Dirt refers to harmful deposits that can form in engines, causing a loss in engine performance. It can build up over time and over a range of driving conditions. Dirt is a well-known issue in car engines.
The critical engine components that dirt affects are the intake valves and fuel injectors in petrol engines and the fuel injectors in diesel engines.
When an engine is affected by dirt the driver may notice a loss of responsiveness, for example the vehicle doesn’t perform as expected when accelerating.
In diesel engines a build-up of dirt in the fuel injectors restricts the flow of fuel causing a reduction in maximum engine power. The loss in power may be felt by the driver as the vehicle may no longer accelerate as quickly as it could when the vehicle was new. In petrol engines slimy or sooty deposits can build up on the intake valves. The driver may notice a momentary hesitation or loss of responsiveness when accelerating.
BP Ultimate Unleaded and BP Ultimate Diesel are specially formulated to remove existing dirt from these critical engine components and protect against its build up. In fact our tests show that BP Ultimate fuels clean away the majority of dirt in just two tankfuls.*
BP Ultimate could give up to 21 more miles per tank.* We tested the fuel economy benefit that could be achieved through the use of BP Ultimate fuels as follows:
Actual fuel economy benefits achieved may vary depending on vehicle type, condition, engine technology, driving style, road conditions and other factors such as length of journey, climate, tyre pressures and vehicle loading.
In our tests we measured the full fuel economy benefit after ca. 6,200 miles for petrol and ca. 1,865 miles for diesel; however it is possible some benefits could be achieved sooner.
BP Ultimate Unleaded has a higher octane (97 RON minimum) than the minimum 95 RON required by law for petrol in the UK. For petrol vehicles that have been designed to take advantage of a higher octane fuel those drivers could achieve some instantaneous benefits although this will also be influenced by their driving style.
BP Ultimate Unleaded also contains a friction modifier component which over the full ca. 6,200 mile test improves the lubrication of the upper cylinders in the engine. This friction modifier can also contribute to improved engine efficiency and therefore fuel economy.
For the vast majority of diesel vehicles (those with direct injection) any fuel economy benefit is primarily derived from the removal of dirt. Since BP Ultimate Diesel cleans away the majority of dirt in direct injection diesel engines in two tankfuls, the fuel economy benefit of up to 21 more miles per tank* should be achievable in two tankfuls.