Front Suspension
A pictorial of suspension components, courtesy of Rob at Wretched Motorsports from this thread: http://www.grrrr8.net/Forums/showthread.php?t=34020
The FRONT of the car is to the RIGHT
From top to bottom in the picture: Remember, the FRONT of the car is to the RIGHT:
Front Strut Mount
Strut mounts generally are available in two flavors, rubber & polyurethane (Poly). Debating which is 'better' is often a matter of personal preference. Some people notice an increase in Noise, Vibration, and Harshness (NVH) with Poly mounts, and others don't. Some people are fine with replacing stock or aftermarket rubber mounts as a part of preventative maintenance.
Note: Strut Mount impact on ride height: Your ride height is directly influenced by the strut mount. A collapsed stock mount will cause the car to sit lower, and conversely, a fresh mount will cause the car to sit higher. A poly mount will also compress less than a new rubber mount, which might result in the car sitting slightly higher than if it had a rubber mount. Keep this in mind when reviewing advertised heights of springs & coilovers because you don't know what mount was used, and in what condition the mount was, when the supplier made their ride height measurements.
Front Strut Mount Bearing
The strut mount bearings aren't usually parts that fail in any unusual amount of time. The reason that many people buy new ones is simply a matter of insurance. If you are replacing the strut mount, then you also have to remove the strut mount bearing. The problem is the stock bearing tends to fall apart as you remove it once there is no more pressure holding it together. Then, little ball bearings then fly all over your garage. At that point, you have to either go to the dealership and pay a markup, or order a new bearing online and wait a few days all while your car waits. Since you're not going to see any performance gains from aftermarket bearings, replacing with stock is certainly acceptable.
Manufacturer
w/link
|
Price per pair
w/link |
Comment |
|---|
| Stock |
$70-$80 |
|
|---|
| Pedders 5030 |
$86 |
|
|---|
| BMR BK025 |
$89 |
|
|---|
Front Springs & Struts
Springs generally come in 3 flavors: Lowering, Stock Height, and Lift. Keep in mind that lowering springs are usually stiffer, which can impact your ride quality. Springs are also either Linear or Progressive. Linear springs have the same spacing between the coils, and progressive springs have different spacing. Progressive springs are generally more appropriate for the street because they provide a slightly softer ride over smaller bumps and have increasing stiffness the further they are compressed. Linear springs are generally more appropriate for the race track due to their predictability since their stiffness is supposed to be the same everywhere. Note that stock FE3 springs are progressive.
You can mix & match springs & struts/shocks to your heart's content. Search & ask around on how different setups feel.
Regarding the ride height, don't forget to read this note "Strut Mount impact on ride height" above.
Regarding Spring Rates
- To convert Lbs/In to Kg/mm, DIVIDE by 55.997348
- To convert Kg/mm to Lbs/in, MULTIPLY by 55.997348
Front Springs
If you buy lowering springs, it's a good idea to also replace your struts. The lower the drop with the stock dampers, the more difficult it is for them to do their job. You might notice a slightly harsher ride, and/or the lifespan of the struts may be reduced. However, some people have used lowering springs on their stock struts and been fine with it. YMMV.
Note that this table contains both Fronts only and Front & Rear kits
Front Struts
Thx to user '00 Trans Ram' for this info:
For a little background on struts/shocks, jump down to the Coilover section. Much of what is written there applies to struts & shocks in this section. A special note on adjustable shocks (non-coilovers): Some shocks feature an adjustable rebound, while compression remains somewhat static. Why is this good? Most often on a street car, compression is significant when hitting a bump. This rapidly compresses the shock. Typically, you want this setting to be somewhat soft to absorb road bumps, cracks, etc. Rebound, on the other hand, is typically used to control body movement. As the car leans to the outside of a turn, it tries to raise the inside wheels. If the shock is set too soft, it will allow the wheels and the body to separate (the shock will extend) and the body will roll quicker. If the shock is set firmer, it resists this movement, and tries to keep the body near the wheels, which reduces body roll.
