Question about down shifting...

[Javaman]

okay, having read several blogs about ultra miling and the wisdom of not braking or trying not to brake as much, since I drive a stick, what is the effect of downshifting to slow down on fuel usage?

[BlooInBloo]

1. I just thought it was a way to keep revs in the power sweet spot and save on brake wear.

[unpossibles]

2. don't unless you need to slow suddenly

I use downshifting if necessary to slow more quickly or for the occasional turn or pass, but it will actually increase your fuel usage because RPMs go up. Plus, it's adds wear to the transmission and clutch both of which are more expensive and harder to replace than the brakes.

[tridim]

3. I'm pretty sure downshifting only saves brake pads.

I've been doing lots of coasting in neutral lately. During a normal 10 mile trip I can probably manage a mile worth of coasting.

[OKIsItJustMe]

4. Yeah, downshifting ("Engine braking") is of questionable ecological value

http://en.wikipedia.org/wiki/Engine_braking#Disadvantages

[sinkingfeeling]

5. Dropping into neutral is the only one that will save gas.

[losthills]

6. Most modern cars with auto trannies have overdrive.

[sinkingfeeling]

7. I only have manual transmissions which by their nature, get better gas mileage.

[dflprincess]

8. That's all I've had

but I was sort of looking around at new cars and it seems to be harder to find them - and I was looking at Civics.

[One_Life_To_Give]

9. Depends on the Engine Programing

I have heard that some of the engine management programs on Multi Port Fuel Injected Engines will turn fuel off completly in an engine (Compression) brake scenario, provided the RPM is sufficiently above idle. (1500 was the figure given)

I think the only easy way for you to find out for sure what your vehical does. Drive a couple of tankfulls with Compression Braking and then a couple with Friction Braking and see if you get a difference.

[lectrobyte]

10. In my experience, clutches seem to cost a lot more than popping in

a new set of brake pads. your mileage may vary, as always... I don't expect that downshifting would have any impact on MPGs.

[kristopher]

11. It's a safety feature when driving a large (5/10Ton) tractor.

Braking a large rig deals with a lot of force; and if the brakes fail (common due to wear on grades) and you are in the appropriate gear, you have a better chance of stopping safely than if you pop it into neutral and decelerate. Or so I was taught.

tire pressure, engine specifications set, no prolonged idle, closed windows, and easy on the gas are all savers, but downshifting through the gears? not so much.