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Discussion Starter #1
I just completed installing the 1LE-style "wide" sway bar that is production on later 5thGen Camaros and the 15-17 SS sedan. The SS sedan version of this bar is designed specifically to clear the spare tire well, unlike the Camaro version.

It requires the use of either the 1LE Camaro rear lower control arms (a kit from Chevrolet Performance--inexpensive) or SS sedan lower arms, as well as conversion to Brembo rear brakes. Some aftermarket lower control arms are now available to work with this sway bar configuration.

It also requires the addition of brackets that are welded to the existing rear bar mounting pads (on crossmember/cradle), as some others have shown in other threads.

The bar is ~25mm diameter, which may not seem very large, but it provides the equivalent roll resistance of the 28mm rear bar used on the 2014 SS sedan, with less harshness and without the potential link failure problems.

The stock 11-13 PPV has a 24mm front/16mm rear bar combination. 14-17 PPV uses a 26mm front/20mm rear (from GXP). G8 GT rear was 18mm, GXP rear was 20mm--not sure of G8 front bar size.

The availability of the SS rear bar (from GM) is not currently clear--but it is identified by a PN as a kit, which includes bushings/insulators and possibly clamps.

Since PPV & G8 used the same basic cradle and sway bar clamp system (single-bolt with tab), this is something that will work for G8.

Below is a link to the thread that provides plenty of detail and pictures--no member access is required.

New Caprice - Discussion forums ? View topic - installing 2015-2017 SS rear sway bar on the PPV

I'll be happy to respond to any questions anyone may have.
 

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Good stuff!

GT and GXP used the same front bar.
 

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Discussion Starter #3
Thanks--just another option to put into the mix.

I was pretty sure the only difference in bars was the GXP had its own unique rear bar (20mm, now common with 14-17 PPV), but I'm still not clear on the size of the front bar on G8--is it 22mm?
 

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Front stock bar is 23mm. Part numbers Please. and a link for those plates too. An easy and clean weld on job. And if you really had to go back the stock bar, aftermarket brackets can replace the GM ones for a smaller bar.
 

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Discussion Starter #5
Parts List

as requested

1LE & Z/28 service modification kit (2 lower control arms) 23484878 or 2015-2017 SS sedan lower control arms or even 2012-2015 Camaro SS lower control arms (same PN as supplied in service kit)
NOTE: this kit MAY affect sedan ride height, slightly raising rear

rear bar (kit) 92457770 - new part number, in release process, not currently available - includes bushings, not sure about clamps (will update when inventory is available)
NOTE: this bar requires Brembo rear conversion for clearance between bar/ink & caliper, as mentioned previously

GM PN's I used:

Bar - 92294343 (discontinued part--purchased several years ago)

Bushings - 22904643 (discontinued part--purchased several years ago)

Bushing saddle clamps (2) - 22831250

Link assembly (2) - 22761221

Lower saddle clamp bolts (2) - 11588737 or equivalent

Original top (smaller) saddle clamp bolts are re-used.

fabricated brackets - my design, locally produced, not on the web except in G8 & PPV Forum threads. Brackets include a nut welded to plate for larger bolt in lower position.

If anyone is interested in having a pair of these brackets, just PM or e-mail me.

The other option to doing this "wide" rear bar installation includes the 2014 SS 28mm bar, which will still require adding stronger brackets with 2 bolts per saddle clamp. I'm not sure what else is out there in the aftermarket other than several 22mm options, or a number of Gen5 Camaro bars, which are not made to fit the sedan without tire well clearance issues.
 

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This is Great, PM sent.
 

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Discussion Starter #7
rear bar (kit) 92457770 - new part number, in release process, not currently available - includes bushings, not sure about clamps (will update when inventory is available)
NOTE: this bar requires Brembo rear conversion for clearance between bar/ink & caliper, as mentioned previously
(above from post #5)

Lookup at GM Parts Direct now prices--still have not confirmed stock on hand status.

Fabricated brackets now available to mount this rear bar to the G8 cradle/crossmember, welding required, along with rear lower control arm swap. PM or e-mail me for details on brackets.
 

