA MX-3 IN BRIEF The Mazda MX-3 is a unique and ambitious automobile with few peers in the automotive world. It has great looks, youthful yet refined, dashing and at the same time elegant, sporty and accommodating. The Mazda MX-3 is a three-door hatchback front-wheel drive coupe that accommodates four adults, two in the front seats with space to spare, and two more in the rear in good comfort for short and medium distance trips. It is not a 2+2 coupe, but an acceptable four seat car, with adequate luggage carrying capacity that can be increased by folding the rear seatback. The MX-3 is 4,220 mm lang, 1,695 mm wide and 1,310 mm fall, on a 2,455 mm wheelbase, and wide 1,460 mm front and 1,465 mm rear tracks. Curb weight ranges from 1,030 kg through 1,115 kg, depending on power unit choices. The MX-3 is offered with two engine series, the type B6E 1.6-litre inline fourcylinder engine and the all new type K8D 1.8-litre V6. The type B6E four cylinder engine employs single overhead camshaft, operating four valves per cylinder and an electronically controlled multi-port fuel injection system. It produces 66 kW (DIN)/5,300 rpm and a maximum torque of 135 Nm ( DIN ) at 4,000 rpm. The B6E engine is offered with the F-type five-speed transaxle. Optionally available is the F-4EA T electronically controlled tour-speed automatic transaxle which incorporates a torque converter lockup facility in the fourth gear to improve fuel economy. The premium engine offered in the Mazda MX-3 is an all new aluminium V6 engine, the type K8D, which features dual overhead camshafts on each bank of cylinders operating four valves per cylinder. The electronically controlled multi-port sequential fuel injection engine has a total cubic capacity of 1,845 cc, and is rated at 100 kW DIN net at 6,800 rpm and puts out 160 Nm DIN net maximum torque at 5,300 rpm. The K8 engine is mated to the G-type five-speed manual transaxle. Both the B6E and K8 engines run on regular grade unleaded gasoline (minimum RON octane number 90.) The power unit is mounted transversely at the front of the car, and drives the front wheels via equallength drive shafts.
www.mazda-press.com
6 / 33
Press Kit Mazda MX-3 1991
The Mazda MX-3's all independent suspension is by MacPherson front struts and TTL-located rear struts, which have been further improved, exploiting the car's wide tracks and adopting new suspension geometry for the optimum combination of handling, roadholding and ride comfort. Power assisted rack and pinion steering is standard. The V6 powered series features an exceptionally quick 15 : 1 overall steering ratio, endowing the car with sports car agility. The brake system for the B6E powered models is a combination of front ventilated disc and re ar drum brakes, with an 8-inch vacuum servo unit and dual hydraulic circuits. The K8D V6 engined series is fitted with disc brakes all around, the front pair ventilated discs of exceptionally large diameter of 257 mm and the rear set solid discs of 251 mm diameter. The V6 brake system is assisted by a tandem vacuum servo unit comprised of seven and eight inch servos. An advanced electronically controlled ABS (anti-lock brake system) is standard on the V6 series, while it is optionally fitted on selected four-cylinder models. The standard tyre-wheel combination for the four-cylinder series is 185/65R14 85H radial tyres on 5.5JJx14 pressed steel wheels with full caps. The K8D V6 powered models are fitted with ultra-low profile tyres of generous dimensions, 205/55R15 87V, on 6JJ pressed steel wheels with 6JJ rim width. The MX-3's body is a utilizing all steel welded construction of exceptionally high rigidity.
www.mazda-press.com
7 / 33
Press Kit Mazda MX-3 1991
2 Technical Information
PACKAGING AND DIMENSIONS Externally the Mazda MX-3 is a compact and stylish coupe with dashing sports car looks, with a sharply sloping, low front end, whose overhang is held at short 929 mm tor maneuverability and drive-war approach and departure. The MX-3 has a 2,455 mm wheelbase and wide 1,460/1,465 mm tracks, which form one of the largest footprints in the speciality coupe segment. The car measures 4,220 mm lang, 1,695 mm wide and 1,310 mm tall. The MX-3 is a four-seat coupe, not belonging to the school of more common 2+2 whose latter number annotates smaller members of a family. The car accommodates four adults, two AM95 percentile male adults in superb comfort in the front seats, two AF50 percentile females in reasonable posture in the rear seats. The distance between the accelerator pedal face to the rear seat hip point (SAE L57E measurement) is particularly long at 1,677 mm, allowing the occupants to assume relaxed postures. The luggage space, with the rear seatback in place, accommodates 289 litres of luggage by VDA measurement standards. It is accessed through a large wrap-around lift-up hatch whose opening is assisted by twill gas-filled struts, or through the folding rear seatback, which may be folded to increase luggage volume to a maximum of 390 litres. The luggage compartment's loading lip height is held at 864 mm. The fuel tank is located under the rear seat, ahead of the rear axle center, and has a capacity of 50 litres.
