I don't really warm them at all in the summer, maybe 15 seconds at most before I put it in gear. It takes about a 1/4 mile to get decent power, but they will certainly move immediately after starting. I tend to let them warm up for a few minutes in the winter, but that has more to do with getting a little heat in the cabin and the defrosters. I keep the rpm down to about 2500 until they start to warm up.