rb-racer
01-12-2010, 10:00 PM
I found some pretty cool designs for intake plenums, to try and avoid leaning out cylinders etc.
In an attempt to divide air equally after the throttle body a dual plenum design has been used for the last couple decades.
The primary lower plenum with connects to the throttle body is gradually tapered like a cone with a continuous single vent slot that allows gas to pass into the 2nd plenum. The 2nd plenum acts as a collector which then feeds the runners to the head. Pressure in the 2nd plenum is equalized since its not effected by gas velocity and inertia or the pressure variation from front to back of the 1st plenum. Since flow equals velocity times area. The reduction in flow which is released through the side slot is equal to the reduction in area of the plenum assuming velocity is constant. So a smooth conical taper with establish equal pressure and air distribution into the 2nd plenum.
The taper on the cast manifold made by audi reduced down to nearly the size of a nickle, the sheet metal intake also uploaded reduces to only a quarter
Lastly the most recent version of the dual plenum is on the r8 race car. Certainly it has come a long way from the old cast look but still maintains the original concepts.
If someone wishes to begin experimenting on a rb26 here are some materials for the project.
http://www.jasperintegration.com/navi.html
In an attempt to divide air equally after the throttle body a dual plenum design has been used for the last couple decades.
The primary lower plenum with connects to the throttle body is gradually tapered like a cone with a continuous single vent slot that allows gas to pass into the 2nd plenum. The 2nd plenum acts as a collector which then feeds the runners to the head. Pressure in the 2nd plenum is equalized since its not effected by gas velocity and inertia or the pressure variation from front to back of the 1st plenum. Since flow equals velocity times area. The reduction in flow which is released through the side slot is equal to the reduction in area of the plenum assuming velocity is constant. So a smooth conical taper with establish equal pressure and air distribution into the 2nd plenum.
The taper on the cast manifold made by audi reduced down to nearly the size of a nickle, the sheet metal intake also uploaded reduces to only a quarter
Lastly the most recent version of the dual plenum is on the r8 race car. Certainly it has come a long way from the old cast look but still maintains the original concepts.
If someone wishes to begin experimenting on a rb26 here are some materials for the project.
http://www.jasperintegration.com/navi.html