The third generation Prelude makes the list for a few reasons. Most significantly; it was the first production car to offer four-wheel steering. Not only was it the first, but was (and still is) the only four-wheel steering automobile to use a completely mechanical system to steer the rear wheels. This means that the driver, through the steering wheel, has complete control over the angle of all four wheels. In other words, there always exists a direct mechanical connection between the steering wheel and all four wheels. This was unique, as every other four-wheel steering automobile since has used a system where the rear wheels are controlled indirectly by a computer through an electronic or hydraulic servo. This differentiation made the 4WS Prelude comparatively intuitive to drive, although this may not have been appreciated at the time of debut, as their was no other 4WS system to compare it against.
At the heart of the 4WS system was a planetary gear which was turned by a central shaft connecting to the front steering rack. This novel hypocycloid gearset allowed the rear wheels to turn in the same direction as the front wheels during small steering inputs, up to 1.5 degrees, and in the opposite direction during large steering inputs, up to a maximum of 5.3 degrees. The latter attribute helped during tight manoeuvering, decreasing the turning circle by a full metre, while the former led to better road holding and stability during sudden lane changes. The increased grip during sudden lane changes was due to the effect of the combined slip angles of all four wheels acting on the road surface, while the increased stability was due to the fact that the car body turned less during such manoeuvers, lessening its rotational momentum which allowed for easier recovery.
Side Note: To see how the hypocycloid gearset worked, go to mekanizmalar.com/hypocycloid.html .
Change the Inner Disk Radius to 200, and the Outer Disk Radius to 100, and the last one to 100 also. You will see that this draws a straight line.
However, in the real world, the 'peg' which draws this line must have some strength. It therefore has a diameter which requires that it is mounted just inside the periphery of the inner gear.
Change the final value from 100 to 70, and you will notice that the line is no longer completely horizontal. In the Preludes 4WS mechanism, the scotch yolk accomodates this slight vertical movement.
The effect of the 4WS mechanism acting in this way was non-linear steering. That is, the effective steering ratio varied from a low ratio at small steering angles, to a high ratio at large angles. This means more steering angle input is required to perform a gradual turn, making the car less twitchy and more relaxed to drive at high speed, without requiring constant corrections; while less steering angle is required to perform a tight-radius turn, giving the car a go-kart like feel during tight manoeuvers. The observed effect while driving might be best imagined as a variable effective wheelbase, from a long wheelbase at small steering angles, to a very short wheelbase at large angles.
Click here to see a 200kb wmv video of the 4WS system in action
The 4WS system gave the Prelude a few unfamiliar quirks: The driver had to allow a few inches clearance from the curb when leaving a tight parking space, this was in order to allow the rear-end the appropriate clearance to swing out at high steering angles. An inexperienced driver, if parked too close, might find himself stuck as the rear wheels dug in to the curb. The drivers side A-pillar sometimes obstructed the view of the road ahead when traveling certain diameter bends, this was due to the 'sideways' effect of the rear wheels steering in the same direction as the front wheels, increasing the effective wheelbase (stretched limousines may also share this problem). The inexperienced driver might also turn too early into a fast approaching corner, veering into the left side of his lane, due to the long-wheelbase effect at small steering angles. This would only occur if the steering wheel was moved suddenly and not gradually into the corner, however.
The engine was a 2.0 litre (1956cc) DOHC 16-valve unit of all-alloy construction, typical of sports cars from the era. It was the last engine designed by Honda before the introduction of VTEC and as such did not feature any form of variable valve timing. The engine was quite powerful despite this and made between 130 and 145 horsepower at 6000rpm with fuel injection. One unique feature of this engine was a variable geometry intake manifold: It consisted of two intake passages per cylinder, one small and one large, the latter containing a butterfly valve. To maximize the mass of air flowing into the engine, such as required during high-rev full-throttle operation, both passages remained open. When signaled by the engine computer, however, the larger passage was closed, thereby forcing the air through the smaller aperture. This increased the air velocity, which allowed better filling of the cylinders at low rpm, improving low to mid-range torque as well as idle quality. The pre-filter section of the intake, which collected cold air from the crevice between the hood and the right-side headlight, was a complex design featuring a baffle and an open-air resonator, all of which helped to minimize noise escaping from the intake.
