norvalwilhelm

The market seems enlist. Locally I can get Pro shocks,Penske shocks and Bilstein to name a few. Also there is Linear valved shocks and Degressive valved shocks.
They also come in 300/100 down to 100/50.
The combinations are enless.
What do I look for in a rear coil over? I can also get 2 1/4 and 2 1/2 springs in any weight?
All this is confussing. I want to order a set but wouldn't have a clue.
Can you guys teach me what I want?
Thanks

GDaina

Norval, surely you jest with your thread eh? :lol: :lol:

Now, if I didn't know any better, I'd be thinkin' you want to see who the knowledgeable ones are, who can pass the suspension test.

Well, it ain't me bud, not into the radical suspension changes, but your thread has peaked my interest to know the answer to the quiz. I suspect only a handful will be able to pass. :D

norvalwilhelm

GDaina I am not kidding. I don't know anything about shocks. I just usually buy the heavy duty set and leave it at that.
Since I will be spending about $500 or so for a set of coil overs I want to make an educated selection.
I would probably pick Bilstein because that is a name I reconize but the valving I don't have a clue.
I do have a good source but I haven't called him yet. I would like to be able to discuss it with him while he give me advice.

Pete79L82

Norval: You will have a LOT of choices here. First you will have to decide what type of body you will what. Chrome, painted steel, aluminum. Then whether you what smooth body and a thread kit or a threaded body shock. Next will be the lenght you need. Then what type of mounting, Heim joint (spherical rod end) or rubber bushing. Next will be the spring diameter. I would recommend the 2 1/2" springs. Your race car buddy will have a line on them used and cheap so you can try different one untill you find the rate you like. Finally you need to decide on valving. Personally I don't care for adjustable valving shocks. I find them to be not very consistent. I would reccomend a 50/50 rate for the street, probably something around a #5 valving. #6 valving if you want it fairly stiff, #4 valving if you want something softer. My prefference would be Carrera, Pro Shock or Afco. I never much cared for Penske or Bilstien but my experience is on race cars, they may be different on the street. Again you might want to check with you race buddy. Most racers will replace there shocks every year and used ones can be bought very cheaply. That way you can try diffent spring/shock combos to find the set you like.

Here is a link that will give you information on what you will need to know to chose the correct ones. http://www.proshocks.com/ Look at their street shock tech and calculators.


[Modified by Pete79L82, 8:36 PM 9/25/2003]

Shark Attack

I have coilovers on my mustang. I got them for a few diferent reasons. 1. I wanted to lower my car past what drop springs could. 2. coilovers are easy to use and weigh less. 3. changing the spring rate to a diferent spring is very easy. I also chose the tockiko 5way adj struts. If I were to do it again I would use the koni yellow DA struts and shocks. I will be looking into setting this up in the future when I get my vette. CO's are the way to go in my opinion.

mrvette

UGHH....since I"m the guy who sold his heavy duty sway bars in favor of better ride quality, do you all think I could pick up any handling with rear coil overs, without killing the ride??? second off, is that shock mount in the rear capable of handling the car weight in a dynamic loading??? frankly I doubt it....only the D shape to keep it from twisting..???

second off how would the handling be differant vs the plastic spring I have now??? in general that is...of course.....

any advantage to coil overs for the front wityh my stock arms?? or is that all just not worth any more messing with??? and isn't the stock arrangement essentially a coil over anyway??? except may weight???

still want a taller spindel....I"m wondering is a longer stemmed balljoint can be found....it's not the welding of the spindle that bothers me per-se, it's the positioning of the parts, and so forth....Norval???

GENE

Pete79L82

Gene: The 3 main benfits of C/O's are weight, ease of service, flexability in placement.

Because the physical size of a C/O is smaller it is easier to place them closer the the centerline of the tire. The closer it is mounted to the tire centerine the more effective it is. If you mount the C/O in the same location as the stock spring and shock(as in the front spring) then there is no perfomance befitis gained other than weight. If you mount them is the same position as the rear shock then the shock performance would be the same as a non-C/O but the spring would be slightly less effective because the lower mounting point would be farther inboard then the stock spring. The main benifit in the rear would be that you would have a much larger selection of spring choices than with a leaf. It is also considerably easier to change a C/O spring than a leaf spring. You also have the added benifit of ride height adjustability.


