overdrive

could someone please tell me,is the car quicker with the overdrive light on the dash on or off? also,wot the hell is overdrive? thanks

yes it is quicker with it on, overdrive keeps the car in lower gears longer. it will drink more petrol if you drive it that way

All overdrive does is engage the 4th gear. So with OD OFF (i.e light on dash showing) the car will only use 1st, 2nd and 3rd gear, with OD on the car will use all four gears.

I have overdrive on most of the time and turn it off when I want to slow the car down (4th-3rd gear i.e. engine braking), and when I don't want the car moving into fourth gear for whatever reason.

Only thing i don't like about over drive is the kick down, If im going around a bend with the od off (light on the dash on) it doesnt seem to kick down as well sometimes, as where with od on(light off) it would have kicked down and id be awwwwaaaaaaayyyyyyyyyyyy

OD off does not make the car go faster. all it does is lock out 4th gear. people always say that it holds the gear longer during normal driving - it does not do this. When you plant your foot it always changes at red anyway. weather ODs off or on. What determins how fast and when gears change is how hard you push the throttle.

You will also find that the Supe will not go faster than 120mph without 4th gear(OD)

I find it handy in the twistys as the car seems to get back to full boost sooner (if my car was boosting, that is )

I love it when people say the car is fater when OD is turned off

it really isnt, it just turns off 4th gear!

yes it is quicker with it on, overdrive keeps the car in lower gears longer. it will drink more petrol if you drive it that way

Every part of this reply, apart from the grammar, is wrong.

Aaaaaaaaaarrrrrrrrrrrrrrrrrrrrrggggggggggggggggghhhhhhhhhhhhhhhh

it's just forth gear!!!!!!!!!!!!!!!!!!!!

Overdrive

By definition, an overdrive has a faster output speed than input speed. It's a speed increase -- the opposite of a reduction. In this transmission, engaging the overdrive accomplishes two things at once. If you read How Torque Converters Work, you learned about lockup torque converters. In order to improve efficiency, some cars have a mechanism that locks up the torque converter so that the output of the engine goes straight to the transmission.

 

In this transmission, when overdrive is engaged, a shaft that is attached to the housing of the torque converter (which is bolted to the flywheel of the engine) is connected by clutch to the planet carrier. The small sun gear freewheels, and the larger sun gear is held by the overdrive band. Nothing is connected to the turbine; the only input comes from the converter housing. Let's go back to our chart again, this time with the planet carrier for input, the sun gear fixed and the ring gear for output.

 

 

Ratio = 1 / (1 + S/R) = 1 / ( 1 + 36/72) = 0.67:1

So the output spins once for every two-thirds of a rotation of the engine. If the engine is turning at 2000 rotations per minute (RPM), the output speed is 3000 RPM. This allows cars to drive at freeway speed while the engine speed stays nice and slow

From here

Basically I use to when pulling on to a motorway or when I need the car to be more responsive at speed... like knocking it down a gear if you will......

I think that the confusion about "overdrive" comes from old gits like me, who remember the o/d units on MGBs and the like. The overdrive unit was an extra little electrically-operated 2-speed gearbox on the back of the 4-speed box to give a higher ratio in 3rd and 4th for cruising (1st and 2nd were locked out because they produced too much torque for the little o/d unit). Because 4th gear was 1:1 ratio, 4th + o/d resulted in an overdrive ratio.

If you look at the ratios in manual gearboxes, the one before top (4th or 5th) is invariably 1:1, and top gear (5th or 6th) is..... an overdrive gear! However, we never call it "overdrive".

If Toyota had just called it "4th" it would be a lot simpler to understand

i thougth overdrive made the car grow wings and take off.