In the United States, the Prelude came equipped with a 2.1 litre (2056cc) engine on SR models, which were available from 1990. This engine used an experimental carbon-fibre reinforced cylinder lining, which allowed for thinner sleeves, increasing the bore and therefore capacity by an extra 100cc. These were designed to expand less during changes in temperature, producing a better seal between the piston and the cylinder, thereby reducing emissions. Unfortunately, these engines later gained a reputation for burning oil after high mileages. These problems were eventually ironed-out and Honda has since used the process successfully on subsequent models.
The SiStates model, which was the last of the 3rd Generation Preludes and sold in Japan only, came with an improved iron-sleeved version of the B21 engine. This engine was the most reliable and powerful of the series, featuring a rather high compression ratio of 10.7:1 for improved fuel economy.
The Prelude was also available with a less powerful engine in some of the cheaper models. This engine, a SOHC 12-valve, with one intake and two exhaust ports per cylinder, was one of the last to use a carburetor, which was a sophisticated computer controlled unit which gave around 110hp. Many engines also utilised Exhaust Gas Recirculation (EGR), which reduced power slightly, in order to meet emissions requirements in some export countries.
The suspension was typical-for-Honda double-wishbones all around. This gave the car sharp handling as well as a comfortable ride. They were designed to be compact, so as to not intrude on engine or luggage space. Nevertheless, the transverse engine layout in combination with double-wishbones, and the wheel clearance needed for operation of the four wheel steering system, dictated a comparatively wide footprint. In 1987, Road & Track published a test summary that shows the 1988 Honda Prelude 2.0Si 4WS outslalomed every car of that year, including all Lamborghinis, Ferraris, and Porsches. It went through the slalom at 65.5 mph. The 1988 C4 Corvette did the same at 64.9 mph.
The Prelude was also Wheels magazine's Car of the Year for 1987.
The transmission was either a slick 5-speed manual or a 4-speed automatic. The automatic, though typical for Honda, wasn't an automatic in the traditional sense: It did not contain any planetary gearsets but was rather equivalent to an automatically controlled 4-speed manual, with a lock-up torque convertor in the place of a clutch. Individual clutches connecting each gear to its shaft were shifted via computer controlled hydraulic solenoids, utilising hydraulic pressure from the torque convertor in the same way as a traditional automatic.
Click here for more information on the Hondamatic Automatic Transmission.
The exterior design of the 3rd Generation Prelude is also worth mentioning. The aim for the designers was high visibility, giving the driver a better awareness of the road. The hoodline was exceptionally low, allowing an unrivaled forward visibility that made this Prelude a joy to drive. The engine was tilted backward 18 degrees, and the engine mounted low, to allow for this. This gave the Prelude an extremely low centre of gravity, which further improved handling. The six pillars that support the upper frame, which housed a retractable sunroof, were comparatively thin. This, combined with a low shoulder-line, helped to minimize blind-spots and increased the confidence of the driver during tight manoeuvering.
Overall, these design features combine to make the 3rd Generation Honda Prelude interesting and fun to drive.
The Honda Prelude was first manufactured in Japan in 1987. It received a facelift in 1989 and was superceded by the more conventional 4th generation Prelude, which had optional speed-sensitive independent 4ws and VTEC, in 1991. Options from 1987 onwards included 4WS, 5-speed manual or 4-speed automatic, and ABS brakes. Some models had an Integra-style nose, with fixed headlamps and grille. These were known as INX models and came in a variety of trim levels. Limited-production 'SiTCV' models, equipped with Traction Control and a Torsen limited-slip differential, were available from 1990. SiStates models, which were the last of the Preludes to be manufactured in Japan, came with power-folding mirrors and extra sound deadening materials, and an optional leather interior. These are the rarest as only around 5000 were manufactured. These also came equipped with a reliable high-compression (10.7:1 compared to 9.5:1) iron-sleeved version of the infamous B21 engine. Both the SiTCV and SiStates models were equipped with automatic climate control and were only available with an automatic transmission.
Click here (or here for my the CarDomain page) to see pictures of my car, a 1991 SiStates.
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