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Evil Pedders Guy Since 06
215 Posts
Discussion Starter · #1 ·
Wow, there seems to be a bit of confusion over the new ZETA IRS. Let's try to get them one at a time.

First, GM's Holden division in AU had primary development responsibility for the ZETA VE chassis. GM invested 1 Billion dollars in the chassis development. It is flexible in that it can be adjusted to fit a wide range of vehicles from four door, to two door to light truck applications. They invested an 800 million in the Holden plant to build these Commodore, a Buick derivative for China and the Middle East and will spend close to a billion on the Oshawa plant. GM says it will be less, but if you check the prices for steel these days and construction in general I am betting on a billion.

Pedders, is a 60 year old Aussie company. We are well known on the GTO forums, the LX (yeah I owned a HEMI back in the day) Forums. We plan to be well known on the Camaro Forums. We design and make complete suspension systems for the vehicles including bushes, coils, dampers, sway, and endlinks. We already have a great deal of experience with your future Camaro Chassis. Here is a link to my G8 that is currently at ProCharger. You may have seen my GTO at the Camaro Superfest last year. The GTO is built on the previous Holden chassis the VZ. We showed thee GTO back at SEMA in 2004.

Here are my thoughts on the VE / ZETA / G8 / Camaro chassis based on having driven and done about a dozen G8s in the USA.

G8 Evaluation and Pedderisation

Over the last week we have started Pedderising G8s in the USA. My personal G8 will be a GT with the Sport Package and Sunroof – Pedders style. If you have seen the Pedders GTO, you’ll know what that means. Before any one even thinks about it, and that includes my wife, the G8 is an addition to our garage. You’ll see both of us at a number of events this year. Both of us meaning the G8 and GTO. We will start with the driving impressions of a bone stock G8 with the Sport Package.

G8 Evaluation

The Pontiac G8 arrives from Australia in GT / Sport Package trim with the front ride height at 660mm and the rear ride height at 559mm. It sits rather tall as though it were an AWD sedan. These heights are deceptive in that the rear wheel arch is lower and smaller than the front. The result is that while the ride heights are virtually identical the rear of the vehicle sits considerably higher than the front. It sits high in the bum. The OE dampers fitted to the G8 are NG – No Gas. These are basic oil and air units installed to keep the price point down – perhaps due to the increase strength of the Aussie dollar.

My initial drives of the G8 left me both impressed and disappointed. The VE chassis delivers almost everything we expected and yet disappointed at the same time. It is a tiger that feels tamed - it feels light and floats in sweepers and at high speeds. This is the Pontiac flagship and I wanted this tiger to claw through a turn. The car sits too tall, is sprung too soft, damped too light with a too much body lean and roll in. Even the ride is too light in my opinion

The all new rear suspension architecture is excellent. The integrity of the chassis design adds depth to the driving experience. The rear suspension has sufficient structure to support the most aggressive driving. The three point differential mount is a significant improvement over the GTO. The sub-frame attaches with a four point mount. The upper and lower control arms are another significant advance over the VZ chassis. Adding trailing arms puts the G8 on another level.

The front suspension is more evolutionary than the all new rear design. The familiar GTO strut assembly mounts to the vehicle with the exact same strut mount as the GTO. The lower control arm runs from the knuckle to the front sub-frame. The radius rod Z bar GTO design has been replaced by a more modern arm. The radius rod mounts to the front with a steel-jacketed hydraulic bush. It ties to the knuckle with a joint.

The G8 uses a virtual pivot point suspension in the front. The benefit is that the wheel pivot is moved out from the inside of the clevis / knuckle to a virtual point of intersection that is closer to the outside of the tire. Where the GTO plowed through turns the G8 storms through turns. The scrubbing that was typical on my GTO with a highly tuned complete Pedders suspension is gone from the OE G8 suspension. This is a direct result of balance -- the weight distribution is spot on – almost 50/50 though most magazines have weighed the G8 in at 51/49 – chassis integrity and a more advanced design.

