HSV Walkinshaw Commodore VL

Introduction

Following the split with Peter Brock, Holden formed their own Special Vehicles operation, aptly titled Holden Special Vehicles (HSV). Tom Walkinshaw Racing (TWR) from the UK was contracted to carry out wind tunnel development of a radical body kit designed to improve aerodynamic efficiency of the racing Commodores.

HSV was established in October 1987, a 10 year agreement being struck between Holden and Tom Walkinshaw Racing, and their first iteration, a Group A, was produced in March 1988. Such was the hurried development of the car the HSV were unable to display the actual vehicle at the 1987 Sydney Motor Show, instead opting for a life-size cardboard cut-out.

To be eligible for Group A Touring Car racing, Holden needed to manufacture 5000 examples, which is exactly what they did, with some 500 sporting versions among the number. The Group A’s engine was now fed electronically, which was just as well because it now had to lug around an additional 65kg’s of fibreglass aerodynamic body kit.

Like the proverbial “dogs balls”, the Walkinshaw inspired HSV’s were anything but subtle, prompting then HSV managing director John Crennan to state at the vehicles launch; “…to some people it may be over the top, but everything on the vehicle is there for a good reason. In many ways this is the most advanced car ever produced in Australia”.

Soon dubbed the “Walkinshaw Commodore”, it was at first rather difficult to sell. For starters, it was not a “Brock Commodore”, and the price was almost as over the top as the gregarious body kit. Holden had undeniably got it wrong, deciding that instead of producing the required 500 units they would instead produce 750.

Meanwhile HSV set about creating a more sedate Calais SV88 model, which was released in April 1988. Using the standard Calais V8 as a donor car, they set about performance tuning the engine and suspension, while making subtle interior trim modifications. On the exterior, new front and rear spoilers were fitted, along with a louvered grille. Today the Walkinshaw Commodore, complete with “bird-bath” rear spoiler and over-the-top body kit is a highly prized collectors car - just don’t be tempted to add fluffy dice.

Group A SS

In the aftermath of the sudden split with Peter Brock, Holden started to get serious about the business of building high performance motor cars. The third generation Group A SS represented Holden's first full-on attempt at producing a world class homologation special road car. And it was, as we now know, just the first of a range of modified Holden cars to be produced under the guidance of the newly formed Holden Motor Sport Group (HMS), headed by John Lindell. The VL Group A's startlingly different profile was not the result of stylists working out of a think tank at Fishermens Bend. Instead the radical aerodynamic add-ons were carefully honed in full sized wind tunnel at simulated speeds of up to 240km/h.

The testing, carried out in Britain's MIRA tunnel, was undertaken by Tom Walkinshaw's Oxfordshire-based TWR operation, which was contracted by HMS to develop the homologation variant of the VL Commodore Group A racer. Basically, said Lindell during a press interview in 1987, the Group A's aerodynamics had been honed to work on a race car at race speeds. And because the Group A regulations insisted such spoilers, skirts and strakes must also appear on at least 500 identical cars, that meant the road-going Group A SS was by default going to look very similar to its on-track brethren. At the front was a very deep air dam, not unlike that used on the previous Group A SS.

In truth, however, the new air dam was quite different - the brake cooling ducts, for example, were moved towards the centre of the car for improved air flow. In addition, the standard VL grille was virtually blanked off - the large centre duct under the bumper provided more than enough cooling air, according to Lindell. More importantly, however, the used cooling air was extracted by way of a large vent set into the bonnet. Excess under-bonnet air pressure was a major problem with Group A tourers at speed, said Lindell, as it tended to create lift at the front end, almost negating the effect of the air dam. New side-skirts were developed to help channel fast moving air under the car and improve down-force. The skirts featured three vents on either side, however, which allowed a controlled leakage of air out from under the car.

The vents allowed a satisfactory balance between an optimum drag coefficient, and ultimate down-force. It was aft of the B-pillar that Holden's race special looked the most radical, however. The VL's sixth window was covered by a one piece panel which extended aft of the C-pillar to form a 'fence' on either side of the raised boot lid. This panel - like all the other Group A aerodynamic add-ons, was made of lightweight reinforced fibreglass - and it markedly improved the air flow around the C-pillar, according to Lindell, who admitted at the time to having fought quite a battle to get it accepted by Holden's styling department. TWR's wind tunnel work - conducted overnight at the MIRA facility, were the full power runs required to simulate racing speeds which, rumour has it, tended to strain the local electricity supply. But the improvement in the Commodore was fantastic, the drag co-efficient dropping by a whopping 30 percent.

