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2014 vs 2015 SS rear sway bar

54K views 114 replies 20 participants last post by  Navy Lifer  
#1 · (Edited)
As I had mentioned in the Master List of changes (differences) for 2015 SS there are significant differences in the rear stabilizer configuration between model years.

This includes different lower control arms, in addition to the bar itself, in order to provide the reinforced hole in the control arm for the bar link attachment.

Note in the parts illustrations (attached below) for the 2 bar configurations where there is an arrow and notation to show the difference in the reinforcement plate size--the 2015 version of the reinforcement is smaller to allow the stabilizer link to extend into the channel of the arm. The photos show the reduced size of the reinforcement and the hole for the link to mount.

It is easy to see the difference in bar design between 2014 & 2015. I do not presume this is anything directly related to F55, as the parts book only calls out FE3 as the common "must have". In other words, if someone is thinking of converting to 2015 spec on a 2014 SS, or even a Caprice PPV or G8, it may be a matter of just identifying the correct mix of parts, and bolt it on.

Here are the 2015 PN's (some may be preliminary, not all price currently:

1) 92294343 Shaft, rear stabilizer (no price)
1) 22786267 Clamp (L)
1) 22831250 Clamp (R)
2) 20942228 Insulator
2) 22761221 Link (kit)

As mentioned above, the lower control arms are specific to the stabilizer configuration, or at least a matter of keeping parts proliferation from creating assembly line issues.

The rear LCA's required (common with 2015 PPV):
1) 92457895 (L)
1) 92457894 (R)

Even though LCA's are common between 2015 SS & 2015 WN, the Caprice (PPV) uses the same rear bar for both 2014 & 2015--similar to 2014 SS, but smaller (20mm vs 28mm). The 20mm bar actually was first used on the production G8 GXP.

There is research to be done here, but I'm basing my initial thoughts on the fact that the aftermarket suppliers of replacements for these parts lump all Zeta (including G8 & Camaro) into a single PN that fits all variants--not to suggest that use of aftermarket LCA's would allow fitting the 2015 SS bar on a 2014 SS, or any G8, or PPV.

Case in point: BMR specifies the same part (TCA028) for G8, Camaro, and SS sedan, all years. Without seeing the part, it is not confirmed that the BMR arms work with the 1LE (direct-acting) rear bar. I do not know what could be radically different in the various GM control arms to prevent use across different models, as dimensions appear to be the same.

The 3 photos below show the current Camaro rear LCA, with the provision for the 2015 style bar. These are offered as a kit (2 arms), which are not side-specific, under PN 23484878--the individual PN is 20942237. If these will work in place of the 2015 LCA's listed above, the cost difference is significant, and will make the mod a more pleasant experience, financially.

The PN's provided were what was available at the time of my research, and are subject to change--if anyone pursues this, please re-verify the information. If I become aware of PN changes, I will update this thread.

I caution anyone evaluating this as a potential mod to your 2014 SS, that nothing has been verified as to fit/form/function, so unless or until someone does, I make no claims that this will work/fit, nor do I claim it will be an improvement of any sort.

Regardless of the relationship of this change to MRC (RPO F55), the theory of the new stabilizer configuration is that it is a direct-acting design. To me, this means it can reduce possible harshness in suspension reaction that may come with the narrower bar design (2014), and as stated in the original thread, the bar diameter may not need to be as large, for reduced mass.

There have been issues with the earlier (narrow) bar setup and links pulling apart--whether it was link failure or the attachment point for the bar on the LCA, or possibly both, I am not certain. The G8 community dealt with this, and the aftermarket recognized that the bar link attachment point was susceptible to failure--BMR, for example, makes a reinforcement kit (for VE - ie. G8--not sure about 2010/2011 Camaro) to address this, but, to be clear, the reinforcement kit is not applicable to VF, as the sway bar link on 2014 SS is different, even from early Gen5 Camaro.

The final interesting note is found in the Chevrolet Performance Parts Catalog, when you look at the 1LE suspension kit (springs, shocks, and bars--rear similar to 2015 SS):

The V6 1LE suspension kit requires use of SS brake kit (from PP book) for proper rear stabilizer bar clearance.

