I Have a 315c cat and am looking into buying a mulching head that requires a minimum of 35 gallons per minute hydraulic flow. I was wondering how well my machine that puts out 40 gpm would run something like that and how bad it would slow down the machine??
It depends on the pressure in which that 40 gallon a minute is happening at and the type of plumbing in the machine.
I have a customer that put a mulching head on a 312. Said works great just can't travel and mulch at the same time.
I have a Hitachi ZX160-3 which should have similar hydraulics to the Cat 315 (2-50gpm pumps). I tried hard to put a ProMac mulching head on the machine. It needed a constant 35-40 gpm @4000psi. I adjusted the relief valve on the aux port to get 4K and had already had all other aux line needs like splitter valve from the thumb, oversize lines, motor return line. When installed the mulcher worked fine BUT, you couldn't use any other machine function without losing power to the head. Any machine function takes priority and gets oil before the aux circuit. If you track, your head will immediately slow down. If you simply want to swing the boom to run the head or raise the boom into the work, it will affect the operation of the head. If your Cat is new enough it may have a feature in the computer to change the priority control of the oil to the aux circuit. If not, you will need to install a custom priority control valve into the system. That may cost $5k-10K depending on where you get it. If your Cat is like my Hitachi, you won't like it. The only way I could make it work was to set up my position, spool up the head, and very slowly swing the boom or lower the boom into the work. Production rate was too slow. I'd suggest you contact the mulch head company and find out exactly what the machine requirements are and then talk to Cat. The sales side doesn't understand priority control and many techs haven't dealt with the operation of motor driven attachments on machines. You can Google and find info on aftermarket auxiliary kits for excavators that feature the priority control or I can send you the name of an outfit that just sells and installs the priority valve without the piping. Good luck, I spent a lot of time and money and finally gave up not willing to spend another $8K for the valve. As a side note, the reason the machines are built this way is for safety. They don't want any aux function to interfere with the safe operation of the machine, so machine functions come first. I thought the aux circuit could run from the 2nd pump only and leave pump 1 for machine functions, but they couldn't devise a way to make that work.