Overdrive ON or OFF?

[wicked1981]

Just wondering..... When does the auto vibe have the best acceleration when the overdrive is on or off? I dont really have a place to test when is it faster with it on or off or does it make any difference? Any one know the difference if any?

[joatmon]

Welcome to genvibe!The best power/torque for these cars is at higher RPMs, so the best acceleration will be in a whatever gear puts your engine in the power band at whatever speed you're at. If you're rolling down the highway and floor it, it should downshift to a lower gear automatically, which will let he engine RPMs go up. If you have overdrive off, that is basically the same as disabling your top gear, which will hurt your fuel efficiency if you leave it off all the time. I have the 5 speed, but have had auto tranny cars with an overdrive on/off control. There were only two times I turned it off. Sometimes I'd be going up a hill, and I'd have to push the gas pedal down so far to keep up speed that the tranny would downshift, giving more power, get me up to speed, and then it would upshift, start lagging, downshift, etc, so I'd turn OD off to force it to stay in the lower gear. The other case was going down a long hill, where if in overdrive the car would go too fast, so I'd turn OD off to force it into the next lower gear, and the engine would provide some braking force so I didn't have to ride the brakes all the way down. Any other time, I let the transmission downshift for me when I hit he gas hard. Some people shift their auto transmissions kinda like a manual, and that can be useful I guess if you want to wind up the engine RPMs to stay in the power band longer, to prevent the tranny from upshifting early, and dropping the RPMs out of the max torque area of the engine performance curve.

[dmitri]

i love my 6 speed.

[Flip-Side]

quote:Just wondering..... When does the auto vibe have the best acceleration when the overdrive is on or off? I dont really have a place to test when is it faster with it on or off or does it make any difference? Any one know the difference if any?Do you mean faster as in, 0-60 times, or top speed? The overdrive gear is only used when cruising at a constant speed for fuel economy. Day to day driving does not require you to turn O/D OFF, unless you drive on a lot of grades as stated above. I have also used it when on I-75 on trips through the mountains. If you want top speed, like on the autobahn over here, you need the overdrive gear for top end. I don't see how O-60 time will be any different with it on or off.

[wicked1981]

Well yeah i guess i meant 0-60. I just didnt know if there was any difference in speed acceleration with it on or off. I noticed with it off the RPM's are higher at same speed than with it on.

[joatmon]

quote: I don't see how O-60 time will be any different with it on or off.Me either. If you have it floored for max acceleration, the transmission shouldn't shift up into overdrive till you're going a lot faster than 60, so disabling overdrive shouldn't have any effect.