These are all acronyms describing a class of modern engines referred to as Direct Injection (DI), Gasoline Direct Injection (GDI), or Direct Injection Spark Ignition (DISI). Unlike Port Fuel Injection (PFI), a GDI engine injects its fuel directly into the combustion chamber. This leads to greater power and efficiency. Fuel economy improves, as does the overall driver experience.  

However, because of their advanced design, a GDI engine brings new fueling challenges. The fuel often needs additional help from fuel additives to enhance engine cleanliness and durability. Especially important is fuel injector function, which must remain “like new” during thousands of miles of operation. Compared to PFI, GDI injectors are twice as hot. High temperature can lead to increased deposit formation and a new need for thermally stable detergent additives.

Actually, a properly functioning small engine can be just as efficient and powerful as a larger one when operating at peak performance. And a properly designed fuel additive helps ensure that your vehicle will continue to perform throughout its lifetime. For this to happen, the engine and fuel injectors must remain free of deposits. The smaller the engine, the greater the impact from deposits. 
Injector cleanliness is paramount. A plugged injector can lead to mis-fueling  and severe power loss. The driver may experience hesitation and poor acceleration. Afton’s gasoline fuel additives contain thermally stable detergent components to protect injector nozzles from performance-robbing deposits in these small, modern GDI engines.

No, it might not. The lower grade will not cause harm, but it might not allow for the best overall performance, e.g. both fuel economy and power output could be compromised. 
In addition, lower grades of fuel may contain less fuel additive that can result in carbonaceous deposit formation  inside your fuel system. Deposits can block the free flow of gasoline into the cylinder, diminishing a vehicle’s efficiency.
Not necessarily. Today’s modern GDI vehicles may be designed to exploit the benefits of octane number to deliver more power and acceleration. In addition, some branded premium fuels often contain a higher dose of fuel additives that are designed to keep the engine clean and functioning properly. Modern GDI vehicles require enhanced levels of protection due to extreme operating temperatures.
​Absolutely not. There are no standardized tests for GDI injector cleanliness. Therefore, Afton has developed its own tests to prove injector cleanliness performance that is robust in all vehicles under all driving conditions. Our unique tests apply to most any fuel. 
Afton has spent more than 20 years developing proprietary tests in collaboration with OEM partners and Gasoline Retail customers. Quite honestly, our Gasoline Performance Additives (GPAs) provided GDI performance before GDI was mainstream. But stay tuned, there are new industry tests on the horizon!
​GDI engines have been in production since the mid 2000s, and today over 50% of new cars manufactured globally contain these engines. You need to protect your engine with a quality gasoline containing a modern GDI additive system. 
Older additive systems that were designed for Port Fuel Injection may not clean up the unique deposits found inside a GDI injector, leaving your engine less than optimized. That’s why Afton began its development of Direct Injection vehicle tests over two decades ago. And we continue to advance our technology as the engines have evolved.
On the contrary, a quality fuel additive helps to lower combustion byproducts, which can make their way into your oil, resulting in formation of gunky engine deposits, varnish, and suspended oil sludge. Under such circumstances, the quality of your oil will be compromised and diminish the overall efficiency of your engine. A small amount of fuel additive transfers from the fuel to the lubricant during every combustion cycle.  Some high quality gasolines are specifically formulated with chemistry that survives the combustion process, enabling additive transfer and viability to the engine oil, delivering long-term protection and efficiency benefits.