Geartronics Air-shift system in place!

The first of the engine bay accessories to go onto the car! The Geartronics electronic air shifter system is now in place!

The air actuator used for the pulling and pushing of the Sadev gear box’s input shaft, was integrated into the rear bell housing mount. It’s made from 4mm thick laser cut steel plate and has been webbed with reinforcement plates to provide plenty of rigidity for when the actuator is under load.

A small mounting plate was fabricated and TIG welded onto the chassis to retain the air valves used to control the air between the pump, reservoir tank, and air actuator. Small rubber grommets where used between the Valve bodies and the mount so that harmful chassis vibrations will be dampened.

The reservoir canister has been rigidly mounted to the chassis via a fabricated aluminium mount. Small tabs where welded onto the rear subframe of the lotus to accommodate the mount, then small and light riv-nut threads where inserted for quick release. The tank is held in place with 2 large jubilee clips wrapped in shrink wrap so that the canister won’t be scratched.

All 3 accessories have been located as close as possible to each other to maintain a constant pressure for quicker, crisper shifts.

For any more information on the Geartronics air shifter system, check out their website.

2012
01/23
CATEGORY
Gearbox & Drivetrain
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Engine mounted!

It’s been quite some time since our last update. Project N2 is back on it’s feet and getting nearer and nearer to tearing around all the famous race tracks the world has to offer.

In order for any drive train related accessories to be put in place (ie: air shifter system, oil/ coolant tanks, drive shafts, etc.), the engine and gearbox needed to be mounted. Using a series of levels, scales, and inclinometers, numerous surfaces of the engine where picked and related to the chassis to locate the engine in the optimal location.
Once the engine was set in it’s final orientation, engine mounts where designed using the latest 3D Computer Aided Design software, laser cut, then TIG welded together.
Rubber bushing inserts where chosen to support the engine as they will allow for the stiffness the engine will require under load, but will also offer some “give” so that the vibrations of the chassis and drive train don’t effect the inner workings of the engine and related equipment. The standard S2 Exige engine mount has been left in place for now as it’s a hydraulic dampening mount which will also allow the engine some “give” under vibration. This isn’t to say that it won’t be replaced in the future by a superior design.

2012
01/23
CATEGORY
Engine
Gearbox & Drivetrain
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Engine Positioned

The engine has been temporarily positioned so that unique engine mounts can be fabricated, placing the block in the optimum position…

 

2011
06/21
CATEGORY
Engine
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Carbon Dash Design

The design of the unique and complex dash is under way.

Closely matching the process used to produce the bulkhead, stage one is to build the rough dimensions in cardboard.  This freeform method of construction allows us to really get a feel for space, ergonomics and access before committing to a full carbon installation.

2011
06/21
CATEGORY
Interior Fabrication
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GT3 Crashbox

N2’s chassis was factory fitted with the very securely attached standard Exige/Elise composite crash box in faultless condition.  However, to enable the radiators to be orientated at the most efficient angle and run cooler within the restrictive confines of the front clam; N2 will use the aluminium GT3 specification crash structure.

 

By using the GT3 spec aluminium crashboxN2has lost over 1 KG of weight over the front wheels and gained more substantial splitter and clam mounting opportunities.

Now facing the incoming airflow at 50° and coupled with the planned carbon exhaust louvers to the bonnet, the radiators cooling capacity has been greatly increased.  This is especially important to the N2 project as the high poweredToyotaengine requires carefully controlled engine and inlet temperatures.  The inlet temps will be moderated through the PWR charge cooling system which shares the same airflow as the engine radiator and requires efficient packaging.

Removal of the crash box, it transpires, is neither a simple nor a quick task.

Once the composite box had been removed (and sacrificed in the process) the work of cleaning away the bonding residue continued.

The new GT3 specification aluminium structure has been offered up to the spotless chassis and fitted in accordance with original GT3 fixing points ready for the radiators to be mounted.

2011
06/14
CATEGORY
Chassis
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Bulkhead Fitted and Bonded

After carefully cutting the bulkhead to shape using the accurate but time consuming cardboard templates, the bulkhead has been bonded into position.

The join between the two halves has been perfectly aligned and with the carbon weave pattern seamlessly mated in preparation for the heat shielding to be applied to the engine bay side.

2011
06/14
CATEGORY
Bodywork
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Bulkhead cut to shape

The Bulkhead has been cut and positioned ready for final fit and bonding with the seats positioned to enable the Dash Board design to progress.

 

2011
06/01
CATEGORY
Bodywork
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Bulkhead Design & Fitting

Due to N2s very special 1-off 1-piece roll cage (commissioned by us from Safety Devices as a full FIA spec cage), we were put in the position of having to make our own bulkhead.  Normally, flat sheets of aluminium are used for this job, which work well, but are only really suited to flat bulkheads.  Because we have our harness bar running behind our main hoop (Safety Devices insisted on this to make it FIA compliant), we would have to add a pocket to the aluminium sheet.  We then decided to put our charge-cooler on top of the fuel tank box, which complicated it further by needing a box in the bulkhead going into the cabin.  Finally, after receiving our ATL 70 litre bag tank and seeing how the pump access hatch and fuel filler hatches were arranged on the top of the tank, we realised that our bulkhead was going to land up being a very special shape indeed.