Manufacturer
w/link |
Adjustable or
Special Valving? |
Warranty |
Rebuildable? |
Price
w/link |
Comment |
|---|
| GM FE3 92217535 Left |
No |
|
? |
$110 per strut
$335 4-piece kit |
|
|---|
| GM FE3 92217536 Right |
No |
|
? |
$110 per strut
$335 4-piece kit |
|
|---|
| Pedders GSR, 9464LR |
No |
24 Months or 36k mi |
? |
$438 per pair |
|
|---|
| Lovells 7471005 |
Multi-staged valving |
3 yr 36,000 mi |
? |
$459 per pair |
|
|---|
Koni
8641 1506SPORT |
Fixed Compression
Adjustable rebound |
Limited lifetime |
Yes. Custom valving and other modifications are available at Koni Service Centers. For ex, TrueChoice Racing Services will charge $385 per shock to change the rears to be externally adjustable via a knob on top and $635 per rear shock to convert to double adjustable. |
$146 per shock |
Similar to Bilstein, this is a shock, not a strut. The OEM strut housing needs to modified by drilling a hole in the bottom and cutting the top. Remember you can always buy a used set of FE2 or FE3 front struts to modify if you don't want to use your own. Koni modification instructions. Also note that it may also be possible to fit a Koni 8611 insert in the front, which is a double-adjustable shock. Talk to a Koni Service center. Sample Shock Dyno |
|---|
Monroe GT Sport
35-0579 & 35-0580 |
Multi-staged valving |
3 yr 36,000 mi |
? |
$729 4-piece kit(shipped) |
Note that JHP USA may have limited stock |
|---|
Koni FSD 2100-4074 |
Frequency Selective Damping |
Limited lifetime |
No |
$850 AUD (~$767 USD) for all 4 |
Little usage in the states. Other makes & models (incl Commodore VE) usually have very good reviews of this product. It's OEM on the Gallardo. These appear to be slightly more street oriented (i.e. softer) compared to the Koni Sports. Sample shock dyno |
|---|
Bilstein B8 series
F4-PE3-H509-M0 |
No |
Bilstein US: Limited Lifetime
See Comments |
Yes |
$700 AUD per pair ($630 USD), GSL Rallysport in Australia |
These are shocks/inserts, not struts. To make them work, a collar needs to be welded on to the shock. Remember you can always buy a used set of FE2 or FE3 front struts to modify if you don't want to use your own. There is little documented usage in the States - only 3 forum members on TOB (TheStevo, Vz28, JonRobbinSS). Regarding warranty: if you source these from overseas, verify the warranty w/the dealer. |
|---|
Spring & Strut/shock combo kits
These can be a great option if you don't need the fine adjustment in ride-height that a coilover can provide. In some cases, you can find a higher quality and/or higher performing strut & spring combo versus an entry level coilover.
Manufacturer
w/link |
Amount of Drop
(inches) |
Linear, Progressive |
Spring Rate
(F/R) |
Special valving |
Price
w/link |
Comment |
|---|
King Springs &
Bilstein struts/shocks |
varies |
Progressive |
varies |
TBD |
$1588 AUD ($1431 USD), GSL Rallysport |
Includes the collar (not welded) |
|---|
King Springs &
Monroe GT Sport struts/shocks |
varies |
Progressive |
varies |
Multi-staged valving |
$1097 or $1127 USD (shipped)
$720 AUD ($641 USD) |
|
|---|
H&R Springs &
Bilstein struts/shocks |
varies |
Progressive |
varies |
TBD |
$1395 AUD ($1242 USD) |
Includes collar (not sure if the seller welds it on or not) |
|---|
Coilovers (Front & Rear)
Thx to user '00 Trans Ram' for much of this info:
Basic Information:
The following applies to both struts & coilovers. It's absolutely worth a read of this
article on Buying Shocks from Far North Racing's website as well as
this article on reading a Shock Dyno. The buying guide has some fascinating details on how 'adjustable' doesn't always mean adjustable, and how some adjustment ranges are actually much smaller than the 30+ clicks you might think are available. Reading a shock dyno isn't difficult and is really the only quantifiable way we have of comparing shocks, which is actually great news b/c how many times have you read "it's too harsh" and "it's firm but not harsh" in two different reviews of the same coilover/shock. Sadly however, many companies don't publicly advertise their shock dynos, so sometimes you have to ask for it. Some will give it to you and others won't. I fail to understand companies who won't; it's possible for any buyer/owner to take a shock to a 3rd party to have it dyno'd for $50-ish per shock? Shock dynos aren't proprietary, so what's the big deal? Be VERY wary of purchasing from a company that doesn't publish their dyno curve. It's akin to buying an engine without a dyno graph or a camshaft without specs. For a little more discussion on shock dyno's, see this thread:
