While those who follow SuperCar racing in Australia have names like Lowndes and Bowe on their lips, the whole field does not comprise just these top runners. At the other end of the budgetary spectrum are the privateers, the people funding their racing mostly out of their own pockets. Their cars are usually a few seasons old, their crew often volunteers, and their race placings more often Top 20 than Top 5. But they have one huge attraction to us at AutoSpeed - these teams are happy to talk shop, to have us watch their race preparations, and let us photograph pretty well anything we like on the car! Try doing any of those with some of the other teams...
Team mechanic John Keen was happy to show us around 'his' car - the Commodore owned and driven by Adelaide businessman Chris Smerdon. The car was built by Perkins Engineering in 1993 for Smerdon, starting life as a VP model but now updated to VS specs. Today, it's valued at about A$90,000, with a season's running (using a volunteer crew) costing about another A$90,000.
But before we look at the car, a word for our readers who have never heard of Australian 5 litre SuperCars. The formula allows only two types of car - Chevy-powered Holden Commodores and Ford-powered Falcons. Aerodynamics, tyres, the 5 litre pushrod V8 engines and so on are tightly regulated, making for fast, close racing. And as you'll see, even though many of the spectators believe that they are watching 'Commodores' and 'Falcons' speed past them, as with race cars the world over, there aren't too many parts in these cars that came down the respective manufacturers' production lines...
Under the bonnet of the Smerdon car (photographed following a race) you can see a very dirty airfilter hiding the 5 litre Chev. Induction is by a straight-runner crossover manifold which uses eight rectangular throttles - the asymmetrical port spacing means that slide throttles cannot be used on these engines. Intake air temps play a critical part in making power, with fully-sealed airboxes and huge intake ducts universally used. The injectors are also mounted high above the intake trumpets, with the evaporating fuel cooling the intake charge. The engines feature Chev motorsport aluminium heads and a cast iron Chev block. Four bolt mains are used with a chrome moly crank and 6 inch billet steel rods. The compression ratio is 10:1 and JE pistons are fitted.
Power is about 600hp, developed at the enforced rev limit of 7500 rpm. So, how does this compare with a powerful road car, on a power-at-the-wheels basis? While running in a diff, John placed the race car on his workshop's chassis dyno and decided - for the hell of it - to do a power pull. Unfortunately a peak power figure couldn't be realised - the car needed to be dyno'd in a high gear to avoid exceeding the dyno's tractive effort limit, but that meant that instead the car hit the dyno's 200 km/h speed limiter! With the curve still rising, a maximum power of 321kW (430hp) at 6700 rpm was seen at the wheels, with a tractive effort peak of 5742 Newtons. Backing the engine is a dog-type Hollinger 6-speed with straight-cut gears. Sixth is 1:1, so the ratios are stacked very closely together.
Just to the left of the rocker cover is a stainless steel drip tray, present in case of leaks. And why would those leaks be so major? - because within the rocker cover is a 'sprinkler system' to spray the valve springs with cooling oil. The extractors are TIG welded mild steel, using a two-into-one, two-into-one design. Following these the exhaust is 4 inches in diameter and uses a single muffler. No cat converter is required, with the fuel being CAMS-supplied 98 RON unleaded. NGK spark plug leads are used with '8' heat range NGK plugs. They are fired by a single coil and dizzy system working under the direction of an Autronic CDI unit.
A US-made Sweet power steering pump (driven from the water pump) is used in conjunction with a Sweet power steering ram, which connects to the steering column under the dash. The assistance level is fixed - it doesn't vary with speed - and the assistance is set to make steering effort acceptable.
The power steering reservoir is a simple fabricated alloy can. In comparison, the Holden Racing Team use a billet alloy tank with machined cooling fins all over it! (And no, HRT won't let us near their car with a camera!)
The coolant system uses this fabricated swirl pot, which has a number of functions. It joins the water supply of the two heads to a common feed; it mounts the thermostat; and it prevents aeration. The hose connecting to the top of the swirl pot connects to the filler tank, mounted high on a strut tower. An alloy two-row radiator uses ¾ inch wide rectangular section tube.
The crankcase breather catch can is there just to satisfy regulations - the low pressure created in the crankcase by the dry sump system draws most of the vapours to another can in the boot. In fact, there is only a 2mm hole in this breather pipe fitting!
The rear suspension uses Koni coil-over dampers that are adjustable for bump, rebound and spring seat height. The linear springs use a rate of about 400 pounds/inch. Brakes comprise Harrop 4-spot calipers with leading and trailing pistons of different size. The fully-floating discs (from AP Lockheed) uses thin side walls (to generate heat more quickly) and are about 13 inches in diameter. The Panhard rod bracket (on right) uses the standard Holden mount that has been strengthened and reinforced. It has three pick-up point holes which are selected on the basis of the chosen ride height.
