Overdrive off on matrix, going faster ?

[trixareforme]

Ok, i have a 2003 matrix xr. when im on the freeway trying to see how fast i can go , i feel i have more power when i have my over drive off. then when my Rpms get to high, i switch my overdrive on. then keep accelerating. is this bad to switch my overdrive on while going this fast ? plus toyotas are automatically put on overdrive, is it bad for me to drive it off ?

[zdude]

usually overdrive is turned off for towing. if your constantly going up and down hills, the transmission will shift to go up. if you turn it off, it puts less stress on the tranny, but my theory is that since there is no top gear, the engine revs higher, and puts more wear on the engine.

[speedracer41]

The overdrive is basically an "Extra" gear / when it is off it electronically eliminates the top gear / It is not going to hurt it by switching it off and on, but it is best to just leave it on.

[rdulgarov]

From what I seen the overdrive actually turns any gear into a 1.5 gear. to expain you have this. the gear ratios are not real ratios but rather just numbers to show the relationsip that OD has the gear ratio in the end.

1st - 1.0
2nd - 2.0
3rd - 3.0
4th - 4.0

so when they say 5th is over drive its basically true but not exactly before most cars only engaged OD after 4rth gear so it WAS 5th, but what most people dont know is that overdrive is a seperate gear in the verry end of transmission that adds on to whatever gear you are currently in. best i can explain is this

1st - 1.0 ratio (OD off) ... then you can turn OD on and in turn you have
1st gear and half - 1.5 ratio. then turn it off and you go to
2nd gear. then again if you turn it on you have
2nd gear and half.
and so on.

So in turn with overdrive button you have a 8 speed transmission not 4 speed. This is the system they used to use on big rig trucks. If any one know anything abut them and you know of a "Super 10" truck transmission, its same setup but the gearring is setup so that you can actually take advantage of having the gear in between the gears.

So basically if the OD is on all the time instead of starting with 1st gear your allways in 1 and half gear.

1st = 1.5 ratio
2nd = 2.5 ratio
3rd = 3.5 ratio
4rth = 4.5 ratio

so really there is no 5th gear but it creates an effect that there is becaus it lets the car get to a higher speed at same rpm's of the engine.
From what i noticed most cars will switch down to 1st gear even under OD but you have to manually shift the automatic to 2nd possition for it to drop bellow 1.5 OD gear. and you basically have to be moving slowly and come to a stop and it will kickdown to 1st. then when you hit gast it accelerates from 1st and switches to 2nd gear with OD.

Any way the speed with which it switches is slow and the gear ratio it creates are not optimal. so witching back and forth is not gona give you any performance boost. If im trying to take off quick i usually turn it off, drop to 2nd as i slowdown to force it to drop to 1st gear insted of staying in 2nd (sometimes the car wont even kick down to 2nd unless your at wide open throttle possition when you come to a stop light or something and takes off in 2nd thats why there is a delay in begining when you smash the gas. its in 2nd and has to realyze you want to go quicker and kick down) then while the shifter is in 2nd gear and its aproaching redline kick it to 3rd possition, at this point it will shift to 2nd and again as it gets to redline kick it into DRIVE to switch to 3rd gear.

As i said the ratios are not exactly like that i just made them like that to make the math easier to understand but the OD functions as i described in most cars now. Note downshifting while in highrevs and at highspeed can destroy the clutches in the automatic so dont do it unless you learned to match the speed of vehicle to throttle possition and gear. you can drive an automatic like its a semi automatic even without the paddle controls, its just that you have to do all the things the computer does in the semiautomatic manually.