870 - 500 ft hose run

Jim Davisson

Well-Known Member
Aug 23, 2016
Serving the greater Charlotte area
Real Name
James Davisson
Business Location
United States
Right! Something vacuum controlled in the system perhaps that can't exceed 13" hg. Number toting manufacturers usually don't detune something like that without a good reason. I always thought that Hydramaster had mine running 2" under manufacturers spec because of strain on the power transmission of single belt serpentine PTO pulley.

However, playing devil's advocate it's not going to affect dry times whether it's 13 or 15. Heck it's darn near impossible to pin the lift while actually cleaning anyway.
Reactions: waxman


Well-Known Member
Aug 16, 2006
Belton Texas
4.5 blower at max output is around 380 cfm
4.7 blower is areound 500cfm
5.6. Blower is around 520 cfm

It depends on what is the rpm pully and exctly what the blower is
Spinning and holding its rpms...wo bogging down......

Most of these truckmounts do not spin at max rpm!!!!!!
So I would knock off around 100 cfm??????

However I have found that a 4.5 blower at 3600 rpm and
A 4.7 blower even at 3200 rpm is significantly more vacuum