http://www.grrrr8.net/Forums/showthread.php?t=23209
All coilovers will provide a threaded method to allow you adjust the ride height where you want it, which gives you more ride height adjustment options than just a lowering spring does. There is a slight difference in how the ride heigh adjustments are made. Ideally, ride height adjustment should not affect spring compression, which is also called spring pre-load. When a coilover uses the spring perch to set the ride height, it is also changing the pre-load on the spring because the spring is either being compressed or relaxed as the perch moves up and down on the threaded damper body. This isn't ideal because with a more compressed spring the harsher the ride will be - especially if you're using a progressive spring because you're effectively using up the 'soft' portion of the progressive spring when you compress it with the perch. With the coilovers from Pedders, BC Racing, & Megan Racing, ride height adjustment is separate from spring pre-load. It is important that, if your coilovers have independent ride height & spring pre-load adjustment, that you DO NOT use the spring perch to set the ride height. This will kill your ride quality and will dramatically decrease the life of your damper.
Several coilovers feature adjustability that simultaneously stiffens both compression and rebound. This can be a great thing for a racecar, when they are racing on very smooth surfaces. While in a turn, the resistance to rebound on the inside shock and resistance to compression on the outside shock both help eliminate body roll. However, on the street, the most noticeable effect of "firming up the shock" is a harsh ride over bumps (compression). While a driver may be willing to compromise a rougher ride with perceived greater performance in the corners, too much compression resistance will actually reduce cornering grip. This happens when the tire encounters bumps in the corner and is not allowed to move quickly enough (too much resistance). It ends up bouncing or skipping over the bumps. If the tire is not on the concrete, you are losing traction. Again, refer to a shock dyno to see how much compression & rebound adjustment actually exists...you may be surprised that in a single-adjustable coilover, there really isn't a wide range for compression adjustment.
Another common question that comes up is "what is the difference between a 30-way adjustable shock and one that has 2.5 turns on the knob?". That is an exceedingly technical question to answer. If you want an answer, research "disc deflection", "Monroe valves" and some related terms. Additionally, one is not better than the other. The easiest way to figure out the differences are to look at the dyno curves of the shocks.
Reliability
It also seems like all the coilovers listed here have had a small percent fail/leak before you'd think they should (e.g. less than 20k miles). Let's face it, dealing with a 4k lb car is hard work for the damper. Part of this could be related to early designs that used softer springs, which increased damper strain, but issues seem to persist even on kits using the higher spring rates. Simply put, you should be prepared for potential rebuilds of these kits.
Upgrading coilover springs to Swift Springs:
Swift Springs is one of the better spring suppliers out there and it's sometimes possible to swap out the coilover spring to a Swift Spring. Many people have found that Swift springs produce a more comfortable ride even with the same spring rate & size as the spring that came with the coilover. The Swift spring accomplishes this by having a wider spacing/less coils, which makes them
lighter with a longer stroke. However, due to the design of the rear suspension on the G8, there are no Swift springs available for the rear. They are only available for the front. Some retailers will let you upgrade to Swift springs if you buy the coilovers from them. Otherwise, you'll have to find someone else to source the Swift spring. To source your own Swift spring, you'll need to know the specs of the coilover's spring, the inner diameter, the total length, and the spring rate. This should be stamped on the spring, for example: 62 180 008, which means 62mm ID, 180mm long, 8kg rate. To find a supplier, just search for "custom Swift Spring" and take your pick.
