Hills, taller gears and fuel economy

[shiftmate]

Often I'll be in cruising in 4th or 5th gear, and hit an upslope where maintaining speed will require more fuel, but because my revs are in the 1.5k-2k range, even pressing quite a bit on the throttle will only slow the deceleration and then slightly increase acceleration. Is all the fuel being sent to the engine being combusted here or is some being wasted? Would I get more efficient fuel usage by downshifting and accelerating from a higher rev range?

The latter would, of course, be more fun, so if it's also more fuel efficient (or better for the engine in any way), then it's a no-brainer.

[Shadow]

Without goint into too much detail, modern cars are tuned to not "waste" fuel by injecting more than is necessary. And it's not just for fuel economy reasons, but also for emissions. Any unburned fuel that makes it past the catalyst exits the vehicle as hydrocarbons.

The question whether to downshift into a numerically lower gear or just stay in the higher gear and provide more throttle really depends upon the car and the exact situation. On my own car, I think I'd just stay in gear and give a bit more throttle in the situation you described. The turbo would spool up a bit to provide the extra bit of power needed to continue up the hill in gear. If I were in a situation where I could no longer accelerate without downshifting (or if I needed full or near full throttle just to maintain my speed), then I'd definitely downshift. Actually, I'd probably downshift before I reached that point in the first place.

[Squint]

Without goint into too much detail, modern cars are tuned to not "waste" fuel by injecting more than is necessary. And it's not just for fuel economy reasons, but also for emissions. Any unburned fuel that makes it past the catalyst exits the vehicle as hydrocarbons.

The question whether to downshift into a numerically lower gear or just stay in the higher gear and provide more throttle really depends upon the car and the exact situation. On my own car, I think I'd just stay in gear and give a bit more throttle in the situation you described. The turbo would spool up a bit to provide the extra bit of power needed to continue up the hill in gear. If I were in a situation where I could no longer accelerate without downshifting (or if I needed full or near full throttle just to maintain my speed), then I'd definitely downshift. Actually, I'd probably downshift before I reached that point in the first place.

Yeah, I usually downshift if I get close to losing speed on a hill. For safety reasons, if you are pushing it to the floor and slowing down, you need to shift.