Does direct injection provide a solution for our gas guzzling sports cars?  Scouring the internet, I found some great info on DI (direct injection) and why more automotive manufacturers are using it to improve performance and most importantly, MPG.   Here are the basics:

Electronic fuel injected motors run with a combo of air to fuel mixture that is around 14.7:1 (in a perfect world), sometimes around 12:1.  This mixture is considered to be “rich”, meaning the amount of fuel mixed with air is more than needed to run the car properly. The reason why most cars run “rich” has to do with environmental variables that every manufacturer needs to account for.  Temperature, elevation, gasoline quality, and humidity, play vital roles in keeping the motor from self destructing.  Many tuners out there deal with this constantly while tuning customer cars to maximize timing and air/fuel mixtures.

With the use of DI (direct injection), air/fuel has been measured to be around the 40:1 rate, which is considered “lean”.  This on its own is incredible.  Why can DI get away with such high air to fuel ratios?  It’s simple.  It’s all about timing and location.  Rather than having the fuel injectors sit at the intake manifold (further away from the combustion chamber), the injectors on a direct injection system sit within the combustion chamber itself.  This allows for fuel to be dispersed at the optimal time (when the combustion chamber is at its hottest), which results in less amount needed.

Less fuel = less emissions = less money out of your wallet at the pump.  Best of all, performance improves out of the box.  Stay tuned for my next article, DI and the snail….