Metrics
Weight
Performance
K20 Swap
Disassembly
Cooling
HVAC
Firewall
Fuel System
Electrical
Engine
Mounts
Exhaust
Misc
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Firewall
I cut out and replaced the firewall, mainly to give more clearance for a bigger supercharger for the future.
The replacement firewall was made from carbon / kevlar fabric over a nomex ('kevlar paper') honeycomb core. This was laid up using vacuum over a piece of glass - which gave a flat glossy surface on one side. Originally the plan was to use a silicone/ceramic insulation on the engine side of the firewall, but after seeing the finished piece everyone else convinced me to leave the carbon surface raw. I ended up using a sound absorption mat on the inside of the firewall.
Also I filled in 28 unnecessary holes between the interior of the car and either the engine bay or outside world. Some were for plastic clips for wiring; other were just holes for no good reason. From a noise point of view it seems stupid to have 28 holes between the passenger compartment and engine bay / roof shroud, but this seems to escape Lotus.
At part of moving the firewall I made new engine lid mounts, incorporating studs so that you don't need to remove the whole vehicle interior in order to unbolt the engine lid.
I used a lot of dynamat sound insulation on the inside of the firewall. Because the firewall was moved forward in the center, the stock elastic oddment storage was removed and the inside of the firewall carpeted.