4wd dynamometer with linked axles (axle synchronization) – is that good?
All VtechDyno 4wd (4x4) dynos have full front to rear synchronization as standard. This means that front and rear rolls rotate with exactly the same speed (of course only if sync axles, so called „synchronization” is enabled). Such linked axles functionality is offered usually as option by other dyno manufacturers, or is not available at all. The question is: is such synchronization important for nowadays cars?
The answer is simple – yes. There are pretty many modern cars that even while having one powered axle, monitor second one for speed – and measuring them on one axle dyno causes not only ABS error, but also power loss or strange behaviour of traction control. In many cars, even if you switch off the traction control, it is not fully switched off – some functionalities remain, causing perfect power measurement impossible.
For 4x4 cars, the problem of measuring them without front to rear axle connection comes from active power management – many so called 4wd cars are 2wd with the second axle connected occasionally with electromagnetic clutch. Only rolls with synchronization make dyno test of such cars possible (especially with Haldex clutch or similar).
So if dyno synchronization is not needed, it can be simply switched off from control software or from control panel. But considering having 4wd chassis dynamometer with synchronized rolls is an important advice for car tuners – do not invest your money in tools that may not be used with nowadays cars – and for sure won’t be usable in the future.
Dyno rolls synchronization – how does it work
VtechDyno 4wd dynamometers are equipped with a belt interconnection with self tensioning system that guarantees the same tension of belt at any dyno bench length setup. Belts from front and rear axle meet in the middle, where pneumatically controlled clutch is installed. This clutch can be engaged via software or button at control panel. In that case rolls are synchronized front to rear. Belts delivered by Gates are certified up to 1000 HP power transfer. If clutch is disengaged (open), front rolls are not connected to rear rolls. No special maintenance procedure for belts and clutch is needed.