Pete


[Modified by Pete79L82, 7:23 AM 9/26/2003]

norvalwilhelm

Thanks Pete. The choice of chrome, painted or alumimun, threaded or not and type of ends is just person choice.
I am leaning towards digressive shocks. As you know and some might not a digressive shock has alot of resistance to movement right away. A Linear shock moves easy at first then gets stiffer with more movement.
Shocks are rated in inches per second of movement.
Move a linear shock 1 inch per second and it has little resistance, eg 30 pounds for 1 inch. Move it 2 inches per second and it's resistance is 60 pounds etc, etc.
Move a digressive shock 1 inch per second and it might be 150 pounds for the 1st inch but move it 2 inches per second and it might only be 175 pounds.
The linear shock constantly increases the resistance while the digressive shock tops a peak quickly and stays the same from then on.
3 things require a shock, bumps, dive and roll. For a bump you want a softer shock that increases with the severity of the bump. For dive as in braking it would be nice to have a fast acting shock to prevent dive like digressive, the same with roll, we want to resist the roll so a digressvie shock with it's high initial resistance prevents roll.
The digressive shock if pushed too hard will not respond with increased pressure while the linear shock responds by increasing pressure the harder you push it.
A popular setup is linear front, digressive back.
Pete what is a 50/50 split? If you have a true 50/50 split the shock moves in and out at the same rate but what about the spring? It is resisting the shock moving in by #200 plus pounds per inch while pushing the shock out with the same force.
I want a soft compression like a #4 but a harder rebound or pull out of #6
I will seriously consider Pro Shock if you recommend them.
I want the 2.5 springs as long as the OD is not over 3.5 inches.
I too do not want a adjustable shock as I wouldn't have a clue as to what I am doing.
The compressed length and extended length is easily measured by knowing the installed height and make it about in the center of the shocks travel.
Thanks again Pete for taking the time and last night Pete measured roll centers with a stock spindle and a 2 inch extended spindle. It took alot of his time to measure and calculate the roll centers but it confirmed to me that I made a good guestimate at 1.5 inches longer spindle.

norvalwilhelm

Good morning Gene. I just looked at it briefly but I would not use the stock upper shock mount. The upper mount was not meant to hold the weight of the car but the big thing is it is angles towards the center of the car and our coilovers want to hang straight down.
We have about 3.5 inches between the swing arm and the fiberglass wells. The shock with the coil needs to be centered in this space so I will remove the upper shock mount, reinforce the front and underside of the frame with 1/8th plate and add a new upper mount that points straight down and not one that binds the top mount like the stock one would.
For a lower mount I will weld it to the OUTSIDE of the trailing arm between the arm and rotor and have is sweep under the trailing arm and end up flush with the inside of the trailing arm. This will allow the shock to hang straight down in the allowed space.
As for welding the spindles mine are done, painted and waiting to be installed. I built a jig to hold the spindle in alignment so welding was not a problem.
It will totally destroy my pump steer settings so I will have to go through that again. It is not hard the second time around since you know what you are doing.

norvalwilhelm

Thanks Shark Attack, I also have a mustang but the spings are just lowering springs. I don't want coil overs on the front but for the back it will make adjusiting height easy, not that it is hard now, spring choice is unlimited and easy, it will weigh less then the stock steel spring but not necessarily lighter then a composite spring,

groovyjay

I know these pics have been shown on the forum before, but now that discussion is about Coil Overs for C3 I think it won't hurt anyone if I post them again:



Here's the front coil over mounted on a modified STOCK A-arm.



Another shot.



And another.



Rear coil over in place, notice the Offset TA's.



Here's the stock trailing arms modified to accommodate the coil overs.



The kit.



Rear CO in place.



Rear coil overs in a 80 vette.



Last shot.

I'm no expert about the coil over set ups, but what I've read about them is that the adjustability goes beyond normal coils and shock or shock and leaf spring. They are more compact in size and will provide suitable ride feel for almost any kinda driving. :steering:

:steering:


[Modified by groovyjay, 9:18 AM 9/26/2003]

Twin_Turbo

Yeah, with coil overs like those expensive 8212 Konis you can adjust bump & rebound on the shock and the spring load can be changed too w/ ride height. The only thing you can't change is spring rate since that's a constant dependant on spring material coil thickness and coil diameter.

