This paper presents the experimental analysis of aluminum BPHX, with dimensions of 215 x 80 x 61 mm, having transversal offset strip fins with two pitches of 5 and 6.8 mm using liquid to liquid to measure the heat transfer and pressure drop performance in the Reynolds range of transitional to turbulent regime [10(3), 10(4)]. Firstly, the heat exchangers were tested using water on both sides. A heat transfer and friction coefficients empirical correlations were determined, and the resulted functions were compared with two other models presented in the literature. Secondly, the heat exchangers were measured using water and engine oil as hot fluid.