Squeezing horsepower out of an engine can be done by adding cubic-inches, bolting on a power-adder, and massaging cylinder heads to flow more air. Another way is by ensuring you have the right vacuum pump for an engine combination, and that it’s functioning properly. Moroso’s Scott Hall covers some frequently asked questions the company gets about vacuum pumps at idle.

The job of a vacuum pump is to draw air out from the engine and reduce the pressure levels that are created as gases blow by piston rings during the combustion process. An external vacuum pump reduces the elevated levels of crankcase pressure and that helps to improve ring seal to create more horsepower. There are other benefits to a vacuum pump that is functioning correctly, including improved oil scavenging, lower levels of lubricant contamination, and less windage experienced around the rotating assembly parts.

Since Moroso makes a wide range of vacuum pumps they receive many different questions about how they operate. A common question the company receives is why a racer will only see a few inches of vacuum when their vehicle is at idle. Hall explains how a pump functions to produce vacuum and how someone can get a better reading on how much vacuum their engine is producing.

Click play on the video to hear Hall discuss why a vacuum pump might not be giving you the best reading at idle and how to get a more accurate reading. You can also see all of the different vacuum pumps Moroso offers right here.