For a ram air setup, you need an "external" device. "internal" wastegates are built into the turbo. Since you are installing one on a pressurized airbox, you need a stand alone unit. That means external.

 

is this a preasurized box that is going to have a fan or something pushing air into it? If you are just building a ram air set up you will not need a wastegate for this! That is if you are going to use just the outside air to do this as the car goes faster so the incoming air does to! no need for a waste gate on something like this! There won't be enough preasure to need it! wink

 

yea wastegates are only for turbo/supercharger setups, not ram air ram air @ the most will only creat 1 psi of positive pressure