www.mazda-press.com
8 / 33
Press Kit Mazda MX-3 1991
EXTERIOR DESIGN AND AERODYNAMICS As in any automotive design endeavors, dozens of image sketches has been drawn by Mazda's designers assigned to the MX-3 project, in search of the right design concept for a unique automobile the company was about to create. For them, it was no mre theme search, but more like soul searching. What should this ambitious car look like? One that would combine the attributes of a grand tourer, a sports car, a four-seat car with ample luggage space. Obviously no mundane transport, it must have great looks, animated and dynamic to a degree that it would look as if it would breathe, purr, growl, dash and turn on its lithe limbs and wide paws. Yes, it must accommodate four adults in comfort. Above all, it must be Mazda through and through. A tall order indeed. Mazda's creative talents tackled the job enthusiastically and earnestly, drawing many image sketches. Some contemporary and right in a coming trend, some wild and others traditional. But none hit home, until a young Hiroshima designer came up with his image of the MX-3. It breathed in his sketch pad, looking ready to jump out of it. It became the basis of the MX-3 design, which was nurtured by a team of Mazda's designers and sculptors. The two-pillar-on-either-side configuration with an exceptionally large wrapover rear hatch impacts the appearance of a thoroughbred sports-GT car, in the direct lineage of the famed RX- 7. The lower body has the wheels as its tour corners, shod with wide and low-profile tyres, emphasizing the car's stability and strength, to which a sharply raked and toned-in greenhouse delivers a marked contrast, creating visual impressions of litheness and agility. The front-end graphics feature the fully integrated bumper with unusually sharp slant, at 45 degrees from vertical, and blend smoothly to the surrounding surfaces. They flank a small slit-like air-intake atop the bumper. Another unique MX-3 feature is a pair of powerful polyellipsoid projector fog lamps integrated in the front bumper. The compact power unit and ancillaries enabled the designers to lower the front end, without incurring a penalty of excessively lang and awkward overhang. The smoothly contoured bannet flows up to the large and sharply raked compound curvature windscreen (65 degrees from vertical - more raked than the RX-7 one,) www.mazda-press.com
9 / 33
Press Kit Mazda MX-3 1991
through the short roof panel onto the large rear light/hatch, which is one of the largest single piece glass panes. The rearmost vertical section of the hatch has a see-through mini-window, which improves rearward view, particularly in reversing maneuver, enabling the driver to spot a child of about 130-cm height who is standing immediately behind the car. The tail-lamp cluster shape matches that of the headlamp shape, rendering ready identification of the MX-3. The pressed steel wheels with full-face caps and the optional cast aluminium wheels are specific to the MX-3, and their designs emphasize the car's sportiness. With the aero-pack standard on the K8D V6 powered model, consisting of a large front airdam, side deflectors on the rocker panels and a raised rear wing-spoiler, the MX-3 has achieved an aerodynamic drag coefficient of Cd=O.31, combined with low lift characteristics.
www.mazda-press.com
10 / 33
Press Kit Mazda MX-3 1991
INTERIOR The integrated and contoured interior environment of the Mazda MX-3 impacts sportiness, security and comfort, perfectly matching the car's dynamic exterior design. The wide and large facia's softly padded top slopes down gently, opening up forward visibility, yet producing a sense of security. The facia raises up and forms a compact and integrated instrument nacelle, directly within the driver's natural field of vision. The instrument nacelle contains three large dials, a speedometer in the center, flanked by a rev counter on its fight and a set of auxiliary ganges on the left, comprising of fuel level, coolant temperature ganges and a digital clock. Two vertical rows of waming lamps are located on either side of the dials. Two side and two central heating and ventilation outlets are located on the facia's forward edge. The central console hauses slide-lever type climatic controls as well as audio equipment. The upholstery runs continuously from the facia, through the door trims and wrap around the rear seatback, comfortably enveloping the occupants. Pleasant colour-keyed cloth fabrics are used throughout the cabin, leaving no exposed metal surface. The front seats are sporty and supportive bucket types with high seatbacks and integrated head-rests. The rear seat accommodates two adults in reasonable comfort, and its seatback may be folded down to increase luggage capacity. A removable hardboard luggage compartment tray is standard fittment.
www.mazda-press.com
11 / 33
Press Kit Mazda MX-3 1991
ENGINES The Mazda MX-3 models offer two new types of overhead camshaft engines. The type B6E electronic fuel-injection unit is the latest version of the B-series family of inline four-cylinder engines that have proven outstanding performance, smoothness and fuel efficiency in various Mazda models, including the Mazda 323 and MX-5 sports car. The B6E has further been refined and improved for the MX-3, one of its main features being a new SOHC 16-valve cylinder head. The premier power unit is the all new type K8D 1,845 V6, the first and only one of its kind in the capacity class, which combines brilliant performance, unparalleled smoothness and good fuel economy, and it is a beauty to behold when the bonnet is opened. The light alloy engine features dual overhead camshafts on each bank of cylinders which operate tour valves per cylinder, and electronically controlled fuel injection (EGI) and centrally managed ignition system. The Type B6E SOHC 16-valve EGI Engine The type B6E SOHC 16-valve EGI 1,597 engine features four valves per cylinder in a compact pent roof shaped combustion chamber with ample squish area for efficient breathing and accelerated and thorough combustion. The valves are operated by single overhead camshaft. The engine combines high power output and generous low- and mid-speed torque for brisk and srnooth on-road performance, flexibility and excellent fuel economy. The B6E engine has internal dimensions of 78 mm bore and 83.6 mm strake, obtaining a total 1,598 cc cubic capacity. It is rated at 66 kW DIN net at 5,300 rpm, and produces torque through a wide rpm range, which peaks at 135 Nm DIN net at 4,000 rpm, on a 9.0:1 compression ratio. The overhead camshaft is operated by a silent and durable YU-tooth cogged belt in single stage. It acts on four valves per cylinder via three rocker arms; two separate arms operating the intake valves, and a single arm on the exhaust ones. Each rocker arm incorporates a hydraulic lash adjuster on its valve stern side. This ensures quieter operation and eliminates periodical adjustment.
