Why a new Power Steering option?
01-17-2013, 03:20 AM
#2
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All current Porsches do have power steering, as you say. Power Steering Plus deals with a problem in the design of modern steering racks. With ingenuity in their design, it has been possible for ... I'm not sure how many years. Decades anyway, it has been possible to arrange for a different ratio of steering wheel movement to road wheel movement at different steering angles. That is important to allow stable handling at high speed when we don't move the wheel very far, yet provide a relatively quick ratio for the low-speed turns around town that require big movements of the steering wheel.
All well and good, except tires keep getting wider and sticker. That makes the comfortable effort in a 20-mph corner turn into a wrestling match at 2 mph when parking. Or it can. It's caused by the quick ratio we applaud at normal speeds around town. Lots of ingenuity has been expended on dealing with the issue of quick-ratios at parking speed. The stock steering in a Carrera has some protection against that problem, but it still troubles people with weaker hands than say a blacksmith if they have to maneuver a lot at those low speeds. Seriously, lots of women and quite a few men find the steering effort at parking speeds to be noticeable, which is fine if you only parallel park once in a blue moon, but it is annoying enough to be worth design attention for others.
My own hands are growing weaker from a chronic spine disorder and I am very pleased that my car is equipped with the Power Steering Plus to help with low speed manuevers. Basically, it raises the boost -- the assistance -- as the car speed drops toward zero (although it isn't really that simple). I find the feature well integrated, and I have very experienced -- albeit weakening -- hands. Boost begins to rise around as I slow below thirty mph and my effort on the wheel is still quite manageable at parking speeds. It never feels lighter than at higher speeds. It just doesn't get as much heavier as the actual force being applied to the front wheels increases.
Excellent option if you need that, and essentially invisible if you don't. In other words, it doesn't interfere with steering feel, even at autocross venues.
Gary
01-17-2013, 08:14 AM
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Gary, I think you may be the first to give a really nice, readable (and correct) description of what this option is and does.
You have demonstrated that you exceed the combined knowledge of 90% of motoring journos or wannabees without even trying hard.
Thanks.
Rainier
(Yes, I have this option too and I like it very much)
You have demonstrated that you exceed the combined knowledge of 90% of motoring journos or wannabees without even trying hard.
Thanks.
Rainier
(Yes, I have this option too and I like it very much)
01-17-2013, 09:45 AM
#4
Burning Brakes
My car has Power Steering Plus, the other similar car I test drove before buying didn't, and honestly I couldn't notice much difference. Then again I don't often have to parallel park, etc. I would agree that it probably does exactly what it's supposed to, as Gary describes, without being intrusive at all.
01-17-2013, 01:05 PM
#5
My main fear with this option was that it's supposed to change steering feel under 30 mph. Thanks for your description Gary, but do you (or anyone else with this option) feel that it changes the steering feel unpredictably for low speed maneuvering, such as on very tight corners that require you to be under 30 mph? Or maybe when you're stuck behind slower traffic that's below 30 mph (or just following speed limit)? Or have these situations never really arisen?
My line of reasoning was that I didn't want anything to "taint" the steering feel, and people were already complaining about the move the electric steering and this option would just push it along in that direction.
Thanks for your thoughts.
My line of reasoning was that I didn't want anything to "taint" the steering feel, and people were already complaining about the move the electric steering and this option would just push it along in that direction.
Thanks for your thoughts.
01-17-2013, 02:09 PM
#6
Burning Brakes
Thread Starter
Thank you for the excellent explanation. So I guess they decided to offer a basically more "highly-boosted power steering" for people that deem it necessary for low speed maneuvers. So they are offering it now rather than before because of the constant increase of tire sizes?
I ordered my Panamera GTS without it and I am very happy with it, so I wouldn't know what it is like with it. I also test drove a 991S cabriolet with it and without even knowing that it had the option, I was surprised how light the steering was and did not like it. Afterwards, I looked at the options and saw that it had it. I drove a 991S coupe without it before and and preferred it. I guess it is nice that Porsche offers it as an option so people who prefer it can order it. I am just glad that it is not standard on all of them.
I ordered my Panamera GTS without it and I am very happy with it, so I wouldn't know what it is like with it. I also test drove a 991S cabriolet with it and without even knowing that it had the option, I was surprised how light the steering was and did not like it. Afterwards, I looked at the options and saw that it had it. I drove a 991S coupe without it before and and preferred it. I guess it is nice that Porsche offers it as an option so people who prefer it can order it. I am just glad that it is not standard on all of them.
