I used to try and save money on air filters, now I just change them. Some machines are, like the one my daughter uses, is running in very dusty condition, replace it more often.
I have used a pre-spray from AFE, my son left a bottle here, just like Dan says it is nice to use. no fuss or muss.
Usually I just go dry. All of my workers are big twins and they suck a lot of air.
hey cut a hole, double stack and run 2 years!
shaker hood