I know build ing your own cold air intake is possible... but i was wondering is anyone could give me an idea of the measurement of aluminum pipe to use... ive just been looking around for couplers and pipe but i feel like when i do look i get lost because i dont know exactly what to buy... the only thing is do know is that the intake diameter is 3.25 inches... if you have any information please help thank you

 

I made my own and I think you want to be close to that but, I don't think it necessarily to be. What is important is that you have a snug seal from your intake to the pipe. This is the most important part of the fit and you want that transition fit(sock) to be a good fit, other wise you will know it. I used a 4" black thick pvc pipe with an ID of probably 3.75, instead of aluminum. I went that route, just because the PVC was less conductive and the breather hose and vacuum hose fittings were easy to do. I'm still playing around with it, but I'm looking for a better sock for the perfect long term fit from the intake to the pipe.