Are you talking about the "Power Steering Plus" option, Terrence?
All current Porsches do have power steering, as you say. Power Steering Plus deals with a problem in the design of modern steering racks. With ingenuity in their design, it has been possible for ... I'm not sure how many years. Decades anyway, it has been possible to arrange for a different ratio of steering wheel movement to road wheel movement at different steering angles. That is important to allow stable handling at high speed when we don't move the wheel very far, yet provide a relatively quick ratio for the low-speed turns around town that require big movements of the steering wheel.
All well and good, except tires keep getting wider and sticker. That makes the comfortable effort in a 20-mph corner turn into a wrestling match at 2 mph when parking. Or it can. It's caused by the quick ratio we applaud at normal speeds around town. Lots of ingenuity has been expended on dealing with the issue of quick-ratios at parking speed. The stock steering in a Carrera has some protection against that problem, but it still troubles people with weaker hands than say a blacksmith if they have to maneuver a lot at those low speeds. Seriously, lots of women and quite a few men find the steering effort at parking speeds to be noticeable, which is fine if you only parallel park once in a blue moon, but it is annoying enough to be worth design attention for others.
My own hands are growing weaker from a chronic spine disorder and I am very pleased that my car is equipped with the Power Steering Plus to help with low speed manuevers. Basically, it raises the boost -- the assistance -- as the car speed drops toward zero (although it isn't really that simple). I find the feature well integrated, and I have very experienced -- albeit weakening -- hands. Boost begins to rise around as I slow below thirty mph and my effort on the wheel is still quite manageable at parking speeds. It never feels lighter than at higher speeds. It just doesn't get as much heavier as the actual force being applied to the front wheels increases.
Excellent option if you need that, and essentially invisible if you don't. In other words, it doesn't interfere with steering feel, even at autocross venues.
Gary
All current Porsches do have power steering, as you say. Power Steering Plus deals with a problem in the design of modern steering racks. With ingenuity in their design, it has been possible for ... I'm not sure how many years. Decades anyway, it has been possible to arrange for a different ratio of steering wheel movement to road wheel movement at different steering angles. That is important to allow stable handling at high speed when we don't move the wheel very far, yet provide a relatively quick ratio for the low-speed turns around town that require big movements of the steering wheel.
All well and good, except tires keep getting wider and sticker. That makes the comfortable effort in a 20-mph corner turn into a wrestling match at 2 mph when parking. Or it can. It's caused by the quick ratio we applaud at normal speeds around town. Lots of ingenuity has been expended on dealing with the issue of quick-ratios at parking speed. The stock steering in a Carrera has some protection against that problem, but it still troubles people with weaker hands than say a blacksmith if they have to maneuver a lot at those low speeds. Seriously, lots of women and quite a few men find the steering effort at parking speeds to be noticeable, which is fine if you only parallel park once in a blue moon, but it is annoying enough to be worth design attention for others.
My own hands are growing weaker from a chronic spine disorder and I am very pleased that my car is equipped with the Power Steering Plus to help with low speed manuevers. Basically, it raises the boost -- the assistance -- as the car speed drops toward zero (although it isn't really that simple). I find the feature well integrated, and I have very experienced -- albeit weakening -- hands. Boost begins to rise around as I slow below thirty mph and my effort on the wheel is still quite manageable at parking speeds. It never feels lighter than at higher speeds. It just doesn't get as much heavier as the actual force being applied to the front wheels increases.
Excellent option if you need that, and essentially invisible if you don't. In other words, it doesn't interfere with steering feel, even at autocross venues.
Gary
01-17-2013, 03:06 PM
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My main fear with this option was that it's supposed to change steering feel under 30 mph. Thanks for your description Gary, but do you (or anyone else with this option) feel that it changes the steering feel unpredictably for low speed maneuvering, such as on very tight corners that require you to be under 30 mph? Or maybe when you're stuck behind slower traffic that's below 30 mph (or just following speed limit)? Or have these situations never really arisen?
My line of reasoning was that I didn't want anything to "taint" the steering feel, and people were already complaining about the move the electric steering and this option would just push it along in that direction.
Thanks for your thoughts.
My line of reasoning was that I didn't want anything to "taint" the steering feel, and people were already complaining about the move the electric steering and this option would just push it along in that direction.
Thanks for your thoughts.