www.mazda-press.com
12 / 33
Press Kit Mazda MX-3 1991
The valves are Vee-inclined at a narrow included angle of 40 degrees in a compact pent roof shaped combustion chamber with large squish area in the aluminium cylinder head. Valve diameters are 29.5 mm tor the intake and 23.5 mm for the exhaust, and lifts are 7.8 mm and 7.5 mm respectively. The valve train arrangement allows the placement of the sparking plug close to the center of the combustion chamber tor rapid flame propagation. Mazda' s effective noise and vibration reducing methods are applied to the new B6E, one of which is MBSP, short for Main Bearing Support Plate, an intricately shaped steel plate that has two functions: stiffening the cylinder block in the critical lower opening area and effectively reducing vibrations that might occur as a result of the block's torsional and bending distortion in the medium frequency zone, and secondly supporting the lower crankshaft hearing caps to minimize another critical source of vibrations. The ductile cast iron crankshaft is balanced with eight counter-weights, and is supported by five main bearings whose tolerances are closely controlled. It is fitted with a torsional damper within the accessory driving pulley to enhance smoother running. The lubricant sump is made of stift and sound-damping die-cast aluminium, and its rear end is bolted onto the clutch housing (torque converter housing in the automatic transmission models) forming a rigid power unit structure, thereby precluding vibration-inducing power plant bending. The electronically controlled fuel injection system employs multi-port injectors which inject fuel into two groups of cylinders in sequence (No. 1 and 3 in one group, and No. 2 and 4 in the other.) The plenum chamber-intake manifold assembly incorporates a resonator chamber to utilize resonance charge effect of the incoming air pressure waves. The induction system employs ISC (Idle Speed Control,) which is integrally built within the throttle body, and minutely and precisely controls the air volume required tor stahle and smooth idling operation. '" Ignition is by an electronically controlled, fully transistorized and contactless system that provides high energy and precisely timed firing. The exhaust manifold is a stainless steel fabricated and welded four-into-two system with near-equal pipe lengths, not unlike the one on the MX-5 sports car, for maximum extracting effect and minimum flow resistance.
www.mazda-press.com
13 / 33
Press Kit Mazda MX-3 1991
The B6E engine is a compact lightweight unit that facilitates installation in the transverse position in the low and sloping MX-3 engine compartment. It is canted 10 degrees forward. The Type K8D DOHC 24-vaIve EGI V6 Engine The Mazda MX-3 is endowed with a new premium engine, the only one of its kind in the capacity segment, whose performance and smoothness may only be matched by Mazda's own rotary engine. The V6 must fit in the low and sloping nose of the sleek coupe with no unsightly add-on bulge on the bannet. A tall order indeed, which could only be filled by an all new design trom the sump up, the type K8D DOHC (per each bank) 24-valve V6 with 60-degree bank angle. The type K8D engine has oversquare (a shorter strake to the bore) internal dimensions, 75.0 mm x 69.6 mm, to obtain a total cubic capacity of 1,845 cc. The engine is the smallest capacity V6 in volume production at the time of information release. It is also One of the lightest in weight and the most compact. The K8D produces 100 kW DIN net at 6,800 rpm and 160 Nm DIN net at 5,300 rpm on a 9.2:1 compression ratio using regular grade unleaded fuel (minimum 90 octane RON.) The engine's cylinder heads are aluminium, each carrying dual overhead camshafts. The camshaft drive is unique in that it is in two stages. The front bank exhaust camshaft and the rear bank intake camshaft are driven by a common singlestage cogged bell. These camshafts in turn drive the front bank intake camshaft and the rear bank exhaust one by a pair of gears, which are two phasing gears with odd and even numbers of teeth (55:56.) The driven gear with one additional tooth meshes tightly against the driving gear, as their name "friction gears" implies, leaving no room for noise-generating backlash. Mazda has bad considerable expertise in the design of the friction gear drive in its high output diesels, which has been applied to the K8D valve gear. The cast iron camshafts are drilled longitudinally in order to reduce weight. The primary camshaft drive, of the front bank exhaust and rear bank intake camshafts, has enabled the front of the engine and consequently the nose of the car to be lowered considerably.
