Using OVER DRIVE saves gas?

[enyce2k9]

Hey folks,

So I keep browsing around how to save gas tips, and keep coming upon the tip of using overdrive, common sense to me is that the vehicle will go faster thus consume more gas.

How would it save gas? if so...

 

[cKGunslinger]

...

 

[randomlinh]

you probably want to look up what overdrive actually means first

 

[bmacd]

Overdrive is a gear. The engine won't be working so hard to maintain the speed (especially on the e-way) if you have it in overdrive. It's either a taller or shorter gear. Either way, it takes a small load off of the engine.

 

[Eli]

Wow.....

I'm going to be nice.

Basically, you do not understand the way things work. Overdrive means that the transmission is in a gear that provides more than a 1:1 gear ratio, typically around 0.8:1. That means that the engine only has to turn 0.8 times to turn the output shaft on the transmission once.

This will save you fuel, because you are at a lower RPM for a given speed.

For example, if you are crusing along at 65MPH @ 2500RPM, and you hit the overdrive button, your transmission will shift, and your RPMs will drop to, say.. 1800RPM. You will still be going 65MPH, but you will be using less fuel due to the lower RPMs.

In short, speed has little to do with MPG at cruising speeds. It only takes a few tens of horsepower to keep a car moving along at 60MPH.

 

[enyce2k9]

I must be mistaking the on/off feature then, because when the button is pressed in the RPM's Fly all the way up and i thought that was when overdrive is ON...

So when overdrive is ON the RPMS should go lower right?

 

[bignateyk]

Its like a hyperdrive. Make sure you buckle up before engaging, however.

 

[Eli]

Originally posted by: enyce2k9
I must be mistaking the on/off feature then, because when the button is pressed in the RPM's Fly all the way up and i thought that was when overdrive is ON...

So when overdrive is ON the RPMS should go lower right?

Yes.

And, I really don't mean to offend, but man... Are you sure you should be driving? lol

 

[cKGunslinger]

Originally posted by: enyce2k9
I must be mistaking the on/off feature then, because when the button is pressed in the RPM's Fly all the way up and i thought that was when overdrive is ON...

So when overdrive is ON the RPMS should go lower right?

Yes, most autos have an "Overdrive Off" button, for the rare instances where you'd want to turn of the feature. Normally, you leave it on.

 

[enyce2k9]

alright, i was confused because i remember driving a corolla a few years back and when OD was ON then car literally overdrives and goes way faster, and YES i should be driving heh, gas prices are a frikin pain but its a necessity to move.

note due to the corolla story i thought i had a bad sensor when i saw o/d off and the rpms flying. now i understand, thanks.

 

[StrangerGuy]

Nope, but it overclocks the engine.

 

[randomlinh]

Originally posted by: enyce2k9
alright, i was confused because i remember driving a corolla a few years back and when OD was ON then car literally overdrives and goes way faster, and YES i should be driving heh, gas prices are a frikin pain but its a necessity to move.

corolla... fast... huh? I think it "going way faster" was all in your head

 

[Eli]

You have a funny perception of "faster".

Having overdrive OFF will result in the greatest put-you-back-in-your-seat feeling. Having it on will reduce fuel consumption at all speeds, but also reduce available torque.

 

[SlowSpyder]

No. Do not use overdrive to save gas. The best method for saving gas is to keep your gear selector in the "1" or "L" position then go drive on the expressway as close to expressway speeds as you can get to. This will give you eleventy billion mpg. Take that big oil, the secret is out.

 

[StrangerGuy]

Originally posted by: SlowSpyder
No. Do not use overdrive to save gas. The best method for saving gas is to keep your gear selector in the "1" or "L" position then go drive on the expressway as close to expressway speeds as you can get to. This will give you eleventy billion mpg. Take that big oil, the secret is out.

But you need to place magnets on your fuel line to ionize the gas first!

 

[cKGunslinger]

Originally posted by: SlowSpyder
No. Do not use overdrive to save gas. The best method for saving gas is to keep your gear selector in the "1" or "L" position then go drive on the expressway as close to expressway speeds as you can get to. This will give you eleventy billion mpg. Take that big oil, the secret is out.

Actually, that will save you tons of gas in the long run... with that car, at least

 

[BUTCH1]

Maybe he's referring to a "tap shifter" my Malibu has one of these.. on mine if it's used@
hyw. speeds it will downshift to passing gear when engaged.