Manufacturer
w/link |
Adj Ride Height? |
Adj Compression/Rebound |
Warranty |
Spring Rate
(F/R in kg/mm) |
Price
w/link |
Comment |
|---|
Megan Racing
MR-CDK-PG808 |
Yes, independent of spring perch |
Yes, C/R adjusted together |
1 year |
7/12 |
$873 |
Limited usage in the States. |
|---|
BC Racing ZB03
(BR Series) |
Yes, independent of spring perch |
Yes, C/R adjusted together |
1 year |
7/12 |
$999
$1025 w/strut mount |
Front Springs are available (but not rear) from various sources, 65mm ID x 180mm long x 7kg. Other makes & models have found that Swift Springs improve ride quality dramatically. Sample shock dyno |
|---|
Tein DSJ28-LUSS2
aka Tein Basic |
Yes, via spring perch |
No |
12 Months or 12k mi |
7/9 |
~$1000 sources vary |
Possibly discontinued and replaced with Tein Sport. Isn't listed as a Pontiac application |
|---|
Tein RSF34-ZZSS2
aka Tein Sport |
Yes, via spring perch |
No |
12 Months or 12k mi |
7/9 |
$1400 AUD (~$1200 USD) |
For Commodore VE. Limited usage in the States. |
|---|
| Ksport CPT030-KP |
Yes, independent of spring perch |
Yes, C/R adjusted together |
18 month |
8.7/12.4 |
$1300
$1196 (shipped) |
|
|---|
| Pedders Extreme Xa 160064 |
Yes, independent of spring perch |
Yes, C/R adjusted together |
24 Months or 36k mi |
7/12 |
$1773 |
|
|---|
BC Racing ZB03
(ER Series) |
Yes, independent of spring perch |
Yes, C & R adjusted independently |
1 year |
9/12 |
$1165 GBP (~$1800 USD) |
Other makes & models have found that Swift Springs improve ride quality dramatically. Sample shock dyno |
|---|
| H&R GFW35620-1/1 |
Yes, via spring perch |
No |
Limited Lifetime
(unconfirmed) |
9/12 |
$2599 AUD MSRP
$1830 AUD (~$1630 USD) |
H&R Holden product list. I cannot locate warranty policies, but googling suggests that it's a limited lifetime warranty |
|---|
Tein QSF34-GZSS2
aka Tein Super Street 1 |
Yes, via spring perch |
Yes, C/R adjusted together |
24 Months or 24k mi |
7/9 |
$2200 AUD (~$2000 USD)
$2700 USD (shipped) from JHP |
Listed for Commodore VE. Some sellers call this 'double-adjustable' b/c both Front & Rear are adjustable (like most coilovers here). It's not double-adjustable in terms of the ability to adjust Compression & Rebound independently. JHP USA may have limited/no stock. |
|---|
Tein RSF34-TZSS2
aka Tein Monoflex |
Yes, independent of spring perch |
Yes, C/R adjusted together |
12 Months or 12k mi |
7/9 |
$3800 AUD (~$3500 USD) |
Listed for Commodore VE. Some sellers call this 'double-adjustable' b/c both Front & Rear are adjustable (like most coilovers here). It's not double-adjustable in terms of the ability to adjust Compression & Rebound independently. This is also compatible with Tein's EDFC system, requires:
- EDK04-K4469 (Controller)
- EDK05-12120 (Motor Kit)
- EDK06-K4474 (Opt'l Strut kit)
|
|---|
| Pedders Supercar Xa 164064 |
Yes, independent of spring perch |
Yes, C & R adjusted independently |
24 Months or 36k mi |
8/12 |
$4028 |
|
|---|
Front Sway Bar Endlinks
Endlink replacement is not generally required just because you might want to use a sway bar. It is certainly acceptable, to a degree, to use stock endlinks with an aftermarket sway bar. However, the stock endlinks are pretty small, just 3/8" in diameter, so they may bend & deflect with higher loading. Thicker ones are available, either non-adjustable or adjustable. Adjustable endlinks are useful for people who want to corner balance their cars and/or for people who want to dial in the behavior of their sway bar. If you don't know how you'd use the adjustable endlink, chances are that you don't need them.
Steering Rack Bushing
There is a single steering rack bushing on the G8. The stock bushing is rubber, and aftermarket replacements are Poly. The poly will prevent the steering rack from flexing during hard cornering, allowing a consistent toe angle, and steering should feel more crisp compared to the mushy stock bushing. The aftermarket options are inexpensive, and the bushing is easy to change. This is not really a *must-have* on any list. And, you're not likely to feel much difference unless you have also replaced the other front bushings. Point being, if you have to choose, do the Front LCA bushings before the steering rack bushing, or do them all together.
