Owners of supercharged cars get worried about the noise that comes from the front of the supercharger. some have a rumble some have even rang in a panic saying there supercharger sounds like a rock crusher. Many of the people who have had the noise issue have found that alot of it will disappear once the engines tune is sorted. An engine with a fluctuating idle can indeed give of a noise from the front of the supercharger that sounds like there is some gravel bouncing around in the gear case. If you are worried a simple test once you know that the correct amount of oil is in the supercharger is to bring the engine up above idle. As RPM increases the lash in the supercharger drive gears is taken up and the rock crushing noise should disappear. If the noise doesnt go away as rpm increases you may have an internal problem with the super charger. If the gears on the supercharger are worn or there is misalignment the noise will continue to be there regardless of the superchargers rpm. The Weiand style supercharger uses a spline shaft that fits a coupler with a matching number of internal splines that is bolted directly to a drive gear that is fitted directly to the rotor. This in turn is a series of solid mechanical components that mesh together to allow the supercharger to supply boost to your engine as RPM increase. When this happens you are going to get mechanical noise.
Some superchargers use a helical gears and these are quieter than straight cut gears and when used with nylon style drive couplers like many of the Eaton superchargers used on production cars the mechanical noise is also some what reduced. A supercharger when fitted to an engine produces pulses and a rib belt will allow for slippage in case of backfire and can take some of the torsional vibrations from being sent through to the harmonic balancer. This is why it is important to use a harmonic balancer with additional rubber and preferably a chemically bonded harmonic dampener to try to absorb some of the vibration.
When it comes to filling your supercharger it is not recommended that you just use any old oil. Aussiespeed has dedicated full synthetic blend supercharger oil that can be used in M series eaton and Weiand superchargers as well as brands like Whipple, The Blower Shop, Hampton, Fisher, Holley, B&M, Edelbrock as well as other roots type chargers. Aussiespeed full synthetic blended supercharger oil is a 75/90 weight oil that is blended in the USA from the highest quality base stock to give your superchargers internal the best protection. The oil unlike many oils designed for gear boxes and diffs that can foam at high RPM. Our 100% synthetic Blower oil has stabilizers added to stop foaming and to give maximum protection to gears and internal components at extremely high temperatures and high RPM.
A supercharger running high boost for extended periods can over heat or cook the oil. When this happens seals can be damaged as the heat from the oil burns the seal.
One thing you need to remember id that the rotors in your supercharger can turn up to 22000 RPM and require an oil that will not foam and loose its lubrication properties at that type of rpm. It has been suggested by many supercharger companies that the higher the boost level the less oil should be run in the supercharger.
Aussiespeed AS0515-300 supercharger oil is sold in a 300ml bottle and AS0515-200 is a 300ml bottle