 

[chris7b]

When you turn it off you usually get a warning light on your instrument cluster. Maybe thats why you're thinking you're turning it "on" when in fact your are turning it off.

 

[Pepsi90919]

they really should do away with the D and OD selectors and just leave it at OD. too many people get misinformed and confused.

 

[LordMorpheus]

On my car (Ford 40R70W transmission) overdrive is just 4th gear. That's all it is. If you cook the overdrive band the car drives like a three speed automatic.

So it only comes into play when you are going fast enough for the car to shift into fourth, and at lower speeds any touch on the throttle will drop it to second or third right away.

If you ever were to tow anything or drive up a mountain you'd probably want to turn OD off, that's really the only reason given in the owner's manual that makes any sense.

 

[statik213]

Originally posted by: enyce2k9
I must be mistaking the on/off feature then, because when the button is pressed in the RPM's Fly all the way up and i thought that was when overdrive is ON...

So when overdrive is ON the RPMS should go lower right?

No, the overdrive button is to turn overdrive OFF. this prevents the car from shifting into OD i.e. 4th gear on most auto transmissions.
Basically, OD Off => more gas consumptions

 

[JEDI]

Originally posted by: Eli
Wow.....

I'm going to be nice.

Basically, you do not understand the way things work. Overdrive means that the transmission is in a gear that provides more than a 1:1 gear ratio, typically around 0.8:1. That means that the engine only has to turn 0.8 times to turn the output shaft on the transmission once.

This will save you fuel, because you are at a lower RPM for a given speed.

For example, if you are crusing along at 65MPH @ 2500RPM, and you hit the overdrive button, your transmission will shift, and your RPMs will drop to, say.. 1800RPM. You will still be going 65MPH, but you will be using less fuel due to the lower RPMs.

In short, speed has little to do with MPG at cruising speeds. It only takes a few tens of horsepower to keep a car moving along at 60MPH.

so why not use a gear with .01:1 ratio. wont that boost mpg thru the roof? (ok, make the gear out of antamantium so it wont break.)

also, speed has little to do w/mpg at cruising speeds???

so i'm using almost the same gas at 90mph as i am at 65mph?

 

[mugs]

Originally posted by: enyce2k9
alright, i was confused because i remember driving a corolla a few years back and when OD was ON then car literally overdrives and goes way faster, and YES i should be driving heh, gas prices are a frikin pain but its a necessity to move.

note due to the corolla story i thought i had a bad sensor when i saw o/d off and the rpms flying. now i understand, thanks.

Are you sure you're not talking about "sport mode"? Some automatics have that, it changes the shift points so you will be in a lower gear than normal at any given speed.

 

[JEDI]

Originally posted by: SlowSpyder
No. Do not use overdrive to save gas. The best method for saving gas is to keep your gear selector in the "1" or "L" position then go drive on the expressway as close to expressway speeds as you can get to. This will give you eleventy billion mpg. Take that big oil, the secret is out.

u also chew up the gears doing that.

<------------ accidently drove in 2nd gear at 65mph on the Turnpike.

 

[Eli]

Originally posted by: JEDI

Originally posted by: Eli
Wow.....

I'm going to be nice.

Basically, you do not understand the way things work. Overdrive means that the transmission is in a gear that provides more than a 1:1 gear ratio, typically around 0.8:1. That means that the engine only has to turn 0.8 times to turn the output shaft on the transmission once.

This will save you fuel, because you are at a lower RPM for a given speed.

For example, if you are crusing along at 65MPH @ 2500RPM, and you hit the overdrive button, your transmission will shift, and your RPMs will drop to, say.. 1800RPM. You will still be going 65MPH, but you will be using less fuel due to the lower RPMs.

In short, speed has little to do with MPG at cruising speeds. It only takes a few tens of horsepower to keep a car moving along at 60MPH.

so why not use a gear with .01:1 ratio. wont that boost mpg thru the roof? (ok, make the gear out of antamantium so it wont break.)

also, speed has little to do w/mpg at cruising speeds???

so i'm using almost the same gas at 90mph as i am at 65mph?

Because engines don't have enough power at 150RPM to move the car forward at 65MPH.

And.. MPG is fuel usage over time. So yes, of course you are using more fuel at 90MPH than 65MPH. You're also traveling 25MPH faster. Whether this will result in a net gain or loss of overall MPG depends entirely on your car and driving conditions.