SP95, SP98 and E10 describe fuels with different octane ratings and ethanol content. They do not represent three automatic power levels. The right fuel is the one compatible with the vehicle and with the calibration used.
Octane is resistance to knock
The octane number indicates how well petrol resists uncontrolled combustion. A higher number gives the engine control system more margin against knock under demanding conditions, but it does not contain a fixed amount of extra power.
A standard engine designed for SP95 may show little difference on SP98. An engine or calibration that can use the additional knock resistance may maintain a more favourable ignition target under load.
What E10 means
E10 petrol may contain up to ten percent ethanol. Ethanol changes the fuel’s composition and energy content and can affect materials on older vehicles. Most recent petrol vehicles are designed to accept it, but compatibility must be checked rather than assumed.
E10 is not the same as E85. An E85 conversion requires a much larger change in fuel delivery and must be assessed separately.
Fuel and calibration must agree
When Swaptune prepares a calibration for a stated fuel, the driver must continue to use fuel that meets that requirement. Switching to a lower octane fuel can reduce the available margin, particularly at high load or temperature.
FAQ
Does SP98 always add power?
No. It provides greater knock resistance. Whether the engine can use that margin depends on its design and calibration.
Can every petrol car use E10?
No. Check the manufacturer’s compatibility information, especially for older vehicles.
Is E10 an E85 conversion?
No. Their ethanol proportions and fuelling requirements are very different.