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Old 07-15-2007, 05:27 PM
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I haven't driven a car with this setup yet but I agree with people that If something were to go wrong there could be some big problems. I like the cable setup because you are in control. Its kind of interesting the difference in vehicles with the cable setup. My Bonneville takes little effort to put the pedal down but my K5 i really have to push on it but its not like I'm planning to go fast with that old diesel engine but i still get about the same mpg with both though.
Old 07-15-2007, 06:56 PM
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On the Malibus (with the exception of the SS), the steering is electric. The steering column houses an electric motor, which energizes when needed. The steering rack is all manual, and looks vaguely familiar to a Mustang II / Pinto rack. And there have been many complaints with the intermediate shaft.

Unfortunately, most new cars GM is coming out with are DBW. As Don said, it really isn't bad once you get used to it. Cruise control will freak you out though, since the gas pedal will not move at all on its own (nor does it need to). I am sure once someone cracks the PCM coding, the delay time between request and execution could theoretically be shortened.

Welcome to the present
Old 07-15-2007, 08:55 PM
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Wow, sounds like GM isn't on the ball at all with their DBW. As far as I know, Diamler Chrysler used the same DBW setup from 99-04 in the 300M. In our 2001 there is no lag what-so-ever. In fact, until I first opened the hood about a month after we got it, I couldn't tell it was DBW.
Old 07-16-2007, 12:24 PM
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GM had been using the system for quite a while now. The Corvette was the first to get it back in 2000 or so. As for lag..... guess what.... GM programs that into it. It reduced the wear on drivetrain parts.
Old 07-16-2007, 01:33 PM
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Both my cars are drive by wire and I can hardly tell the difference.
Old 07-16-2007, 01:56 PM
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The most likely failure is a loss of power to the servo; the return spring (may be internal) will just shut the throttle. The worse case failure would be the pcm commanding WOT when not desired.

The advantages are in the engine management department.
Torque control, traction control, top speed limiters no longer need to pull timing or shut off fuel, just reduce throttle.
Old 07-16-2007, 10:17 PM
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Looked at in that light it could be seen as a simplification, by reducing separate systems like cruise control, idle speed control (and the torque limiting, traction control and top speed limiting) into a single system.

I suspect that there are also benefits in controlling exhaust emissions with things like the rate of throttle close on decel.

Another one is that dips in the power/torque curves can be masked (which may be related to driveability issues generated in controlling emissions).

Parking speed throttle response can be made less sensitive.

There is no possibility of a customer accelerating and braking at the same time (ask Audi about that ) as the system is disabled with a brake switch (or switches with redundancy for safety). That also precludes left foot braking, so no more FWD Scandinavian flicks :( .

I agree that sooner or later they will be hacked to allow alteration of response.

Here'* an idea: a progressive N2O system related solely to accelerator pedal movement, much easier (only possible?) with FBW.

As an observation, the ones I have any knowledge of work by both opening and closing the throttle, with the default throttle position setting a fast idle. This is to allow a 'limp home' back up, with very much reduced power, if the system fails.
Old 07-16-2007, 10:56 PM
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There is no possibility of a customer accelerating and braking at the same time
so this tell me no more throttle against the converter on the track . that bad
Old 07-17-2007, 11:34 AM
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Originally Posted by firebuick
so this tell me no more throttle against the converter on the track . that bad
All depends on the programming and what transmission is used. A conventional TC automatic can physically do it, but it may be setup to not to it from the factory electronically to save wear.

Cars with a launch control usually can build revs, and then when they get off the brake pedal, the transmission engages into first like dumping a clutch. These cars are generally a type of clutched/sequential transmission and you can't push against a TC, and not move. You're not pushing against the TC (and therefore building heat) but you do have the time between brake release, and transmission engagement.

As mentioned, DBW is mainly setup for engine management however. IMO it'* kinda unneccesary, but if it simplifies it for tuning down the line with things such as timing tables, etc it'* not a bad thing.

Braking by wire is something i'm not a fan of by any means, I think the Merceded/McLaren SLR has it...
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