This note/concern may or may not be applicable to a 2014 SS, or earlier PPV, G8 GT or GXP, as the Camaro V6 does use different/smaller rear brakes than any of the VE/VF or WM/WN platforms. It's another validation point to be checked in the modification process--no idea what creates interference with the smaller brakes, and even though the 1LE kit is Camaro-specific, I would suspect the potential for a fit/clear issue might also apply to the sedans.

Comments/feedback welcome!
 

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Discussion starter · #4 · (Edited)
Makss, if the Service Arm kit will work, from the standpoint of R&R time, and that they're already in the proper configuration, I'd save the OE arms for spares (or return to stock 2014 spec), but I understand that some would rather do it themselves--not out of the question, I will concede.

(from 2015 Chevrolet Performance Parts Catalog)
23484878 NEW!
1LE & Z/28 Service Modification Kit
(2010-2011 model years only)*

This kit includes the rear lower control arms and hardware necessary to properly install the stabilizer bars included in the 1LE and Z/28 suspensions.

(I don't quite grasp what this means)
This kit is needed for 2010 and 2011 model year Camaros only, as the size of the stabilizer bar clamp stud changed starting in 2012 for both the front and the rear bar clamps.

My take is (if these arms will work) that it does not rule out possible use on 2014 SS or other platform variants to permit installation of 2015 SS rear bar on an earlier model year sedan.
 
Discussion starter · #8 · (Edited)
Rear on 1LE is 28mm solid--fairly substantial, when considering the 2014 SS sedan has a 28mm tubular bar, albeit with a different shape, so generated force numbers could be much the same.

One difference is the 2014 SS bar has shorter "arms" than 1LE or 2015 SS. Your statement is accurate, but look at it this way--for a given bar size, one that is direct acting will provide greater resistance than one that is at half the distance to the pivot point of the suspension member.

Conversely, to achieve the same force (roll resistance) of the 2014 bar with the 2015 direct-acting design, the bar diameter SHOULD be less--but it still depends on the 2015 bar "arm" design vs 2014. Suspension motion inputs over the longer length of the 2015 bar, to my way of thinking, will be less harsh in the loading > unloading (dynamic) mode (if I'm making sense).

The real question is what is the diameter and working length of the 2015 "arm(s)" compared to 2014. The center portion of the bar (between the cradle clamps) is basically inert to the calculation, other than it's diameter and whether it is solid or hollow.
 
Discussion starter · #12 ·
If so, the '15 rear bar most-likely not work in a converted '14. -BUT, too many unknowns at this point.
All the assumptions about interaction with MRC aside, why wouldn't the '15 bar setup work? The production '14 bar is 28mm, compared to 26mm front.

It may be necessary to consider '15 rear springs to soften the spring rate if the (rear) bar rate is higher. Valving may not be perfect....as you say, too many unknowns at present.
 
Discussion starter · #14 · (Edited)
I really think too much is being made out of the MRC/rear bar relationship.

All high-performance variants of Camaro have the same direct-acting type of rear bar used on 2015 SS:

1LE - standard SS springs, 28mm solid rear bar, 1LE-specific conventional shocks

ZL1 - springs unknown, MRC shocks, bar size not confirmed

Z/28 - stiffer springs, smaller bar(s) compared to 1LE, Multimatic adjustable shocks


It makes sense (to me) that IF, as has been mentioned, the MRC system (in case of SS Sedan) utilizes "softer" springs to provide a more compliant ride in the softest setting of the MRC, the change to a direct-acting rear bar would be desirable to aid in maintaining that level of compliance, while at the same time providing F/R balance & roll resistance similar to what the 2014 rear bar provided with stiffer (rear) springs--without the harsher reaction to suspension motion inputs when using the 2014 bar.

The question then becomes just how much difference there is between 2014 & 2015 rear springs. It is a fair question to contemplate whether the 2014 rear springs and 2015 rear bar would shift the F/R balance to a point that the car would become unstable toward oversteer--loose or tail-happy.
 