I read those original complaints about the new "electric steering" and you have to read those comments with the understanding that the writers were full of what we spread on the fields every year. We've discussed it at length in other threads, but briefly -- and skipping the very long list of things it is not, like 'fly-by-wire' -- it is simply using an electric motor to assist instead of a hydraulic one. This has the advantage of permitting computer control that is much more refined than hydraulic techniques. (I'm talking about all the current cars, not just the PSP option.)
The big difference in feel to me in driving this and a 997 back to back is the change in the chassis, not the change in the steering assist. I can feel the road surface through the steering, and the work being done by the tires, just as easily. Possibly even a little better, because the 997 has some chassis effects going on that distract from the essential information about the tires.
ChuckPDC has a good description of the older feel that I haven't time to dig out just now. Besides, we've talked it to death already. Bottom line: certainly no problem with omitting the Power Steering Plus if you don't need it, but if a car you like has it installed, it won't detract from your enjoyment. And if you need it, it is wonderful.
[Forgot to answer this:
So they are offering it now rather than before because of the constant increase of tire sizes?
Gary
Last edited by simsgw; 01-17-2013 at 03:16 PM. Reason: Added answer to question about why now.
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01-29-2013, 12:20 AM
#8
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Coming from BMWs, the Power steering plus is similar to "Servotronic" option, which varies steering effort/assistance from different speed.
Since the new 991/981 steering rack are assisted by electric motor, this option can be easily added/removed by PIWIS II.
From Vehicle order selection, delete 657 - Power steering standard then add 658 - Servotronic, save, then code vehicle - Wala, the steering boost is now power steering plus!
I feel positive that Porsche is offering two options. IMHO the question is really matter of personal preference. Both standard steering and PSP has similar feed back, but VERY different steering assist boost. I drive quick around slow mountain corners often, with boosted steering assist I find the overall steering feel actually better than standard, with these heavy 20" wheels in question.
Since the new 991/981 steering rack are assisted by electric motor, this option can be easily added/removed by PIWIS II.
From Vehicle order selection, delete 657 - Power steering standard then add 658 - Servotronic, save, then code vehicle - Wala, the steering boost is now power steering plus!
I feel positive that Porsche is offering two options. IMHO the question is really matter of personal preference. Both standard steering and PSP has similar feed back, but VERY different steering assist boost. I drive quick around slow mountain corners often, with boosted steering assist I find the overall steering feel actually better than standard, with these heavy 20" wheels in question.
No, I don't feel that way at all. I wouldn't even agree that steering is lighter than the same car without it until you get into the lowest speed ranges. And nothing is unpredictable about the transition. In fact, I can't feel the transition. As I say, it doesn't get lighter, it just doesn't let the steering grow heavy as fast as a car without the feature.
I read those original complaints about the new "electric steering" and you have to read those comments with the understanding that the writers were full of what we spread on the fields every year. We've discussed it at length in other threads, but briefly -- and skipping the very long list of things it is not, like 'fly-by-wire' -- it is simply using an electric motor to assist instead of a hydraulic one. This has the advantage of permitting computer control that is much more refined than hydraulic techniques. (I'm talking about all the current cars, not just the PSP option.)
The big difference in feel to me in driving this and a 997 back to back is the change in the chassis, not the change in the steering assist. I can feel the road surface through the steering, and the work being done by the tires, just as easily. Possibly even a little better, because the 997 has some chassis effects going on that distract from the essential information about the tires.
ChuckPDC has a good description of the older feel that I haven't time to dig out just now. Besides, we've talked it to death already. Bottom line: certainly no problem with omitting the Power Steering Plus if you don't need it, but if a car you like has it installed, it won't detract from your enjoyment. And if you need it, it is wonderful.
[Forgot to answer this: Without knowing their motives, I'd say no. We have been complaining of the compromises caused by this issue for decades. It is notorious in muscle cars with all that engine weight on the tires that do the steering. Make it easy to park one and you have a dangerous light steering feel at higher speeds. Hydraulic systems just do not have good solutions that are cost effective. Computer control makes them feasible but it's awfully expensive to do it with this precision in a hydraulic system. It is feasible with an electrical assist motor. At least on a car with a manufacturing cost roll-up that's already as high as the Carrera.]
