Mannucci said the money would go towards the team retaining Kimi Raikkonen for 2014, amid reports Red Bull is making moves to sign the 2007 world champion.
"Kimi's position (beyond 2013) is going to be based on a bunch of things and not on what Red Bull say," Genii's Gerard Lopez is quoted by the Sun newspaper.
"I can guarantee you Kimi is not the kind of guy who is going to sign any sort of pre-contract — not with anybody.
"If we keep giving him what he wants then I don't see there is any reason for him to go anywhere," added Lopez.
Lotus, like the other customer engine teams, will also need a bigger budget for next year's more expensive V6 engines, whilst technical director James Allison will reportedly be offered a pay-rise to prevent him from leaving for a bigger team.
Mannucci also claimed Red Bull may be back in talks with Middle Eastern investors about selling its second formula one team, the former Minardi outfit Toro Rosso.