I just got the Comptech Blower on my car along with a SOS 3inch pulley. After reading instructions I got a little confused.

"Check the belt tension by applying 20lbs. of force to the
drive side of the belt (side opposite the tensioner), deflection
should be .500” to .625”. If correct torque the tensioner
pivot bolt to 33 ft/lbs and tighten the adjustment
bolt."


How do I know that I'm applying 20lbs of force on the belt? Do I have to buy a tool for this or is there another way?

 

The best method I have found , is to get it about as tight as you can and go do some test drives and see what max boost you make, then lower the tension until the belt starts slipping. Then you will start to learn how tight you will need it. As loose as you can run it without it slipping is best. make sure you have a belt that is longer so that you can get more "Wrap" around the pulley for better traction.

A method that I have created for tightening the belt easily and effectively, is to tighten the lock nut up just snug enough so that the adjuster will stay put when there is significant belt tension, but not so tight that it wont move. Take a large rubber mallet or hammer and a 2'-3' long breaker bar ( I use aluminum becuase its soft ) And put the end of the breaker bar on the tongue of the adjuster with a rag or something to protect if you like and bang down on it. If you get some belt tension but the adjuster bounces back, then tighten up the lock nut a little more until you get the desire belt tension. You should be able to twist the belt about 90-100 degrees with your thumb and fore finger.

 

Yeah ^^^ Not too tight that will wear out the blower faster...but not too loose...belt will slip.