For VW, the sports car market has always seemed to be a blind alley. However, blind alleys don’t have to be dark and dingy. In the case of the VW Corrado it was more a pleasant cul-de-sac
Volkswagen had never made a true sports car before — some would say it still hadn’t — when the Corrado was introduced in 1990. In many ways it represented the rebirth of the famous Karmann-Ghia, except that despite being much sportier, it was less successful sale-wise.
The business case for the Corrado was based on filling a gap left by the now defunct Porsche 924, for a high quality sports coupe. VW clearly hadn’t taken account of how much of the 924’s relative success was due to it being called a Porsche.
Like its forbear, the Corrado body was once again built by Karmann in Osnabrück, but, as far as we know, only prototype convertibles were built — a shame as this was something that Karmann did particularly well. The lack of a convertible and the fact that it was a full four seater failed to convince the market that the Corrado was a true sports car, something that VW tried very hard to emphasize in its sales literature. It had the disadvantage of appearing to directly replace the VW Scirroco, which finished production in 1988, once again, a fine car with attractive styling, but no sports car. Billed as Volkswagen’s “first full-blooded sports car,” the Corrado measured 6.3 inches shorter than the Scirocco, but nearly three inches longer in wheelbase. It was also two inches wider and weighed some 450 pounds more.
Golf Handicap
Both the Scirroco and Corrado had one huge rival that they could not shake off — the VW Golf GTi. It was difficult to make a case for either when presented against this much cheaper but nearly as effective bread and butter hot-hatch. I don’t believe, despite VW’s press releases, that the Corrado was ever seen as anything but a hot hatch, or nicely clothed Golf by car buyers at large, although those who got to drive them were immediately smitten.The Corrado was designed to compete with the Celica, Starion, RX-7 and Prelude, but VW believed its essentially European appeal would attract a rather different customer.
Based on the Golf/Jetta platform, the Corrado got standard four-wheel disc brakes, with anti-locking optional. A comfortable four-seater, Corrados featured an ‘active’ rear spoiler which extended automatically when the car reached 50kph to reduce aerodynamic lift by 60% at high speeds. As speed dropped below 20kph, the spoiler retracted again. It was no gimmick apparently and made a noticeable difference to stability over 100kph, which is when the spoiler eased out of the body on German market versions.
Following a recent Volkswagen tradition, the Corrado was named after a Spanish wind, like the Scirocco, Jetta, Vento and Golf. The name is also taken from the Spanish verb ‘Correr’, which means to run or to sprint; precisely what Corrado was designed to do. The 1987 prototype, named ‘Typhoon’, featured the 136bhp (101kW) version of the 1781cc engine that has helped the Golf GTi 16V storm the sales charts. This engine had proved an enormous hit in Formula 3 racing and endowed the aerodynamically smoother (0.32 drag coefficient) Corrado body with a top speed was of 132mph (212kph), whilst its all-important 0-100kph dash took just over 8 seconds.
Surcharge
Volkswagen launched its front-drive, hatchback sports car in 1990 with a supercharged eight-valve version of the four-cylinder engine used in the Golf called the Corrado G60. The 1.8-litre supercharged engine produced 158bhp (119kW), driving a five-speed manual transmission. Dubbed ‘G-Charger’ or ‘G-lader’ in Germany, the engine had a crankshaft-driven supercharger shaped like the letter G. The supercharged G60 developed 160bhp (119kW) giving a top speed of 140mph (225kph) with 0-100kph coming up in 7.5 seconds.
The supercharger was designed to give the performance of a turbocharged motor but without the turbo lag which effected cars with that technology at the time. Performance of the supercharged coupe was similar to that of the current 139bhp (104kW) Golf 16V because the G-Lader takes 16bhp to run at full load and the Corrado is also a good 150kg heavier than the Golf.
Whilst the supercharger was less evident than a turbo to the occupants, giving a slight whine but no huge blasting noise, the crank driven advantage was slightly lost by the length of the induction system. The pressurised air travels from the blower across the engine bay to an intercooler and back to the inlet of the Digifant electronic injection; A long column of air to move, even at the turbine’s 11,000rpm maximum.Peak torque was l661b/ft at 4000rpm, and 100lb/ft from 2500 to 5600rpm.
As presented the G-lader was an interesting piece of technology which was strong and powerful but had neither the surging mid-range gallop of a turbo or the instant thump of a big capacity unit. What it did give was impressive flexibility without the revs needed in the 16V version. Performance was deceptive rather than impressive.
The chassis was first class; better than the GTI’s, good though that was, since it managed to have less roll and yet feel more compliant over the rough stuff, which VW achieved by employing very long springs. A MacPherson strut front end and the torsion-beam rear with its selective-deformable mountings with fore-and-aft compliance conferred a small, measured dose of rear-wheel steer at high cornering forces. The tuned rear suspension mounting bushes reduced road noise and thump at the same time as neutralizing the natural understeer, meaning you had to charge hard at a corner to break the grip at the front or rear.
Pay Dirt
There is no question that the Corrado has excellent road manners and a fair turn of speed. It also had quite individual styling at the time, and was a car for the discerning customer. The major problem that Volkswagen had was in persuading discerning customers to drive the GTi and Corrado back to back, and then even if they did, convince them that the excellent handling was worth the extra money, and with the G60, the extra complication.
