Marmorini oversaw the development of Ferrari's power unit but departed the outfit when his organization was reshuffled at the end of July, after the team claimed just two podiums across the opening 11 races of the year.
Marmorini claims that Ferrari Chief Designer Nikolas Tombazis assured him that the power loss from the engine side would be compensated by the aerodynamic improvements made to the F14T, compared to recent Ferrari machines.
"In short: it was made â€‹â€‹to pass the idea that all the woes of the F14T are the fault of the power unit," Marmorini is quoted as saying by Italian journalist Leo Turrini. "As if in a company with the history of Ferrari had forgotten how to make engines! I mean, I accept any accusation, but do not tell that to Maranello [as] there are people who do not know the business, the turbo, hybrids, etcetera.
"With my colleagues I packed a power unit with a certain size, ie, [a] smaller version of the Mercedes and Renault, because we were asked by the project manager of the car, Mr. Tombazis.
"[They] said we want a very compact Power Unit, with small radiators, because the less power [we] will compensate with aerodynamic solutions that will guarantee us an advantage over Mercedes and Renault. It's been exactly like that, except that, when we are confronted with the competition, the horsepower was less obviously, but this was not compensated by aerodynamics!"
Marmorini also admitted feeling sympathy for the engineers at the team and revealed that he was rarely in communication with Team Principal Marco Mattiacci, who joined the outfit in April.
"I would like to explain [the problem] to Mattiacci, but in three months I exchanged a few words, we saw each other twice: the first for the greetings, the second when he subjected me a letter that confirmed my farewell to the company," he said.
"Look, I do not want to accuse anyone. For real. [I must] point out, however, that Ferrari took a road racing department plans to entrust to inexperienced people.
"Ferrari also runs the risk of damaging the bedrock on which many successes have been built on in the past. I do not speak for me, I am now out. But I'm sorry for the engineers I know who are still there, good people who are demoralized."
Marmorini also wished his successor, Mattia Binotto, well and denied signing a deal to return to Formula 1 with Renault.