Gary
I read those original complaints about the new "electric steering" and you have to read those comments with the understanding that the writers were full of what we spread on the fields every year. We've discussed it at length in other threads, but briefly -- and skipping the very long list of things it is not, like 'fly-by-wire' -- it is simply using an electric motor to assist instead of a hydraulic one. This has the advantage of permitting computer control that is much more refined than hydraulic techniques. (I'm talking about all the current cars, not just the PSP option.)
The big difference in feel to me in driving this and a 997 back to back is the change in the chassis, not the change in the steering assist. I can feel the road surface through the steering, and the work being done by the tires, just as easily. Possibly even a little better, because the 997 has some chassis effects going on that distract from the essential information about the tires.
ChuckPDC has a good description of the older feel that I haven't time to dig out just now. Besides, we've talked it to death already. Bottom line: certainly no problem with omitting the Power Steering Plus if you don't need it, but if a car you like has it installed, it won't detract from your enjoyment. And if you need it, it is wonderful.
[Forgot to answer this: Without knowing their motives, I'd say no. We have been complaining of the compromises caused by this issue for decades. It is notorious in muscle cars with all that engine weight on the tires that do the steering. Make it easy to park one and you have a dangerous light steering feel at higher speeds. Hydraulic systems just do not have good solutions that are cost effective. Computer control makes them feasible but it's awfully expensive to do it with this precision in a hydraulic system. It is feasible with an electrical assist motor. At least on a car with a manufacturing cost roll-up that's already as high as the Carrera.]
Gary
01-29-2013, 12:32 AM
#9
Three Wheelin'
I inquired about this at the dealer and was told not possible.
To turn off the "Plus" part, that is.
Your logic makes perfect sense to me. Maybe I need to revisit the issue.
Anyone changed their 991 option post-purchase?
To turn off the "Plus" part, that is.
Your logic makes perfect sense to me. Maybe I need to revisit the issue.
Anyone changed their 991 option post-purchase?
01-29-2013, 12:48 AM
#10
There is a small chance I am wrong about this (although I don't think I am.. ) , but as I understand it the power steering in the 991 (and by that I mean the new electrically assisted PS) has variable assist / effort to the steering applied electronically by default and this is standard in every 991. So the effort at low speeds would be different than at higher speeds. Again this is standard.
The "Power Steering Plus" option adds a planetary gear assembly inside the steering rack that changes the overall ratio of the rack at lower speed ie: total number of turns of the steering required for maneuvering the car.
So, in addition to the ease of turning the wheel (again standard), you use a lesser amount of steering input to maneuver / park the car with steering plus.
The "Power Steering Plus" option adds a planetary gear assembly inside the steering rack that changes the overall ratio of the rack at lower speed ie: total number of turns of the steering required for maneuvering the car.
So, in addition to the ease of turning the wheel (again standard), you use a lesser amount of steering input to maneuver / park the car with steering plus.
Last edited by rpilot; 01-30-2013 at 02:54 PM.
01-29-2013, 01:35 AM
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This is a small chance I am wrong about this (although I don't think I am.. ) , but as I understand it the power steering in the 991 (and by that I mean the new electrically assisted PS) has variable assist / effort to the steering applied electronically by default and this is standard in every 991. So the effort at low speeds would be different than at higher speeds. Again this is standard.
The "Power Steering Plus" option adds a planetary gear assembly inside the steering rack that changes the overall ratio of the rack at lower speed ie: total number of turns of the steering required for maneuvering the car.
So, in addition to the ease of turning the wheel (again standard), you use a lesser amount of steering input to maneuver / park the car with steering plus.
The "Power Steering Plus" option adds a planetary gear assembly inside the steering rack that changes the overall ratio of the rack at lower speed ie: total number of turns of the steering required for maneuvering the car.
So, in addition to the ease of turning the wheel (again standard), you use a lesser amount of steering input to maneuver / park the car with steering plus.
I can see someone not bothering to check that PSP box on a custom order, but I can't imagine anyone bothering to screw with the controller to try suppressing it.
Gary
01-29-2013, 02:26 AM
#12
, but maybe I am stereotyping.FWIW, I have not driven a 991 with PSP. The cars I test drove before ordering did not have one and I did not think I was missing anything, nor did I find it hard to maneuver, but every one is different in this respect. Either way it should not detract from the driving experience at proper speed. Again i do not remember but the ratios only change at less than 12 mph or is it 30 mph?
01-29-2013, 03:03 AM
#13
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Well I have "borrowed" the PIWIS II at dealer for 2 hours tried experimenting with a few setups and changes.