Discussion starter · #17 ·
Glen, if you look at Post #1 in the thread, you can see the link configuration for the 2014 SS (first illustration). The lower (on control arm end) link joint is revised to be a double-shear design, and the LCA link attachment has been rotated 90 degrees.

The BMR LCA's are designed for the configuration found on earlier VE/WM LCA's. The use of the BMR adjustable link provides the ability to connect the rear bar (even if stock) to the BMR LCA's--at the mid-point of the LCA.
 
Discussion starter · #18 ·
VF platform & sway bar design evolution

Posted Dec 31 2013 <<click to view - some here may not have seen this. The article (linked below) only offers some specifics, so some things, as we've been discussing the sway bar, for example, may be based more on assumptions, hunches, or past experience/observation, even in other vehicles. At the point of the transition to VF, the direct-acting (DA) rear sway bar was found only on the Camaro in the Zeta family. That it has now been adopted for this particular VF application is something we've been speculating about.

My theory is that the chassis re-tune and mass reduction implemented in VF permitted/included an overall reduction in spring RATES relative to VE. As mentioned in the bullet-points below, smaller spring wire diameter (for reduced mass) will - and we can disagree about this - result in lower spring rates. Even though the last bullet point mentions "stiffer bars and springing" it does not specify in comparison to VE, and I'm assuming it refers to lower level (FE1/FE2) VF models.

The one thing I struggle to reconcile is the mass-reduction efforts implemented in VF, based on the most-common brake packages found on these vehicles - 321mm front/324mm rear for the previous generation G8 and both VE/VF Holden "standard" V8 models, and 355mm front/324mm rear for 2014 SS. Along comes 2015, and suddenly a rear 360mm rotor and 4 piston caliper gets added to the SS/Lowndes special variants, as if mass no longer matters....especially on the unsprung side of the equation.

So, I'm of the belief that, like the Firebird TransAm WS6 from the mid-70's (the Herb Adams years), a relatively soft spring package combined with stiffer sway bars approach was taken in the course of re-tuning the VF platform. There are obvious differences--imagine VF with nice squishy 70 or possibly 60-series tires!

The revised VF platform allowed this to be implemented, and the move to a DA bar in the rear (front is DA already) is a refinement of the product, and now part of the SS. Tires--both width and aspect ratio, wheel widths, and shock tuning play a much bigger part today, but the stiff spring/soft bar approach is generally less desirable, since tire profiles are so much lower than 40 years ago. Softer springs and more refined corner damping are what make it possible to have a vehicle with such low profile tires maintain a reasonably comfortable ride today.

In case anyone is not clear on the term Direct Acting in regard to sway bars, it means that the link to and working end(s) of the bar respond based on actual wheel motion/displacement -- whatever amount of movement of the suspension member(s) occurs, the bar arm at the link point moves that same distance. On most GM cars (take a B-body front suspension, for example) the end link of the sway bar is moving only part of the distance of the knuckle/ball joint, since the link is well-inboard of that position. To generate the same resistance effect of a DA bar, if one was possible, requires a larger diameter bar - realize that a sway bar/stabilizer shaft is a torsion spring that adds to the dynamic spring rate, thus has to be allowed for in damper (shock absorber) tuning.

Examples of DA bars on GM vehicles in the past:

- Beretta GTZ used a DA front bar (mounted on McPherson strut) - bar is MUCH smaller than the standard front bar linked to lower control arms

- Pontiac Grand Prix GXP used a DA front bar (mounted on Bilstein strut) - again, bar is significantly smaller than the standard bar

To me, this suggests that where chassis design allows it, and the engineers can overcome the bean counters, the preferred bar configuration will be a direct-acting setup.

