POWER PUNCH

CCC has propounded previously on the benefits of bike engines - lightweight all-alloy units producing high power outputs at high rpm. The Suzuki GSX-R motor, though no longer current, is one of the more popular choices for powering small racecars because of the availability of engines, tuning parts and expertise. And the S1100 was designed specifically around the GSX-R 1100 motor because its carbs are side draught (which fitted with the over the engine chassis concept) most other bike engines having more of a down draught angle. Slight over-boring to 75.9mm with standard 60.0mm stoke give 1086cc swept volume. In current specification it produces around 190bhp at the crank at 10,000rpm. That's pretty respectable 175bhp per litre.

Rob Barksfield's engine is prepared by Ray Debben, at Debben Performance in Ringwood, Hampshire and Ray outlined some of the tuning background: "It's basically about blueprinting and parts selction. We've taken weight out of the crank and pistons and so on, and we've also had the luxury of about 50 dyno runs in which we tried all manners of ideas with carbs, cam timing, ignition curves and so on. With the head the trick is to do surprisingly little - basically we've found what not to do. It's all about removing little bits from the right places to induce tumble rather than high gas speed, then you don't need big carbs." The engine uses flat-slide Keihin 39FCR carbs - "good for mid-range power" - but Ray says that fuel injection is on the development list.

"There's a lot of expensive set up work to do though. With carbs there's about 100 years of experience available, and I've got over 30 years myself, so we know what to do with them." But he says he wants to get into fuel injection and reckons the MBE ignition management system, new on the engine this year, has helped boost performance from 6000rpm and upwards. The engine is wet sumped, partly because of the extra weight of a dry sump system. Ray reckons that the engine runs so little oil in its shallow sump that the windage losses are small enough not to worry about. Weight was the over-riding issue, and with other savings made from lightening (knife-edging and polishing) the crank, not running a starter or the attendant gears and starter ring, or an alternator, and using a lighter electrical loom, the weight of the engine and transmission less carbs and exhaust is just 62kg, The exhaust is made in 30thou (0.76mm) wall thickness ceramic-coated mild steel so it isn't exactly heavy either.

SUSPENSION AND WHEEL SYSTEMS

Suspension is by double wishbones and pushrods all round, with a 'monoshock' at the front and dual spring/dampers at the rear. The front spring/damper system isn't really a monoshock because within the small anti-roll coil springs there is a separate damper to control them, as well as the usual one within the larger bump/pitch spring. There is no separate anti-roll mechanism at the rear. The dampers are re-valved Formula Vee units and are non-adjustable. On suspension design Ogilvie says:"I've basically gone for fairly standard geometry and I've allowed more movement, especially in roll." The narrowness of the car means that the inboard suspension pick-ups are on a narrow base, which means the wishbones are pretty long. Longer wishbones give less wheel camber change for a given amount of wheel movement, keeping the tyres flat on the road. Ogilvie reckons: "If you've got good roll centre control, correct camber change, correct weight distribution and good roll centre heights the car will handle anywhere." There is a modicum of anti-dive at the front and (adjustable) anti-squat at the rear built into the geometry. Ogilvie's not a fan of too much of either parameter because they deaden feel and have other adverse effects but he acknowledges that some can be advantageous. There is also Ackerman angle built into the steering (to steer the inner wheel on a tighter radius), beneficial where there are tight corners.

As long as driver of single seater have to sit at least slightly upright, there will be a practical minimum frontal area. The S1100 chassis/body is just about down to that minimum, which together with the sleek shaper should ensure minimal drag. As mentioned earlier, the radiators are tucked in almost behind the driver's backside. The car was originally going to use the oil-cooled Suzuki engine, which needs plenty of air to cool it too, hence the scalloped sides to direct air at the engine block. Following the descision to use the water-cooled engine, those scallops enabled twin radiators to be used without adding much to the car's frontal area.

Low drag from the body is significant when it comes to how much wing the car can carry. Front wings do not add significant drag but rear wings do and the low body drag allows a reasonably powerful two-element rear wing without undue concern over the induced drag. This will obviously provide a fair bit of downforce. To balance that, the front wing, slung under the nose via a shapely carbon moulding, is a fairly large single element device. Ogilvie says they've started with a basic aero package but developments will continue. "Because we've got no sidepods and it's a narrow car we've got a lot of scope along the side and at the back to put what we like. You want to produce downforce and the right distribution (front to rear). That's where we require a bit more research. Ground effect aerodynamics depend on constant ride height, and you don't want an aerodynamic package which is sensitive to the variations of ride height you have on a hillclimb.

But as Ogilvie was a part of the team at Lotus, with Colin Chapman adn Peter Wright, who first properly expolited ground effect on a single seater (on the Lotus 78), expect him to come up with somthing effective.

SPARTAN OFFICE

The moulded cockpit is so full of impressive composites detail work that you don't notice the lack of instruments beyond the Alpha steering wheel. Who needs 'em? Not Rob Barksfield, or several other hillclimbers these days. Apart from checking the engines warm and setting revs at the start-line, hillclimb drivers rarely look at the instruments, and probably never during an actual run. So that's a few hundred grams more weight saved.

To assist the timing of gear changes Rob has a bleeping earpiece in his crash helmet, an aural shaft light if you will, that tells him when he arrives at shift rpm. It's less distracting than a system which relies on vision - particularly in a demanding competitive environment like hill climb events when drivers have little time to peer down at the instrument panel. Currently a lever and cable on the left side of the cockpit operate the six-speed sequential manual gearshift.

Rob is to get a custom-moulded carbon seat soon so the car is going to feel like it's a part of him. All single seaters are like that but the low weight and compact dimensions of the Saxon makes may others seem like pantechnicons [one for the dictionary lovers there - Ed].

PERFORMANCE AND COST

The S1100 has yet to turn a wheel under its own power as I write, so performance can only be guessed at. But its power to weight ratio without driver is almost in the same ball park as the unlimited capacity hillclimb single seaters like the ex-F1 V8-powered Goulds and Pilbeams, and well ahead of even the lightest 2-litre-powered hillclimbers. In the 1100cc class the lightest competitor is maybe 40kg heavier, giving the Saxon a driver-aboard power to weight ratio advantage of 14 per cent, assuming similar power. Providing grip, handling and reliability are adequate, performance should be highly competitive. If it grips and handles well, watch it fly.

As for cost, Ogilvie reckons the first S1100 rolling chassis stands him in at £28,000 including parts, pattern and moulds but not including labour. So you could reckon on paying somewhat more than that if you wanted a replica. He aims to get the first car developed into a competitve and reliable package first, though he is considering the possibility of making more.

With the S1100 taking on the already developed and rapid Force (which is also running in the 1600cc hillclimb class and in Monoposto on the circuits, and with another carbon-chassis racer still to come from DJ Racecars, hillclimbing is a fascinating hotbed of technical ingenuity at the moment.