A total of 10 weeks was spent in the preparation and assembly of the engine itself. The head was fully stripped and checked for cracks etc, three-angle valve seats were cut and lapped, all valves were replaced with +1mm oversized custom items, all lifters were replaced with RB26 solid units - all the necessary modifications to the head were performed to suit. All ports were extrude honed with ONLY exhaust ports polished, inlet ports were left with a semi coarse finish to enhance fuel atomisation and to prevent formation of droplets. The combustion chambers in the head were clearance to enhance gas flow.
The factory inlet plenum, lower inlet manifold and runners were also extrude honed and port-matched to the head - this gave me major headache to get perfect but it turned out beautifully. I originally picked up a Plazmaman front-facing plenum which bolts straight up to the stock lower inlet runners, but due to more research, I went against that idea and simply high-flowed the factory unit instead. This is because the rear cylinders tend to lean out at higher boost levels due to the positioning of the throttlebody. For high performance street tuning, the factory unit is simply more than sufficient for up to 400rwkw and retains great response. This is the same reason why I kept the 2.5 inch intercooler piping instead of going up to 3 inch. After much research, I've discovered that there is a trade-off between gas velocity and flow quantity. It is the velocity of the inlet flow that enhance bottom end response of the engine and it is smaller pipe diameter that is needed to achieve this. I didn't want to go too small to the point it becomes a restriction but at the same time, not too big so that it promotes turbo lag having too much internal volume for the turbo to fill up.
I retained as much of the factory steel intercooler piping as I could, these are good at reducing heat soak from the engine bay. Heat soak is another reason why I reversed the path of the intercooler piping. Traditionally with most aftermarket intercooler piping kits out in the aftermarket, the piping goes from the turbo, enters the intercooler at the left side, exits from the right side of the intercooler, passing over the radiator and then around back over the the top of the rocker covers into the throttlebody. The piping absorbs a lot of heat when it passes over the radiator, so what I did was reversed the path direction so the flow travels from the turbo over the radiator where it is affected by heat soak BEFORE it enters the intercooler on the driver's side. Once it has been cooled, it then travels into the throttlebody. Therefore, minimun piping has been affected by heatsoak between the intercooler and the throttlebody. I also ceramic coated and then wrapped the section of piping affected by the heat from the radiator with exhaust fibreglass wrap. A lot of effort was put into preparing the intercooler piping to protect it from the heat created in the engine compartment.
To enhance the intercooler even more, I installed a second thermo fan that is mounted directly on the left side of the intercooler (the main 16 inch thermo fan is mounted on the right of the radiator so the two fans' flow paths do not overlap), this 10 inch fan switches on when the car is stationary and is triggered to switch off when the car reaches and exceeds 60km/hr. The relay for this system takes it's trigger-signal off the speedo-meter. The reason for this is; as front mount intercoolers do not start working until there is moving air passing through the core to actually cool it.
To make the intercooler even more efficient, I have installed a water misting system. This is activated by a Hobb's pressure switch which is preset to trigger the system to start spraying when positive boost pressure is detected in the inlet system. Three 0.2mm brass jet nozzles designed for industrial evapourative cooling are installed and positioned around the central opening of the front bumper, these nozzles are also equipped with ballbearing antidrip fittings to stop the system leaking. I have seen a lot of water spray systems where it shoots streams of water onto the intercooler - These are not very efficient at cooling at all because the finer the droplets, the more droplets there are, hence more surface area available to aid cooling.
16 weeks in total was spent in the detailing of the engine bay. All components were fully prepared and restored to new or better. All components were disassembled and removed from the engine bay, all mounting brackets were sand blasted, prepared with primer and finished with chemical-resistant enamel. Nylon washers were used during reassembly to protect the finish. All fasteners were replaced with stainless steel allen-key items.