www.mazda-press.com
14 / 33
Press Kit Mazda MX-3 1991
The valve train design allows a narrow angle between the Vee-inclined valves, forming a compact pent roof-shaped combustion chamber with large squish area and the centrally located sparking plug that ensure rapid and thorough combustion. The camshafts act on the valves via inverted buckel-type tappets which incorporate maintenance-free hydraulic lash adjusters (HLA.) The precision-die-cast aluminium piston's skirt surface is coated with molybdenum disulfide, allowing tighter clearance without inducing slapping noise against the cylinder wall. Connecting rods are forged of special steel alloy, and are light in weight and have high rigidity, benefiting the engine's short stroke. The three-plane even-throw crankshaft is made of forged steel, and ported by tour main hearings, of which the rearmost one is extra 26.5 mm to the other three's 20 mm, to provide secure support to minimize vibration from this critical part. The crankshaft journals' filleted sections are strengthened by the latest deep-roll manufacturing process. The 60-degree V6 configuration has inherently superior merits in noise and vibration suppression, as compared with an inline-four cylinder engine, because of its shorter and rigid block structure and of its smaller unbalanced dynamic inertia forces. Mazda's engine designers have adopted the unique split-construction cylinder block to further enhance the V6 engine's attributes. The cylinder block is precision-die-cast aluminium with elaborately shaped wall contours and reinforcing ribbing for exceptional robustness and light weight, achieved by Mazda's engineering expertise and its computer-aided design and analytical programmes. The open-deck upper block has a cast-in iron cylinder liners. The lower block also has cast-in iron bearing cap carriers, which together with integrally cast aluminium longitudinal twin beams form an extremely sturdy ladder-like structure which precludes thermal distortion of the block, as well as providing exceptionally rigid main bearing support. The two banks of cylinders are connected by the front and rear bulkheads of the block body, and are further reinforced by an upper horinzontal cover plate. Thus, the entire block structure, with the upper and lower blocks rigidly bolted, forms a short closed box with immense rigidity, yet light in weight and compact in size. The lower block with a pressed-steel pan also forms a lubricant sump, which is again sturdier and lighter than a conventional pressed-steel sump, contributing to minimizing radiant noise from this area.
www.mazda-press.com
15 / 33
Press Kit Mazda MX-3 1991
Lubrication is supplied by a force-feed system with a high efficiency rotarytype pump driven directly by the crankshaft. The cooling system comprises of a beltdriven centrifugal water pump, an electric cooling fan and a cross-flow aluminium radiator. The radiator type, its first use dating back to the rotary powered RIGG coupe and used by several high performance European cars, is both low in height and light in weight, fitting neatly in the MX-3' low nose, yet has ample heat dissipating capacity under most arduous climatic and driving conditions. Exhaust gas is collected from each of the three-into-one cast iron manifolds, into the exhaust system comprising of an under-floor catalytic converter and a large volume silencer, and let out through dual styled tailpipes. The entire system minimizes exhaust back pressure, and produces subdued yet unmistakably high-revving V6 notes throughout the engine's wide operating range. The K8D V6's Advanced Fuel-injection and Induction Systems The fuel-injection system is the latest in the digital-electronically managed Ljetronic multi-point port injection system. An 8 bit microprocessor centrally controls the variable induction system, ISC (Idle Speed Control) and on-board diagnostic function in addition to the fuel injection system. The fuel injection system employs two new and significant features; the first the integrated intemally metering side-feed injector, two of which are used for the V6's two banks of cylinders. The unit integrates three injectors, each of which is fed fuel from its side, rather than a conventional injector's top feed, which facilitates ready and stable restarting after high speed and load operations. The unit internally meters fuel, which improves the engine's throttle response from ticking through to wide-open running. The integrated metering-injector assembly is light and compact, and emits less operating noise, the last an important consideration when the whole engine has become so quiet that even ticking of ordinary injectors might have become obstructive. The injector unit is fitted with an integrated electrical harness, eliminating individual wiring to the injectors. Fuel is injected sequentially to the individual intake ports, allowing finer mixture control and precise injection timing which improves performance, responsiveness and fuel efficiency. Air flow in the induction system is measured by Mazda's new “Linearic" airflow meter, first adopted in the latest RX- 7 rotary engine, in place of a conventional vane-type flow meter. Made largely of precision-formed plastics, the www.mazda-press.com
16 / 33
Press Kit Mazda MX-3 1991
cylindrical unit is almost one half the weight of a metal air flow device (0.6 kilogram vs 1 kg,) and much more compact, facilitating installation. It employs a sliding measuring cone within the cylindrical casing, whose displacement by incoming air is translated as air flow. Mazda's dynamic supercharge effect induction system, VRIS (Variable Resonance Induction System,) has progressed to a new level sophistication in the K8D engine application. Resonance and inertia supercharge effects are fully exploited in six zones in the engine's entire rpm range, instead of the original VRIS's two zones (lowand mid-speed zone, and high-speed zone,) to optimize the engine' s torque characteristics. Mazda Variable Resonance lnduction System (VRIS) The type K8D V6 engine's induction system exploits two unique supercharging effects, Inertia Charge Effect and Resonance Charge Effect. Air within the induction tract is accelerated by the piston movement in the first half of the intake stroke and then pushed into the cylinder by its own inertia in the last half of the intake stroke. Air column in the intake manifold may be likened to a weight mass, and air within the cylinder aspring. The lowering piston induces the weightmass' resonance, whose optimum frequency is utilized to push air into the cylinder. The length of the induction tracts are determined to maximize the filling of the cylinders by Inertia Charge Effect. Resonance Charge Effect is unique to the V6 engine (actually two inline threecylinder units in one,) wherein air column vibrations produce supercharging effect. The weight mass-spring equation also applies to Resonance Charge Effect, in this case the air column within the resonance tube is the weight-mass and air in the plenum chamber is the spring. The K8D's induction system comprises of two separate plenum chambers which also act as resonance tubes (resonance chamber No. 1 in the schematic drawing.) Each chamber feeds air through individual tuned tracts to one bank of cylinders (three cylinders.) The plenum chambers-resonance tubes are connected by an intricately shaped resonance tube No. 2 on the outer ends and another resonance tube, No.3, in their mid-length. There are two butterfly-type valves in the resonance tube matrix, one at the entrance of the No. 2 tube (valve A in the diagram) and the other within the No. 3 tube www.mazda-press.com
17 / 33
Press Kit Mazda MX-3 1991
(valve B) which are opened and closed according to engine rpm, in six rpm zones, thus giving variations to the resonance tube length. The engine's torque curve "rides" on the best values produced by three different torque characteristics obtained by various resonance tube length.