My car was ordered without PSP, while changing VO and coding the PSP functionality works in full. I assume most dealers do not know how to make these changes or simply would not do it for some policy/procedure considerations.
There is no differences in steering unit or gears between STD and PSP, only different coding controls different boost map.
I think the advertisement is wrong. Having driven with standard steering since September, the PSP boost is still lower (lighter steering) above 70km than standard, albeit heavier than walking speed.
Steering weight at walking speed is now actually lighter than my daily driver - a BMW F10 - but much more accurate and spot on!
While experimenting with PIWIS, the auto stop/start memory can be turned on by similar method, now restarting the car the setting would remain.
Good luck.
My car was ordered without PSP, while changing VO and coding the PSP functionality works in full. I assume most dealers do not know how to make these changes or simply would not do it for some policy/procedure considerations.
There is no differences in steering unit or gears between STD and PSP, only different coding controls different boost map.
I think the advertisement is wrong. Having driven with standard steering since September, the PSP boost is still lower (lighter steering) above 70km than standard, albeit heavier than walking speed.
Steering weight at walking speed is now actually lighter than my daily driver - a BMW F10 - but much more accurate and spot on!
While experimenting with PIWIS, the auto stop/start memory can be turned on by similar method, now restarting the car the setting would remain.
Good luck.
01-29-2013, 03:15 AM
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The power steering plus is what generally referred as "Servotronic" on all other German cars, and is described the same on PIWIS, which is the Porsche computer for our cars. It is actually a variable steering boost control, activated by different electric motor assist forces at different vehicle speed range.
On older cars with hydraulic steering gear, such as the 997 or alike, hardwares are different with or without this function.
The "variable ratio from steering center" is a different thing in question. It is built in all steering gear with or without power steering plus. Different manufacturer has different approach, for example BMW, whom offers active steering which adjusts steering gearing by function of vehicle speed.
In my opinion the Porsche (As a first time P owner) system offers much linear feel than BMW system, which is more focused on user convenience than sheer steering feel and accuracy.
On older cars with hydraulic steering gear, such as the 997 or alike, hardwares are different with or without this function.
The "variable ratio from steering center" is a different thing in question. It is built in all steering gear with or without power steering plus. Different manufacturer has different approach, for example BMW, whom offers active steering which adjusts steering gearing by function of vehicle speed.
In my opinion the Porsche (As a first time P owner) system offers much linear feel than BMW system, which is more focused on user convenience than sheer steering feel and accuracy.
The dealer is correct that you cannot turn it off. Like I noted and if I am correct the only way for you to do this is probably not in software, unless you perform a hack (always a very bad idea even if you have or can find the expertise) that makes sure that the controller specifies only one ratio/gear for the steering rack throughout the speed range. In other words you cannot have PIWIS or whatever Porsche Dealer software is called simply choose a different setting or module. You will have to get the different steering rack / assembly whatever, which I am sure is not cheap and have the dealer install it which again would add a significant cost. I don't mean to offend or second guess your intentions, but as Gary mentioned why would you want to? Besides I am sure your significant other would not be too pleased with the change , but maybe I am stereotyping.
FWIW, I have not driven a 991 with PSP. The cars I test drove before ordering did not have one and I did not think I was missing anything, nor did I find it hard to maneuver, but every one is different in this respect. Either way it should not detract from the driving experience at proper speed. Again i do not remember but the ratios only change at less than 12 mph or is it 30 mph?
, but maybe I am stereotyping.FWIW, I have not driven a 991 with PSP. The cars I test drove before ordering did not have one and I did not think I was missing anything, nor did I find it hard to maneuver, but every one is different in this respect. Either way it should not detract from the driving experience at proper speed. Again i do not remember but the ratios only change at less than 12 mph or is it 30 mph?
01-29-2013, 10:16 AM
#15
Three Wheelin'
Thx guys.
I am not at all unhappy with my PSP. As stated above it is very unobtrusive.
But if it is a pure software thing (factory -- not interested in a hack), then I would be curious to live with it in PS setting for a while to see which one I prefer for my setup (not just a test drive).
I am positive I will survive in either "setting"...
I am not at all unhappy with my PSP. As stated above it is very unobtrusive.
But if it is a pure software thing (factory -- not interested in a hack), then I would be curious to live with it in PS setting for a while to see which one I prefer for my setup (not just a test drive).
I am positive I will survive in either "setting"...