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  #1  
Old 12-13-2006, 05:22 PM
PDSides PDSides is offline
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Rear-Wheel-Steering: Myth or Miracle?

Anybody here an expert on rear-wheel-steering as rumored on JDM SVXs? I am wondering how complicated an active rws system has to be in order to be workable and practical. Was the JDM rws system active or passive, and if it was active, how was it powered and how did the system work? I may have posted this in the wrong section but wanted to scare up an expert if one exists on this forum. Thanks.
Preston
PS - I once had a swing-axle Corvair that essentially had passive rws that kicked in at just the wrong moment.
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  #2  
Old 12-13-2006, 05:25 PM
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We have at least 2 members here that have an AWS SVX. I'm not sure who they are, But I'm sure somebody will chime in.
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  #3  
Old 12-13-2006, 05:33 PM
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The rear wheel steering on those ones are active. I believe they were operated by an electric motor and could turn the wheels up to 15 in a direction determined by vehicle speed. The rest of them have "passive" rear wheel steering.
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  #4  
Old 12-13-2006, 08:11 PM
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Exclamation

[QUOTE=PDSides]Anybody here an expert on rear-wheel-steering as rumored on JDM SVXs?


Perhaps Aredubjay will emerge from his hiding place, & provide us with enlightenment on this once beaten-to-death subject

Ron. (Where for art thou, eddycat?)
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  #5  
Old 12-14-2006, 08:53 AM
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"Perhaps Aredubjay will emerge from his hiding place, & provide us with enlightenment on this once beaten-to-death subject."

Ron, I'm sure it was "beaten-to-death" and I hesitated to bring it up again, but GM's use of rws on its light-duty pickup trucks and Lexus' use of rws on its "parks itself" LS450 has given me pause to wonder how an active rws system works. Seems to me that only low-speed use of such a system is practical because of all the position sensors and instant reaction mechanical gizmos that would be necessary for high-speed use. Passive, on the other hand, makes more sense to me for everyday driving, although I'm on the skeptical side when it comes to altering a car's "normal" steering response, especially at high speed. OK Aredubjay, send me something offline so we can trash this thread.
Preston
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  #6  
Old 12-14-2006, 10:45 AM
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Can you read Japanese?
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  #7  
Old 12-15-2006, 09:39 AM
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Quote:
Originally Posted by huck369
Can you read Japanese?
No, I couldn't read it but it gave me a pretty good idea of how the rws was designed to work in the SVX. It read steering input, probably coupled with speed readings to determine the degree of rear-wheel turn out/in. This is pretty much what I suspected it to be but with fewer mechanical gizmos to do the job. I'm not a fan of such a system which, to my way of thinking is likely to be more trouble than it's worth. Again, I'm glad they didn't export this to the USA. I'll stick with low-speed rws as the practical application of such technology, for use in parking a trailer, getting into a very tight spot, or for parallel parking (maybe other low-speed uses - my list is not complete). Thanks for the info.
Preston
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  #8  
Old 12-15-2006, 09:44 PM
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Quote:
Originally Posted by huck369
Can you read Japanese?
Yes I can. I have problems with English though

It basically says

Some SVX equipped with electric controlled AWS system. It only activates in mid-hi speed range, up to only 1.5 degrees.(rear steers same direction as front) Meaning it doensn't work when you are parking or etc. It was only meant for hi speed stability improvement. The steer angle is determined by the speed sensor.

Since it's not oil pressured pump system, it won't put any load on the engine.

When the system failed, it will cut the power to the motor immediately and hold the angle at that point. (means may not be streight)


Make sense?
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  #9  
Old 12-15-2006, 10:20 PM
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Quote:
Originally Posted by SubaRyu
Yes I can. I have problems with English though

It basically says

Some SVX equipped with electric controlled AWS system. It only activates in mid-hi speed range, up to only 1.5 degrees.(rear steers same direction as front) Meaning it doensn't work when you are parking or etc. It was only meant for hi speed stability improvement. The steer angle is determined by the speed sensor.

Since it's not oil pressured pump system, it won't put any load on the engine.

When the system failed, it will cut the power to the motor immediately and hold the angle at that point. (means may not be streight)

Make sense?
I was told several years ago, by the wife of an SVX owner with AWS, that she hated the car, because the AWS caused complete confusion when trying to park, particularly when reversing into a space..
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  #10  
Old 12-16-2006, 07:38 AM
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Originally Posted by Ron Mummert
[
Perhaps Aredubjay will emerge from his hiding place, & provide us with enlightenment on this once beaten-to-death subject

Ron. (Where for art thou, eddycat?)
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  #11  
Old 12-16-2006, 12:22 PM
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Quote:
Originally Posted by Trevor
I was told several years ago, by the wife of an SVX owner with AWS, that she hated the car, because the AWS caused complete confusion when trying to park, particularly when reversing into a space..
Perhaps that happens when you try to reverse into a space at more than 40km/h (the speed at which the 4WS activates)

There is some technical info in my locker about the Mitsubishi 4WS system. They use a hydraulic rather than our electrical system but the principles are the same.

