In this study, the effects of the amount of water injection and timing on engine performance were investigated in a water injection with exhaust heat recovery six-stroke engine converted from single cylinder, four-stroke, spark ignition engine. The experiments were performed at constant injection timing and four different injection pressures (25, 50, 75 and 100 bar) at full load and stoichiometric air/fuel ratio (lambda = 1). Experimental findings were evaluated according to first and second law of thermodynamics. The highest brake power was measured at 3000 rpm as 1345.9 kW when the 13.44 mg/cyc water was injected at TDC. At this time, thermal efficiency, thermodynamic efficiency and irreversibility were calculated 14.73%, 21.88% and 52.57% respectively. It was seen that brake power, thermal efficiency and thermodynamic efficiency decreased but irreversibility increased when the different quantity of water was injected at the same engine speed and different injection timing. As a result, water injection timing and the quantity of water are important in order to provide optimum exhaust heat recovery for higher engine performance. (C) 2015 Energy Institute. Published by Elsevier Ltd. All rights reserved.