Released: VF Commodore Technical Details

Here are selected quotes from the linked story:

  • Monroe Shocks installed new equipment to double-coat coil springs allowing a thinner wire for reduced weight.
  • Rear sway bar links are crossbolted with extra fasteners in V8 models.
  • Evoke now uses larger anti-roll bars, and on Sports V8 models these are much larger, including an 18mm rear bar. Newly-developed tyres from Bridgestone with different sidewall characteristics maintain comfortable ride and great grip with precise steering and stability despite firmer overall settings.
  • In every case, and there are more, not only was a weight loss targetted, but the resulting component also had to meet strength and durability requirements as well as being improved in it's primary function and aid in NVH suppression.
  • Finally - and yes America, this is the basis of the Chevrolet SS - is the SS-V Redline. It has stickier 245/40 and 275/35 f/r wheels on 8.5 and 9.0" rims, FE3 suspension which has stiffer antiroll bars and springing,
 
Discussion starter · #22 · (Edited)
Not that it really matters, unless the park brake actuation cable routing is different, but Camaro park brake is larger (diameter), so the use of the Camaro rear upright would mean using the Camaro-specific park brake, thus 365mm rotor.
Above was my earlier response to one of your points--without knowing the way it works, the SS uses an electric (or maybe it's "electronic"--I call it electro-mechanical) park brake actuation system (EPB), while Camaro still has a manual hand-brake. Some sort of actuator/motor attached to the back of the rear backing plates--going to the Camaro upright and rear brake package - including backing plates & park brake configuration - could make it more complicated to transfer or integrate the EPB

Well, I blew that....wiped out most of one of my posts! It's getting kinda late--I should quit before I do more damage!!!
 
Discussion starter · #25 ·
2014 rear bar pictures

Here's some pictures that show the end link detail, as well as the spare wheel tub clearance offset in the center section (between cradle mounting points).

I didn't realize it until viewing these pictures again that the difference in half-shaft size can be seen in the two link photos--RH being larger, though I don't know the sizes or difference in L vs R.
 

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Discussion starter · #27 · (Edited)
....because the bar has to be wider to span all the way to each upright. Bars can always be made lighter by making them hollow with thin walls and large diameters, and/or by using shorter arms (but they have to allow for reason suspension movement, of course).

If the 2014 and 2015 both gave the exact same amount of roll resistance at the wheels, then there is no difference in the ride quality due to rate. There can be some benefits in ride quality due to the direct actuation putting less bending force on the control arm and less vertical force on the inner control arm bushings. This is the same reason why cars with inboard-mounted springs (e.g., a Fox Mustang whose front springs were about halfway between the control arm bushing and the ball joint) actually see an improvement in ride quality when their springs are replaced with coilover setups.
The information I've been working with is largely anecdotal--since we don't (yet) know the difference in rear bar size or any other specific characteristics, there are a few things that have surfaced. Knowing that there is a difference in the model years, it may be possible to compare the bar insulator ID's (inside diameter) to get some idea whether the 2015 part is, in fact, larger. The 2015 shaft PN 92294343 is not yet available here.

1. Video of GM Rep describing differences in 2015 SS. for dealer tech update purposes, mentions "larger rear sway bar" with no specifics

2. From road test reports, descriptions of ride with MRC at lowest (Touring) setting being quite "comfy", leading to the ASSUMPTION that 2015 spring rates are or may be lower, or at least springs may be softer (does the choice of terms matter?)

3. If (2.) is correct, the (1.) may be as well, since--regardless of change in bar design--the use of "softer" springs would bring about the need for an increase in bar rate to maintain the same overall chassis performance. The question, of course, remains just how MRC figures into this, if at all.

While it is possible to confirm that spring PN's for 2014 & 2015 are different, the 2015 springs are not available to measure.

Without an equivalent VE (G8) FE3 spring to compare to the VF (SS) FE3 spring - PN 92290028 (R) & PN 92290030 (F) for 2014 - all I can offer is the difference in a WM PPV spring to compare to what is fitted to 2014 SS. The PPV is a different application, with higher ride height, more weight, and the chassis spec considered greater equipment loads when compared to the typical VF/SS

2014 SS w/FE3
F - 0.550 wire diameter, 4 full coils w/1/4 coil (90 degree)/pigtail, 13.5" free length - linear-wound
R - 0.618 wire diameter, 6 full coils, 13" free length - linear-wound

2011 PPV w/7B3 Special Suspension


Front
OE PPV PN 92246827 (linear)
wire diameter - 0.600" (15.24mm)
free length - ~13.5"
5 turns

Rear
OE PPV PN 92256816 (linear)
wire diameter - 0.630" (16mm)
free length - ~13.25"
7.6 turns, including pigtail

For comparison, here's another spring alternative I've researched:
Pedders 2956/2957
- "zero drop" lowering springs - these are the mid-level lowering springs, with 2954 & 2955 as their true "lowering" springs.

