Ah, forgot to post this yesterday. The '15 Mustang is 1.4 inches lower and 1.5 inches wider, an inch wider track up front, 3 in the rear.
Man, an extra inch in the track is worth 2 in the tire...
That's a plan view showing either an upper "control arm" or a lower "control arm". Not both, and it doesn't care one iota whether the rest of the suspension comprises some form of SLA or if it's a Mac Strut. And "control arm" is in quotes because strictly speaking it isn't a single arm any more but two components that combine to behave like one.Virtual meaning "Imaginary" and the pivot point (or joint) is the axis. All modern suspension (SLA and MacP) has to incorporate more moving parts to get the clearance a Double Wishbone does.
The suspension diagram above is the basic (and true) Virtual Pivot Control Link. You can see the "Pivot Point" is an imaginary joint beyond the wheel. You can see, on VPCL, you need an upper and lower arm to create the point.
If you ever try to mathematically model MacStrut geometry, you'll probably find the easiest way is to assume that a VIRTUAL upper control arm exists. You have all of the information necessary to define its direction without needing a second pivot point; all you need to know is one pivot point and a slope. (you know it passes through the point in the strut mount bushing/bearing about which the strut shaft pivots as seen in front view, and that by definition this line must be perpendicular to the strut axis). Any sketch that shows the geometric construction for a MacStrut front view instant center and geometric roll center will show what I'm trying to describe in words.
Don't know if I'm glad I missed this thread before or not.Virtual Pivot Control Link
The S550
Virtual pivot steering doesn't change a MacP system into a SLA/Double Lower Control Arm. A MacP system is a MacP...
I'm pretty sure the 1.4" is the average of the lowered hood and decklid. If they lowered the ride height of the car 1.4", then you are effectively saying that they had no proportional changes to the hood or roof height.
There shouldn't be a mystery concerning the S550. It is pretty close to what BMW and Benz use... They both ditched the Virtual Pivot Link systems for the cheaper and stronger MacP system.
Look at a pic of the S550 next to a S197 and make your own educated guess. I highly doubt they lowerd the minimum ride height of the car that much. None of the supplied press photos or cars appear to be that low.
Not sure if it's stronger. Any double A-frame suspension is a lot stronger than a Strut -which has a TON of load and especially side-loading on the damper itself.
I have a question about this "virtual pivot point" Norm. In Germany, I was taught that the "Pivot" joint is actually made up of an outer pivot link (Lateral link in the Mustang's case) and the inner pivot arm (Strut/upper Control Arm). The actual "Pivot" happens between the Lateral Link and the Upper Control Arm. As in, the outer pivot (Lat Link) rotates around the inner pivot. The Tension Link (the 2nd lower link) actually stabilizes the movement of the pivot action. The common misconception is that the two lower links are what causes the "pivot" action... That is not the case...
The suspension actually rotates around the line drawn through the upper bearing plate and the intersection point of the lines drawn through the tension link and the lateral link. That point it creates is called a virtual pivot point. So to simplify the language, the axis of rotation is the line drawn through the virtual pivot point and the upper bearing plate. That line is also called the steering axis inclination. That was the diagram I made earlier.I have a question about this "virtual pivot point" Norm. In Germany, I was taught that the "Pivot" joint is actually made up of an outer pivot link (Lateral link in the Mustang's case) and the inner pivot arm (Strut/upper Control Arm). The actual "Pivot" happens between the Lateral Link and the Upper Control Arm. As in, the outer pivot (Lat Link) rotates around the inner pivot. The Tension Link (the 2nd lower link) actually stabilizes the movement of the pivot action. The common misconception is that the two lower links are what causes the "pivot" action... That is not the case...
The Tension Link stabilizes the pivot action throughout it's range of motion. The actual pivot is between the main and lower link (the Lateral Link) as it pivots around the upper control arm OR, in the Mustang's case, the MacP strut. The old VPCL used an upper A Arm/Wishbone...
Ah yes, the actual pivot on the BMW consist of all three. A 3 way pivot... However, all three arms together make a stable system Norm. Each arm relies on a natural pull/push method for stability. As in, each arm provides resistance/force opposing the other two arms force/resistance. The two virtual control arms (MacP strut and the two lower links) are actually forming a virtual Tripod. Each link (3 total) has a ball-joint...
I have a question about this "virtual pivot point" Norm. In Germany, I was taught that the "Pivot" joint is actually made up of an outer pivot link (Lateral link in the Mustang's case) and the inner pivot arm (Strut/upper Control Arm). The actual "Pivot" happens between the Lateral Link and the Upper Control Arm. As in, the outer pivot (Lat Link) rotates around the inner pivot. The Tension Link (the 2nd lower link) actually stabilizes the movement of the pivot action. The common misconception is that the two lower links are what causes the "pivot" action... That is not the case...
The Tension Link stabilizes the pivot action throughout it's range of motion. The actual pivot is between the main and lower link (the Lateral Link) as it pivots around the upper control arm OR, in the Mustang's case, the MacP strut. The old VPCL used an upper A Arm/Wishbone...
Look at the GIF above. The "Virtual Pivot" changes continuously with steering. It's not as simple as a fixed pivot of a traditional 1-balljoint LCA like in the S197:
I'm not sure who the comment was aimed at but I'm not arguing it's fixed. All that I am saying is where the two points are to figure out the steering axis inclination and by virtue of that, where the suspension pivots around. The virtual pivot point doesn't have to be fixed for it to still be the bottom pivot point! ;)Look at the GIF above. The "Virtual Pivot" changes continuously with steering. It's not as simple as a fixed pivot of a traditional 1-balljoint LCA like in the S197:
Edit: I think there is a lot of confusion and cross-referencing in regards to a "PIVOT" with steering vs. pivoting with bump travel (vertical motion). The above diagram illustrates pivoting with steering motion.
I think your concern was adequately answered by those who stayed online later last night than I did. A 4-bar mechanism needs exactly four links (and four hinges or pivots). Any fewer than four of each and it won't move geometrically at all; any more than four and it won't be stable and will collapse about itself into some indeterminate shape limited generally by the pivots' ranges of angular motion. Let's mention but not get into how well compliant cylindrical bushings approximate the necessary pivoting, and simply say that they can do this job (more or less).
