Bioethanol is one of the new renewable energy alternatives that have the potential to be used as vehicle fuel by mixing a certain percentage of gasoline. However, the characteristic of this mixture has some differences from pure gasoline fuel. These differences may cause that the mixture fuel is not matched with the standard engine requirements. It will cause a reduction in the value of engine performance. All of these matters have brought us to research for optimizing engine performance that uses gasoline-ethanol fuel. In this paper, a study about ignition time is carried out as a solution for optimizing the performance. The purpose of this research is to optimize the engine performance through engine test using a dynamo testbed. We all know that the Engine Control Module (ECM) is a device to control some systems that run-in engine. One of the systems that controlled by ECM is ignition timing. In this paper, we change the degree for ignition time by expecting that these changes will have some effect on the result. The ignition time and the fuel mixture are the parameters for this research. As a result, we find that changing the ignition time become an advance mode will increase the engine performance and the specific fuel consumption. Keywords: Gasoline, Bioethanol, Engine Control Module, Engine Performance, and Ignition Time.