Product Description

***THIS PRODUCT IS IN-HOUSE ONLY AND INCLUDES LABOR.  DO NOT PURCHASE IF YOU CANNOT BRING
YOUR VEHICLE TO OUR FACILITY FOR SERVICE.***

Brief Overview: Direct Injection v Port Injection

When looking at fuel injection systems there are two main injection methods for Multi-point Injection Systems: Direct Injection (DI) and Port Injection (PI). This refers to how fuel is delivered to each cylinder in your engine for combustion. With a port injection system, each cylinder has its fuel injected through its intake valves from a dedicated port injector. With Direct Injection Systems, fuel is injected directly into each cylinder after the intake valve.

In the last 10 years, the industry has started a shift in OEM’s such as Subaru, Porsche, and Volkswagen move from the older industry standard Port Injection Systems to Direct Injection Systems with the added benefit of being able to get more power out of smaller high compression motors that require less fuel while also reducing emissions. There is also more control over when fuel is added to the cylinder since it doesn’t need the intake valve to be open to add fuel to a cylinder to optimize Air/Fuel Ratios.

Drawbacks and Caveats

That all sounds great right? While this technology is becoming more and more common in performance vehicles giving us a number of benefits, it also has several drawbacks. The injectors are more expensive than PI injectors, because of the materials that are designed to withstand the heat and pressure inside of a motor during the combustion cycle, and fuel components such as fuel lines, and pumps have to be able to hold and deliver fuel at higher pressures. The last drawback that is often overlooked is the added maintenance which is required for vehicles with Direct Injection, called carbon cleaning.

Since Direct Injection motors have the fuel being injected directly into the cylinder, fuel doesn’t flow over the vehicles valves. This means that deposits can settle on the back of the valves and over time will build up causing issues with the valves being able to seal properly, turbulent the air coming into the cylinder, in turn, causing issues with air/fuel ratios, rough idling, cold start issues, and misfires if the carbon buildup is bad enough. This is a service that requires you to remove the intake manifold to gain access to the intake valves for cleaning. Depending on the vehicle and driving conditions the car could require carbon cleaning every 30k-60k miles.