Originally Posted by Valk
RG knows what he speaks. Though, if you were to opt for the 8500...I'm pretty sure you wouldn't be disappointed. It is a larger engine that is likely not working quite as hard to move even more air than the 7500...though the 7500 has the edge in MPH due to it's smaller tube...thus giving it its improved scouring ability.
I own an 8001...and until it needs replacing it is my #1 blower for Nov's leaves. I currently run/operate a Dolmar 4-cycle blower that is a nice 'everyday' unit Apr-Oct. But for HUGE piles of Nov leaves...it is RedMax time, FO SHO.
The tube on the 7500 and on the 8500 are the same exact size. The only
difference is at the end of the tube on the 8500. It is flared out to create a different turbulence as the air exits the tube, which is designed to allow the high CFM's to work on a slightly wider area at normal operating distances. If you were to cut that flare at the bottom of the inside radius, you'd basically have the tube end that is on the 7500/570. Trust me when I tell you, the 7500/570 fan isn't overworking the engine in the slightest. It operates at a minimum of 750 rpm's below its maximum rated power speed (max rated power speed= 8000 rpm's vs maximum operating speed of 7250 rpm's). The 8500/580 on the other hand, actually operates at its maximum rated power speed of 7200 rpm's.