The G8 is an excellent car in OE trim. It has the potential to be dramatically better. While the GTO arrived in the USA with a more traditionally tuned performance suspension as would be expected in a performance coupe. The higher than the sedan version of the VZ chassis coil and damping rates were judged to be too soft for a performance coupe by many owners in the USA. The G8 arrives as a performance sedan. The difference in obvious is ride heights, spring and damping rates. On your first G8 test drive you will notice that there is an enormous amount of body lean and roll. This is directly related to ride height, spring and damping rates. With smooth driver inputs and modest amounts of throttle the G8 will blast through twists and turns. As a driver you must ignore the lean and roll. The car will go where you point it.

If you accelerate hard out of a turn you will identify the primary weakness in the G8 platform. The rear –sub-frame connectors allow far too much twisting and turning of the sub-frame in relation to the monocoque. This is very different from the GTO. The new G8 sub-frame mounts to the monocoque with four sub-frame bushes. The G8 rear suspension design is similar to the excellent Mercedes derived Chrysler LX platform (Charger, Magnum, 300C and Challenger). The sub-frame bush squirm does not explode in violent wheel hop as you would encounter in the GTO. In the G8 the sub-frame motion results in rear end step out and rear end bumpsteer. This is evident when you run an aggressive slalom using heavy braking and acceleration.

Judging the G8 by the spring rate, damping rate or body lean in relationship to older less advanced vehicles would be a mistake. The bone stock G8 is a more advanced design that performs better than the previous generation GM / Holden / Pontiac VZ chassis.
Suspension is always subjective. What is too hard for some will be too soft for others. The G8 in GT trim with a Sport Package feels too light and floaty to me. The car leans an enormous amount, but does hold the line through tight turns. High speed cruising feels just a bit light. It is not in any way unstable, but it is too light for my taste. It doesn’t inspire the same confidence you would experience in a Benz or BMW. Just as the GTO was a significant step up in the GM performance coupe tradition from the F-Body the G8 is a huge advance from the GTO. There are differences of substance. The G8 should be a smooth ride luxury performance sedan. If you are expecting ZO6 Corvette flat corning, you bought the wrong car. If you were expecting a BMW the G8 is close but not close enough.

G8 / Camaro Low Hanging Fruit

1. Sub-Frame Bushing Inserts, Pedders EP1169
2. Front and Rear Lowering Coils: Pedders 2954 & 2955
3. Pedders GSR Front Struts: 9464L & 9464R
4. Pedders GSR Rear Struts: 9295
5. Front Castor Correction: 5421

Adding Pedders sub-frame inserts to the G8 completely changes the character of the vehicle. GM did it right with the mounting point. The G8 sub-frame mounts with two long ‘pilots’ from the monocoque passing through the larger rear pair of sub-frame bushes. The installation of these eight inserts seemed to reduce the trace amounts of noise from sub-frame to monocoque contact under extremely aggressive maneuvers. The car becomes significantly more predictable which is a surprise as the platform was already very good. Pedders engineers did a brilliant job of using the existing sub-frame bushes. This simplifies installation and reduces your completed costs for parts and labor. This is hands down the biggest bang for the buck mod for the G8.

With a more predictable rear suspension from the installation of Pedders EP1169, your next limiting factor is the ride height and damping rate. The G8 is a luxury performance sedan. You don’t want top turn this world class vehicle into a boy-racer kidney-belt required hot rod. To that end the changes in ride height for the G8 are roughly 20mm in the front with fresh Pedders 5851 strut mounts and 40mm in the rear. These changes allow the car to sit with a slight front to rear rake 622mm rear and 640mm front.

The G8 does use the same strut mount, the exact same strut mount as the GTO. We are finding 4 to 6mm of compression in fresh off the boat G8s. A modest increase in spring rate paired with Pedders nitrogen charged GSR dampers bring the G8 to life. Pedderised it drives like true performance sedan while retaining a luxury sedan like ride. It is easy to drive this car hard. The light sensation at high speed is gone. The rear step out, the rear bumpsteer, is banished. Suspension travel with your lowered ride height is long enough to be supple over most any road while delivering an amazing driving experience. Does it have more body lean and role than a maxed out GTO – it does. Does it ride better than a GTO – yes it does. Does it drive better than a GTO – yes it does.