Front Lower Control Arms
There are TWO lower control arms in the front of the car, which confuses people. It's not like the rear suspension where there is an upper & lower control arm. No, in the front there is no upper control arm, and there are two lower control arms. One is placed more toward the front of the car, and the second one is placed more rearward. The Front LCA's have been a sore point in the G8 platform due to failing ball joints, which serviceable, and GM has made a few revisions to the Front LCA's over the years. Note the existence of TSB, 09-03-08-008: Knock Clunk Or Click Noise From Front Suspension Over Small Bumps. Upgrade options for the arms (not the bushings) are limited. If you're replacing the Front LCA's for any reason, you might as well also get replacement bushings too. You may be able to order the 4-arm kit from Pace Performance and have it shipped somewhere else like BMR, and they can swap the bushings for a small fee. Obviously, arrange this with the suppliers before ordering.
Front LCA (front)
In the picture above, this is labeled "Radius Arm (Forward)". This has many other names, for whatever reason. Here are a few: Outer LCA, Caster Arm, Radius Rod, dogleg arm, the Service Manual calls it "Front Lower Control Front Arm", and gmpartshouse calls it "lower control arm G8; Front". Suffice it to say, it's the big one up front and isn't straight.
Manufacturer
w/link
|
Price
w/link |
Comment |
|---|
| GM 92244046 (right) |
$160 for 1 |
Per this thread, these were GM's 1st attempt at fixing the ball joint issues in 2009. This is contained in the 4-arm kit below, 92249538. |
|---|
| GM 92244047 (left) |
$160 for 1 |
Per this thread, these were GM's 1st attempt at fixing the ball joint issues in 2009. This is contained in the 4-arm kit below, 92249538. |
|---|
| GM 92253412 (right) |
$160 for 1 |
Per this thread, these were released in 2011. There is no known 4-arm kit with this part. |
|---|
| GM 92253411 (left) |
$160 for 1 |
Per this thread, these were released in 2011. There is no known 4-arm kit with this part. |
|---|
| SuperPro TRC1001 |
$654 per pair, incl Poly bushings |
Can special order through BMR |
|---|
Front LCA (rear)
In the picture above, this is labeled "Control Arm (Rearward)". This one also has a few other names: Inner Rod, Inner Arm, Inner LCA, the Service Manual calls it "Front Lower Control Arm", which is totally useless, and gmpartshouse calls it "lower control arm G8; Rear". It is confusing when talking about the 'rear LCA' because sometimes people don't know if you're referring to the LCA at the Rear Suspension or the rearward LCA of the Front Suspension. This gets worse when you talk about the bushings...
Manufacturer
w/link
|
Price
w/link |
Comment |
|---|
| GM 92244050 (right) |
$104 for 1 |
Per this thread, these were GM's 1st attempt at fixing the ball joint issues in 2009. This is contained in the 4-arm kit below, 92249538. |
|---|
| GM 92244051 (left) |
$104 for 1
Check with Greg @ Pace |
Per this thread, these were GM's 1st attempt at fixing the ball joint issues in 2009. This is contained in the 4-arm kit below, 92249538. Currently, searching on Pace Performance for this part only returns a different part number, 92250641, which is the latest & greatest arm as seen below. |
|---|
| GM 92250640 (right) |
$116 for 1 |
Per this thread, these were released in 2011. There is no known 4-arm kit with this part. |
|---|
| GM 92250641 (left) |
$114 for 1 |
Per this thread, these were released in 2011. There is no known 4-arm kit with this part. |
|---|
| SuperPro TRC1000 |
$422, incl Poly bushings |
Can special order through BMR |
|---|
Front LCA kits (all 4 front LCA's)
Manufacturer
w/link
|
Price for 4 arms
w/link |
Comment |
|---|
| GM Kit 92249538 |
$228 |
Per this thread, this kit should use the following part numbers:
- 92244046 - Front LCA (front), right
- 92244047 - Front LCA (front), left
- 92244050 - Front LCA (rear), right
- 92244051 - Front LCA (rear), left
|
|---|
| Pedders G8 ARM KIT |
$1126 |
Contains Pedders parts: PBJ3309R, PBJ3310L, PBJ3311R, PBJ3312L, EP6560, EP6561, which are replacement ball joints & Pedders Poly bushings. |
|---|
| Spohn |
|
Please see Caution Spohn LCA failure! |
|---|
Front Lower Control Arm Bushings
Both of the Front LCA's have a bushing on the inner side (where it meets the frame of the car), and they have a ball joint on the other end where they connect to the hub/knuckle.
