I don't believe so (on the 2stage). Of course the ratio of the pulleys mean a lot.
The bigger the chipper the bigger and heavier the flywheel. Rotating mass I believe is the secret. Plus bigger and more knives.
That's where all the hp is needed.
All my own opinion...😉
This chipper goes up to 3". Does green as well as dry in the chipper part. The dryer the better in the shredder. And doesn't like green viney stuff in the shredder.
The 147d is only rated about 10 pto hp. Honestly never been a problem. It will slip/burn the belts before it runs out of power..
I've used these guys
Very knowledgeable about the 620d. I've used myself for parts. They rebuild, sell replacement motors and parts. I believe they're in the Lancaster County area.
BTW. I'm in Bangor too..!