February 10, 2017
In my last post I said I didn’t like the way my vacuum switch was working. I bought the adjustable switch from Dave Lenzi and he said to adjust it so that my pump turned on at 16 inches of mercury and off at 18 inches. I did that but because my engine only pulls 15 inches, the pump turns on every time I use the brakes. I asked Dave about this and he said that the booster works best at 16 inches or more and that a normal engine should be able to pull about 18 inches at sea level. He said that for each 1,000 feet of altitude above sea level that number will go down by 1 inch. I am at about 2,600 feet at home. That would make my vacuum at sea level be almost 18 inches and my pump would not be coming on anywhere near as much.
Dave’s advice is to let the pump run and keep the vacuum up where the booster is the most effective. I told him I would heed his advice and leave it the way it is.