Renault Formula 1 fears that the sport "risks losing one of its current manufacturers if the escalating costs of engine development are not cut in the near future," according to Jonathan Noble of AUTOSPORT. Amid "growing signs that engine budgets are ramping up" in the battle between F1's current four manufacturers, Renault thinks that spending requirements "are now getting to the point where they are harder to justify to parent companies." Renault F1 Managing Dir Cyril Abiteboul said that the "huge investment" Honda has made to get its engine program back on track "is proof of how spending is now accelerating." Asked about the progress that Honda made with its latest upgrade, Abiteboul said, "It is not a surprise because it was very clear last year already that Honda were making very rapid progress. Reliability was not there last year, but it was extremely clear, and I remember in Spa, there was a very clear signal that Honda was on the move given the huge investment which we understand that Honda is putting in." With F1 manufacturers "already braced for added investment to revamp engines" for '21, when louder and "higher-revving" power units will be introduced, Abiteboul "thinks that questions may be asked about the current escalating costs." He said, "That [rising cost] is in my opinion untenable" (AUTOSPORT, 10/15).