If I were to go to coil overs (and I'm certain I will but not those 650+$ konis) I will get some spherical end ones because they give no deflection and I don't drive a lot anyway (hell, not 1 mile in the last 2 years :) )

About the koni's, the ones pictured above are 8212 double adjustable aluminum. There's 8211 too, single adjustable aluminium and 8112 is single adjustable steel body.
Most of the 8212 shocks you see available are SPA1, those are 90/10 (well not really) valved for drag application. Those are a lot cheaper than the ones you'd need for a street/slalom setup.

groovyjay

Try 0 miles in last 3 years :D I noticed that they are using H&R's springs with the Koni's. Is it possible to order them seperately and choose the right spring rate? What are your thoughts about the rear TA mounts for coil overs? :cheers:

Twin_Turbo

The coil overs ALWAYS come without the springs. Koni doesn't make springs, H&R is a damn good brand, those germans jut use high quality stuff there. You could use about any spring available, most are 2,5"diameter. I wouldn't use the progressive rate ones (they have sections with more/less coils), although it's a good idea there's now ay to tell what the actual rate is going through the suspension. Just stick with one rate, the softer the better. If it hits the bump stop, whoc ares. The stop is kind of a variable rate spring itself since it gets wider. It will really help stiffen the suspension those last few inches (that's what it's there for, removing it is just plain stupid)

norvalwilhelm

I have decided on a shock. I am going with Pro Shocks because they have a distributor locally and Pete said they are a good shock.
I an going with Digressive shocks because they have a very high resistance right off the bad, up to 3 times more then a linear shock so they resist pitch as in braking and roll and is leaning in corners really quickly but they loose resistance as the travel goes up like over a severe bump so they are softer under hard usage.
I am going to start with 200 pound springs so for a shock I will choose 300 pounds on pull out and 100 pounds compressing. I am using the 200 pound spring to resist compression so the shock should with the help of the spring act like a 50/50 shock. Equal pressure in or out, again like Pete suggested.
The car went away today because I am anxious to get started on modifications.
I did look at the rear upper shock mount and I am convinced the stock shock mount will not work. Beside being crooked so it would bind the upper mount it is mounted to the rear of the frame pushing the shock towards the wells. The shock needs to be centered between the trailing arm and well so I will install a new reinforced centered upper mount and weld a mount on the trailing arm.
Monday I will try to order my coil overs and springs. I also want the long travel 14 inch 2.5 diameter springs.
The length of the shock will be 10.5 compressed and about 17 inch extended. The working height hopefully will be in the center of the shocks range.

norvalwilhelm

So GDaina what do you think of my choice? Anyone? :) :)
Anyone find flaws in my reasoning? Speak up now before I spend $500-$600.

Twin_Turbo

Are they for the rear? If so, note that mounting the shocks under and angle reduces their effectiveness, so if you run a 360lbs rear leaf spring and you are now going to run 360lbs but the shocks are under a 10deg or so angle yit's still close to 100% effective but when you mount them under a 30 or so deg. angle you will need stiffer stuff (30% stiffer roughly) to get the same suspension effectiveness. It's pretty easy to calculate, draw the shock under the angle, then draw a force vector for the shock inline with the axis and split that in X and Y components. The X component is the effective one, as you see the larger the angle the less effective.

I've been looking at the pro shocks too, also looking at afco and QA1, don't know what to choose. Does anyone have the price list on those Pro Shock ones? I want threaded bodies, not a standard shock with a sleeve.


[Modified by Twin_Turbo, 5:53 AM 9/28/2003]

norvalwilhelm

Our rear shock are mounted straight up and down, no angle whatever. We are limited in the space so they end up straight up and down.
I don't have a price on the ones I want but Pro shock, aluminum, full threaded body, digressvie about $132 AM. The ones I want are actually gold anodized, threaded only the bottom half, gas with a set compression #2-#6, I will choose #3 for soft with a complete adjustable rebound which I will set fairly stiff or #6.
I will phone Monday for prices. As for springs I think #200 are a little light but I will start there and work up. I would rather be too soft then too hard. I would also like the 14 inch long springs so they have lots of travel. Ideally I want my rear to use most of it's travel in normal high speed driving. I don't want it locked down with stiff springs.
I am counting on the digressive shocks to keep it from squating off the line, not stiff springs.

norvalwilhelm

Twin Turbo look at the bottom pictures from Groovejay. Those are of the rear, the first pictures are from the front. That is how I will mount mine on the back.

Twin_Turbo

Oh, I didn't know how you were gonna mount them. I thought you were going to use new mounts so I thought I'd mention the effectivness.

The pics from groovyjay are those pics from ACP Germany and they use the stock upper mount for the coil overs.


[Modified by Twin_Turbo, 10:21 AM 9/28/2003]