www.mazda-press.com
18 / 33
Press Kit Mazda MX-3 1991
DRIVETRAIN The Mazda MX-3 offers the refined type-F five speed manual transaxle for the B6E inline four-cylinder engine powered series and an updated version of the type-G five speed manual transaxle for the K8D V6 powered models. Optionally available with the B6E engine is the latest type F-4EAT electronically controlled 4-speed automatic transaxle with torque converter lockup facility on the fourth gear. All engine and transmission options drive the front wheels via equal length drive shafts, which minimizes torque steer effect on starting and rapid acceleration. The Clutch for Manual Transaxle The manual transmission's clutch is hydraulically operated for light, smooth and positive operation. It is a single dry plate type with diaphragm spring. The type-F transaxle clutch has a 190 mm diameter disc, while that of the type-G is 215 mm. The Type-F Manual Transaxle This 5-speed manual transaxle was designed and developed specifically for the high torque output of the new B-series inline four-cylinder engine family, including the MX-3's B6E SOHC 16-valve unit. The gear assembly carries its third, fourth and fifth ratio synchronizers on the primary shaft, instead of on the secondary shaft of the previous generation F gearbox. These gears, except the one that is engaged, "free-wheel" on the shaft, thus greatly reduce the primary shaft's moment of inertia, enabling quicker and lighter gear changing. This arrangement also eliminates the clatter of gears when the vehicle is at a standstill as the secondary gear is stationary. The primary shaft is supported by ball bearings that have a lower rolling resistance, again contributing to smoother gear changes. The lateral travel of the gear lever in neutral between the longitudinal gates is a short 33 mm. The lever's fore-and-aft strake, between neutral to each of the gear positions is 58 mm. The lever's ball pivot rests on plastic upper and lower supports, which reduce noise and vibration transmission to the driver' s hand. The transaxle is housed in a two-piece aluminium housing of high rigidity, the design of which was aided by Mazda's computer model analysis program.
www.mazda-press.com
19 / 33
Press Kit Mazda MX-3 1991
The internal gear ratios of the type-F transaxle are closely spaced and are: first 3.416, second 1.842, third 1.290, fourth 1.028, fifth 0.820 and reverse 3.214, combined with a final drive ratio of 4.105:1. The Type-G Manual Transaxle The K8D V6 engine is mated to this updated version of the type-G high-torque manual transaxle, originally introduced in the Mazda 626 series. The type-G shares the same internal refinements as the type- F transaxle. Additionally, the reverse gear is synchromeshed in order to ensure smooth and quick engagement. The internal ratios are: first 3.307, second 1.833, third 1.310, fourth 1.030, fifth 0.837 and reverse 3.166, combined with a final drive ratio of 4.388:1. The Type F-4EAT Electronically Controlled Automatic Transaxle The F-4EAT electronically controlled 4-speed automatic transaxle is available with the B6E engined series. The transaxle’s torque converter lockup (on fourth gear) and gear changes are controlled by the dedicated transmission ECU (Electronic Controlled Unit,) and the hydraulic circuits are actuated by solenoid valves. The automatic transaxle permits the driver to choose Mazda’s unique HOLD mode in addition to the usual forward D-S-L positions. The Hold mode is switched on or off by a small push-button located )ll the selector knob below the selector-unlock button. The mode allows the driver to select and "hold" each of the lower three gears by operating the selector lever. It enables sustained second or third gear driving in mountainous terrain or on slippery surfaces. There is a safeguard feature that even in the HOLD mode, the transmission automatically downshifts from third to second when the vehicle restarts after a stationary period, so that adequate acceleration is obtained. The internal gear ratios of the F4-EAT are: first 2.800, second 1.540, third 1.000, fourth 0.700 and reverse 2.333. Final drive ratio is 3.833:1. Drive Shafts and Wheel Axles The drive shafts are of the same diameter and equal length, with a central support bearing. The shafts incorporate angular-contact tripod constant velocity joints. Each wheel axle is now supported by angular ball bearings that have lower revolving resistance.
www.mazda-press.com
20 / 33
Press Kit Mazda MX-3 1991
Power Unit Mounting The power unit is elaborately mounted at four points; at the lower sides of the transaxle's clutch/torque converter housing (No. 1 and 2. mounts) on the fight side of the engine (No. 3 mount,) and at the upper transaxle casing (No. 4 mount.) A steel-sheet-and-tube fabricated longitudinal frame supports the shear type rubber No. 1 and 2 mounts. The front end of this frame is rubber-mounted onto the body's foremost lateral frame, and the rear end rigidly bolted onto the suspensioncarrying cross member. The longitudinal frame and the cross member form a T shaped structure that contributes to the overall body rigidity. The right side of the B6E inline four-cylinder engine is attached to the carrier member on the body side structure via No. 3 rubber mount, which is fitted with a dynamic damper. The No. 3 mount unit ofthe K8D V6 engine is a fluid- filled rubber mount that absorbs power unit vibrations by damping action, which allows the adoption of lower spring rate that minimizes transmission of resonance to the passenger cabin in high frequency zone. The fourth shear-and-compression mount attaches the upper transaxle casing onto the body shell's left main frame member.
