Hey embe. If you were to remove the intake manifold, there is a channel that directs air to each of the cylinder heads with a 6mm hole leading down to the exaust port of the head. The CDmanual describes putting dowells into these orifices with locktite to permanently close the passages. If you remove the pump and one-way diverter valve on the engine, the engine will sound as if there is an exaust, leaking percussion sound coming from the fitting on the engine. Instead of the dowells, I tapped the holes to 7mm and fitted 7mmhead screws in. 2 for each with plenty of loctite while I had the heads off. That way, carbon won't build up towards the intake. Euro models w/o pumps are set up this way. Since the car lives at 2400-2600 rpm at 65-75 mph, I don't anticipate a carbon build up. However, the emission Nazis would differ; there are some here... Hope this helps