We started off by measuring the cage accurately (it has a 3° rearward lean), and then looking at the size and placement of the charge-cooler plus the inlet and outlet of the tank, transferring it all to CAD and then coming up with a design.

The next stage was to make the wooden buck, which starts as a large sheet of thick MDF (for stability), then has holes routed in it and boxes built up on it, all with 2° draft angles so that it will release from the mould.  Finished off with a 3° bottom flange plate, it was then filled and sanded and painted ready for moulding.

The mould was made, into which the final bulkhead was laminated.  The bulkhead is made from 4 layers of 2×2 carbon twill, and finished with a carbon / Kevlar® final layer to keep the whole thing integral in case anything from the engine bay decides to try to get into the cabin!  The laminte is wet laid up in epoxy, but then vacuum bagged to ensure the laminate goes firmly into all the corners and also has the minimal epoxy in the laminate to save weight.  The result (before trimming down) is a final weight of 1.2kg which is significantly lighter than a fabricated aluminium one would have been.  It also looks a lot nicer too!

We used stiff cardboard to work out the exact shape of the edges of the bulkhead as it goes into the side cill upper sections, then the final shape can be worked out off the car and transferred to the bulkhead sheet.  This will then be cut to shape and then fitted to the car.

2011
05/31
CATEGORY
Bodywork
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FIA Bag Tank

The standard Exige/Elise uses a 40L steel tank that uncomfortably resides within a much larger space behind the cabin.  For N2 to be FIA compliant as well as competitive in endurance races, a much larger capacity of fuel needs to be carried in an approved fuel cell.

Following the removal of the original tank, a new Lotus Sport bag tank to FIA standards was ordered (made by ATL).  The new fully homologated FT3 standard ‘Fuel cell’ neatly fits every available space that the Lotus chassis has to offer.  Construed from a flexible fuel resistant (of course!) ballistic membrane and filled with foam baffling, the cars endurance potential is stretched with an impressive new 70L capacity.  The installation process requires several sharp edges, notches, rivets and holes had to be smoothed and prepared ready to accept the bag tank.

In order to fill this impressive new capacity with fuel, N2 will need to employ a high-flow dry-break system.  The standard holes in the tank bulkhead must be increased in order to accept the large diameter fuelling hoses and associated roll-over valves and breathers.  Working with accurately drawn templates, the tank bulkhead has been cut and all the edges de-burred allowing up to 2.5L a second to be dumped into the cars now mammoth belly.

With the tank closely matching the chassis’ form; it’s no simple task to fit and requires the efforts of a team to squeeze it into its final position, saving just over 4KG on the standard steel tank.

2011
05/27
CATEGORY
Fuel System
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Fuel System Design

One thing for sure is that 400hp is going to need a lot of fuel, so we knew we would have to change the stock in-tank fuel pump. 

On investigation, we found out that the 70 litre ATL Lotus bag tank comes ready to fit the standard Toyota in-tank pump housing.  It can even be used with the standard fuel level sender.  Inside the bag tank there is a compartment for the housing, with special trap doors to allow the fuel to flow into the chamber (on right hand turns) but not back again on left turns.  So we decided to stick with the Toyota system, which comprises a gauze mesh filter, a high pressure injection pump, a secondary finer filter, a collector pot, a pressure relief valve (to return excess fuel straight back into the tank), an outlet to the fuel rail and a breather that breathes both ways unless the fuel level rises or the car inverts.

For the Toyota fuel system to work as we need, we fitted the Walbro 255 litres per hour pump, which is tried and tested and is used by many of the high horsepower Mitsubishi Evos.  This is a longer pump and needs a special aluminium end cap to allow it to fit into the Toyota housing.  The Walbro pump wiring loom is sliced onto the Toyota loom, and this is all that needs to be done. 

 As we are using an open ended fuel rail, we have a return fuel line that needs to be fed into an external adjustable pressure regulator, and then back into the tank.  To do this, we are using the tank pressure sensor required by US Lotuses, and using this as a return port.  As we want to use screwed-on fuel pressure hoses (rather than push-fit plastic pipes as Lotus /Toyota use), we designed our own aluminium fittings that can be fitted to the housing from the outside.  We can now fit proper dash 6 racing fuel hose to the car and not worry about pipes coming off under high pressure!  As the fuel return now comes back into the housing, the internal pressure relief valve is no longer required, so we designed an exact copy of the original valve but machined from solid aluminium which will allow full pressure to be achieved.  The vent pipe continues to work as a vent pipe, and through the MoTec we will be able to use the fuel level gauge (as this is still technically a road-legal car!).

The fuel hose will go directly from the pump housing to the fuel rail, then from the other end of the fuel rail to an adjustable fuel pressure regulator (which will be connected to the induction system so that it takes account of the supercharger boost pressure to raise the fuel pressure), then it goes back to the tank.

2011
05/26
CATEGORY
Fuel System
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