I have done my mowing for the week. Temperatures here in North East Texas are lower than normal this week. It was in the upper 80s this morning while mowing so my testing will have to wait. Running prettly hard my needle only got up to about the 3/8 point. This is running for a couple of hours. I do believe there is considerable difference in the cooling but until I get a 100 degree day to try I won't be satisfied.