Overdrive questions

[fernandoh]

The other day I was playing with the OD switch while driving my 2003 Pathy on the highway. When the O/D orange light is on (OD is then avoided) I understand that the gearbox will be permanently in 3rd max. If you move the switch to on the rpms will move to the rpms of 3rd (do not confuse the converter lock up torque converter function, which propably is disabled by then). But I got a second observation. At the same rpms the "roaring" of the engine sound different. Is there a change in the PCM maps when the swith is on? (cluster O/D orange light on). The engine is complex and the engineers maybe decided to increase torque when you choose to disable the O/D (as when doing off road or pulling a boat or whatever). The search I did here produced me more doubts than answers.

[alexf20c]

the engine note is only different because the engine is at high rpm with less load. typically, when you're at 4000rpm, the engine is under heavy load because you are accelerating. if you are cruising at highway speed and turn off OD, you are forcing the engine to spin at a higher rpm than is required. at this rpm, there is very little load on the engine, and the engine/exhaust note will be slightly different.

there is no alternate fuel map on our vehicles. the tow haul mode (and the OD override switch) only control the transmission computer.

[fernandoh]

I can't know about your last paragraph but my test was driving a steep portion of an uphill road (highway with 8% maybe) at some 120 kmh (80 miles/h), probably 3/4 or more throttle then, with the gearbox in 3rd at some rpms I can't recall. This condition is meaning converter unlocked. When the O/D was comdened by the switch the gear, speed and rpms were the same, but not the sound. Computers are controlling a lot of things today and I tought something happened. Maybe I'm wrong. I don't know. Ask the Toyota's guys and the pedal issue. Just in case the Ssangyong vehicles when they are receiving both accelerator and brake inputs at the same time, just after 2 seconds brake signal over rule. Simple.

[miamiheat3332]

all i know with OD off i can accelerate faster, the car plays around gear shifts alot less then when OD is on, so if your at a stoplight or w.e and someone wants to race which is what i use this for, turn off the OD and when u get around to 65-70 or so and then let off the gas quick and switch od on then floor it again.

Thats my expirence with OD so i assume it does give your more torque/hp in each gear.

[alexf20c]

turning off OD affects absolutely nothing off the highway. it does not give you more power, it does not change the fuel map. the ONLY thing it does is prohibit the transmission from shifting into OD, thus keeping the engine rpm higher (for more power) at highway speed.