I much prefer the handling of our 4WS car over that of our non-4WS car. It feels more stable at speed and can change direction very quickly.
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  #12  
Old 12-16-2006, 02:07 PM
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Quote:
Originally Posted by Trevor
I was told several years ago, by the wife of an SVX owner with AWS, that she hated the car, because the AWS caused complete confusion when trying to park, particularly when reversing into a space..
I wonder Trevor if that lady had ever driven an early 90s Honda Prelude with 4ws? And then convinced herself the SVX was behaving the same?

The Prelude, at least some of them, had also a 4ws set-up.

The control system in the Honda was set to turn the wheels the same direction as the front steer axle beyond certain speeds, maybe about 50km/h, not sure on that. As Phil mentions, this makes for rapid lane changes on the motorway, and good stability.

At parking speeds, the rear wheels in the Honda turned the opposite way to the front steer axle. In theory this meant the car could turn quickly into a tight space. In practice, particularly if you were not a good parker, it meant you might be put out a little by the car turning in faster than you expected.

It is possible she may have had trouble with a Honda, then changed to an SVX with 4ws, and convinced herself she did not like it, knowing it had also got 4ws, but not knowing it was different.

I have seen ads for the SVX describing that it accelerates quickly when the "turbo" comes in I'd say these people genuinely think the SVX has a turbo, because the Power mode comes on.

Joe
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Old 12-16-2006, 07:12 PM
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Quote:
Originally Posted by svxistentialist
I wonder Trevor if that lady had ever driven an early 90s Honda Prelude with 4ws? And then convinced herself the SVX was behaving the same?

The Prelude, at least some of them, had also a 4ws set-up.

The control system in the Honda was set to turn the wheels the same direction as the front steer axle beyond certain speeds, maybe about 50km/h, not sure on that. As Phil mentions, this makes for rapid lane changes on the motorway, and good stability.

At parking speeds, the rear wheels in the Honda turned the opposite way to the front steer axle. In theory this meant the car could turn quickly into a tight space. In practice, particularly if you were not a good parker, it meant you might be put out a little by the car turning in faster than you expected.

It is possible she may have had trouble with a Honda, then changed to an SVX with 4ws, and convinced herself she did not like it, knowing it had also got 4ws, but not knowing it was different.

I have seen ads for the SVX describing that it accelerates quickly when the "turbo" comes in I'd say these people genuinely think the SVX has a turbo, because the Power mode comes on.

Joe
Merry Christmas Joe,

There was no confusion with a Honda and as it was described to me the SVX is the same in reverse. No one took to this stuff and the sales depts quickly took note.

I had a friend who had a Honda with AWS and I tried it for handling, by way of interest. As a result there is no way I would own an AWS vehicle and I had this in mind when I purchased my SVX.

Cheers, Trevor.
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  #14  
Old 12-17-2006, 03:40 AM
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Quote:
Originally Posted by Trevor
Merry Christmas Joe,

There was no confusion with a Honda and as it was described to me the SVX is the same in reverse. No one took to this stuff and the sales depts quickly took note.

I had a friend who had a Honda with AWS and I tried it for handling, by way of interest. As a result there is no way I would own an AWS vehicle and I had this in mind when I purchased my SVX.

Cheers, Trevor.
Hello Trevor, Merry Christmas to you and family as well.

That is interesting what you say. Maybe the reverse steering happens at parking speeds in reverse then?

Phil likes his and has put many miles on it. not having driven one, I'll reserve judgment.

Joe
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Old 12-17-2006, 10:10 AM
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Quote:
Originally Posted by Trevor
Merry Christmas Joe,

There was no confusion with a Honda and as it was described to me the SVX is the same in reverse. No one took to this stuff and the sales depts quickly took note.

I had a friend who had a Honda with AWS and I tried it for handling, by way of interest. As a result there is no way I would own an AWS vehicle and I had this in mind when I purchased my SVX.

Cheers, Trevor.
Not wishing to disagree with you Trevor, and incur your poetic wrath , but I haven't experienced the problem you are talking about. Our system seems to work exactly as described in the Subaru document translated by SubaRyu above.

However, if your friends 4WS system had failed then it is possible that the back wheels may have become stuck at 1.5 degrees left or right. I imagine that would cause the car to steer in a rather unusual manner.

Phil.
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