Because the Pedderised G8 is so quiet and composed, high speeds seem to occur in slow motion. The G8 is a serious vehicle for the sophisticated driver that truly appreciates sophisticated automobiles. Because it is so balanced the Pedderised G8 is almost effortless to drive. Stability and Predictability are the primary characteristics that will leave you with SEGS. Take your time and learn the limits of your newly Pedderised G8 on a road course or an autocross. A Pedderised G8 is as weapon of higher priced vehicle destruction with minor suspension upgrades.


There are some concerns I have after getting into the G8 Pedderisation. While the wear of the OE strut mount bush in the GTO is well documented, there is some cause for concern with the use of the same mount in the G8. In the GTO, the upper spring perch / bearing plate had a rather modest angle. In the new G8 the upper spring perch / strut bearing plate is on a more aggressive angle. This increases the clearance between the strut tub and the tire sidewall. There is no cause for concern that we will see strut rub in the G8. What we will see, in my opinion, is wear in the strut mount as a result of the increased load on the strut mount from the angle of the spring perch / bearing plate. New information from GM indicates the design of the G8 bearing plate / upper spring perch will decrease the loads on the strut mount. When examined out of the car, it appears to be under load before being installed in the vehicle. According to GM, when installed in the vehicle there should be less load on the strut mount bush. We will all know from real world experience as we accumulate miles on the Pedders G8 and see more G8s with miles in Pedders Shops in the USA and AU. The update from Pedders Shops in AU -- they are seeing no unusual where on the G8 OE strut mount bush.

Before we wring our hands about this, the removal and installation of new strut mounts is roughly a 90 minute job. Replacing the mount with an OE or Pedders bit will be roughly $80 in parts. That is a small price to pay in annual maintenance cost to drive such an exciting luxury performance sedan. If you visit the BMW forums you will find that BMW has numerous issues with various suspension bushes. Even the ultimate driving machine has bush failures. Once again it is my opinion that the driving style of the performance luxury sedans contributes to the issues. Performance vehicles require performance based maintenance programs. An annual alignment, strut mount replacement including parts and labor is less expensive than picking up a cup of coffee at Starbucks on your way to work.

On two of the G8s I have seen on racks, the driver’s side parking brake cable was stretched across a hard metal sub-frame edge. GM / Holden / Pontiac seem to be aware of the chafe potential. The cable is protected by a yellow plastic anti-chafe device. These two cars had already shown signs of wear in the yellow plastic. We wrapped them with a piece of heat hose zip tied in place. It is a short list of concerns.

Pedderisation: Pontiacs (CHEVY), Businesses and People

Pedders USA, LLC will be campaigning a Pedderised G8. I pick up and Pedderise my new G8 at Brian Harris Pontiac Buick GMC on April 8, 2008 – THANK YOU William Southall!. With the help of their lead Pedders technician we will install a full Pedders eXtreme Suspension before my family and I drive our new G8 from Slidell, Louisiana to West Olive, Michigan. We’ll post photos of the car before, during, after and include our road trip. That is the first leg of our trip in the G8 build.

Step #2 With the assistance of Disc Brakes of Australia (DBA) we will be installing a DBA Big Brake Package.

Step #3 is courtesy of ProCharger, our original marketing partner. ProCharger will prototype and install their G8 forced induction system. Sounds familiar, doesn’t it?

Step #4 Corsa will handle the exhaust. I love the G8 quiet cabin, but this tiger does need a bit more growl….

Step # 5 Early on, we’ll be adding coolers for oil, trans and power steering. We have yet to determine what we should do with the interior, tires and wheels.

Step #6 More Road Trips and Events! The Pedders USA, LLC G8 will be on the Hot Rod Power Tour, the GTOAAs, the LX Nationals in Ohio, the Camaro Superfest and a couple of other events before the year is over.

