The aim of this study is to investigate experimentally gasoline fumigation (GF) and to apply heat release (HRR) analysis for two different compression ratios (CRs) for different gasoline fumigation ratios (GFs) at two engine speeds in an automotive diesel engine. Here, gasoline at 5-20 % (by vol.) ratios was injected in to intake air by using an adapted carburetor. Firstly, GF tests were conducted for original CR (18.25, high compression ratio, HCR) of the engine. Then, CR of the engine was reduced to 17 (low compression ratio, LCR) by changing of cylinder head gasket thickness and GF were also investigated for LCR. In this study, HRR was analyzed by using measured cylinder pressure values. At the end of the experimental study; it was seen that GF creates two peaks in HRR curve for selected all of the operating conditions. The first peak occurs before top dead center (TDC) and the second peak occurs after TDC. The first peak becomes larger and second peak decreases with increasing GFs. This indicates that combustion process is better than that of neat diesel fuel (NDF), especially for low GF ratios. In addition, GF increases cylinder pressure and temperature. (C) 2018 The Authors. Published by Elsevier Ltd.