Front PN 2956 (progressive wound)
wire diameter - 0.560" (14.22mm) - 6.7% smaller than OE PPV/7B3
free length - ~13.375"
5.75 turns

Rear PN 2957 (progressive wound)
wire diameter - 0.590" (15mm) - 6.25% smaller than OE PPV/7B3
free length - ~13.25"
8.5 turns, including pigtail

Pedders AU identifies the above springs as fitting both VE & WM, and 2954/2955 fitting both VE & VF, with different PN's for "mid level" springs for VF - catalog does not address WN Caprice.

View of lowered Caprice with 2954/2955 springs

I did some "calculating", based on the info provided in the Pedders website regarding springs, and came up with this (for my PPV):

Front drop with Pedders 2956 spring on PPV - 1.3"

Rear drop with Pedders 2957 spring on PPV - 0.7"

Additional comments on Pedders springs

Pedders springs are smaller wire diameter than OE PPV springs = lower rate. Pedders springs have more coil turns, which translates to "softer", although the progressive winding design means the coils that are closely spaced, when installed & loaded, will close up into a solid "stack", and the actual working section of the spring is fewer turns, which, for a given wire size, translates to being stiffer--it becomes a shorter linear spring (less working wire length in free coil for same or similar wire diameter = stiffer/higher rate). The working height of the spring at load will be shorter, thus lowering the car. This is much more noticeable on the Pedders rear spring, although the Pedders front spring also has a slightly closer (progressive) spacing of the first couple of turns at the top. (somewhere I have pictures)

My issue is that the car (my PPV in this case) is already "raked" too much visually (front lower than rear), and if my calcs are correct, this spring combination would lower the car noticeably, but the front drop being greater than the rear, the raked appearance would actually increase, the opposite of what I am looking for.

Sorry to bounce from bars to springs....but they're all related, at least.
 
Discussion starter · #29 · (Edited)
I don't agree with your assessment of the 2015 rear bar being a direct acting bar and the 2014 isn't. The differences between the 2014 and the 2015 rear bar, is the location of the end link, all things being equal. Loosely defined, a Direct Acting (DA) sway bar is one that directly follows the wheel movement, so technically, it could be mounted to the LCA or the UCA, since they both move in the same motion as the wheel moves. Therefore, the 2014 and 2015 rear bars are both DA bars, because both attach to the LCA, only in different locations.

Although I have had a hard time finding an exact definition, all references to Direct Acting sway bar refer to the front suspension, and the end link attaching directly to the strut, no such reference to a DA bar could be found for the rear, even in GM publications that referred to the front as such, no mention to the rear as the same, only that they had a rear bar, and that includes the Camaro. So I am led to believe that the term DA isn't used to describe the rear bar.

If you have a location for the definition I would appreciate it, I'm always learning.
You've probably looked at THIS already....it doesn't really resolve the question.

By your assessment parameters, I would not conclude either 2014 or 2015 rear bar could be considered direct-acting designs.

While it might be more accepted IF the rear bar was attached to the the strut, the practical reality is that the point of attachment of the rear bar to the LCA for 2015 is VERY near to identical to the actual motion - ie. movement distance - of the strut and end of bar are the same, whereas the 2014 bar works through a lever from the point of where forces are applied (the length/distance being from the link attachment point on the LCA out to the lower ball joint or center of the strut "in plane").

From this, I do consider the 2015 bar to be direct acting--or very close to it--but not the 2014 bar. Not sure whether the debate is more about who wins the argument or that we understand what the effects of each variant are, and what effect was intended by the change. I hope it's the latter.
 
Discussion starter · #34 ·
I would agree with that, and concede that the location of the 2015 is the more preferred location, but both ways are acceptable with the solution to be a larger bar in the 2014s location, or shorter arms.

