2015 Mustang IRS to use Integral Link Design?

[Falc'man]

On this link there is interesting info on the new rear suspension that was designed for the CD4 program.

You need to sign up to read the paper but it is free

http://www.automotiv...w-ford-mondeo/#

This presentation by Dr. Paul Zandbergen, Dr. Wolfgang David, Ed Knoy, and Dr. Thomas Schmitz compares the rear suspension of the previous and current Ford Mondeo models. Learn about advanced suspension design principles and the new Integral Link suspension. A comparison of control blade vs. integral link is made in terms of NVH performance and vehicle dynamics.

http://www.falconforums.com.au/show...egral-Link-Suspension-under-Fusion-and-Mondeo

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[Overboost]

That certainly looks familiar. Theoretically, if the platform was designed for AWD, then a rear drive configuration should be fairly simple as well. Based on the limited shots we've seen of the underpinnings, the new car looks to be outfitted with a beefed up integral link design.

 

[thePill]

Integral Link!?!?!? What the hell!!!

 

[HGFireHazard]

Integral Link!?!?!? What the hell!!!

For those of us without the proper knowledge, what are the implications of this style of suspension? How does it compare to CBIRS?

 

[Dub347sbf]

I just hope it's better than my 01 bra suspension. Corners great, wheel hops like a biatch

 

[GTsquid]

I couldn't see anything so captured larger images. Here they are.

Thanks for the info Falc'man. This is good stuff.

 

[Icy]

Integral Link!?!?!? What the hell!!!

For those of us without the proper knowledge, what are the implications of this style of suspension? How does it compare to CBIRS?

I would like to know as well, if someone can explain.

From the info provided sounds like... improved ride comfort, reduced road noise and improved steering/handling?

 

[Norm Peterson]

The upper pivot for the upright/hub carrier needs to have its fore/aft location controlled, and a single upper lateral link (aka camber link above) is not capable of providing this control by itself. So instead of an upper arm with two inboard pivots or two separate upper lateral-ish links, a vertical-ish link triangulates the upright back to the lower control arm (think side view here) for a similar effect. I suspect it sends more of the road generated NVH through the LCA and its two chassis side pivots, which might simplify other NVH treatments . . . and that this arrangement might be somewhat sensitive to integral link pivot wear. Similarly, I can't see the integral link being successfully mounted in compliant bushings and still provide adequate fore/aft control of the top of the upright.

The control blade configuration shown provides roll understeer, a little of which is desirable. But as noted, one of the paybacks is in poorer NVH performance. Another is poor anti-squat or actually "pro-squat". If you were to mount point A (the chassis side) above point B, NVH and anti-squat get better, but now the roll steer is oversteerish in nature which is poor practice for most purposes outside of drag racing.


Norm

 

[thePill]

It appears that the Integral Link eliminates the upper control arm/short arm (less weight). It also retains the ability to tune the ride and handling separately so both can be optimized.

The IL uses a full size shock, while it still protrudes through the rear wheel, their is enough room to provide some models 3rd row seating. The CBIRS that used a compact shock would have been difficult for the aftermarket (and Do-It-Your-Self Mods).

To tell you the truth, this is almost exactly what is used on the BMW M5 and 7 series and the little Z8. This is almost a spitting image of BMW's Multi-Link. Some had a trailing arm, some had coil-overs and air shocks (X5 I believe). What this system does is allows each wheel to move completely free of the body. Upper arms would communicate the harshness to the cabin/part of the sub-frame.. The Integral link replaces the upper arm (and rear cradle of the CBIRS/Less weight) and communicates the NVH to the suspension system, in which the spring and damper (optimally tuned as well as independent from each other) talk some sense into that NVH so you don't have to deal with it. Actually, the damper talks to the wheel (which is arguing with the road) and the spring is working on the ride. This also means, there is very little vibration being transmitted to the other wheel and the system allows for really nice travel as well as a lower ride height.

As far as it's performance properties, because the system was designed with anti-dive and squat geometry, both should be maximized. The Integral Link does the exact same thing the Control Blade does but it's 1/64th the size (Less weight). That doesn't mean Ford can't put a trailing arm on it if they wanted... It is pretty much an evolution of the trailing arm IRS anyway. Most Multi-Link IRS requires a HUGE sub-frame which is like bolting on 120lbs, that sub-frame was transferring the vibrations to the cabin (Control Blade too). This new IRS design is fairly lightweight...

Edit: The old Multilink designs provided poor camber control...

As the suspension is compressed (due to road surface, body roll or acceleration) the wheel moves upwards in relation to the car body, as this happens the 'camber' angle (or tilt) of the wheel changes. This leads to inconsistent handling and traction, especially during periods of body roll and heavy acceleration.