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Discussion Starter #8
SS rear bar is available

Confirmed inventory on hand at GM for both 2014 SS rear bar (28mm) and 2015-2017 SS bar (25mm). The 28mm bar has the same contour as production G8 bars. The 25mm bar is wider, same as found on 2015-2017 SS sedan. Both have the proper offset/kickout between the cradle bushings to clear the spare tire well.

The 2014 bar puts more load on the links and lower control arm link attachment brackets--using all 2014 SS parts takes care of this. The 2015-2017 bar, even though smaller, offers as much roll resistance as the 2014 configuration, provides better link durability and reduced harshness.

Both configurations require the bracket modification (or similar) described earlier in this thread to mount the bar to the cradle/crossmember.

using 2014 bar: (requires aftermarket links, or change to 2014 SS lower control arms & 2014 links)


Parts Illustration (items 1, 3, 4) add items 2, 6, 7 if using 2014 SS control arms
NOTES:
1. For 2014 "narrow" bar, individual parts must be purchased.
2. Bushings & clamps from aftermarket may be substituted--typical clamps are slotted, allowing some adjustment vertically.
Example: energysuspension.com | Sway Bar Bushings (PN 9.5163 - 28mm, with lube fitting)
3. Suggested control arm & link mods to use stock G8 lower control arms (BMR):
ELK006 End Links
ELK009 Brace

using 2015-2017 bar: (requires 2015-2017 SS or Camaro upgrade lower control arms & Brembo rear conversion) Some aftermarket lower control arms are now upgraded for the later sway bar link design.

Bar 92457770
Link 22761221 (2 required)
NOTE: The 2015-2017 bar is sold as a kit (bar, bushings & clamps), and only links need to be added (other than changes required to use this "wide" bar configuration).

This mod applies to any 2008-2009 G8.
.
 

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The reason the 2015-2017 sway bar is thinner that the 2014 is because those models have the Magnetic Ride suspension.

Magnetic suspension has the ability to replicate the function of a sway bar somewhat so the engineers decided a thinner bar was all that was needed.
 

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Discussion Starter #10
Steve, I won't deny/argue that there's a potential impact with MRC being in the mix, however I have to offer some further thoughts on bar size.

The difference in lever "ratio" of the 2 bar configurations produce different dynamic responses.

The 2014 SS rear bar (28mm) is shaped the same as the G8 rear bars (18 or 20mm). The attachment point on the lower control arm is about mid-point between the inner & outer bushings/pivot points of the arm.

The 2015 - 2017 SS rear bar (25mm) is smaller because it will develop equal roll resistance as the 2014 bar, since it's connection point is very near the outer end of the lower control arm pivot point--if the newer bar configuration had been maintained at 28mm diameter, the bias in front vs rear roll rate would skew rearward with no other compensating changes.

The bigger problem with the original Zeta bar design was the issue of link failure or even clamp failure (for the shaft bushings) when increasing bar size, using higher spring rates, or altering ride height without improving the stock bar connection points or adjusting the bar position vertically.

The 2014 SS used unique lower control arms and much more robust links, as well as a double-bolted saddle clamp on the crossmember/cradle.

The later SS bar is derived from the design that originated with the Camaro 1LE program and became standard for Camaro in 2012 or 2013. Among other things, since the Camaro SS came with Brembo calipers in production, the bar design pushed the limits such that the 15-17 sedan bar required the Brembo (fixed) calipers. The G8 and 2014 SS have the same floating rear calipers, which move inboard with pad wear, so the new bar config necessitated the brake change as a clearance issue.

The change to a straight link from the bar to the outer end of the control arm was the final improvement, combined with the beefier bushing clamps to make for a much more robust design compared to the previous sedan bars.

There are several aftermarket lower control arms that have added the provision for the 2015-2017 bar, FWIW.

As far as the 1LE bar design, remember that it was first used on cars without MRC, so I tend to discount the connection with regard to the bar sizing difference, when the motion ratio differences of the 2 configurations are understood.

BMR does offer a 32mm tubular 1LE-style rear bar for Camaro--it is not direct fit to the sedan since it lacks a clearance "kickout" for the spare tire well. A bar of this size would be oriented toward track use, as in a street situation the behavior would be biased significantly toward oversteer. I did ask [email protected] whether there might be a sedan version in the works...."being considered", and if this interests anyone here, contact BMR with your input.
 