Formula for Sway Bar Resistance from Fred Puhn's book 'How To Make A Car Handle' it's an old book

NOW we're getting serious....

In relation to the 2014 Vs 2015, I think #4 is very important to the discussion.

From the former Circle Track mag.

1. The length of the portion of the bar that will twist with chassis roll affects its rate.

2. The outer diameter of the bar affects its rate. The larger, the stiffer it will be.

3. Hollow bars are less stiff than solid bars and the wall thickness affects the rate.

4. The arm length affects the rate, the longer the arm, the softer the bar rate.

5. The material the arm is made of ultimately affects the rate if it is too soft and bends.

6 The material the bar is made of, or the hardness of the steel, affects the rate. There is a modulus of elasticity for each type of steel that depends on the mixture of metals and the hardening process used in the manufacturing process.

7. The installation ratio affects how the bar rate is translated to the wheel rate.

:)
I kept thinking that I should go dig out Fred's book rather than "wing it"....it's a very useful item.

Yes, #4 (and #7) is the key to what we're discussing, I think. The interesting thing will be to discover the size and config (hollow or solid) to compare it to the bar on 1LE. That's a pretty stout bar, so I'd also be curious what the rear spring characteristics are on Camaros. As previously mentioned, in the Z/28, there was intentional mention that springs are stiffer and bars are smaller (I assume relative to other Camaro chassis specs).
 
Discussion starter · #36 · (Edited)
Shocks are included in the kit, too....

Camaro 1LE Track Pack is fully SCCA-
approved and offers the same suspension
components found in the production 1LE
performance package
. Contents include
a larger, 27-mm solid front stabilizer bar
and 28-mm solid rear stabilizer bar
for
improved body control, as well as ZL1
toe links and rear shock mounts for
improved on-track performance.

Camaro 1LE Track Pack - Street
Upgrade your V-6 or SS Camaro’s suspension with the same parts used in the 1LE Trak-Pak. This kit features a stiffer 27mm solid front stabilizer bar and a 28mm solid rear stabilizer bar for improved body control in cornering.

The front struts were redesigned with improved damping curves for more body control and quicker response times. It also includes new faster reacting rear monotube shocks to replace the V6 and SS twin tube design and combines them with a stiffer rear upper shock mount to increase vehicle agility, both are shared with the ZL1. The bushings in the rear toe link are replaced with spherical bushings to eliminate compliance in cornering, which is also common with the ZL1.

The V-6 kit also includes the stiffer front springs used on the 1LE and SS variants.

NOTE: The V-6 1LE suspension kit requires use of SS Brake kit #’s 23120542 and 23120543 for proper rear stabilizer bar clearance (not included).

23123397 V-8 system includes:
Part Number Description QTY
11516078 Nut-FRT STAB HYD SHF Link 2
22942442 Emblem-F/End UPR Tie Bar 1
23123399 Installation - ACSRY 1
11569638 Nut-FRT SUSP Strut MT 2
11516078 Nut-RR S/ABS (UPR) 2
22845487 Link ASM-RR SUSP ADJ 2
23115372 Absorber ASM-RR SHK 2
22922445 Mount ASM-RR S/ABS UPR 1
22922446 Mount ASM-RR S/ABS UPR 1
22761221 Link ASM-RR S/ABS UPR 2
22786260 Shaft ASM-RR STAB 1
22812942 Shaft ASM-FRT STAB 1
22812984 Strut ASM-FRT SUSP 1
22812985 Strut ASM-FRT SUSP 1

23123398 V-6 system includes:
Part Number Description QTY
92245257 Spring-FRT 2
23123400 Installation - ACSRY 1
11516078 Nut-FRT STAB HYD SHF Link 2
22942442 Emblem-F/End Upper Tie Bar 1
23123399 Installation ACSRY 1
11569638 Nut-FRT SUSP Strut MT 2
11516078 Nut-RR S/ABS (UPR) 2
22845487 Link ASM-RR SUSP ADJ 2
23115372 Absorber ASM-RR SHK 2
22922445 Mount ASM-RR S/ABS UPR 1
22922446 Mount ASM-RR S/ABS UPR 1
22761221 Link ASM-RR STAB SHF 2
22786260 Shaft ASM-RR STAB 1
22812942 Shaft ASM-FRT STAB 1
22812984 Strut ASM-FRT SUSP 1
22812985 Strut ASM-FRT SUSP 1
 
