depends on what you are driving on. it will give you more traction on a dirt road. It won't add any power to the engine output. It will probably give you a slight loss in power output because you are adding more load to the power train. But not a noticeable amount most likely. If you are thinking about like when you are pull a long grade on the highway, no, it won't help you. Unless you rear wheels are loosing traction, 4wd won't help your engine get you up the hill.