Coilover FACTS.
 

Coilover FACTS.

1. RACING coilovers adjust height by screwing into or out of the lower mount. Other types of coilovers, like Pedders OLD eXtremes, use the lower spring perch to adjust for height. This creates a litany of issues in car set up. The most critical is the lower you set the vehicle the less jounce / bound travel there is. This adversely alters ride quality. Lowering the car decreases the pre-compression on a coil. Raising the car by spring perch increases the pre-compression on a car. Having uneven coil pre-compression at each wheel after corner weighting in not desirable for optimal setup. Pedders Xa and Supercar coilovers adjust ride height like a RACING coilovers screwing into or out of the lower mount while preserving coil balance, and ride quality.
   
2. Some brand-x coilovers do NOT use OEM mounts for their coilovers. An example would be removing the rubber bush from the rear upper spring perch and converting it for use as the load bearing point for the rear coilover. The shock bush in the Camaro upper spring perch was not designed or intended to be used as a load bearing point for the rear spring. ALL Pedders coilovers use the OEM mounting points.
   
3. Inverted coilovers require maintenance. What cause failure of the shaft seal? Dirt. Debris. Abrasion. In an inverted coilover the seal shaft seal is pointed down to the pavement, mounted in the lower control arm. The most delicate wear component is exposed to the harshest operating conditions with an inverted design. That is why inverted coilovers are best suited for track use -- limited exposure and miles. Does your customer want a coilover that requires seal maintenance? Does your customer know the inverted coilover seals require routine maintenance? Can ANYONE tell the customer what the expected shaft seal life will be for an inverted coilover on the street? The answer is no. Do they drive down dusty roads? Do they drive near the beach where sand blows on the road? Do they drive in the rain? It will be different by customer depending on driving habits, road conditions, climate variables and more. NONE of Pedders coilovers are inverted and do NOT require routine maintenance like an inverted coilover.
   
4. The clevis on Pedders Xa and Supercar coilovers are 10mm wider than OE to allow for increased negative camber range WITHOUT any additional parts. This also help balance the front and rear track to reduce understeer
   
5. RACING coilvers have independent bound and rebound adjustment. If you are a racer, if you are a wannabe racer, if you autocross, if you drag race, if you are an enthusiast you want a coilover to be able to adjust, to tune your Camaro. The hands down class leader for the Camaro is Pedders SUPERCAR coilovers. It adjusts height by screwing into and out of the clevis. It has bound adjustment. It has rebound adjustment. It is not inverted. It does not require routine shaft seal maintenance. It has 10mm of extra clevis width to allow for great negative camber. Pedders Supercar Coilovers have independent bound and rebound adjustment.
   
6. The bigger the piston diameter, the smoother the function. Pedders Supercar coilovers are 52mm. Our Xa range and most coilovers on the market are 46mm. The larger the diameter of the piston, the larger the volume of oil the SMOOTHER the control will be. This is a rule of fluid dynamics. Pedders Supercar coilovers will deliver the smoothest, the best possible ride quality you can get out of a Camaro. Supercar coilovers will be a superior ride for the owner to OEM because of the fluid dynamics and independent bound and rebound adjustment.
   
7. Pedders Supercar Performance, alliance with GM and GMPP make Pedders the Camaro leader. Every GM owned Camaro at SEMA 2009 was on Pedders. Jay Leno's Camaro is on Pedders. All the 2010 NASCAR and INDY Camaro Pace Cars ride on Pedders.

These are the facts and nothing but the facts.

Issue #1 is what I'm running into with the Pfadt's. Also, #2 is a problem because I had to remove the rubber bushing for the Pfadt's.

Would you happen to know the part number for the rear upper rubber bushings?

do not, but i'll see what i can find

Hmm... many things to consider.

SSteve did you get the PN from Pett's post?

We have been in the suspension business for several years and the facts in this post is why at our shop we recomend Pedders suspension parts for our customers cars.They mount as the OEM designed them and now they are a GMPP part.

I can honestly say I am very happy with my Pedders supercar coilovers! They have met every expectation, and I am very hard to please. Now all I need is to beef up my drivetrain and add MORE POWER!!!!!:yikes:
I know while I am currently at 564 RWHP...can we ever really have enough power?:drool:

It never hurts to use fact and data when you choose suspension parts. The Pro Touring event by Motor State includes a number of suspension companies. The Pedders Camaro was faster than the competition last year (the time posted in the chart) and is even faster this year (time withheld at the request of two magazines).

http://forums.peddersusa.com/imageho...5c61975f6c.jpg

Rob/Pete, thanks for taking the time to post up the information. I just wanted to get a better understanding of some of your points because I am still researching the eventual route I'd like to go with coilovers once I get to the point that my driving skills get beyond the lowering springs I currently run on the car.

Forst and foremost, for the sake of full disclosure and to not appear to be a mole infiltrating the thread, I currently am running Pfadt sways and springs and their coils were one of a few toward the top of my list for future suspension upgrades along with the Pedders units, KW units and now even possibly the Penskes that were just posted about.

The main points I'd like some more insight into are #1 and #2.

