I found on the following website (said as preliminary info) that the ratio of the crankshaft pulley divided by the supercharger pulley is 1.85 ! The stock supercharger pulley is exactly 3.34", so multiplied by the ratio it gives a crank pulley of 6.18". I had previously myself measured to roughly 6", so I think 6.18" is the real measurement.

http://www.saturnfans.com/Cars/Power...tecspecs.shtml

2004 Ecotec 2.0 Liter Supercharged Engine
Preliminary Specifications

Type: 2.0L inline 4-cylinder with supercharger
Displacement: 1998 cc
Compression ratio: 9.5:1
Valve configuration: Dual overhead camshafts (4 valves per cylinder)
Valve lifters: Hydraulic roller finger follower
Firing order: 1-3-4-2
Bore & stroke: 86 x 86 mm
Bore ctr. to ctr.: 96 mm
Supercharger: Eaton M62 helical roots compressor
Intercooler: Water to air
Max boost pressure: 12 psi
Pulley ratio: 1.85:1
Oil cooling: Oil cooled pistons and direct mount oil cooler
Fuel type: Gasoline (premium unleaded recommended)
Fuel system: Sequential fuel injection with high pressure (56 psi)
Fuel shut off: 6500 rpm
Intake manifold: High flow, low restriction with integrated intercooler system
Throttle body: 68-mm electronic throttle control
Ignition system: High energy coil-on-plug
Horsepower: 200 hp @ 6200 (estimate - final figures in fall 2003)
Torque: (lb-ft): 200 lb-ft @ 4400 (estimate - final figures in fall 2003)
Spark plugs: Platinum tip (1.5-mm gap )
Oil: 5W30 / 7 quarts with filter change

 

good find

 

its actually 1.86.. but close enough..

now we just need to find a company that will make a larger crank pulley..

 

Impossible, no room for it.

 

Why
You can do a 2.5" pulley with a ZZP tensioner and spin the blower to around 18,000 rpm @ 7k motor rpm. Why would we need a bigger crank pulley.

 

because 18k isnt fast enough...