1062112
The function of the spacer is to increase the force of air into the manifold by increasing the distance the air loads up above the manifold - literally stacking the air. Believe it or not, air has weight, like water. That’s how water towers function, gravity. This theory only works when the air is stacked vertically. A long runner on an intake will reduce airflow.
The newer 'spinning' spacers are contradictory to the physics of pneumatics. The faster the air can get through the engine, the faster that heat pump can intake, ignite, and exhaust the air, the more power.
So, if you 'spin' the air, you aren't making the air go through the engine faster, you're actually causing the air to build-up a pressure block where the spinning occurs actually slowing the air flow.
Do jet engine intakes have this spin feature? No
This is a gimmick to make money. Get a spacer without the spin - a smooth bore will flow more air.
Save your money, get a cheaper smooth bore spacer and spend your savings on a quality lift set.
[addsig]