I've heard that it's the belt either too loose or too tight, worn drive gears, air rushing through the carbs, etc, etc. Does anybody know for sure?...
If I had to guess I'd say it's the drive gears for the rotors making most of the noise, kind of like the sound a gear drive for a cam makes.
can't se it being a loose belt..my baby blower was brand new..weiand has a spring loaded tensioner and it's a stick prick.....rotors???i do know that when i put my foot in it, it would get louder...... more air gettin stuffed????
The toothed belt (when interfacing with the pulleys) creates the whine, similar to what happens with straight cut gears. You can minimize it if you'd like with some strategic drilling, but why would we want to? Al in CT
yeah no kidding, not to mention its spinning at some outrageous rpms. what is it like 16k or maybe more?
It's the drive gears that makes them whine. Stop and think for a minute, where did the first blowers come from? Detroit diesel engines, right? Well, a Detroit diesel engine did not use a belt at all anywhere in the system and they whined too. So, what was the common factor? The drive gears are the answer. Steven.
My blower whined right out the box, and when I got had it Teflon stripped it whined even louder. I think it's just the noise the gears make, just like a loud "gear" drive instead of a chain.
Most roots blowers have straight cut gears that turn both rotors. Thats what makes the noise. Same as a gear driven cam.
Had An 8-71 On a312 in a 55 ford pu With a holley 3 bolt carb in side and 2 holley 600's on top (butterflies removed) no roters no gears with a 1/2 pitch 3" wide gilmer belt at 29% over and the s.o.b. whinned at idle
That's it. GMC blowers have helical gears (that's why you can time the rotors by shimming the gears), the gears are quiet.
This is pretty much the bulk of it. Thats why there is a different tone to the "while" depending on if you have an 8mm belt, 1/2 pitch cogged belt or very little noise with multiple V-belts. Drilling the hole's as Al mentioned will alter/quiet it down if someone wanted that..
Yep, the belt makes most of the noise. If your belt is tight it will be louder than if it is loose...BUT, a tight belt is harder on your front main bearing. Ask Kerry how much noise his makes...he has 3 V belts instead of a toothed 8mm or Gilmer. -Abone.
Not trying to argue here, but what makes them whine on a Detroit diesel engine? I listen to one everyday and it sure does have mucho whine. It's not a Gilmer belt whining on this one because the blower is mounted to the side of the engine and runs on gear drives. Steven.
If i had to guess, it's either the gear drive system that turns it, or the style/cut of gear that is in the drive assembly that's making the noise you are hearing.
10-4 I do admit they seem to have more whine with a belt setup. I've always chalked it up to the gears. I learn something everyday. Steven.
I know on the old 3 in drive deals it use to be the air trapped between the belt and pulley's. The gears were helical cut no noise. Now it's boost on a big show car. Hi Al!! Lippy
The drive gears make some noise. The rotors make most of it. Go to the far end of the strip and listen to blown alky or gas dragsters. When they open the throttle and the rotors are loaded with back pressure and the air fuel mixture, that's when things get interesting. Everything on a blower setup contributes to the sound. At full throttle, the rotors are the main offender.
This was told to me by BDS when i was setting up the blower on my old coupe..Just about word for word. I ran a 3" Gilmer drive on mine..It was LOUD.
The gears at speed, and it's the best damn sound in the world. I grew up around Clark Skidders running DD's at full rap, and it still makes me all warm and fuzzy to hear 'em!
Like others have said, its the gear drives, the rotors and the toothed belts. The tighter the belt the louder the whine. I knew a guy back in the 80s that would take a couple of spare belts one size too small for the setup and put one on at whatever event he was at. Had to unbolt the blower, tip it to get the belt on then someone stood on the blower while it was bolted back up. That son of a bitch whined like nothing else! Doc.
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