Whats a cold air duct?
So… You’ve improved the exhaust, fitted a “high-flow” air filter, replaced the ECU, fixed the suspension, and generally had a great time. Where is the air coming from that’s being fed into the engine? Right… It’s being drawn in from the engine bay and the stock air sensor position is close to all those hot parts. The inlet side of the factory air filter can be modified to accept a pipe that runs down beside the intercooler ducting to the undertray area (on an S14-style car). Another option is if you replace the stock airbox with a pod, there is a small flat plastic cover which shields the LH headlight wiring. If you remove this, (it just clips in) you can get a length of pipe between through there to draw air in behind the grille opening. The S14a cars have a simple cold-air pipe that can be adapted to feed your new filter This draws air in from the main stream, which may be up to 60 degrees cooler than the engine bay. It’s simple physics that cooler air is more dense, so you get m