www.mazda-press.com
21 / 33
Press Kit Mazda MX-3 1991
CHASSIS The Mazda chassis designers have come up with a combination of suspension, steering and brake systems that achieve the highest order in vehicle dynamics and comfort, with special emphasis on "STAGILITY (Mazda's own acronym, combining STAbility and aGILITY, that expresses the targeted handling characteristics)" and positive safety. The MX-3's all independent suspension system features MacPherson struts at the front and rear TTL-located struts, the hallmark design of the front wheel drive Mazda cars. The system has been further refined and improved with specific geometry and components for the MX-3 application. The suspension's movement must be supple in order to obtain optimum ride comfort, yet it must be securely located for stability and agility. The MX-3 suspension's structural rigidity is augmented by a front transverse tie-bar and a rear lateral reinforcement rod (the latter for the K8D V6 powered models only.) The suspension is combined with wide-section, low-profile and large diameter tyres on wide-rim wheels. Steering is by a power-assisted rack and pinion system, whose assistance is varied according to engine rpm. The K8D V6 series features a quick 15:1 steering ratio, requiring only 2.7 turns of the steering wheel from lock to lock, for agile maneuvering. The brake system for the B6E inline four-cylinder series consists of front ventilated disc brakes and rear drum brakes, with vacuum servo assistance. The K8D V6 range had an upgraded all disc brake system with front ventilated and rear solid disc and a tandem vacuum servo boost unit. An advanced electronically controlled four-wheel ABS anti-lock brake system is standard with the K8D V6 powered range, while it is optionally offered in the B6E inline-four cylinder series in conjunction with rear disc brakes. Front Suspension The front suspension is a lightweight and space efficient MacPherson strut type. It employs lower pressed-steel transverse A-arms, with wide mount base. The Aarm design is specific to the MX-3 and exploits the car's wide 1,460 mm track (the
www.mazda-press.com
22 / 33
Press Kit Mazda MX-3 1991
arm is 15 mm longer than that of the Mazda 323.) The arm's front rubber-bush mount point is in line with the wheel axis, and the rear mount is a fluid-filled rubber-bush type. The arm mount method assures ample fore and aft compliance in the mount pivots, and provides high lateral rigidity while eliminating unwanted compliance steer effect. The A-arms are carried on the pivots on a cross member, a sturdy fabricated steel closed-section subfrarne, on which the steering gear assembly is also attached. The cross member in turn is rigidly bolted onto the body shell, and is further reinforced by a steel-sheet fabricated transverse member that ties the A-arm mount hases. The structure and mounting method have greatly added to the suspension assembly's lateral rigidity, an essential element tor precise and agile handling, as weIl as secure roadholding. The strut-damper unit and the coil spring are offset mounted to preclude frictional interference between them. The damper tor the K8D V6 powered models is fitted with a valving system that minutely and precisely controls damping force in the very low speed damper range, from as low as 0.01 meter per second, which minimizes initial roll attitude when the vehicle is subjected to such maneuvers as lane changing and cornering. A tubular steel bar that crosses over the engine compartment ties the strut's top mounts of the K8D V6 powered range. This top bar together with the lower transverse member that connects the A-arm pickups on the cross member form an extremely rigid suspension-mounting base tor this performance oriented series. An anti-roll bar is standard on the front suspension. That of the K8D V6 powered series is a solid bar of 22 mm diameter, and that of the B6E four-cylinder range a tubular 19-mm diameter bar. The anti-roll bar is mounted onto the A-arm faces via ball-jointed links, which enable the bar to quickly react to the smallest difference between the left and fight wheels' vertical movements. The front suspension's geometry incorporates a negative camby value of -0º48’ (unladen) for improved grip, and an acute caster angle of 2º38’ (unladen) with a 12.8 mm trail for better straight-line stability. The front suspension allows 75 mm of jounce (upward) and 90 mm rebound (downward) wheel travel.