As I close this initial installment of Pedderise My G8, I want to mention how excited I am to be involved with Pontiac community, the GTO community, G8 Community and the automotive community. Our car culture is an amazing blend of diverse groups of people with a common interest. The G8 project will take me to places I had never dreamed of and people that I would never have met as did my original journey with my GTO. As many of you know, I lost my mother last month. The support provided from people I would never have known had I not become involved with the GTO and Pedders was incredible. In 2008 armed with a G8 and a GTO I can only imagine what the year will bring. Life is an adventure best traveled in a Pedderised Pontiac... err GM....errrr Camaro :roxor:

The Camaro and More on Topic

The differential in the ZE is mounted by three aluminum jacketed bushes that are voided for NVH reasons. In stock trim with OE bushes the transfer of energy is reasonably efficient. The mounting points make this far more stable than the prior generation VZ. Upgraded to Pedders urethane mounts, which are made of urethane, but are also voided to keep the vehicle OE like civil the transfer of energy is more efficient.

While I have not yet been in a production version of the VE Camaro, I can tell you that the four sub-frame mounting point / rubber bushes are also voided. I find the vehicle is prone to rear-end step out from sub-frame movement in straight line hard acceleration and in corners. By most production vehicle standards this would be acceptable and even excellent performance. The VE is so well designed, we can firm it up, maintain a civil ride, eliminate the rear-end step out and be on par with vehicles like a BMW M series.

We are an Aussie company. I am an American from Chicago. You'll find Pedders USA to be blunt to the point of being politically incorrect. Some consider me to be rude. I consider my manners to be perfect as I am equally blunt / rude / honest to everyone. I hope you will find our / my posts to be informative -- although they do get lengthy. I look forward to seeing some of you at the Camaro Superfest in Ypsilanti. I'll have my Pedderised G8 / your Camaro chassis hopefully in the air on the garage lift so you can see for yourself.
There are six bolts and a locating pin in the front sub-frame -- all hard mounted. The rear mounts with four bolts, two pilots and voided for NVH reasons bushes. Unlike the Camaro unibodies that preceded the VE / ZETA based Camaro, I believe you will find the monocoque to be robust and the need for sub-frame connectors limited to those that are hard core races. The twisting / racking that occurs in the new generation VE only shows at the extreme end. If you install a full cage and tie it to sub-frame connectors you'll see a benefit. If you don't need a full cage by speed or racing style you won't need sub-frame connectors based on the Holden Commodore / Pontiac G8. I have every reason to believe the the Camaro will be just as robust, in no more so...
When Pedders does a urethane bit, we take ride comfort into consideration from the beginning of the design. Most people are not building track use only vehicles. They want to have razor sharp track handling AND the comfort of an OE ride. To accomplish that we use shape, voids, lower durometer urethane and carefully watch the ratio of urethane to metal. Urethane is a liquid solid. It flows under pressure. using this property we taper some bushes, and void other bushes to create a progressive reaction from a material that is not progressive.

The geometry, the inherent stability of a platform is another core element of the ride comfort / control equation. The new VE / ZETA chassis is very well designed. It doesn't need to be rock hard to deliver excellant control. If you drive a G8 with the 19" wheels you'll find the car goes where you point it -- even though there is a tremendous amount of body lean and roll. Getting this chassis to stay flat with anything other than full race compound oversize tires is a wasted effort. You'll end up with an over sprung, over damped and under tired vehicle. If you compare the performance of a C6 ZO6 to a Viper you'll find that the Viper is a bit faster on a glass smooth road course. Very few road-courses are glass smooth. The more compliant suspension in the ZO6 will make the Vette faster than the Viper. The Viper, IMO, is over sprung, over damped and under-tired in the rear. It chatters over imperfections and converts from pseudo race car to lawnmower in tight turns over imperfect surfaces. The IRS is the new VE / ZETA responds well to lowering with damping and coil rate up to 50% higher than OE. Past that point you will experience a significant decrease in ride quality.

The GTO which rides on the Holden VZ chassis that is much less sophisticated and robust in comparison to the VE, has people at the strip running over 800 RWHP with modified OE bits. Compared to the VE the VZ was weak. Most VZ owners upgraded their OE dif covers to a Harrop cover to improve the mounting points and stability. That will no be the case with the VE. The VE has a triangulated three bush mount. While I find the dif mount bushes to be overly compliant, voided rubber with aluminum jackets and ferules it is generations better than the VZ. The half shafts are roughly 50% larger than the VZ. It have upper control arms and trailing arms. It uses a coilover as opposed to a mini-bloc rear coil with independent shock.

