GP2, one of Formula 1's main feeder series, could actually be as fast as F1 cars in 2014 as new engine and aerodynamic rules come into effect.
The warning comes from the former Ferrari and Williams technical chief Enrico Scalabroni who later went on to set up his own GP2 team.
The move from V8 to V6 turbo power may not see a huge drop in power as the ERS makes up for much of the difference, but smaller front wings and the end of the blown exhaust era will see a chunk of downforce disappear.
"I hate to be alarmist," Scalabroni is quoted by Spain's El Mundo Deportivo newspaper, "but I would not be surprised if a GP2 car is as fast as a F1 (car).
"You only have to make simple calculations to see that this could occur, at least at the beginning of the development phase in F1.
"Some (people) are concerned with this possibility," he added.
During 2013 the GP2 cars were around seven to 10 seconds slower than their F1 equivalent but only a couple of seconds slower than the back of the grid teams, therefore with lap-times thought to be five seconds slower next year that is where some teams could find themselves slower than GP2.
Meanwhile development of the 2014 engines may have already reached the track as two of the three engine suppliers are rumoured to have tested their V6 units.
With a ban on testing in F1 cars until pre-season testing begins in January it is believed Ferrari and Reanult have found a loophole to give their new units some early running time.
Over the weekend a video emerged on YouTube of Ferrari secretly testing their turbo unit in the back of a LaFerrari and their Fiorano test track while speculation claims Renault used a Formula Renault 3.5 car to test their V6 at a test at Magny-Cours.
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