The initial project started way back in the early days of our Honda conversions. We already had an S1 normally aspirated Honda engine demonstrator and we decided an S2 supercharged Honda should be added to the fleet. By chance I was offered the prototype panels for the S2 Exige so it was decided to purchase an S2 Rover engine Elise as a good basis to convert to a supercharged Honda and rebody it as an S2 Exige. The car was built in 2005-6 and run as a company demonstrator and personnel car for the next 5 years. In this time, it was continually upgraded and ended up being a Supercharged and charge cooled Honda K20A2 producing about 350bhp.
After years of road and track use it was looking a bit tired and it was time for a refresh. We wanted to move away from supercharging the Honda’s and this was the ideal opportunity to develop our turbo upgrade to our Honda engine conversion. After much thought and discussion, it was decided to build to a high-speed record car and try and crack the 200-mph mark. Work started with a single goal insight and everything at this stage was engineered for this purpose. The rear subframe was removed and strengthened and cross braced. The 6-point roll cage was extended to become an 8-point cage. All the wishbones were heavily gusseted and rose jointed bearings fitted along with 2-way Nitron NTR40s and 1-inch adjustable roll bar and solid toe links.
Lotus Exige GT3 clamshells were purchased and then heavily modified and strengthened to deal with the down force that would be encountered at very high speed. A new aluminium honeycomb front crash structure was built to accommodate the custom-made large capacity triple-pass angled aluminium radiator and the bespoke charge cooler radiator.
The 2 oil coolers were placed either side of the front grill and fitted at an angled so air would be channelled through the coolers and out through the extra ducts with pipe work running through the sills. This would increase oil capacity and maintain a stable oil temperature. All the ducting was custom made in carbon fibre or Kevlar.
Braking would be taken care of by using AP5000+ 4 pot calipers and 330mm floating AP brake discs at the front and 315mm AP aluminium belled rear brake discs with AP5000 calipers. These were the same spec as were fitted to our championship winning S1 Exige.
It was about this stage that after much head scratching and discussion it was decided there was to be a change in direction with project. If we carried on and built this record-breaking car what would we do with it afterwards? We would have a car that after its record attempts was now pointless that had cost a fortune and was only fit for one purpose. So, the decision was taken to carry on the build but build the ultimate road car. It was not to be a track day weapon, we had built many of these before but a proper bespoke supercar. The work carried out to date would not be wasted as it was a great starting point but from an engineering point of view we were softening the final product. It was not to be so hard core and we would not be chasing every last bit of weight saving.
With the suspension and braking packages already completed our attention turned to the powertrain. Obviously, we would be using Honda power but this time it would be turbo’d. The original specification required an engine with over 600bhp and probably nitrous as well to propel the car to 200mph. In a road car over 600bhp and nitrous was deemed excessive even for us. The engine would be built to the highest spec but we were no longer after every last drop of power. The internals were uprated to forged pistons and rods and all the usual upgrades. Externally the engine was fitted with an RBC inlet manifold and 70 mm throttle body, A custom-made exhaust manifold and system were built by Simpsons racing and matched to a Garrett GTX35 turbo and 45mm hypergate. All exhaust components were ceramic coated to contain engine bay temperatures. Pro alloy built us an aluminium 48 lt baffled fuel tank which was fitted with Bosch internal high capacity pump to maintain fuel pressure and run 750cc injectors. The cooling capacity and efficiency was increased by fitting rear mounted charge cooler barrels above the engine. Oil temp was controlled by two large Mocal oil coolers at the front with pipe work running through the sills. It is imperative oil, water and air temperatures are controlled to allow for correct engine running and a maintained low intake temperature so cooled air is used and boost maintained.
We had always specified a digital dash and AIM MXs Strada was fitted and the engine was to be run using an Hondata K Pro ecu. The gearbox was fitted with a Kaaz LSD and 3.7 final drive and organic clutch and uprated driveshafts.
The clutch was only a stage 3 organic as we wanted a standard pedal feel and the clutch would be sacrificial.
As this was now to be road car far more attention was given to body fit and finish. The front and rear clams would mainly be secured using plush fitting non-locking quick release catches and stainless fitting. The rear had fabricated rear space frame to hang and secure firmly the rear clam. This frame also provided fixings for the exhaust, under trays and diffuser. We fabricated our own rear diffuser but it looked more race oriented than road car so we utilised the rear diffuser and spoiler from an S3 Elise and Exige and modified these to fit.
The wheel arches we made in Kevlar as with the GT3 body the arches were a lot wider and the standard wheel arch liners were to small. These now had rubber edging seals to stop any squeaking. All the bespoke ducting was now fitted with grills to stop stones shooting out from the front and back, the original car would have had open panels at the back which would not have suited a road car. An electric engine cover release was also fitted.
Instead of having a puny exhaust tail pipe a Lamborghini Murcielago tailpipe was to give the rear a look of menace. We fabricated new grills which were made to fit around the new tail pipe.
Wheels maketh a car and we were unable to source any of the shelf wheels to suit this application the only option was to have the alloy wheels custom made by Braid to suit this unique application and fill the arches as we wanted. We agreed on a design and sizes and the wheels were made and refinished in a bronze colour which we felt really suited the cars aggressive stance.
