MSC Lotus Cup UK Race Car Build
Maidstone Sports Cars having been responsible for the build of the majority of the modified class B & C cars in the inaugural year of the Lotus on Track Elise Trophy. It seemed only fitting that 2012 will see the return of Maidstone Sports Cars to the Lotus on Track Lotus Cup UK race series.
Racing in Britcar for the last 2 years has certainly been an experience for the MSC team and much of the experience gained will be now used on our new car. The new open class seemed ideal for MSC to build a new Honda powered Exige to meet the new regulations. A donor S1 Elise was tracked down to be used as the basis for our new car.
As this was to be a total MSC project we could at last build the car exactly as we wanted with no outside interference. The donor car was duly stripped down to a bare tub and then extensively steam cleaned to remove years of debris. The roll bar and bulkhead were removed along with the rear sub frame.
The first task was to fit the new 6 point full roll cage powder coated white. We then fabricated a new bulkhead in aluminium which we lined in carbon fibre. The engine side was coated in reflective gold material.
The old original wiring loom was then removed and dismantled and all unnecessary wiring was removed just leaving the bare essentials. We fitted quick release wiring plugs for the front and rear clam looms to aid their quick removal.
We specified an AIM dash with GPS and managed to pick up a nearly new unit for a fraction of the new price. This was wired in using a JDM engine loom, JDM ECU and Hondata K Pro which was all mounted on the inner bulkhead for easy access. The dash and facia were already removed and we made a new one piece panel in carbon fibre. This certainly tidied the dash area and was very light. Switch gear was kept to a minimum with just light and fog light switches along with FEV fire extinguisher control panel and Cartec GT battery isolator system.
The standard gear change mechanism and lever were reinforced and raised to aid gear changes. A removable steering wheel was also fitted to aid vehicle access. The original wishbones were stripped, sandblasted, plated and refitted using Nylatron bushes and all new joints. The front uprights were changed to S2 items with their better bearing design.
The rear we used an original pair of lotus Motorsport steel uprights which use a bigger bearing and have a rose jointed bottom mount. A solid toe link kit was fitted and our original sub frame was re-plated and fitted.
The steering rack was stripped and we replaced the fragile plastic end buttons with the MSC phosphor bronze items. The unit was then rebuilt and refitted.
Using our endurance race experience we had our own brake system made using AP 330mm front discs with large AP 4 pot callipers. The rears utilised the original front 2 pot AP callipers with 304mm AP discs. A lotus motorsport master cylinder completed the set up with an AP bias valve.
This set up had been tried and tested by MSC during their time with Britcar.
It had always been our intention to panel the car as an S1 Exige for the better aero available and more engine room. We were fortunate to have used set of original panels available. These were repaired and painted white in our bodyshop to match the recently painted sills and roll cage.
The car would look very striking in these colours.
Wheels for the S1 Exige have always been an issue especially and choice is very limited and for us non-existent as our car has now got S2 stud pattern! We also wanted a wheel that would fill the arches properly with the right offsets. Having used Braid wheels in the past after much discussion they were able to make a wheel that suited our needs. They are not the lightest but they are very strong and not overpriced.
The specification of the drivetrain was our next consideration. We had to remain normally aspirated but were allowed 240BHP at the hubs. We also intended to fit a dry sump system as we did not want to repeat the engine failures suffered in the early days of Britcar.
We knew our system worked and it would be a lot easier to design and fit all the oil lines/oil tanks etc. if planned from day one. We were also going to run a conventional air/oil cooler in the front with all the oil lines routed through the sills. An 8 litre oil tank was to be fitted onto the rear bulkhead and all lines were to be braided with Goodridge ends.
As Lotus cup UK is endurance racing we specified a 70lt bag tank with an internal fuel pump. This increase in capacity would give us the range and is a lot lighter than the standard tank.
We also took the opportunity to fit a dry brake refuelling system. This is an absolute must for safety.
Having worked with Guy at Nitron for years on other projects we chose Nitron as our preferred supplier who came up with a suitable spec for the new car utilising Nitron's new 46mm bodied 2 way units along with unique valve and spring rates. Let's hope they work as well as they look.
The original Honda K20A2 engine and 6 speed gearbox were stripped .The gearbox was rebuilt using a Wavetrac LSD. The engine was rebuilt using Cosworth internals to our specification and the gearbox was mated to the engine and the whole assembly was fitted into the car using our Honda conversion engine and gearbox mounts. A set of our motorsport driveshafts were fitted at this time. The dry sump pump and associated pipework was installed discreetly with most ending up hidden in the sills. An S2 throttle cable was then connected to the larger throttle body and RBC inlet manifold.
The exhaust manifold and silencer were entrusted to Chris Tullet exhausts who have made a bespoke system with re-packable silencer. Exhaust manifolds are critical to K20 engine performance and we have great expectations for this new system.
With the mechanical aspect nearly complete it was time to bolt on the freshly painted clamshells, roof and doors. We fitted a quick release vented engine cover and front cover to aid maintenance.
With the roof section fitted we could now design and build a proper carbon fibre air box and collector to aid the induction system. A front splitter was fabricated using aluminium honeycomb which is immensely strong but very light. A carbon fibre rear spoiler was fabricated to meet the regulations and was fitted which is fully adjustable. Side pod air vents were added as was a rear diffuser.
With all new fluids and all systems checked/bled and adjusted now as the time for initial start-up. All systems operated correctly from the start. The AIM dash was configured and all systems were calibrated. Using the dry sump allows you to set the oil pressures manually but allowances must be made for pressure variations between hot and cold oils!
A full geometry set up was carried out along with corner weighting to ensure optimum set up. We had a target weight of 760kg with 240bhp at the hubs. This figure would have to wait until the engine was bedded in.
So the MSC Lotus Exige is ready for track testing which took place late March 2012 ready for the start of the season in April.
This is a total in-house MSC project and will even be driven by MSC race technician Adrian Hall. With Maidstone Sports Cars being the market leader in Honda Engine conversions it is only fitting that we are to return to the race track in one of our famous Honda engined Lotus Exige. As we will be attending all the Lotus Cup UK rounds our support race truck will also be in attendance and will be carrying a full range of parts which will also be available to other competitors.