www.mazda-press.com
23 / 33
Press Kit Mazda MX-3 1991
Rear Suspension The real suspension is the latest version of Mazda's TTL (Twin-Trapezoidal Link) independent suspension, in which the strut-damper unit is located on splayed twin-transverse links and a trailing link. The transverse links are again lengthened to receive full benefit of the real track width of 1,465 mm. Both the twin transverse links and the mounting bushes are tuned so that the suspension's geometry further enhances its toe adjusting capability. Specifically the latest TTL geometry reacts quantitatively to the lateral force encountered during cornering and lane-changing. In response to moderate lateral force, the rear wheel assurnes an almost zero toe, thus aiding the car's "turn-in" ability. During increased lateral load conditions, the amount of toe-in becomes larger, thus increasing the rear tyre's comering force and stabilizes vehicle behavior. Like the front suspension's lower A-arms, the new TTL has lengthened transverse links (each 15 mm longer than the Mazda 323's,) and provide suspension travel of 90-mm jounce and 120-mm rebound. The long suspension travel produces an excellent combination of supple ride, low noise and vibration and outstanding roadholding ability. The rear strut-damper and the coil spring are concentrically mounted. The damper for the K8D V6 powered models is similar to the front one, featuring a valving system that minutely controls damping force at very low operating speed. A 20-mm diameter tubular anti-roll bar is standard in the B6E four-cylinder range, while that of the K8D V6 series is a solid bar of 20 mm diameter. The twin transverse links are mounted via rubber bushed through-bolt pivots onto the pressed steel cross member, which is rigidly bolted onto the body shell. The rear pivots on the cross member are tied by a lateral reinforcement rod, which greatly enhances the suspension assembly's lateral rigidity, thus improving the rear tyres' adhesion. The rear suspension's geometry is tuned for optimum handling and stability, and includes a negative camber ( - 0º55’) and an initial 2-mm toe-in (unladen.) Wheels and Tyres The B6E four-cylinder series is fitted with a combination of 185/65R14 85H radial tyres on pressed steel wheels of 5 1/2JJ rim width and styled full-caps as standard equipment. The K8D V6 range features 205/55R15 87V high performance www.mazda-press.com
24 / 33
Press Kit Mazda MX-3 1991
radials on steel wheels with 6JJ rims, one of the widest tyre-wheel combinations in the class. Cast aluminum wheels are optionally available in the K8D series. Steering The new Mazda MX-3 is equipped with rack-and-pinion steering with enginerpm sensing power assistance as standard equipment. The B6E four-cylinder series has an overall steering gear ratio 17:1, calling for 3.1 turns of the steering wheel from lock to lock to execute a 10.6-meter wall-ta-wall turning circle. The K8D V6 powered range exploits the suspension's sportier setting with an exceptionally quick 15:1 steering ratio, requiring only 2.7 turns of the steering wheel from lock to lock. The steering gear assembly is securely attached on the suspension-carrying cross member, eliminating play and enhancing steering responsiveness. The steering's power assistance is provided by a high efficiency hydraulic pump. A new rotary spool valve is employed to minimize torque fluctuation between left and fight turns. The four-spoke steering wheel has soft urethane-filled rim and is 370 mm in diameter. Brakes The B6E four-cylinder series' brakes are a front ventilate disc and rear leadingtrailing drum combination. The disc diameter and thickness, including air-ventilating slit area, are 257 mm and 22 mm respectively. The brake system is assisted by an Sinch vacuum servo. The dual hydraulic circuits are diagonally split with twill pressureproportioning valves fitted to the rear circuits to provide stable braking performance. The K8D V6 series employs all disc brakes. The front discs are ventilated and have 257 mm diameter and 22 mm thickness, and the solid rear discs 251 mm diameter and 9 mm thickness. Mazda's chassis engineers deemed it appropriate that the V6-powered MX-3 should be provided with an ample reserve in its decelerative and stopping capability, if the model's brilliant performance potential is to be fully exploited and enjoyed, thus the choice of larger brakes that produce more than enough stopping power even for vehicles in a higher weight class.
www.mazda-press.com
25 / 33
Press Kit Mazda MX-3 1991
The powerful, all disc system is assisted by a new large volume tandem vacuum servo unit, comprising of 7-inch and 8-inch servos, that assure secure and progressive retardation throughout the car's entire speed range. Additionally, the all disc system is equipped with a new high-output and "short" (in physical size, as it is 40 mm shorter than a comparable conventional unit) master cylinder unit. Mazda's brake designers and development engineers aimed to eliminate "play," or delay in braking response. This objective has been achieved by studier calipers, and expansion-resistant flexible hose which have essentially shortened the brake pedal's operating strake. Additionally in the K8D models, the new compact high-output master cylinder and the tandem vacuum servo contribute to precise and quick braking response. The disc brakes' friction pads are made of asbestos-free, low-steel content semi-metallic material. Electronically Controlled 4-wheel ABS (Anti-lock Brake System) The tatest generation electronically controlled four-wheel anti-lock brake system is standard on the K8D V6-powered series, and optionally offered on selected models in the B6E four-cylinder range, the latter with the rear drums replaced by solid-disc brakes. The system consists of an electronic control unit, four-wheel sensors, each checking the individual wheel's revolution, and a new compact actuator that regulates hydraulic pressure. The front wheel brakes are separately regulated and the rear pair collectively, by four actuator valves, thus eaming the designation "the 4 (wheel)sensor, 4-valve, 3( control)-channel ABS." The main feature of the new actuator is that its pressure supplying motor comes into operation when ABS functions, promptly and smoothly meeting pressure modulating requirements. This compact actuator unit provides superior ABS performance than a simpler 4-sensor, 2-channel system. It is closer to a full 4-sensor, 4-channel type. The ABS ensures optimum braking performance even in such adverse weather and road conditions as rain, snow, ice and other slippery conditions.
