Wheel tyre sizes

RoverP480 · 23rd October 2019, 13:07

Without knowing the specific fuel consumption curve for the engine , one cannot really say what the effect will be by altering the engine revs at the same road speed . If say at 70mph the engine is running at its optimum speed for fuel consumption, altering it either way will make it worse. If though it moves the engine speed to a more favourable part of the curve it will be better, but if it moves to a less favourable part it will be worse. One is also moving it about on the torque and power curve as well so you end up with multiple effects . I suggest moving it by 2.5 % is unlikely to show a noticeable effect. One is more likely to notice the ride changing.

23rd October 2019, 13:07	#10
RoverP480 Gets stuck in None at the moment Join Date: Jan 2018 Location: Hereford Posts: 501 Thanks: 1 Thanked 165 Times in 146 Posts	Without knowing the specific fuel consumption curve for the engine , one cannot really say what the effect will be by altering the engine revs at the same road speed . If say at 70mph the engine is running at its optimum speed for fuel consumption, altering it either way will make it worse. If though it moves the engine speed to a more favourable part of the curve it will be better, but if it moves to a less favourable part it will be worse. One is also moving it about on the torque and power curve as well so you end up with multiple effects . I suggest moving it by 2.5 % is unlikely to show a noticeable effect. One is more likely to notice the ride changing.