We specified Michelin Pilot Sport 375/30 ZR 18 tyres for the rear and Michelin Pilot Sport 215/40ZR17 for the front tyres. These are a good all-round performance tyre and would give us the grip control and traction we wanted.
As this was to be road car. The interior was fully retrimmed and has sound deadening fitted beneath the seats, bulkhead etc. The car was fitted with a bespoke carpet set to give it the quality feel. To make the interior car look different the interior was painted black to cover up the aluminium of the standard car. The roll bar was also covered in leather and hand stitched and matched the leather dash top and sill panels. A carbon fibre binnacle cover and centre panel were fitted to match the interior door pulls.
There was much debate over the seating and colours and it was eventually decided to trim the new V6 seat shells in the style of the original S1 Esprit. This was a tartan pattern with green leather and the door cards were trimmed to match. This colour combination worked really well especially with the white paintwork and is a homage to the early S1 Esprit. In keeping with modern feel halo front and rear lights and carbon mirrors were fitted to complete the exterior look. This project started in 2013 but other things got in its way, like racing and expanding the business so it was often on the back burner and its gestation period was far longer than we could ever imagined when the project started. Obviously after such major work we had a few small issues to sort out like calibrating the dash to register the fuel capacity.
Engine start-up was uneventful however many hours were spent on the dyno getting the map absolutely perfect. The time was well spent as the results are spectacular. Our intention was to have two maps, one for maximum power another for normal road use restricted to 410 bhp. We had to abandon this idea as the mappers could not get the power below 500bhp and that’s even by taking fuel out of it and knocking back the ignition. So, it was mapped for 500 bhp @ 7810 rpm, with maximum torque of 343 lbf @7273 rpm. Obviously, there’s a lot more power available if we wanted to push it but 500bhp plus in a car that weighs 980kg is ridiculous anyway. That equates to 510 bhp per ton so, it’s just got the one map @ 500bhp. No driver aids just you in total or lack of control!
How it Drives
A lot of people would comment it must be undrivable. You could not be further that the truth. The car drives just like a standard Honda powered car, very tractable and smooth. Driving normally, it is quiet and refined and a surprisingly docile driving experience. The handling and road holding are set for road usage with slightly softer springing than would be normally used for track you. With the larger ARB cornering is as expected and the larger tyre combination giving extra grip and traction. The camber has been reduced on the rear wheels to ½ degree to allow more tyre contact with road. Obviously as much extra rear traction is needed considering the power that t is transmitted through the rear wheels. The balance of the car has not been upset by all the changes and the car weights about the same as a Standard Lotus Exige S2 when dry. With this amount of power available it is so easy for the back to step out but by us using the Kaaz LSD as soon as you back off the power the back end straightens instantly which is reassuring and one of the advantages of having a mechanical LSD.
If you were wondering how it goes words cannot describe the performance. If you remember in the original Star trek TV series when they hit warp speed and all the stars rush bye that is the nearest I can get to describing it. It really is a holy s*** moment. God knows what its 0-60 time is but I have driven some fast cars and I have never experienced anything like this. It can spin its wheels in 5th if you want to but god help you if its wet. When boost starts coming in at around 3000rpm the fun begins with all the whistle pops and bang of the waste fate and screamer pipe. It all happens so quick it’s hard to keep your eyes on the road and the dash. Its hard to stop laughing however by this point the passenger is screaming.
It would be nice to take it somewhere to actually time the car 0-60 and 0-100 but whatever official times it makes the sensation that occurs when boost kicks in is amazing.
A lot of people say these cars are pointless and they may be right but who ever said “you need to scare yourself once a day “this car will certainly terrify you if you are not careful. However, I have commuted to work in this car and even though you know what it can do but you don’t need to use it as even when not running on boost its still a quick and very usable car.
Making it go is one thing but making it stop is equally important. The braking system we have fitted is the best of the best using AP components throughout and this gives you the reassurance that it will stop and stop quickly with no fade every time. In fact, most of the braking setup is straight of our championship winning race car and his been tried and tested. I addition we had to fit a handbrake facility as this is a road car. This brake set up is more that capable in dealing with BHP this car produces.
Living with the car
The car is probably no different to live with than a standard Exige S2. The only downside is there is absolutely no storage space on this car apart from the passenger footwell. There is no boot area as it is filled with the rear space frame and exhaust system. I’m not saying this is a hinderance as you don’t buy an Exige for its boot space but going away in this car would be a tooth brush and a pair of pants! At least with the 48lt fuel tank it will have a better range. Maintenance would be no different from a normal Honda powered car with regular and frequent oil changes as the Honda K20A2 does like nice clean fresh oil. Access to all areas is a lot better than a standard car as the front and rear clamshells are easily and quickly removeable for other maintenance/inspection using the quick release fittings. With all the sound deadening and insulation and being fully carpeted the interior is quiet, rattle and squeak free environment and is actually quite refined. The ride is compliant and the suspension is not set too low or hard so you are not constantly having to avoid uneven and bumpy roads. With uprated night breaker bulbs night time driving is not so precarious and being able to turn the brightness on the digital dash is a god send.
The car is not fitted with any gimmicks apart from the electric tail release and the car has been made as user friendly as possible which was always the original plan.
As the car is not an Elise or an Exige and is a bit of a b**tard child and an outcast from the standard range we have renamed it the Lotus Exile which we feel is truly fitting.
With thanks to Andy Marsh – www.maidstonesportscars.co.uk