Lotus became the final team to run their 2014 Formula 1 car in public as the second pre-season test started in Bahrain on Wednesday.
The new E22, with its distinctive 'twin-tusk' nose, did not take part in the first test at Jerez in Spain as the team did not get it ready in time.
That means Lotus have eight days of testing to prepare for the start of the new season in Melbourne on 16 March.
Franco-Swiss Romain Grosjean is driving on the first two days of the test.
His new team-mate Pastor Maldonado, formerly of Williams, takes over for the final two days on Friday and Saturday.
The twin-tusk nose design is Lotus's way of interpreting new chassis rules this year.
The regulations have demanded a lower nose for safety reasons and teams have found different ways of applying the rules while searching for the best airflow over the car.
Rivals have claimed Lotus's design is an "aggressive" way of reading the rules - a euphemism for pushing the requirements as far as is legally possible.
Lotus technical director Nick Chester said: "We have just taken an innovative direction, and one that's different to the other teams. Where there are so many variations in design, there is always bound to be a little talk, but we remain relaxed and focused on our design and progression."
Missing the Jerez test has turned out not to be as big a blow for Lotus as it might have been as a result of major problems suffered by engine supplier Renault with all its teams.
None of the three Renault-powered teams who went to Jerez managed any meaningful running because of problems with hardware, software and control systems on the engine. And world champions Red Bull completed only 20 laps during the entire four days.
Renault admit they still have problems with the software and control systems of the engine but say they believe they have made modifications for the Bahrain test that will allow its teams to do sufficient running to begin to learn about their cars.
After 90 minutes of testing, Red Bull and junior team Toro Rosso were the only teams not to have managed at least an installation lap.
Lotus and Caterham, the fourth Renault team, completed a single lap.