www.mazda-press.com
26 / 33
Press Kit Mazda MX-3 1991
BODY The MX-3's body design presented a unique challenge to the Mazda engineering team. The stylish four-seat coupe body has two pillars on either side instead of the more common three-pillar construction, and it has very large apertures for the doors and rear hatch. The bending and torsional stiffness were not the easiest to attain, because of this unique style and configuration. Mazda's designers and engineers welcomed this challenge, fully adhering to the company's long held and prevailing philosophy that an automobile body of exceptional structural and dynamic rigidity is the basis for superb handling, roadholding, comfort and, above all, solid passenger security. The automobile's various dynamic components, including suspension, steering and brakes function most efficiently when located in a body that provides solid support. Mazda's mastery and accumulated knowledge of designing and manufacturing bodies with maximum rigidity were fully applied to the MX-3 body structure. Advanced computer-aided structural analysis techniques, Finite Element Analysis and Dynamic Modal Analysis, were employed in the design, analytical simulation and development of the MX-3 body. The MX-3's all-steel welded body matches, and in one important measurement surpasses, that of the Mazda 323 hatchback, which itself is truly a milestone in recent automotive body design and construction by the high standards that have govemed Mazda's recent products. Specifically the longer and wider MX-3 body attains the same torsional stiffness as the 323, while bettering it in bending stiffness. Lightness is another important ingredient in an automobile's performance and efficiency. The larger MX-3 body with doors, hatch frame, bannet, weighs the same as the 323 hatchback's. Corrosion protection was another priority design goal; the MX-3 body construction incorporates the latest surface treatment technique on its critical components that assures longevity. Body Structure The MX-3 body is an all-steel welded unitized construction with rigidly bolted power-unit and suspension carrying sub-trames. The underfloor structure follows the
www.mazda-press.com
27 / 33
Press Kit Mazda MX-3 1991
basic design of the 323 hatchback, and features large section, heavy gauge steel side sills, and the longitudinal frame members that run the car's length. To improve torsional rigidity, dual-box sectioned torque boxes reinforce the parts that connect the side sills and front longitudinal frame members. The underfloor cross members, four in all, are also of heavier gauge steel. The upper body structure is unique to the MX-3, which is a two-pillars-oneither-side hatchback with exceptionally large door and hatch openings. To obtain maximum stiffness, torsionally and in bending, each of the major frame members connects to other members at either end, forming a loop. These loops in turn form the body structure. The door and hatch apertures are surrounded by the looped frames. The quarter panels have triangulated inner reinforcing trames that greatly add to the body's overall stiffness. Additionally, the radiator shroud tipper member, a foremost structural member, is dual-sectioned and reinforced at either end, which contributes to reducing idling vibration that affects this area. High tensile steel is used extensively for both strength and light weight. The use includes the bonnet, front fenders, inner A-pillars, lower A-pillar inner extensions, outer door panels, side-sill trays and inner members, rear trames and roof-rail inner members. Corrosion Protection and Sound Proofing The MX-3 body makes extensive use of the latest in sheet metal treatment technology; the organic resin coating of galvanized steel sheet. As its name implies, zinc-nickel plated steel sheet is coated with organic resin clear paint. The process greatly enhances the galvanized sheet's corrosion resistance. The organic resin coated galvanized steel is used for the body's outer panels, front and rear tyre housings and rear side frames. The new organic resin treated steel accounts tor 50 per cent of the galvanized steel, which in turn is 25 per cent of the total steel sheet used in the MX-3 body. The rocker panels and the lower door sections are sprayed with urethane-based anti-chipping primer. Adhesive sealing and wax are generously applied to the critical parts of the body shell to add to its corrosion resistances. The body's underside including the wheel arches is coated with 1-mm thick layer of undercoating to minimize noises transmitted from irregular surfaces as well as protecting from flying gravel. www.mazda-press.com
28 / 33
Press Kit Mazda MX-3 1991
Exterior Fittings and Bumper System The outer panels are closely fitted with minimum parting clearances to maId into the car's flowing contour. Silicon coat is baked on the outer lips of the rubber weather strippings on the body's tipper door periphery as well as on the door's window frame. The treatment gives a shiny metallic appearance to the rubber strips. Each windshield wiper is mounted on a twisted hinge (15-degree twist,) which markedly improves the wiper's resistance to lift by wind force, by as much as 25 km/h. An equally important wet-weather safety feature is the continuous rain gutter on the A pillar and roof-side, which assures adequate visibility through the door-mounted rear view mirror by effectively deflecting droplets. The front bumper system incorporates a blow-mold plastic reinforcement bar, made of lightweight, energy-absorbing material first used in the MX-5 sports car. The front and rear bumper surfaces are resilient polypropylene plastic, which closely match the body's contour. Theft Prevention The MX-3 incorporates a number of theft-deterrent measures on the door and hatch locks, to minimize the risk of tampering and break-in. They include: * A larger part of the interior door lock linkage is located between the door inner panel and the trim, preventing tampering from outside. * A deflector plate on each door window pane deflects a rod or tong from the lock mechanism. *The door lock is fully encased to minimize tampering. It also prevents corrosion. *The exterior key-cylinder is integrated into the pull-handle base preventing "pulling out" of the cylinder. *The hatch key-cylinder has an extended guide-hole. This prevents the lock from being twisted off. Comfort and Convenience The MX-3 is optionally available with a full air-mix type air-conditioning system which employs a new high-output rotary compressor, an improved condenser and smoother air-ducting in order to fully satisfy climate control requirements in this airy cabin with a large glass area. www.mazda-press.com
29 / 33
Press Kit Mazda MX-3 1991
SPECIFICATIONS
www.mazda-press.com
30 / 33
Press Kit Mazda MX-3 1991
www.mazda-press.com
31 / 33
Press Kit Mazda MX-3 1991
www.mazda-press.com
32 / 33
Press Kit Mazda MX-3 1991
www.mazda-press.com
33 / 33