Warwick Bryce

For Holden aficionados, that meant that the road going Group A was measurably quicker at the top end. As an example of the effectiveness of TWR's wind tunnel expertise Lindell cited the TWR Mazda 323 aerodynamic kit, which had been shown to improve that car's top speed by 10km/h. The VL Group A's improved performance wasn't entirely due to TWR aerodynamics, however. There was, for example, a new fuel injected V8 engine which had been extensively reworked by a local team under the direction of Holden's Engine Company engineer Warwick Bryce.

Mods to the engine included a strengthened block, and the adoption of four bolt main bearing caps - now cast iron instead of steel, as it was stiffer and easier to machine to the correct tolerances. The F5000-based crankshaft was carried over from the previous year, as were the strengthened conrods. All fuel injected V8s featured completely new cylinder heads designed specifically to work with the Bosch/Delco metering system. Apart from provision for injector nozzles in the combustion chambers, the new heads featured a different valve arrangement. Previously the exhaust valves for the middle two cylinders on each bank were set adjacent to each other - with the fuel injected engine changed so that exhaust and inlet valves alternated all the way along the head, thus allowing for a more even distribution of heat through the head assemblies.

Although the modified V8 shared the then new Bosch/ Delco fuel injection with the standard V8, the 500 Group A SS engines featured a totally different inlet manifold arrangement. In addition, new headers were developed in conjunction with HM Headers to handle the flow of exhaust gas from the differently configured cylinder heads. The new headers featured a two piece version of the high flange developed for the previous year's Group A SS, which allowed race teams significant freedoms in exhaust design and development. A 65mm pipe, new three way catalytic converter and a reworked muffler completed the road car's exhaust system, however.

In road trim the engine developed 178 kW at 5200 rpm, and 370 Nm of torque at 2800, both healthy increases over the previous Group A's output. Although the Group A's engine development had been done completely in-house at Holden's, most of the dyno work to fine tune the fuel injection system and inlet manifold design was undertaken by Holden Motor Sport backed driver Larry Perkins. John Lindell believed Perkins and other top Holden race teams such as TWR and Les Small would ultimately develop their own fuel injection electronics using the Bosch/Delco system as a base. Privateers, however, were able to buy a range of microchips from HMS which enabled them to tune the standard system to suit varying circuit, ambient temperature and altitude conditions. In addition the Holden five-litre V8 remained both sensitive and responsive to exhaust system modifications in fuel injected form as it ever was, and this was one area where a privateer team, if prepared to do a little homework, could find some useful power gains.

HMS spent a lot of time looking underneath Les Small's racing Commodores to see if there were any useful changes which could be made to the road going car's underpinnings to assist with its on-track performance. In the final analysis it was decided to leave the Group A's suspension unchanged from the previous model, which meant uprated springs, stabiliser bars and Bilstein dampers were fitted all round. Also carried over from the previous car were 16x7 wheels (although they were not the Momo star pattern favoured by Brock) and the durable, yet sticky, Bridgestone RE71 tyres.

The drive-train comprised a higher capacity clutch to handle the 15 percent more torque the new engine produced - Borg Warner's excellent BT5G five speed manual transmission, and the ever reliable 3.08 final drive four pinion limited slip differential (made just that much more reliable with the fitment of shot-peened gears). The Group A was largely built on Holden's Dandenong line, where the uprated mechanicals and different interior trim, which included an all-new Holden sports seating package in place of the Scheels used by Brock, were fitted to standard Commodore shells. The cars were then transported to the Holden Special Vehicles factory in nearby Notting Hill to have the aerodynamic bits and pieces fitted and finished.

Dove Plastics

Because of the rush to put the Group A program into place, the extra panels were actually made in the UK by a firm called Dove Plastics. Dove supplied TWR with the components for its factory approved Jaguar body kits, so the quality was first rate. Within a year (although we do not have a specific date) all of the Holden Special Vehicle components were being made in Australia. In all, some 500 Group were completed by March 10, 1988, to meet the April 1 homologation deadline.