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hmmm.... good question. The screw type air compresors don't whine... don't know why a roots type does. Maybe mechanical noise?

anyways... get the latest hot rod mag.. has a GREAT article on the engine in the new Ford GT... it has a screw type blower.
 

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didn't you mean whine?.[nutkick]

Sometimes if you are going to be a smartass you have to be smart.

Most of the noise is coming from the relatively straight cut on the gears.
 

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fOCUS Zetec 2.0
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is it coming from the belt?
 

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Straight cut gears whine quite a bit, old gear driven transfer cases in broncos ( I have a lifted 69( whine their buts off in low range due to the gears, also pete jackson gear drives are available with straight cut gears to make them whine if you want to. However most of that cool eerie sound comes from the belt, I have been around a few of the older 8-71 and 6-71 gimmie blowers where someone has tried to get rid of the whine ( why?, I love that sound), one guy was running a chain drive and it was MUCH quieter, the other car owner had built a really compex but sweet looking shaft drive set up and it was also very quiet.
Even the new cars with roots types blowers whine ( cobra, jaguar,etc.) still have some whine to them at boost , but are very quiet at idle . I am sure this is important to the o.e.m.'s
 

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The whining is simply gear noise. Some types exhibit more gear noise than others, but all superchargers have gears, and they all whine to some degree.
 

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well a stock JRSC running 5 boost won't whine but if u get the smaller pulley it will whine
 

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Solaris said:
well a stock JRSC running 5 boost won't whine but if u get the smaller pulley it will whine
Oh, it's whining at 5 psi, just not at a frequency that your ears can hear [;)]
 

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The Professor
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Actually it is a combination of gear noise, and air under the belt. You can drill holes in the blower pulley for air to escape and it can all but elimate the noise.
 

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im pissed of ....i have JR supercharger with 3inch pully ,makes 7psi, but it doesnt make any kinda whine. Is it better if it whines. ie. more efficiant?
 

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titan said:
im pissed of ....i have JR supercharger with 3inch pully ,makes 7psi, but it doesnt make any kinda whine. Is it better if it whines. ie. more efficiant?
No, it wont be any better at producing. Just sounds nice.

And most of the noise is indeed caused by the belt.
 

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There was a GREAT article in MM&FF a few monthes back about differnt types of blowers.

The belt has nothing to do with it..

Centrifical blowers don't "whine" due to the design, similar to a turbine on a turbo. Centrifical blowers are also noted to be 'up-top' blowers, giving more boost at higher RPMs. Centrifical blowers will get you a bit of whistle...for instance, Procharger is known for their very high whistling noise at idle due to how the impellar gears are cut (i forget what they call the cut design) on their D1models and up. The Vortech V1 S-trim is very known for its very loud whistle at idle as well.

Twinscrew/roots blowers whine because of their design. A twin screw blower literaly has two long screws inside the blower that force air into the intake due to the grooved ducts on the outside of the screw to hold and move air. Kenne Bell reports impeller speeds of over 55,000RPM inside the blower housing, compared to 6k crank RPM with STOCK KB pulleys.
Roots blowers have a single screw which turns an impellar like fans over each cylinder, pushing air into the intake port.

The common understanding is twin screw blowers get more up top compared to roots blowers with less friction but roots blowers can easily get you more response at very low RPMs, depending on impellar sizes. I think I heard somewhere that at stock 8psi an Eaton on a Terminator reaches right around 30k RPMs with stock pulleys, I know people that have pushed their stock ported Eatons up to right around 18psi.....but they didnt last too long after that, the ammount of heat those things put off is just amazing, running at 60k rpms.

Each type of blower has their benefits and fall backs.
For 4bangers, go turbo...robs less power.
Built v8s, hell yeah...belt drive centrifical blowers!![thumb]
 

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Moved to Forced Induction......

As well, I also cleaned up the crap that was on this thread. Keep it on topic!
 

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lupuri, roots chargers are not what you describe. go to eaton's website and take a look at them. the roots and lysholm screw chargers are very similar to eachother, the biggest difference being the design of the rotors (impeller). eaton corp roots blowers use two rotors, each with three lobes twisted helically around the core of the rotor. both roots and lysholm screw chargers are positive displacement blowers and have very similar desings.
 

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crazymechanic said:
lupuri, roots chargers are not what you describe. go to eaton's website and take a look at them. the roots and lysholm screw chargers are very similar to eachother, the biggest difference being the design of the rotors (impeller). eaton corp roots blowers use two rotors, each with three lobes twisted helically around the core of the rotor. both roots and lysholm screw chargers are positive displacement blowers and have very similar desings.
Your prolly right on point..
I havent seen any REALLY good breakdowns on roots blowers to be honest.
 

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haha u guy are funny.

ok if u spin something at 10,000 rpm or more it is going 2 make a noise.

and another thing the air is getting cut and that makes some noise.

so if that helps
 

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Lupuri said:
Your prolly right on point..
I havent seen any REALLY good breakdowns on roots blowers to be honest.
like I said, go to eaton corp's website, they have a good cross section of their roots blowers, and I know kenne bell's website has a cutaway view of one of their blowers
 

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I would think that having a cone filter (no air box) would help with the noise too. My bro's GTP was pretty quiet stock. Sure you could hear the supercharger, but after he added a cone filter... weeeeeeeEEEEEEEEE anytime he makes boost. It's funny when he revs it... people usually make a funny look and don't know what the noise is... ricers beware!
 

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[idea]whine or no whine, when you are sitting next to rice burner at a light, and the light turns green [ohcrap]
 

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Lupuri said:
For 4bangers, go turbo...robs less power.

Turbos rob no power. They are propelled by the continued expansion of exhaust gasses in the exhaust manifold that would otherwise be wasted (Not the pistons pushing the exhaust out). These can reach 130k RPM. You'd whistle too...
 
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