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December 1997
CCC December 1997 CCC December 1997
Regular CCC Speed addicts will be familiar with the exploits of Vauxhall engine specialists SB Developments’ Steve Broughton and his wickedly quick Westfield-Vauxhall. This 270 bhp cruise missile mopped up the Southern Area CCC Speed Championship in 1995, and followed that up in ’96 by winning the 2-litre Sports Libre class in the championship, which was a bit of a tease really ‘cos Westfields normally run in the production car classes! But Steve has decided to stop teasing, and get a proper sports racing car, his new Jade is a real gem.

But why change from a proven, ultra-rapid, successful vehicle? "Well, we’d done the Westfield to death really," relates Steve, "in terms of development, and as a promotional vehicle for the Vauxhall engine tuning business. And I wanted something different, mid-engined, but not something that people would just say ‘Oh it’s a Pilbeam, it’s bound to be quick in speed events.’. Then I saw the Jade Supersports, which looked really neat, and very attractive, and it looked as though it would suit my needs." Indeed, the Jade design was originally worked around the core of a Formula Vauxhall (or Vauxhall Lotus as they were originally known) single seater racer by Jade Motorsport Engineering (see panel), so some of the packaging requirements for the Vauxhall installation were already there. But the extra power and torque form Steve’s engine, together with the relatively open and free nature of the speed event regulations called for a change of thinking in a number of areas.

Supersports, or Clubmans cars as they used to be known, are required to use 200 bhp versions of the 2-litre 16v Vauxhall lump, within a spaceframe chassis of specified width, and with limitations on chassis panelling, rivet spacing and such like, that preclude the use of stressed skin structures. Hillclimb and Sprint Sports Libre regulations, as applied in the CCC Championship and most other championships, are rather more liberal, with no limits on engine tuning within a given capacity limit, and apart from a few rules about the height of bodywork and aerofoils, construction and dimensions are just about totally free. So by choosing as the basis of his new toy a car designed for Supersports racing, Steve Broughton was, on the one hand, picking a proven product, while at the same time selecting a chassis that could be uprated and improved to better suit the speed event disciplines.

Steve’s decision to go ahead with the Jade project was taken in Autumn ’96, and the tubular steel, nickel-bronze welded spaceframe was completed just before that Christmas. At this stage, one of the first departures from Supersports construction was made. In Supersports, rivets holding alloy panels to the chassis may not be any closer than 6in, which effectively prevents the panels from providing any significant stiffening to the chassis. But, for speed events no such restriction exists (you can make a carbon composite monocoque if you want to), so not only were the rivets much closer, but also the panel were bonded onto the chassis with two-pack epoxy adhesive. Whilst the extent to which this stiffened the chassis has not been quantified, you can be sure it made a big improvement.

'Box of Kicks'

The next major change to the car was the choice of gearbox. Normally the Supersports car would utilise a Hewland LD 200 five-speed racing transaxle, but with the kind of power and torque that was going to be through the rear wheels of this car, and the size and soft compound tyres that were going to be fitted to those wheels, Steve decided to fit a much beefier five-speed Hewland FT 200 ‘box, obtained from Mark Bailey. Even this may prove to be slightly marginal on some of the grippier surfaced hills. But anyway, the very different casing of the FT 200 meant some re-thinking on suspension pick-ups and suchlike was needed. This in turn meant a new bellhousing/adaptor was needed, and here Steve, Jade and Pace collaborated, producing a very neat alloy casting to mate engine to ‘box. Steve confesses to disliking right hand gearshifts, and this was one of the main reasons for investing in the sequential shift kit on the gearbox too. Introduced by Hewland in March 1996, this kit is a retro-fit item to suit FT 200, FGB and FGC ‘boxes, and is claimed to enable even accomplished H-gate users to gain benefit from rapid shifting, with its’ ‘pull back to change up, push forward to change down’ operation.