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I'm still planning the 2014 SS rear sway bar and cradle swap come spring. Will be fun!
 

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A better answer for Steve on the rear sway bar. It is all about leverage. The wider bar is more effective attaching to the outer portion of the lower control arm. The force applied to the control arm by the suspension is the constant. the closer to the pivot point you move the sway bar link , the greater force required to resist the suspension movement. The 2015 wide bar is likely 80 to 100% more effective than the 2014 bar. Think like taking wheel nuts off with a 12" breaker bar or a 24" breaker bar. It takes the same torque to remove the nut, it is just way easier to create it with the longer (wider) bar. There use to be a great chart from Pafdt showing the effective rates of the Camaro FE2 to FE5 Sway bars. the wide bar was a similar diameter to the earlier narrow ones but was 200% more effective.
 

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That sounds great but is incorrect. Leverage plays no part in the equation because both sides are identical and cancel each other out.

A sway bar (or more correctly an anti-roll bar) is designed to try and force the two sides of the car to maintain similar road heights. (Prevent body roll)

It does that via a torsion bar (read spring) that connects the suspension from both sides together.

By the very nature of the setup, the leverage at both sides of the bar is identical and thus whatever force is applied at one side of the bar is replicated to the other side.

The only important factor is stiffness of the torsion bar. That is dependant on several factors including steel type, thickness, whether it's hollow, bushings, etc.

A better answer for Steve on the rear sway bar. It is all about leverage. The wider bar is more effective attaching to the outer portion of the lower control arm. The force applied to the control arm by the suspension is the constant. the closer to the pivot point you move the sway bar link , the greater force required to resist the suspension movement. The 2015 wide bar is likely 80 to 100% more effective than the 2014 bar. Think like taking wheel nuts off with a 12" breaker bar or a 24" breaker bar. It takes the same torque to remove the nut, it is just way easier to create it with the longer (wider) bar. There use to be a great chart from Pafdt showing the effective rates of the Camaro FE2 to FE5 Sway bars. the wide bar was a similar diameter to the earlier narrow ones but was 200% more effective.
 

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Discussion Starter #15
I need to respond--I started this.

Leverage plays no part in the equation because both sides are identical and cancel each other out.

This would be accurate if all the car ever did was travel in a straight line. Otherwise, stabilizer bars are, in fact, all about leverage.

A sway bar (or more correctly an anti-roll bar) is designed to try and force the two sides of the car to maintain similar road heights. (Prevent body roll)

Also known as a stabilizer bar or shaft...it's purpose includes controlling weight transfer across the vehicle to the outside wheel(s) by increasing roll resistance on the outside--which is to keep the chassis as close to parallel to the road surface as possible, thereby minimizing camber change side-to-side and maintaining as much of the available tire contact patch (static setting vs dynamic conditions) as possible.

It does that via a torsion bar (read spring) that connects the suspension from both sides together.

By the very nature of the setup, the leverage at both sides of the bar is identical and thus whatever force is applied at one side of the bar is replicated to the other side.

When a (steering) wheel input forces the vehicle to change direction, the outside front wheel is loaded more heavily than the inside wheel - across the same axle. The outside suspension is compressed, storing energy in the spring at that corner. The inside suspension is unloaded, "releasing" energy. When a stabilizer bar is added, the force inputs on the bar, in the above scenario, create a twist on the shaft, with the outside half being pushed up as the suspension moves up--also storing energy. The opposite reaction is happening on the inside, so your last comment above isn't entirely accurate--total force doesn't change, but the force inputs on the bar are opposite, side vs side.

As any (street) vehicle typically is unable to remain perfectly flat when turning--with physics considered (mass, center of gravity, velocity vectors--just to name a few), the dynamic behavior, with or without a stabilizer bar involved--is going to be impacted by the dampening characteristics of the struts (for this discussion), built into the suspension. The point is, if the vehicle was never going to change direction, a stabilizer would not be needed.


The only importanty does not remain perfectl factor is stiffness of the torsion bar. That is dependant on several factors including steel type, thickness, whether it's hollow, bushings, etc.