Discussion starter · #38 · (Edited)
for the benefit of others viewing the thread, it was my response to the "basically just added bigger bars" comment :wink:

I will say that the changes in SS from 2014 to 2015 do reflect to some extent what has been learned/applied on ZL1 & 1LE Camaro programs, so it's nice to see the engineers get a win for a change....and it makes you wonder what they'd do if given free rein to go after Hellcat.
 
Discussion starter · #40 ·
No, springs are not the main thrust of the thread, but it is helpful to understand the relationship between springs, bars, damping forces, etc.

There was at one time a trade association, AAMA (American Automobile Manufacturers Association), that published vehicle specifications (MMVS - Manufacturers Motor Vehicle Specifications). That group closed up shop in 1999, and the group that it morphed to (AAM - Alliance of Automobile Manufacturers) does not seem to provide the same service.

Point being, the MMVS provided detailed data, right down to spring rates on specific models--both spring rate & wheel rate. View examples at this link:

https://www.gmheritagecenter.com/gm-heritage-archive/vehicle-information-kits.html

Try 1996 Chevy Impala - opens a PDF with 58 pages of information - scroll to page 16 to see the MMVS portion of the data.

Spring data is on page 28 of 58, or page 11 of the MMVS section of the report.

There is probably some sort of data base that exists today that would contain that type of information for current vehicles, but good luck finding where it may reside....anyone have an idea?
 
Discussion starter · #42 ·
I do have a list of Holden chassis springs, courtesy of CP, but have not compared them to anything spec'd for Chevy SS, other than the 2014 springs (92290028 & 92290030) for Chevy are known to be common with at least one version of Holden Commodore (SS or SS-V). Need to have a look, as I recall HSV springs were in the list....

The rear bar PN has been posted, so it will be easy enough to see if it's used on the HSV cars (with F55/MRC) that go down the assembly line...we just can't look up that info here in NA.
 
Discussion starter · #45 ·
yes, there should be options for 2014 SS, but "for now" it's not clear there is anything that will work on the 2015 SS--look up 2013-2015 Camaro to see if there are rear bar options similar to 1LE configuration if you're thinking of going that route. I don't believe the BMR lower arms have the 2015 link configuration built into them.

Have a conversation with BMR and tell us what you find out.....
 
Discussion starter · #47 · (Edited)
...did anyone look up the '15 end link part number to see where else this part is used?
I did look--it is the same part used here - 22761221.

As to the 2015 SS springs, I only have the rear PN at the moment--92261935

The spring is listed as used in 2014 & 2015, but shows no use in NA for 2014 (92290028 on SS)--it IS listed in the Holden list from CP, for 2014 models.

92290028 for Holden shows one application, at least from the data I have:
FR1 Country Pack (heavy duty, increased ground clearance)

It gets interesting from here....this spring (92261935) was fitted to Holden Commodore (SWB) as follows--various combinations of engine & suspension specs, including police use:

EK69 - SV6 etc. (26mm rear bar?) - someone reported VF SV6 used 26mm
EP69 - SS-V (larger rear bar--28mm as in Chevy SS?)
EX69 - Calais

LFW 3.0 V6
LFX 3.6 V6
L77 6.0 V8

FE1
FE2

9C1
9C3

So, I am thinking that if the spring identified above is used on these models--especially Calais, as the upscale "luxury" (softer ride) model Holden SWB variant, the combination of the larger rear bar known to be used on 2015 SS with F55 (MRC), thus classifies the suspension as FE3--and, considering it's use on Calais, it is likely "less harsh" compared to 92290028. This may tend to provide credence to the report of the 2015 SS having a more comfortable ride in MRC Touring mode, compared to 2014 SS.

I've ordered one to compare to 92290028--there is inventory in Lansing.