At the front, large 4 inch diameter brake cooling ducts are held in place by the spoiler (when it is fitted), not octopus straps! Note the separate duct to the small oil cooler under the car, which reduces the temperature of the oil being fed to the valve spring spray-bar.
The front brakes are early-style Harrop four spot designs, also having different sized leading and trailing pistons. A balance tube allows fluid to pass from one side to the other, and the calipers use quick-release clips allowing the speedy change of the pads in endurance racing. The discs are 14 inches in diameter and an inch wide. Front spring rates are approximately 1000 pounds/inch.
At the rear Pagid '4-2' grade pads (shown here) are used, while the front pads are Pagid 'RS9'. The rear pads last two sprint meetings, and the fronts one weekend (ie practice, qualifying and race).
The rear axle uses a spool-centre Ford 9 inch diff, Porsche CV joints and fully-floating axles. From closest to the camera, you can see the rear stub axle, short shaft, flange, Porsche CV joint, and axle. The CV joints are used to allow rear camber to be run. Diff ratios are 3.7, 3.5, 3.25, with the ratio selection based on the track speed.
On-board air-operated jacks are fitted to allow speedy brake and wheel changes. In this view, the jack is extended with a jackstand in place. The jackstand fits around the shaft, preventing the jack collapsing, even after the air pressure has been removed. The formula uses Bridgestone control tyres, 280mm wide by 680mm high. They are mounted on 17 x 11 inch rims all 'round.
The heavily-braced front strut tops use a plate allowing adjustment of castor with minimum changes to camber (camber adjustment takes place at the inner pivot point of the lower control arm). A spherical bearing is used to allow the strut to be swivelled for steering while having little movement in other directions. Front geometry comprises "approximately" 5 degrees negative camber, 5 degrees positive castor, and 0-3mm toe-out. At the back, 2.5 degrees negative camber and 2mm of toe-in are used. The rear toe-in helps reduce oversteer and also generates heat in the tyres through scuffing.
The car uses a MoTeC digital dashboard. The three buttons to the right of it are used to (respectively) cancel alarm codes that appear on the dash; select race, warm-up or practice screen displays; and bring up different temperature displays. Note the floor-hinged pedals - the list of non-standard parts is longer than the list of Holden parts!
The cockpit "control tower" has (from top left) switches for the driver's cool suit (where iced water is pumped through a vest worn by the driver), the poor visibility conditions high intensity rear light, single-speed windscreen wipers, headlights, indicators, ECU bypass (allowing the running of the fuel pump without switching on the ECU), ignition, start button, reserve fuel supply, fuel pick-up pumps, and finally diff and gearbox oil pumps (switched on at 120 degrees C). ULX-110 oils are used in the diff, gearbox and engine.
An Autronic SM2 ECU controls the engine. It has inputs from the following sensors: crank trigger, cylinder reference, throttle position and coolant temperature. It runs fully sequential injection. The Autronic CDI unit that is used is mounted below. This provides multiple sparks at low rpm, changing to single high intensity spark at high revs.
The boot is full of fuel pumps and the dry sump's system oil tank. From left to right, 2 litre oil breather bottle (which draws vapours from the top of the dry sump tank), the fuel filler tube (there's a tank breather of equal size on the other side of the car), the fuel system swirl pot (10 litres with a 5 litre reserve capacity), engine oil tank which holds 7 litres (the whole system takes 14.5 litres). The battery is located in the boot to improve weight distribution, being placed diagonally opposite the driver.
Two high pressure Bosch motorsport pumps are used - a main pump and a reserve. The Holley 'Red' low pressure pump pictured to the right fills the swirl pot, with another (not shown) low pressure pump drawing from the other side of the fuel tank. Both LP pumps are pre-filtered, while a high pressure filter is not used. So doesn't a race car like this needs to use more than one HP pump? John Keen says "Here we have one high pressure pump with 3/8 inch
[9.5mm] fuel lines supplying approximately 600hp, and all those jerks on the road have half-inch [12.7mm] fuel lines to supply 300 horsepower."
Fuel pressure is regulated to 2.5 Bar (36 psi) and is referenced to atmospheric pressure, not manifold vacuum. The engine is mapped with the fuel pressure configured in this way, so appropriate mixtures are still supplied.
To see more on Australian SuperCar 5 litre V8 racing, go to www.v8supercar.com.au
If you would like to become a sponsor of the Smerdon car, call +618 8277 4222
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