In your previous post, you stated the 15-17 SS rear bar was smaller because of MRC's impact. As Andrew pointed out, the bar design (lever length/pivot points vs material diameter) is not the same between the two configurations, such that smaller bar diameter does not presumptively translate to reduced roll resistance (as compensation for MRC's magic capabilities) .

Finally, by your original reasoning as to MRC's impact, we should have seen a reduction in the front stabilizer diameter, yet the same part (26mm) is found on all years of SS, and is even on the WN Caprice PPV, with no MRC and a much smaller rear stabilizer compared to the SS.

My interest here is to ensure that erroneous information and/or resultant assumptions are NOT accepted as equal/alternate facts.
 

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Also to add, I wasn't clear as to the leverage issue. The leverage that makes the difference is in the Control Arm. The control arm is the lever. Attach the anti-roll bar at the outer end of the control arm and the forces are close to equal with suspension movement and anti-roll bar forces. Move to the inner G8 anti-roll bar mount and the control arm is now the lever and multiplies the force applied to the inner bar mount. This is all basic suspension geometry. MRC just is clouding the issues. Camaros use the wide bar without the MRC too
 
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Just pulled the trigger on the rear sway bar and all the accompanying parts. Will be a spring install when the snows come off and I can have the New brackets welded on.
 

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Discussion Starter #19
I know it's a fairly big job, but I think you'll find the results worth it. Nice that the Zeta platform development continued after G8 production ended and that updates like this are possible!
 

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Discussion Starter #20
additional sway bar options - SuperPro

some additional info/clarification based on an earlier post I made:

Front 30mm, adjustable w/ adjustable links - listed at US website
SuperPro rc0001fhz-30kit Front Sway Bar and Endlinks - 30mm - Heavy Duty - 2 Point Adjustable. SuperPro rc0001fhz-30kit

Listed on SuperPro Australia website:
Rear wide version (as on 2015-2017 SS) - 27mm, adjustable
https://superpro.com.au/find/roll-control-sway-bar-for-a-superpro-suspension-parts-and-poly-bushings-for-holden-commodore-vf-sedan-wagon-ute-2013-on-/productnr-RC0087RZ-27/cid-999501248/vid-

Front/rear combined kit 30mm/27mm, adjustable
https://superpro.com.au/find/roll-control-performance-sway-bar-upgrade-kit-for-a-superpro-suspension-parts-and-poly-bushings-for-holden-commodore-vf-sedan-wagon-ute-2013-on-/productnr-RCCOM087KIT/cid-999501248/vid-

Front 30mm bar only - adjustable
https://superpro.com.au/find/roll-control-sway-bar-for-a-superpro-suspension-parts-and-poly-bushings-for-chevrolet-ss-ek69-01-2014-on-/productnr-RC0001FHZ-30/cid-999501498/vid-

Front 30mm bar, with adjustable links
https://superpro.com.au/find/roll-control-sway-bar-for-a-superpro-suspension-parts-and-poly-bushings-for-chevrolet-ss-ek69-01-2014-on-/productnr-RC0001FHZ-30KIT/cid-999501498/vid-

Waiting for response from both AU and US SuperPro regarding availability of above rear bar in US.

SuperPro lists only 22mm rear for early-style (pre-VF) bar (inboard links). Best bang for the buck with inboard link setup is use of 2014 SS rear bar, which is 28mm, and was unique to that year. For G8 with standard rear brakes, this is the bar to use--otherwise the wide bar will require conversion to Brembo rear brakes. It does require the cradle bracket modification to use any of the larger bars--the 22mm bars from SP and other sources will mount on the standard G8 cradle/crossmember mounts, but that mount is not a very robust design.

Don't assume that the 30mm front bar is something that's necessary--the G8 stock front bar is 23mm. PPV, as WM - 2011 to 2013, was 24mm, and WN - 2014 to 2017, was 26mm, and all SS models also used 26mm. There are 26mm adjustable front bars, and 29mm, but going from 23mm to 30mm is a big shift in chassis balance, and could make the car too "tight" (in NASCAR vernacular) - in other words, understeer. It really depends on what you do at the back. A 24 or 26 front OE bar with the OE 28 (narrow mount) or OE 25 (wide mount) bar is a good place to start--and the 27mm rear above would be the next move I would make before going to the 30mm front--that's my last move, if it ever comes to that.
 
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