The introduction of V8 engines for 2006 was confirmed before the end of 2004, while teams already had the V10 in development for 2006. Additionally, the confirmation of the rule details came late, when some teams already had V8s running either as cut-down V10s or new, dedicated V8s. The FIA has mandated restrictions on internal engine dimensions and weight, as well as a ban on moving inlet trumpets and multiple fuel injectors.
All these changes will see engines with lower power outputs, from 900+ bhp, but with the change of format the engines are expected to vibrate more - the 90-degree V configuration not matching the 8 cylinders for a naturally balanced engine.
Honda Racing's technical director Geoff Willis says the problems with the vibrations were to be expected, "certainly the theory shows the V8 will have more vibration. I think we have anticipated that with some of our design features in our car, as I'm sure most teams have. We are not really seeing an issue about it, it doesn't appear to be causing us any issues on the car, in fact we've had two tests now and everything has been fine - hydraulics, wings and bits on the back of the car."