When the flywheel is lightened it provides much faster acceleration of the engine. The stock flywheel weight takes more HP to get moving. So, why did VW make it so heavy? The job of the flywheel is to smooth out firing pulses, stop vibration harmonics, and torsional twist. The most economical way for the factory to do this was to make the flywheel the weight it is stock.
We ran tests for years on lightening flywheels with stock engines and found that indeed VW knew what they were doing to make the engine live a normal life with the stock crankshaft. When I started counterweighting the crankshafts in the early 1970's I found that we increased the engine life dramatically and in some cases as much as 100%. Again, tests were made with lightened flywheels and indeed the counter-weighted crank allowed the use of lightened flywheels with no loss of life.
Further, improvements in longevity were made when we started using our GB 440AE and GB 442E heavy pulleys. The idea came to me again to do the test with a stock crank, our GB 084 lightened flywheel and our GB 440AE pulley. Yes, this provided the faster acceleration I wanted and stopped all the conditions and even improved the engine's life. We found that having weight on both ends of the crank stopped these conditions even sooner and better. See about the Berg Achievers and Equalizers in the pulley section.
Only genuine VW factory forged chrome vanadium flywheels are used. These are approved for race applications and are allowed on NHRA tracks without a scatter shield except when turbocharged. We may appear to be a little more costly to some people, however, in the long run it is far cheaper than using a poorly made aftermarket flywheel that will not work or live, especially if you have it matched to a crankshaft.
Berg flywheels are lightened only on the extreme outer perimeter for maximum acceleration and reliability. We do not take material off behind the clutch surface to do the lightening. Our flywheels maintain this extremely important cross section that avoids distortion (bending) when the clutch is depressed, providing far more rigidity and life. This is especially critical to clutch life, to assure proper release, and full engagement so it will not slip, especially when HD clutches are used.
When improperly lightened, as our competitors are, the pressure plate bends the flywheel when being disengaged, requiring far more pedal travel than normal, often not fully releasing or taking far longer to do so, damaging the syncros or pro rings in the transmission. When re-engaged the disc only touches the outside edges (of the bent flywheel) at first and starts to slip. When enough power is present it may not completely hook-up even when the flywheel is fully returned to a flat position. No material is removed behind the clutch area on our flywheels for this reason and this is also an important heat dissipation area.
We grind the clutch surface with a swirl out pattern to remove heat from this critical area. Grinding assures flatness and removes heat checks that cannot be achieved by lathe machining. Grinding also provides the longest clutch life and smoothest operation. We then re-cut the pressure plate seating height to factory tolerances.
Flywheels are supplied with stock 4 dowel holes. Before you ask about 8 dowel flywheels please read about doweling a crank to a flywheel in the dowel section of this catalog. If you still want us to drill it for 8 dowels, see LA FLY010 or LA FLY012.
We recommend using 12-volt o'ring flywheels as they have induction heat treated ring gear teeth for maximum life. This can be used with either the 6-volt Bosch SR 14X starter which has the small 12-volt bushing size shaft and a 12-volt Bendix for extra fast spin. Or use any regular VW 12-volt starter. Berg lightened flywheel. SW 16# ea.