The Latest unit of interest is the MANIC BEATTIE, an extremely innovative 4 wheel drive CLUBMANS type chassis designed by NIC MANN of the famous ROVER V8 TURBO MOGGY fame. We designed a special 1700 BDT unit with special cylinder head, bronze gas sealing rings and other trick bits, to produce at the moment around 400bhp.This unit is blown with an HELICOPTER TURBINE, which is mounted in the car and uses it’s own fuel system to produce boost which remains at a constant pressure at all times, is then fed into the BDT, permanent boost! NO LAG. This unit was mapped on our dyno using a RACE TECH DEVELOPMENTS ecu with a 6 layer mapping facility with fantastic results.

We had to knock a 12 inch diameter hole in the wall to get the exhaust out of the cell. As the exhausts on turbines are critical, restriction is bad news and so we ran the engine with no exhaust, it sounded like a 747 was flying over the workshop for two days!

NIC has just broken the 20 year old unlimited sports car record at SHELSLEY WALSH with a 26.43 second run.

Eventually help in the form of respected engine tuner John Beattie came to hand with the arrival of a 1700 cc Cosworth BDT. Canted over at only 25 degrees to the horizontal towards the intake side, this satisfied the requirement of minimum centre of gravity and minimised the frontal area and yet still left room for the driveline forward. “With 400 bhp the initial aim, it was evident that a move to a larger turbocharger and quite a large amount of boost would be necessary,” says Mann. “This would result in the dreaded turbocharger lag and while anti-lag or ‘bang-bang’ systems were considered, it was quickly decided to move to a much more radical solution.” Mann’s background in aerospace led him to a solution involving a helicopter gas turbine APU or auxiliary power unit. Supplied by Turbine Technologies Ltd of Carmarthenshire in South Wales, the unit is based on a helicopter emergency air start unit used to fire the main gas turbine engine on the ground.

Running separately from the main engine, initially on diesel fuel, the unit delivers air to the engine at a constant pressure independent of the main engine speed and hence totally eliminates the throttle lag normally associated with high boost turbocharged systems. Currently set at a very “modest” 25 psi gauge boost, the engine delivers something in the region of the initial target of 400 bhp at 7500 rpm. The torque curve is particularly impressive: from 2500-7500 rpm this doesn’t vary by more than 20% from the peak value. It is transmitted to the gearbox by a somewhat elderly AP Racing 7.25-inch triple plate, sintered clutch hidden within the radically modified Ford bellhousing. From the outset the car was designed around a Ford Sierra 4x4 MT75 gearbox, which at the second-hand going rate of about £300 each fitted nicely with the budget. However, as Mann was to find out later, this has been a major stumbling block to development.

With no finance to fund a dog gear conversion, he has resorted to removing the synchromesh cones to speed up changing gear. “Ratios are standard Sierra 4x4 with second gear giving 60 mph, third gear 90 mph and fourth 130 mph,”he says. “Fifth gear has been removed along with reverse, again to save weight. First gear is used only for tyre warming, starting for the timed runs being conducted in second gear.”With such a limited budget, it made sense to use not only the gearbox but as much of the other Ford Sierra 4x4 parts as possible, including the transfer box. Using the standard epicyclic transfer gear train and viscous coupling, drive to the front goes under the heavily-canted engine and up to the Lotus Elan-derived differential housing before cascading out either side, through the inboard ventilated disc brake arrangement and out to the modified Golf GTi Mk 2 front uprights. The brake discs, being inboard, are limited in diameter to 260 mm because of ground clearance considerations but with AP Racing 4 pot calipers, retardation isn’t an issue. At the rear, drive is much like the front with yet another 3.9:1 Elanbased diff, complete with limited slip differential, feeding the drive through a pair of Ralt RT32 rear uprights acquired during the protracted 10-year build. With all these shafts whirling around and the requirement to mount extra differentials and turbocharger units etc, Mann has erred very much on the side of safety and fabricated the spaceframe chassis out of predominately 11/8-inch by 18 swg (1.22 mm) CDS tubing. Although the car has never been weighed properly, all up weight is estimated at “a rather heavy 650 kg,” Mann wistfully reports, with the target 50:50 front-rear static weight distribution.

