Quote:
Originally Posted by gtc
My buddies boat has a 6-71.... noisiest thing ever... i wish it would just die so I can get him a Cat, but it taunts me by firing right up every time.
|
I ran a GMC blower on a chrysler hemi in my drag boat.
Most of the noise is due to the straight or semi-straight cut gears that drive the lobes.
if they had room for a true helix or a double helical gear it would be much quieter.
Straight cut gears are much more efficient as far as power transmission goes but they make alot of noise and vibration.
think of it as a slap vs. a slide. Straight cut gear teeth hit each other all at once and the oil film is all that keeps them from going metal to metal. They also require a little more back lash (usually, not always).
Helical gear teeth mesh more gradually. Kinda like hitting a speed bump at an angle instead of head on. The downside to helical gears is thrust.
The angle creates opposing axial forces and must be dealt with by larger, heavier
bearings. That creates added friction and heat.
Also, most high performace blower applications have wide open intake tracts. No sound deadening or baffling. That makes blowers loud too.