In essence you'd be building an engine as far as the California Air Resource Board would be concerned, meaning you'd have to go through getting an approval from ARB for your new engine design. This will be extremely costly. Most often these types of "home" projects are reserved for off-road type vehicles; not necessarily truck type off road, but a vehicle which will not be operated on public roadways. See the CARB website for manufacturing and receiving approval for new engine designs if you are still interested in pursuing R & D for a new turbo design for your Ford Focus.
posted by SmogTips Support