Thread: Anyone know about cars?

I'm not a mechanic, but here's my 2 cents:

Most modern cars have OD on be default. That increases the MPG at the cost power.

I usually drive with it on, but turn it off when I need a bit more power. It's also harder on your engine.

It is harder on your engine to drive with it off? You engine has to work harder because the overdrive is not on?

Different cars have different set ups but similar to what DOMS said I think it holds the car in gear longer or allows it to go into a higher gear.

Overdrive on - Get the car into top gear sooner, making it more fuel efficient and working the engine less.

Overdrive off - keeps it in a lower gear longer for quicker response.

My old car had a power button, when on it held it in each gear longer.

I am assuming your car is Auto.

yes, my car is auto.

so, then i should be driving in overdrive. it is more efficient for the car.

Overdrive = Good things P. I assume your not a race car driver so having OD is a great thing with freakin gas so high!

Originally Posted by P-funk

yes, my car is auto.

so, then i should be driving in overdrive. it is more efficient for the car.

Like I said, I drive in OD most of the time. When I need quick boost of power (off the line, for example), I turn it off.

Originally Posted by Double D

Overdrive = Good things P. I assume your not a race car driver so having OD is a great thing with freakin gas so high!

great!

thanks guys. I fucking hate cars.

As do I my damn tranny just went out of mine. Love replacing those! Good thing I will pay to replace it rather than do it myself.

OD on will allow your car to shift swiftly into cruising gears for max speed and economy.

OD off is common when you are towing something (trailer, boat, etc) and you want to keep the car in the lower range for more torque.

Originally Posted by Witmaster

OD on will allow your car to shift swiftly into cruising gears for max speed and economy.

OD off is common when you are towing something (trailer, boat, etc) and you want to keep the car in the lower range for more torque.

I don't know about that. I'm pretty sure it has nothing to with shifting smoothly. I"m not an expert, but when took an apprentice at a shop, I was told ....


OD is how many gears your car uses. Say your on a highway, it is possible to drive with 3 gears, but then your RPM will be revving too high, so you should use OD to switch to your last gear.

High rev = engine working more, more noise, more fuel.

But when driving up a hill, you should switch it off, because the tranny would repeatedly switch between 3rd and 4th, which isn't a good thing.

With lots of traffic, I usually drive with OD off........and when I see my RPM rev 5-6k constantly, then I'll switch it on.

Overdrive can refer to two different things. An overdrive is a device which was commonly used on rear-wheel drive automobiles to allow the choice of an extra-high overall gear ratio for high speed cruising, thus saving fuel, at the cost of less torque.

It also refers to a combination of gearing inside a transmission or transaxle which results in the output speed being greater than the input speed. In the latter case, "overdrive" does not refer to a physically separate identifiable part/assembly.

Generally speaking, overdrive (OD) is the highest gear in the transmission. Most automatic transmissions have 3 speeds and overdrive (fourth speed). Overdrive allows the engine to operate at a lower rpm for a given road speed. This allows the vehicle to realize better fuel efficiency, and often quieter operation on the highway. When you switch it on, you allow the transmission to shift into overdrive mode after the certain speed is reached (usually 30 - 40 mph (50 - 65 kph) depending on the load). When it is off, the transmission shifting is limited to the lower gears. For normal driving conditions, operation of the overdrive should be enabled.

It may be necessary to switch it off if the vehicle is being operated in a mountainous area.

The automatic transmission automatically shifts from OD to 3rd gear when more load is present. When less load is present, it shifts back to OD. Under certain conditions, e.g: driving uphill or towing a trailer, the transmission may "hunt" between OD and 3rd gear, shifting back and forth. In this case, switching it off can help the transmission to 'decide'. It may also be advantageous to switch it off if engine braking is desired, for example, driving downhill. For more details, check your owner's manual.

http://en.wikipedia.org/wiki/Overdrive_%28mechanics%29

Originally Posted by Prince

Overdrive can refer to two different things. An overdrive is a device which was commonly used on rear-wheel drive automobiles to allow the choice of an extra-high overall gear ratio for high speed cruising, thus saving fuel, at the cost of less torque.

It also refers to a combination of gearing inside a transmission or transaxle which results in the output speed being greater than the input speed. In the latter case, "overdrive" does not refer to a physically separate identifiable part/assembly.

Generally speaking, overdrive (OD) is the highest gear in the transmission. Most automatic transmissions have 3 speeds and overdrive (fourth speed). Overdrive allows the engine to operate at a lower rpm for a given road speed. This allows the vehicle to realize better fuel efficiency, and often quieter operation on the highway. When you switch it on, you allow the transmission to shift into overdrive mode after the certain speed is reached (usually 30 - 40 mph (50 - 65 kph) depending on the load). When it is off, the transmission shifting is limited to the lower gears. For normal driving conditions, operation of the overdrive should be enabled.

It may be necessary to switch it off if the vehicle is being operated in a mountainous area.

The automatic transmission automatically shifts from OD to 3rd gear when more load is present. When less load is present, it shifts back to OD. Under certain conditions, e.g: driving uphill or towing a trailer, the transmission may "hunt" between OD and 3rd gear, shifting back and forth. In this case, switching it off can help the transmission to 'decide'. It may also be advantageous to switch it off if engine braking is desired, for example, driving downhill. For more details, check your owner's manual.

http://en.wikipedia.org/wiki/Overdrive_%28mechanics%29

Like all this time... I like thought you were smart and now I like find out that you have like been using Wikipedia to like explain everything.
You have been like... hosing us...

Originally Posted by P-funk

It is harder on your engine to drive with it off? You engine has to work harder because the overdrive is not on?

Only turn OD off if you are driving up a hill where you can feel the engine straining (you are dumping gas on it and the RPMs are low), many V8 vehicles wont really need OD to be off during this time but it may be hard on a V6. Otherwise OD reduces RPMs which saves you gasoline during cruising, OD is a gear just like any other so even if its turned on it is not really in use until you are at approximately freeway speeds.

Yeah Overdrive is good. The gear ratio becomes either 1:1 or less.

My manual transmission is built up like it has an over drive. My 6th gear is less than 1.

1:1 is actually not overdrive, that is one to one

1:1 would be 4th gear on most stick shift cars, my 6 speed car has two overdrives .75 and .5 (T56). Overdrive is normally a 15% or greater overdrive, 15% being 1970s overdrive where it feels like you have two 4th gears, my Z car 5 speed felt like that.