Front LCA (front) Bushing
Remember that just like the arm, the bushings have other names, just add the word "bushing" to the different names of the LCA. The most common name is Radius Rod Bushing. As a reminder, this is for the bigger of the two LCA's in front - the one that also has a slight bend to it. All of these are Polyurethane; none are rubber. These can come with or without caster washers. Adding caster washers will increase the positive caster, which is generally desirable on the G8.
Front LCA (rear) Bushing
Remember that just like the arm, the bushings have other names, just add the word "bushing" to the different names of the LCA. This is for the LCA that is smaller and perfectly straight.
Manufacturer
w/link
|
Camber Correction? |
Price per pair
w/link |
Comment |
|---|
| Whiteline W53150 |
No |
$71 |
|
|---|
| Whiteline W53347 |
Yes |
$72 |
Camber adjustment is possible because the hole in the bushing's metal sleeve is offset from its center line. Camber adjustment is then set based on the bushing's position prior to being pressed into the LCA. |
|---|
| BMR BK009 |
No |
$109 |
|
|---|
| Pedders EP6561 |
No |
$155 |
|
|---|
Front Sway Bar
Sway Bars are a frequently misunderstood suspension component. Sway bars do not increase or decrease the total amount of weight transfer. Sway bars do directly change the distribution of side-to-side weight transfer, which indirectly impacts how the front & rear behave. Yes, sway bars do reduce body roll in a turn, but at the expense of reduced traction on the inside wheel. There is also a strong relationship between your springs & sway bar. For example, if you have a very stiff sway bar and soft springs, the inside wheel can leave the ground when turning. This is because the downward force of the spring may not be strong enough to overcome the upward force from the sway bar on the inside wheel. If the bar is too soft for the springs, the bar will have a negligible affect. It's worth it to read up on sway bars if this doesn't make sense to you. Take a look at the Background Information section, specifically this Weight Transfer article. Lastly, understand that sway bars to not affect front to rear weight transfer at all; if your car nosedives & squats before the sway bar, it'll still do that after adding a sway bar. However, you might want the squatting behavior for drag racing/launching...
If you have no intention of driving your tires at the limit of traction [while turning], and if all you want is reduced body roll on the street, a sway bar is the cheapest way to reduce body roll.
However, if you do plan on driving the limit of tire traction [while turning], before buying a sway bar, consider lowering springs + struts/shocks or coilovers because these items can lower the center of gravity and decrease weight transfer distribution everywhere (both side to side & front to back) with no penalty of traction loss. Many people believe that a sway bar should be one of the last items you upgrade, and it should be paired with adjustable endlinks so that you can properly corner balance your car, which will help you dial in your understeer & oversteer once all your other suspension components have been finalized.
Don't ask about Hollow vs Solid bars; it's like politics & religion. Just google the topic and start reading if you're bored.
Front Adjustment Hardware
Toe kits aren't necessary in the front b/c the tie rods on the steering rack give you plenty of adjustment range.
Caster kits
Caster kits are generally desireable in the G8.
Camber kits
Camber kits may or may not be necessary; they are easy to add later-on if you determine that you can't get your front camber where you want it after making your various suspension changes. Also note that you may be able to use certain Front LCA bushing (rear) to increase negative camber.
Manufacturer
w/link
|
Adjustment
Amount (deg) |
Price per pair
w/link |
Comment |
|---|
| Eibach 5.81260K |
+/-1.75 |
$35 |
|
|---|
| Spohn C10-Camber2 |
+/- 2 |
$39 |
|
|---|
| Ingalls 35420 |
+/- 2 |
$14 (for 1 bolt) |
|
|---|
| Ingalls 81260 |
+/- 2 |
$28 |
|
|---|
Suspension Upgrade Summary
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