Focus Big Mouth Performance Data


Mass flow is the key ingredient in making more power. If you can increase the mass flow of air to the engine, you are increasing the potential to make more power. This is the basic concept behind a ram intake.

Using the forward motion of the car, you are able to effectively increase airbox pressure (or decrease vacuum in the airbox) as a result of increased mass flow. The faster you go, the more stagnation pressure is available to do useful work. Shown on the left is a 3rd gear pull shifting into 4th gear, plotting air mass flow vs time.


This plot is a 3rd gear pull air mass flow vs. engine speed. By the time you are done with 2nd gear, the engine is already starting to see a boost in airflow. By the end of 3rd you are picking up about 0.5 lbm/min of air which is equivalent to about 5 horsepower.


Here is 4th gear mass air flow vs engine speed. In 4th gear we saw close to 8 horsepower worth of airflow just by the efficient use of forward motion due to a properly designed ram intake.


Wastegate Duty Cycle is an important parameter for validating the BIG MOUTH ram intake. If WGDC is effectively reduced, it means the turbocharger is spinning slower for a given mass flow, and that means you can potentially turn the wick up by letting your tuner know.


4th gear showed a much happier and more efficient turbocharger with the following WGDC vs engine speed plot as validation.