The Corrado did not hit pay dirt until Volkswagen installed the narrow angle V6 towards the end of its life. The customers could now easily justify the additional style and expense because of the smoother, silkier, torquey engine which clearly differentiated the Corrado and convincingly took it out of the hot hatch arena, and into the refined sports coupe market.
Either way, the Corrado would not enjoy a long production run, and was a victim of the Golf GTi’s success, particularly when the Golf cabriolet version came along. VW needed the production space taken up by the Corrado for the the Golf cabriolet, which was a real money spinner. In total Karmann produced 97,521 Corrados which will ensure that in years to come it will be a bit of a collector’s piece.
In driving these cars today it is apparent that they, like most VWs, are extremely well built, and typically Germanic inside, lacking the sense of occasion of an Alfa for example, but simple, efficient and well equipped.
The Supercharged car did feel like it had more torque, but not so much that it felt more lively overall than the modified white four valve car, which really went like the wind (ahem). The gearchange in the Corrado is excellent and really helps the driving experience. All of them handled well, giving very faithful turn-in and grip, but the modifications to the white car made it easily the most rewarding of the bunch. I guess the true test would have been to have checked out the Golf GTi at the same time to show what everyone was missing by passing over a sports car in casual clothes, in favour of a sedan in a track suit. However, the VW sports car (in casual clothes) has an enthusiastic bunch of Kiwis who will ensure that these rare cars do not become extinct.
The G-Lader
Conventionally boosting engine torque is achieved by increasing swept volume. The alternative is to supercharge by means of exhaust driven turbo or a mechanical supercharger. VW chose to develop a supercharger despite wide experience with diesel turbos.
As a principle, supercharging was certainly known about in the 19th century and many of the classic cars of the ‘20s and ‘30s were ‘blown’. By far the most popular supercharger was the Roots-type with interlocking rotors. In 1905 a Frenchman, Louis Creux had the idea of squeezing air between two interlocking scrolls, metal sheets wound into a simple snail-shell shape. These moved relative to one another in such a way that, as the air was hustled between the fixed and the moving scroll, it was also compressed. In 1905, Creux’s idea worked beautifully on paper but not in practice.
Even if the materials had been available, the technology necessary to machine and assemble the parts with sufficient accuracy was not. Volkswagen’s research and development engineering department felt that if these problems could be solved with 80s technology, the G-Lader might overcome the drawbacks of other kinds of mechanical supercharging, principally high operating noise and narrow speed bands of peak efficiency.
The problems were indeed overcome with the aid of hard work and genuine innovation in the area of casting and then machining the scroll profiles. In its definitive form the G-Lader contains two scrolls, one fixed and the other driven, between two end- plates. The end-plates and the fixed scroll, which form a single assembly, are of aluminium alloy. The driven scroll is made of magnesium alloy to keep its inertia low. In its fully developed form the G-Lader is deceptively simple. The moving scroll is driven by a simple eccentric mechanism which gives it exactly the right motion relative to the fixed scroll. The original drive comes from the engine crankshaft via a poly-V belt, automatically tensioned.
The air intake lies at the periphery of the scroll housing, and each wedge of intake air, squeezed tighter as it is pushed round, finally exits at the centre. There is no contact between the moving and fixed scrolls (just as there is no contact between the lobes of a Roots blower) and the efficiency of the unit depends on maintaining a close but consistent separation ” hence the need for precise manufacture.
The G-Lader delivers reasonable air pressure much sooner than an equivalent turbocharger, mainly because its own output depends purely on its driven speed and not on the engine load. In fact there are several points in the speed range where it delivers too much boost, and in these phases a linkage direct to the throttle ensures that a bleed valve redirects surplus air. Volkswagen made the G-Lader reliable and quiet with no special lubrication requirements. It matches engine outputs more closely to actual road driving by boosting lower and mid range torque without lifting peak power too much. The maximum output of the G-Lader (for a given maximum speed of around 11,000rpm) can be varied by altering the width of the scrolls, keeping the end-plates standard.
Corrado Timeline
1990: First production cars were all G-60, left hand drive only, the 16V RHD becoming available later in the year.
1991: Four-speed automatic transmission became available, and wider (205/50VR15) tyres on new BBS alloy wheels. Leather upholstery and a theft-alarm system also joined the options list.
1993: Minor facelift. The G60 is replaced by the narrow angle 15 degree V6. Front suspension redesigned, and new five-spoke wheels were used. Standard equipment now included antilock brakes, and electronic differential lock.
1995: Production of the Corrado ends
Our Featured Corrados
1990 VW Corrado 16V (red): Owned by Neil Penfold for one year. Standard specification, New Zealand new.
1990 VW Corrado 16V (white): Owned for last four years by Aaron Ross. UK import in 1996 and modified by BR Motorsports in the UK, head, Schrick cams. Fitted with 2.0L block in New Zealand with Miltec headers. Lowered by 40mm with 16-inch Porsche replica wheels.
1990 VW Corrado 16V (blue): Four New Zealand owners, now owned by Tristan Zlami who only purchased the car a week before our test.
1992 VW Corrado G60 (red/with flash): Originally imported from Singapore, this car has been owned by Timothy Ousley for last three years, and remains original apart from aftermarket alloys.
1990 VW Corrado 16v (white): Stock standard, New Zealand new car owned for two years by Ian Fraser.
