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iTrader: (5)

Anybody have a sound clip of a roots style blower like a 142 or 144? Just curious how much whine they let out.

flrtin1

The blower "whine" that you are probably asking about will not be found on the "smaller" blowers because they have a serpentine belt on them and the "whine" is caused by air being trapped in the cogged belt as it wraps around the pulley on the larger blowers.....you will get some gear noise from the smaller blowers but not the sound I think you are asking about

TonyC

iTrader: (1)

I thought it was from the gears meshing, no? Ever heard a car with a gear drive instead of a timing chain? Sounds like a big huffer under the hood. The smaller Mustang Cobra blowers make plenty of noise.

flrtin1

If you hear a gear drive vs a cog driven blower side by side there is a big difference between the two sounds

SeeYaSucker

I had a Weiand 177 on a 377 smallblock and it definately had a blower whine, it was a 10 rib serpintiene. also the old style B&M mega blowers were like 20 rib serpintine and the whine from them things is anoying.

flrtin1

The sound on the 177 was from the gears and B&M mega blowers were cog driven belts

Shagwell

one of the biggest things to create "whine" is straight cut gears in the blower drive. Yes, the big whine you hear from big(race) blower is partially the belt, partially the teflon strips in the blower. Some of the smaller blowers have helical cut gears, therefore whining less/not at all. Same goes for gear-drives/ manual transmissions. That's why factory trans. all have helical gears. They're quite. Straight cuts make noise, but are stronger because they don't try to push apart like helical gears do.

flrtin1

Not to argue but
Most people do not understand the blower whine (positive drive cog belt) and gear whine are two different sounds also the only sound teflon tips make is some clicking until they wear in.

But don't take my word for it here is a quote and link from BDS (blower drive service)

"Can blower whine be eliminated or made louder? Blower whine can be increased or decreased by tightening or loosening the blower belt tension. CAUTION! Improper belt tension can cause severe belt, blower, and engine damage. It is not recommended to adjust the belt to get the sound you want. Worn pulleys and belts as well as mis-machined pulleys can contribute to blower whine. "

http://www.blowerdriveservice.com/faq.php

flrtin1

Also as you can see from this exploded view the drive gears on the full size blower are helical cut not straight cut

Shagwell

in that pic, yes they're helical. As for our 1471's(both striped, one high helix) and the Kobelco 1671 Superman I've been around on our drag cars, they're straight cut. I've taken/seen them apart.

I do agree that the belt makes most of the noise, just saying there are other factors that contribute...

SleeperFromHell

Forget about the roots. Go straight to the twin screw's. Sound so much more nasty then the roots do.

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iTrader: (5)

Guessing a twin screw is like a procharger that needs a blow through carb?? Im wanting to stay away from that.

SleeperFromHell

Nope. The twin screw is a lot like the roots. It just produce's a ****load more power.

The Twin Screw Supercharger
The twin screw supercharger at first glance appears to look similar to a roots supercharger both inside and out. The two technologies are indeed similar, however there are significant differences. At the heart of the twin-screw supercharger are two rotors, or "screws" that rotate towards each other. The rotors mesh together and draw air from the back of the supercharger. The twisting rotors move the air to the front of the supercharger, while compressing the air before discharging through a port at or near the front of the supercharger.

Because the compression is done inside the supercharger, this design produces less heat than a roots supercharger - in fact, it is almost as thermally efficient as a centrifugal design. Like the roots design, the twin-screw is a fixed displacement supercharger (meaning that it pumps a fixed volume of air per revolution), and because the tolerances between the rotating screws are very tight, its ability to create boost at low rpms is unparalleled. These characteristics make it ideal for trucks and towing vehicles, where low to mid range power is primary in importance. Another important advantage of the twin screw compressor is its reliability. Unlike a roots supercharger, the rotors in a twin screw supercharger do not actually touch, so there are virtually no wearing parts. For this reason, twin screw compressors are commonly used to pressurize cabins in passenger aircraft. Like roots superchargers, twin screw superchargers are self lubricated and do not tap into the engine's oil supply.

One disadvantage of the twin screw design is that, because it has an internal compression ratio, the twin screw is compressing air even when it is not sending boost to the engine (i.e. under cruising or deceleration). An internal bypass valve releases the pressurized air, but because it takes work to pressurize the air in the first place, the twin screw supercharger draws more power from the engine than while not under boost. Like the roots, the throttle body must be placed before the compressor because it is a fixed displacement supercharger.

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iTrader: (5)

Ok, now back to the original question, Does anyone ahve a sound clip of a roots blower??? All the info given is great.

flrtin1

.

Damon

I have a Weiand 142 on my very mild 383. It sounds like this: zzzzzZZZZZZZ!!! Increasing in volume and frequency as the RPMs climb.

Sorry, that's my best sound clip. Sad, isn't it?

It only makes that noise at or near WOT. The belt never makes noise as it's just a little 6-rib serpentine. The synchro gears make a little noise (very little- less than a gear drive) when cold but completely disappears when fully warmed up. Only makes "that noise" when it's laid to the wood.

The sound you are referring to- that unearthly blower noise- is from the lobes inside the blower rippign the air into little bite sized pieces and cramming them down the engine's throat. It sounds aboslutely nothing like any N/A, centrifugal or turbo combo in any way. It's a noise all to it's own.

Drowned out only by an open element air cleaner, it can be easily heard over 2-chamber flowmasters with turn-downs in front of the rear axle on my 78 'Bu. Yep, it's loud, but in a very entertaining way.

Driving around on the street normally you have absolutely no way of knowing it's got a blower.

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iTrader: (5)

Thanks Damon, thats what I was looking for. At least when I get one ill know it wont be quitewhen im running it.