A lost Asset in Auto Transmissions

[jejeosborne]

Which if you think about it means that it would be fairly simple for the ECU to say "when stopped in first gear, make the first half of the pedal travel not do much to facilitate driving on slippery conditions"

Aaron Z

Our new Toyota rav has some of this logic built in. It had 3 driving modes and when in eco mode, more throttle movement is necessary when compared to sport mode which is very very very touchy. Sport mode would be terrible in snow.

 

[Bluest]

You get something similar with "Terrain Response" in Land Rovers/Range Rovers. Select "snow" on the dial and the throttle pedal becomes very soft response.

 

[s219]

Which if you think about it means that it would be fairly simple for the ECU to say "when stopped in first gear, make the first half of the pedal travel not do much to facilitate driving on slippery conditions"

Aaron Z

That's about how my GMC's throttle response is, but for fuel efficiency purposes. You have to really press on the throttle to get "regular" response.

 

[schmism]

my 2001 Ford E350 auto trans

D 1-2-3-OD
2 - starts in 2 stays in 2
L - starts in 1 stays in 1

 

[MossRoad]

Which if you think about it means that it would be fairly simple for the ECU to say "when stopped in first gear, make the first half of the pedal travel not do much to facilitate driving on slippery conditions"

Aaron Z

I think that would cause drivability problems with it fighting the traction control.

Our 2013 Impala is a fairly powerful car for its weight. It also has traction control, which happens to be set fairly forgivingly compared to the earlier models. It has throttle by wire that is, to put it bluntly, awful feeling. With decent tires, it gets out in the snow pretty well with the traction control on, yet on dry pavement, you can still stomp on it and get pretty decent wheel spin that won't slow you down off the line even with the traction control on. The only problem is, since there is no feedback feel in the pedal, it's essentially a foot operated potentiometer. It doesn't push back against you. You can't tell where your foot is in the travel of the pedal.

 

[jejeosborne]

I think that would cause drivability problems with it fighting the traction control.

Our 2013 Impala is a fairly powerful car for its weight. It also has traction control, which happens to be set fairly forgivingly compared to the earlier models. It has throttle by wire that is, to put it bluntly, awful feeling. With decent tires, it gets out in the snow pretty well with the traction control on, yet on dry pavement, you can still stomp on it and get pretty decent wheel spin that won't slow you down off the line even with the traction control on. The only problem is, since there is no feedback feel in the pedal, it's essentially a foot operated potentiometer. It doesn't push back against you. You can't tell where your foot is in the travel of the pedal.

What kind of feedback to you get from the old cable style? Isn't it too just spring back pressure with the spring in a further location?

 

[MossRoad]

What kind of feedback to you get from the old cable style? Isn't it too just spring back pressure with the spring in a further location?

A throttle cable connected directly to a carb or TBI has a lot of feel to it. You can feel pressure in your foot. The GM drive-by-wire foot pedal has no feedback. For example, in the old system, if you were going up a hill with cruise control on, you could feel the cruise control pull the pedal away from your foot. And if you were going down a hill, and didn't move your foot, that car wouldn't slow down because your foot keeps the throttle on, even though the cruise is letting it off. The new system won't do that. The pedal stays were it is. Its much harder to finesse a car around with the throttle with a drive-by-wire system that lacks feedback.

 

[downslope]

Way, way back I used to have a 1970 Vega Hatchback with the 4 banger and a 2 speed tranny (NOT a Powerglide). It was an auto but you had to manually shift it. In the winter time with 2 bags (roughly 80 lbs) of sandblasting sand tucked up tight against the back of the "trunk" it rarely could spin the tires when I started off in high gear. It was great leaving from a stop.

Yeah, that was a long time ago. Nova's also had that tranny option back in the 70's. It was really just a cost-cutting feature.

 

[jejeosborne]

A throttle cable connected directly to a carb or TBI has a lot of feel to it. You can feel pressure in your foot. The GM drive-by-wire foot pedal has no feedback. For example, in the old system, if you were going up a hill with cruise control on, you could feel the cruise control pull the pedal away from your foot. And if you were going down a hill, and didn't move your foot, that car wouldn't slow down because your foot keeps the throttle on, even though the cruise is letting it off. The new system won't do that. The pedal stays were it is. Its much harder to finesse a car around with the throttle with a drive-by-wire system that lacks feedback.

I can understand the lack of feel when using the cruise control although I normally don't touch the pedal when using cruise. I don't feel any difference in my drive by wires vehicles other than that other than easier to press due to less linkage.

Drive by wire is much superior for throttle response and mixture control. Plus it is easily programed for different scenarios.

 

[MossRoad]

I can understand the lack of feel when using the cruise control although I normally don't touch the pedal when using cruise. I don't feel any difference in my drive by wires vehicles other than that other than easier to press due to less linkage.

Drive by wire is much superior for throttle response and mixture control. Plus it is easily programed for different scenarios.

I have great trouble doing slides, drifts, donuts, etc... with the GM electronic throttle VS the cable throttle. I do this in snow, when no one is around, generally at the start of snow season to get use to how a car handles in snow again. I have a much easier time controlling wheel spin with the cable throttle cars and trucks.