pumps
The reason the pumps are so loud is that they run at 60psi or higher. If you were to pinch the return line the pressure would hit 150 in a second. I dont understand GM or the other car man. as they put huge pumps then regulate them down to 60psi. By the way thats why they die 5 times as much as 5 years ago. My 16psi pump is still going strong at 200,000. By the way some new cars trucks are not even using regulators they are using a variable ground in the ECM to contoll pressure. Im sure glad I got out of the buissiness in 96 as all the crap on the new cars is cool but the labor prices are and will have to reflect that soon.