As the racers / abusers / I can break anything to win guys flog the VE we'll all know more about the weaknesses. At this point in time, I am comfortable in saying that the new Camaro will be well suited to the weekend track warrior.

We say a number of front end tire wear issues with the GTO in the USA. That makes us all a bit wary of using the same strut mount in the G8. That said, there is no reason to be concerned with strut rub issues on the VE / ZETA. We do want to watch and evaluate the wear of the VE strut mount. We refer to that bit as a 5851 in the Pedders range.

This is a GTO strut mount after about 7K.

You can see the wear on the bit. We THINK much of this was incurred in shipping the vehicle from AU to the USA. That will not be the case with the Camaro. The strut mount is like a tire or a brake pad. They do wear. The harder you drive the faster they wear. They should last the life of the strut or about 40K. If they wear faster it isn't all that big a deal to pull a pair of struts and fit them with new HD style mounts.

This is a Pedders 5851 taken out of my wide body GTO that runs 275/35s on 18x 10 front wheels and in general is run hard, some would say abused, by me.

Here is a comparison of a used and new strut mount out of a GTO.

Here is the strut mount and bearing plate assembly from the G8 / VE / Camaro.

It is not something to lose sleep over. It is something to be aware of and maintain. It is no different than changing the oil, rotating tires, changing out worn brake pads or any other form of normal maintenance. If swapping out strut mounts is the price we pay to drive the best handling, best built Camaro to ever come out of GM it will be worth every penny. The Mustang is not only vintage in look, it is vintage in chassis design. The Challenger has a Mercedes derived chassis and drives very well -- especially Pedderised. The Camaro is a generation ahead of the Challenger in terms of sheet metal and chassis design. The Camaro will drive more like Mercedes or BMW coupe than Muscle Car -- but it will have more muscle than most Muscle Cars ever dreamed of. GM / Chevy have go it spot on.

I just found out this forum does not automatically resize pictures. :BangHead: I'll if I can get these resized latter in the day.

Evil Pedders Guy Since 06
215 Posts
Discussion Starter · #2 ·

No wheel hop. None. The ZETA IRS is a robust design. My car puts done 470+ RWHP. At the GTOAA Nationals this past week the strip was lightly prepped for an amateur day. It was prepped only once and probably no more than 100'. It was a hot day. My G8 ran 12.7 @ 113 my best times. I am running on the OE tires. I am also not a drag racer. My guess is that with my four door ZETA chassis and some form of drag radial to let the car hook up better my family sedan will run high 11s.

There is wheel hop / axle tramp in many IRS systems including Porsche. The Camaro will come with a larger rear wheel well that will accommodate much larger rear tires and hook up better than the G8. My guess is you will see some astonishing numbers from the new ZETA II Camaro at the drag strip and that same car will eat corners and not cones at the autocross.

GM put a billion dollars into the development of the ZETA chassis. It is the BEST chassis GM ever built. Yes I believe it to be better than the C6 chassis. There is a reason GM came out with the ZR1 C6. The Corvette all ways will be the fastest Chevy built. There will be at least one version of the Camaro that is at least equal to the performance of a C6 ZO6. GM got this one right. I know from the inside out. I know from the Commodore in AU, the G8 in the USA and the Camaro based on first hand knowledge. Ooopppsss I think I just said to much.

As for being anything like a Mustang, if and when the Mustang grows up it wants to be a new Camaro. The Camaro is so vastly superior to a Mustang I don't have time to write all my thoughts. Aside from putting the steering rack in front of the wheels there isn't much to get excited about in a Mustang. The various handling packages from Ford and Ford's partners amount to using a light pole sized front sway bar and the rear axle bump-stops for suspension improvement. It is a cheap to build great looking car with modest performance. Like a Crown Vic police car it is reasonably predictable, but technologically a dinosaur with technology more closely related to the look of the original Mustang. The new Camaro is not only forward looking, it has one of the best chassis designs available from ANY manufacturer and at pricing more closely related to a Mustang than a 2 door BMW.