I guess this is a huge issue with IRS systems (see Camaro, Terminator). This is what cases wheel hop or the wheels to shutter in a turn. The forces applied in the corner cause the tire to tilt and reduce it's contact patch. The I Link prevents the geometry changes under heavy loads.

As Norm mentioned, Point A and point B in the CBIRS... ILIRS actually attaches that I Link parallel with the center of the wheel hub. This is how they maximized the design to prevent dive and squat. The geometry keeps the tire on the road so, naturally, body roll is eliminated (or greatly reduced) in conjunction with the shock/spring/wheel/tire setup.

CBIRS fought dive and squat with brute force where the ILIRS uses physics and geometry.

 

[Overboost]

Camaro IRS, for reference:

 

[thePill]

Camaro IRS, for reference:

Thank you sir!!!

Also worth noting, this type of IRS (or any) that uses an Integral Link instead of the typical SLA (Short-Long Arm) is highly flexible as far as applications go. With no Upper sub-frame/spring housing, No short arm (Upper Control Arm) and No Control Blades/trailing arms, there is very minimal contact between the suspension unit and the chassis. All those components were usually unique to the application. Especially Sub-frame based Multilink where the sub-frames were designed for the specific vehicle (and heavy). Control Blades/Trailing Arms were also designed specifically (Terminator had Trailing arm SLA which also required a sub-frame).

The ILIRS suspension is used in large sedans, SUV's, Sports coupes and even 2 seat sports cars. FWD, RWD, AWD, 4WD... They can use trailing arms and it's worth noting that BMW uses trailing arms in large sedans like the 7 series and the old V12 8 series. The lighter cars were equipped with the version similar to the Mustang (Under a 5 series weight).

 

[thePill]

I would say that the S550 may be a highly evolved CD4 platform to me...

This Mustang may not cost Ford too much after all...

For those that want to learn about the CD4 chassis, in depth, please see the link.

http://www.autosteel.org/~/media/Files/Autosteel/Great%20Designs%20in%20Steel/GDIS%202012/Advanced%20High-Strength%20Steel%20Technologies%20in%20the%202013%20Ford%20Fusion.pdf

 

[JohnZiraldo]

Any thoughts on what IL IRS will mean for normal (non-Cobra Jet) drag racing?

 

[thePill]

Any thoughts on what IL IRS will mean for normal (non-Cobra Jet) drag racing?

Less wheel hop than the traditional SLA IRS because the vertical movement is controlled/limited with the I Link. It will take far less shock/spring energy to damper than violent rattle. Solid Axles could easily compensate with stiffer spring/shock and larger/lighter control arms. However, if one tire started hopping for whatever reason, the other side would start to hop too. Both wheels are in direct relation... One goes up violently, the other goes down just as violently... On basically two rubber balls filled with air mind you.

It may be a cheaper IRS system and a lightweight design as well... Durability is compensated in the Integral Link somewhat. It does indeed absorb the fore/aft and lateral torque the wheel is subjected to BUT, the issue with IRS is usually the half shafts and U joints those shafts use. That is the issue with IRS an drag racing now... Before, the wheel hop was hard to tune out AND, half-shafts were weak and sometimes smaller because of packaging restrictions on SLA IRS setups. Most SLA IRS is forced to use a coilover to provide some room for a half-shaft which reduces maximum rear wheel sizes and interior space. Overall weight of the unit keeps half-shafts small too... The small links the ILIRS uses allows some pretty big half shafts. No Control Blades, Trailing Arms or Large Sub-Frame allows for a more direct exhaust system too.

I imagine Steeda and Roush will have some serious half-shafts available almost immediately. They get the specs, and in some cases, look over the shoulder of Ford while new systems are being tested. The Ford Mustang commands an $8 billion dollar a year after market, this is where most IRS systems get little or no support for other vehicles unless they are high end tuners. Just as there are super high strength drive shafts a plenty for the S197, those companies will offer half-shafts very soon.

 

[thePill]

I questioned if the spy photos were even CBIRS at all back on post #21.

I know one thing... this suspension doesn't exist in Ford's current lineup... Can this even be control blade? Could this be a Short-Long-Arm version of Control Blade? Could the cradle be reversed and sit up into the body to increase ground clearance?

For example, could the cradle link the two spring towers together directly (shown in red) instead of the bulky cradle shown in the diagram. It would also allow more freedom with the exhaust paths. Look how close the exhaust is to the rear differential in the photo above. The diagram below couldn't support that exhaust.

Good eye Falc'man!!!

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