For #1, I don't follow how the use of the spring perch to raise or lower the car effects the compression on the spring, as long as the strut rises or falls with the raising or lowering of the perch I would think that the pre-compression on the spring would remain the same. With the rise and fall of the strut I would think 1000 ponds of car sitting on the corner is going to pre-compress the spring the same regardless if it is one inch higher or two inches lower. I apologize if my terms are a bit off but I am coming from the "mortal man using layman's term" side of the suspension equation.

As for #2, looking at the construction of the OE rear strut, it appears that the shock bush is load bearing already and the rubber bush is just in there to help GM meet their "ride quality"/ NVH specs. I don't see how removing that rubber bush all of a sudden makes the shock bush load bearing when it already appears to have to handle the full load presented to it by the rear strut with the bush in there to dull the NVH.

I want to make sure you guys understand that the reason I am getting involved here and probing a little bit more is I just want a better understanding of the points you are trying to make about the design some manufacturers have chosen to use in the past and even the present. I'm not going to try and hide the act that I know a couple of the design points you reference here are found in the Pfadt Coilovers for the Camaro while at the same time you admit that the spring perch to adjust ride height has been used by yourselves in the past. It is sometimes very difficult to come across as sincere with questions on a forum so I am doing my best to do just that and not have my questioning appear as though I am trying to start a vendor war. I hope you'll view it the same way and offer some further insight into your points above as it will probably help me and many other in my/our decision-making process.

Thanks in advance....

Your are welcome here.

Think of the coil spring as being perfectly cylindrical with the winds perfectly spaced at 25mm with 2mm of preload. They general are not, but for sake of discssion we'll say they are. 2mm of preload is Pedders specification for the Xa and Supercar front coilover. To raise the car from the mid-point on the coilover by spring perch 20mm you would need to screw the spring perch up 20mm. The coil has no where to go because it is captured between the upper spring seat and the lower spring seat. So the coil spacing will change as you raise the car. The inverse is also true until the coil actually become loose when a at full droop on a lift. Not only does this change how the coil reacts, it changes the jounce travel the amount of travel in the damper until the bumpstop is fully compressed. In the previous generation eXtreme coilover we made, we used helper spring to offset this. That creates different issues and there is no need to over complicate this.

Going back to the 2mm of preload specified in Pedders Xa and Supercar Coilovers. We set the preload at 2mm. The coil spacing is exactly where we want it. There is roughly 3" of adjustment in the front of a Pedders Camaro coilover or 75mm. If we adjusted height by moving the spring perch we would not come close to maintaining the 2mm of coil preload once we move up or down 2 or 3mm. By setting the coil preload at 2mm we also set the jounce travel. No matter how high or how low you set your Camaro with a Pedders coilover the travel to full compression of the bumpstop remains the same and so does the ride quality.

A damper / shock does not carry load. The spring carries load. The center bushing in the Camaro was designed ONLY to mount a damper. The surrounding spring perch was designed to carry load. The load bearing rear mounting points in a 5th Gen Camaro are the upper and lower spring perches / seats and not the shock mount.

This is very interesting information. :)

At some point, can't the serious racer look at the 'Ride Quality' factor and say you're a sissy for even making it a factor???

I just wonder how much performance is lost due to 'Ride Quality' being a factor when a manufacturer makes a suspension product.

Just curious.

If ride quality was something I didn't care about, (and vibrating wheels don't count) are their some other coilovers or springs I would want to look at from anyone?

On the rear perch vs shock mount I think I understand the point you are trying to make now after looking at the picture you have above as well as from a picture in Eric Berry's build thread (friggin lucky SOB, now I know where that work of art intake manifold is getting installed )

I am understanding you to say the load bearing portion of the rear perch/mount is going from the #1 arrow below to the #2 arrow.

http://gallery.me.com/robertandlisaw...12829912450001

From the underside I guess the load bearing point that the spring presses against is best shown. And going to the shock mount would put the load up up higher "inside" the whole perch/mount piece.

http://gallery.me.com/robertandlisaw...12829912610001

Now that I think I am on the same page with what you're referring to, what is the problem I could run into using a unit that implements this transfer of load?

I think this is where I am getting confused with the ride height/lower perch thing. I clearly understand the fixed design you guys use where the upper and lower spring perches have a fixed distance between them and that fixed unit rises and falls out of the clevis below (I think I have the right name for what I am thinking about) to adjust ride height. The part I am stuck on is in the inverted design and the notion that the adjustment of the lower perch changes the compression on the spring. I could understand that being the case in a design like yours if the top and bottom perches both resided on a fixed structure and adjusting the lower perch changed the distance between the two perches but in a non fixed design where the two perches are not on the same fixed structure/tube (not sure of the terminology here) I would think that the pre-compression on the spring would be determined by the weight of the car resting on the spring. If the lower perch is lowered, the strut will shorten a bit and the height and weight of the car will come down as well to once again rest on the spring and pre-compress it to the same length it was at the higher ride height.

As for the jounce/travel and hitting the bumpstop I think I see your point that there is a certain lowered height that is so low the spring never gets to use its full range before hitting the stop. Does the possibility exist that the spring will go solid before the bumpstop would even come into play? No clue here about the design aspects that go into solid spring height and bumpstop height so just throwing that out there.

Thanks in advance again for tolerating me here, this exercise definitely helps me to understand things and hopefully others as well.