Before you get the impression I don't like the Mustang, understand that Pedders is developing a complete suspension systems for the Mustang. Just as we are doing for the Commodore VE, G8 ZETA and Camaro Zeta II. I know these cars intimately form underneath the car and in the drivers seat. The ZETA derived vehicles are the easiest to drive fast cars being built today. They are stable, predictable and quiet. Because they are so composed, so sophisticated triple digits appear on the speedo when you are expecting 75 or 80. I intended to take a Dealer up to 100 MPH. When I looked at the speedo I was doing 152. Dumb thing to do, but it happened. The Camaro is going to get a lot of people into similar trouble. It is just to easy to drive stupid fast.
Reposting this info that Pete posted, but this section has since been opened up and is more appropriate.

Evil Pedders Guy Since 06
215 Posts
Discussion Starter · #4 ·
Most of you already know that Riley Tech has been selected as the EXCLUSIVE builder of the Camaro for the Grand Am Challenge GS Camaro.

What you don't know and I can now say that Pedders worked with GM on the development of this vehicle. The Grand Am Challenge Camaro will run the circuit using what Pedders considers to be daily driver bushes and bits. The OE Camaro will arrive with hydraulically damped radius rod bushes. The OE radius rod bush performs well on the street for most drivers. For the enthusiast driver a hydraulically damped radius rod bush is about as useful as the wrong size driving shoes. They are too compliant. GM asked Pedders to develop a radius rod bush that would withstand the demands of track use. You will be able to buy EP6560C Camaro Radius Rod Bushes, the same bushes we developed for the Grand Am Challenge. It is the same bush we will be using as a basic component of the Camaro suspension.

The Grand Am Challenge is a full on race car. It does not use street style dampers and there are other revisions to the suspension and drive-line. These cars will also be using Pedders eXtreme Castor Washers in addition to the full on hard mount strut bearing with Castor and Camber adjustment. In the rear suspension Pedders EP7267 Toe Link Bushes, 5422 Toe Link eXtreme Washers and EP7266 Rear Control Arm Bush. In testing at the Milford Proving Grounds GM determined that our Pedders Bits met or exceeded their engineering and driving expectations.

Pedders is a unique company. We do not make parts for race cars. We do make some street parts that just happen to perform incredibly well on the race track. Our warranty is also unique. Pedders does not have a racing exclusion. You can take your Pedderised street legal Camaro to the track, flog it. If a Pedders part fails within 24 months or 36,000 miles it is covered under warranty.

We were absolutely thrilled to be invited to work with GM on the development of the Grand Am Challenge GS Camaro. We consider it an honor to have been selected for such a special project. Working with is another honor. I can't even begin to imagine a better way to introduce Pedders to the Camaro enthusiast community.

4,544 Posts
Pet peeve: I can not stand "Bush" "Bushes" or "Bits". We are in the United States. We call them Bushings. Why all of a sudden do people want to act like they are Australian?

It bothers me so much that I started a thread on LS1GTO. This is a bush. This is a bushing.

With that said, Pedders has obviously made a name with the GTO crowd. Hopefully the Camaro will not have the inherit problems the GTO had with its suspension. I am more of a *******, so I prefer to put money under the hood rather into urethane.

Throw another shrimp on the barbie, Mate. :poke:

217 Posts
Pet peeve: I can not stand "Bush" "Bushes" or "Bits". We are in the United States. We call them Bushings. Why all of a sudden do people want to act like they are Australian?

It bothers me so much that I started a thread on LS1GTO. This is a bush. This is a bushing.
In searching for something else I just stumbled on this thread and your post. The reason for the Aussie version of autospeak is that we are an Australian company. As much influence as my Aussie partner has had on my vocabulary we have done the same to them. I went out to dinner on my last trip to AU with some of the guys from the company. The next day my partner tells me that Andrew got really pis*** with me last night. I said I thought he had a great time. My partner say he really did and really got pis*** ! Huh? In AU pis*** means drunk.

So I say we should meet up with Rob and get pis***

105 Posts
Pedders X-frame bushing pics on G8

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