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The excerpt is from a description of the 2008 Exige Cup 260's engine configuration. I don't understand what the BOLD part means.

The supercharged and intercooled engine in the Exige Cup 260 has a maximum power output of 260 PS (257 hp) at 8000 rpm and a torque figure of 236 Nm (174 lbft) at 6000 rpm.This significant amount of extra power and torque now available together with the VVTL-ivariable cam system ensures that there is a smooth and linear surge of power from lowengine speeds all the way to the maximum 8000 rpm (8500 rpm transient for 2 seconds).
The Roots-type Eaton M62 supercharger (with a sealed-for-life internal mechanism meaning
that it does not require the use of the engine’s oil) is run from the crankshaft and has an
integral bypass valve for part load operation.
Charge air (air under pressure from the supercharger) is cooled through an air-to-air intercooler (the air enters via the enhanced roof scoop) before being fed into the engine itself. All charge air ducting has been kept as short as possible with large diameter pipes to minimise restriction and maximise throttle response
and efficiency. Four high capacity injectors and an uprated fuel pump add additional fuel
under hard acceleration or continuous high speed driving.
 

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Well I guess there are 3 parts there

1. The M62 is a supercharger that forces more air into the engine. It is bolted in place of the intake manifold. The name comes from being able to displace 62 cubic inches of air per revolution of the screws.

2. The supercharger uses gears to move various bits inside (both the impeller "screws" as well as the step up gearing). Some older designs used the engines oil to lubricate these parts. Most turbo's to this day still use the engine oil *note a turbo is different then a supercharger.

3. The bypass valve allows the supercharger to make a "leak" around itself, thus negating the boost when you would not necassarily need it. However depending on how the system is hooked up as well as the application you may not need this part. I don't remember who does what, but I believe between the Lotus designed superchargers and aftermarket ones (Sector111 & BWR), some use the valve and some don't. I believe that since the throttle body is before the compressor in our application, that even though the supercharger would always be "boosting", when the throttle body closes it limits the actual amount of air the supercharger can grab and thus no real boost is made.
 
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