People believes that the using after market modify products makes worth on fuel economy.
Mini-van has heavy weight and using the after market intake lose the torque.
Super Jet Chamber is the one possibly adjust the air speed and capacity.
Here are the example on the TOYOTA PRIUS and TOYOTA ALPHARD Hybrid.

PRIUS OEM intake system


PRIUS Super Jet Chamber

It has short range (100 km) and long range (400 km) drive.
This information showed on the PRIUS information display and could see the
differences only change the intake system.

Here are the rest result on the ALPHARD Hybrid

OEM intake system 13.4 km/L average


Super Jet Chamber (adjustable valve close) 15.4 km/L average


Super Jet Chamber (Adjustable valve open)9.6 km/L average

Here are the data on the ALPHARD Hybrid.  It is really heavy car and has 2.5L Hybrid system.
The Super Jet Chamber could increase the fuel economy with the closing adjustable valves.
However, if the adjustable valve makes open, it gives you powerful acceleration.  Of course,
it gives you worth fuel economy.  Super Jet Chamber’s main point is possible to adjust the valve
depends on the user’s usage.

Super Jet Chamber Installation image
 
PRIUS (ZVW50)                                                ALPHARD Hybrid (AYH30W)