CCC December 1997
Supersports 200’s run on regulation Dunlop 175/510-13 front and 210/570-13 rear tyres on 8 and 10in rims, but to put the extra grunt Steve was planning to use down onto the road, he’s upped that to 8.5/21.0 by 13in diameter fronts, mounted on 9in Image rims, and by 12/23.0 by 13in diameter rears on 14in rims. The front rims are only a bit wider than the Supersport fronts because this was the widest that could be fitted with the existing suspension, bearing in mind that more steering lock also had to be engineered in for tight hillclimb corners. Tyres are Avon’s super sticky, bubblegum soft A39 compound front and A40 rear, so this car was not going to be short of grip! To keep the thing off the deck, pushrod operated 2.25x5in Falconer springs, 600lb. in front and 700lb. in rear (currently) are fitted over Proflex 2-way adjustable dampers with remote reservoirs, KAD 6-pot alloy brake calipers clamp the relatively soft road pads onto the 10.5in iron discs front and rear.

Steve had planned a new engine with a variety of sophisticated electronic controls for the Jade, but he’s been so busy this year that for the time being he has dropped the engine from the Westfield straight into the Jade. Far from being a handicap, this at least provides a known quantity with which to sort the rest of the car, with all manner of details like suspension settings, and gear ratios to be figured out. And frankly, the performance of the Westfield’s engine will make this car competitive even at National hillclimb level. However, various new systems were needed for the Jade installation. Cooling is performed by a lightweight bespoke Pace alloy radiator, said to be almost too efficient, while a MOCAL oil/water heat exchanger balances the fluid temperatures, and actually helps to warm the engine oil up more rapidly from cold. The neat oil pump houses an integral filter, while internal design ensures good oil pressure even at idle speeds.

BTB did the exhaust manifold and primaries to Steve’s specification, while the secondary pipes have been modified to go up and over the left rear suspension to allow for the next phase underbody diffuser, which is of the twin tunnel variety rather than the gentle, singe sweep affair that was fitted as a prototype when CCC drove the car. The silencer is one of SBD’s very smart carbon can items, which not only look neat, but resonate less than metal cans, and give lower noise readings as a result. The clutch is a 7.25in AP item equipped with Helix Kevlar faces for durability.

‘Stand by to Launch’ Longer term, the engine will be equipped with upper and lower fuel injectors, which will require a new airbox to be fabricated, ‘launch control’, and a sophisticated traction control system that will know what gear the car is in (facilitated by the sequential shift mechanism) and will include this fact in its calculations to determine how much wheel slip can be permitted before power is reduced. This cunning trickery will be made possible by the MBE Systems engine management system, which already ‘talks to’ the Stack dash system, enabling the logging of engine parameters and wheel speeds. The software for the traction control is being sorted at the time of writing. The modified injection system, with an extra set of injectors above the ram pipes, is said by Steve to release a chunk of extra torque from 4500 rpm, equating to about 6-8 bhp at those revs, rising to 12-15 bhp at maximum power rpm.

So far this season, Steve and co-driver Dick Hulbert have only done a couple of events, debuting at the CCC Speed Championship sprint at Castle Combe on July 12 after a virtual all-nighter to get the car ready. The team arrived too late for the pre-event convoy runs, and so the wheels first turned in practice for the event itself!

But in spite of some minor problems, the car immediately showed its potential pace. And that was with suspension, aerodynamics and gearing on suck-it-and-see settings. Steve took advantage of our test run in August to try some different spring and damper settings, then went on to the British Sprint Championship round at Colerne on Bank Holiday Monday (soon to be christened ‘Wet Holiday Monday’), where conditions altered from wet to dry, and prevented any really meaningful running.

Nevertheless, Steve was not far off the time needed to qualify for the run off, and must have been pretty chuffed. His main target this year though was the Brighton Speed Trials in mid-September. This straight-line dash down the prom is all about acceleration, so power, low weight, accurate gearing, low drag and good traction come to the fore at the expense of all else really.

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