There is scope to significantly reduce weight by rationalising gas turbine and fuel system parts as well as those in the transmission but only when funds allow. Perhaps the biggest effort required in any home-build project is that of producing the bodywork. Always a compromise between effort required, weight and cost, the temptation is either to give up totally and hand it over to a professional or invest your own time in the tedious task of making a body buck, taking a female impression of this and then making the actual body out of carbon fibre/GRP. Wishing to eschew both options and using clear engineering logic, Mann’s answer was to make the front and upper bodywork out of sheet aluminium while the sidepods, incorporating the cooling system on one side and the turbocharger and oil tank on the other, were made out of 3 mm birch plywood. Carpenter Mann explains: “Although I was limited to 2D curves, the panels are bonded together using pinewood strips and coated with several layers of epoxy resin before being finished with a 2-pack polyurethane paint system. The resulting finish is exceptional with only a slight weight penalty over the more normal GRP arrangement.”

Starting the engine(s), as you might expect, is not that simple and is somewhat reminiscent of starting a helicopter. Since the turbocharger oil feed and scavenge system are operated off the main engine, this needs to be running first. Next in the strict sequence of events, the auxiliary gas turbine turbo unit needs to be started using compressed air from the off-board starter unit. At 1 psi boost with the turbo spinning at 10,000 rpm, ignition and fuel (initially diesel fuel held in a separate tank) can be switched on. At 5 psi the system is self-sustaining and the starter unit can be disconnected. At 13 psi with the turbine spinning at 40,000 rpm and the main engine at idle, the system is ready to go. Tyre burnouts are conducted at 13 psi boost in first gear but timed runs, for 2005 at least, used the higher 25 psi boost limit, manually selected from the dashboard Not surprisingly, there have been issues. “Control of the turbine was initially a problem,” he remembers, “with the unit flaming out upon changing gear and losing boost.”

The latest problems are more serious and potentially more expensive to fix. Out of the car’s first four meetings – one of which was the Shelsley Walsh Centenary event at which it lowered the hill record for Shelsley Specials by a magnificent half a second – two gearboxes failed. Each time the offending part was third gear on the MT75 gearbox when for the first time during a run the transmission experienced the full engine torque. Examination of those recognisable parts remaining suggested simple low cycle fatigue. In other words, the box is not strong enough! The winter rebuild was focused on improving the strength of the gearbox and reducing the inertia of the driveline. The weight of the propshafts (both front and rear) has been substantially reduced by replacing them with TORQline – carbon fibre wound – versions from the Crompton Technology Group. Support in the form of a 51/2” aluminium triple plate clutch has come from Tony Tewson at Superclutch, while a lightweight flywheel and starter motor were supplied by Ark Racing.

After tests conducted towards the end of last year, further weight has been saved by dispensing with the diesel fuel tank and running the turbine on gasoline fuel from the main tank. Along with the adoption of a lighter battery, the car now weighs 25 kg less. The major issue of the gearbox, however, has yet to be resolved. “The original plan was to graft the much stronger Borg Warner T5 gearbox complete with a Glebe Transmissions dog clutch conversion to the existing 4x4 transmission,” says Mann. “Unfortunately, since space is very tight, this wasn’t possible. “Plan B is to fit the T5 gears into the existing 4x4 Sierra casing. Rated at around 450 lbs ft (610 Nm), this should give me enough reserve to increase the boost pressure a little towards the 43 psi maximum – but maybe not this year!” While Mann has completed all the design work and manufactured the new gear linkage, he awaits the new gear parts with relish as the season gets ever closer. With a little extra finance from Aldon Automotive, the target is the Gurston Down event at the end of May. Fingers crossed.