complete suspension, 71 camaro

[71rs]

looking for advice/input/commentary/discussion on suspension plans for my 71 camaro.

first, about the car. it's a work in progress (aren't they all), but these are the components that the suspension will be accomodating:
71 camaro
aluminum-headed 406 smallblock, flywheel HP ~ 450
T56 6spd manual
9" rear w/ 3.90 or 4.00 gears, truetrac or trak-loc
16x8 wheel, 4.5" BS, toyo RA1 255/50/16 all the way around

my goals so far include:

1) keep weight in check. hollow sway bars, aluminum center for the 9" rear, etc., where possible/practical

2) balance of street, strip, and track manners. No 90/10 shocks, no 900 lb/in coils, no slapper bars/caltracs. If I can cut a 2.0 or better 60ft, get above 0.9g on the skidpad, and keep the ride nice enough to keep all my teeth in my head after a 2 hour cruise, I'll be happy.

For frame of reference:

* My 1991 Z28's FE2 (stiffer IROC-rate springs/swaybars) suspension is definitely too soft, I want something more "sporty" than this

* my 2002 miata (with factory suspension package including stiffer springs and bilstein shocks) is more of what i'm looking for

3) avoid the use of solid bushings in the rear end (I presently have solid aluminum bushings in the front spring eyes, and they transmit an obnoxious amount of gear noise to the car)

4) maintain a near stock ride height with no rake (i.e., flat) for multiple reasons - front tire clearance in the wheelwells, header clearance, etc. etc.

So, what I think I'm looking for is:

1) rear leafs in the 170-185lb/in range, stock or near stock ride height, with some kind of anti-axle-wrap design (most of the leafs towards the front, double-front eye, etc.) Herb Adams front perch modification (re-drilled holes 3/4" higher in perch). Preferrably rubber bushings, metal to metal bushings as a last resort. How quiet can the lined bushings (i.e. del-a-lum types) be?

2) front coils in the 450-500lb/in range, with stock or near stock ride height. More (+) caster, (-) Caster around 0.75*. Tubular arms if they offer a weight savings or geometry improvement. SC&C street-comp stage 2 stuff?

3) Good shocks all the way around (bilstein or koni, potentially QA1 or others but I'm not familiar with their stuff much).

input/commentary?

[71rs]

comments, commentary, anything? did I leave something useful out, or put too much in?

After more consideration, I guess I could go up to 600lb/in on the fronts and 200lb/in on the rears. Understand that with the right shock valving (maybe use the hotchkis-valved bilsteins) that this can be very streetable.

I'll add that the hotchkis TVS is actually not that far off from what I'm looking for, though I have a bit of concern that the front springs might be borderline too stiff? Also concerned with the amount they lower the car and that it might be too low for me...

[novanutcase]

So, what I think I'm looking for is:

1) rear leafs in the 170-185lb/in range, stock or near stock ride height, with some kind of anti-axle-wrap design (most of the leafs towards the front, double-front eye, etc.) Herb Adams front perch modification (re-drilled holes 3/4" higher in perch). Preferrably rubber bushings, metal to metal bushings as a last resort. How quiet can the lined bushings (i.e. del-a-lum types) be?

2) front coils in the 450-500lb/in range, with stock or near stock ride height. More (+) caster, (-) Caster around 0.75*. Tubular arms if they offer a weight savings or geometry improvement. SC&C street-comp stage 2 stuff?

3) Good shocks all the way around (bilstein or koni, potentially QA1 or others but I'm not familiar with their stuff much).

input/commentary?

1. I'd look at Lateral Dynamics 3 link for the rear:

http://www.lateral-dynamics.com/

2. S.C. & C. Package is a tough one to beat!

3. You may want to look at some Chassisworks Double Adjustable Varishocks.

Good Luck!

John

[71rs]

I guess I should mention that I need to stay with the leaf spring suspension for cost reasons. The base kit price for the 3-link is $3600, I'd like to keep the entire suspension under that. Even with the SC&C kit, custom rear leafs and some fancy bits thrown in, I should be able to do that.

[novanutcase]

I guess I should mention that I need to stay with the leaf spring suspension for cost reasons. The base kit price for the 3-link is $3600, I'd like to keep the entire suspension under that. Even with the SC&C kit, custom rear leafs and some fancy bits thrown in, I should be able to do that.

I would look at DSE for the rear leaf kit then..........

[79T/Aman]

600 front springs and 150 rears would work well, 200 in the rear will start to make for a rough street ride ( the rear gives ride quality remember riding in the back of the bus?)

[vaquero]

In my -75 Trans Am 400/350 I have Roadrace 650 adjustable hight front springs and a Hotshkis rear 1,5" lowering kit. It does not really lower the car very much but it has rubber front and poly rear bushings. I think they are about 190. I use 18mm lowering blocks and with the front adjusters it is easy to make the car level. I have Bilsteins allaround and when I bought them I was told they are a bit stiffer than the US versions. Adjustable uca's from Mark at SC&C to easilly get 5deg+cast. and 1deg-camb. Very nice! My tires are 245/45-17. I don't know if your motor and trans are lighter than mine but I think my car is a bit too soft both front and rear for inspired driving but very nice for cruising. And I must get solid body mounts, just put on new rubber ones but still too much body flex.

[71rs]

The more I've read and learned, the more I think I'd like to work with Chicane67 to design a set of custom rear leafs (the FIA-inspired design he has spoken about). Anyone have an idea how I can get ahold of him? I sent a PM a few weeks ago.

Thanks for all the input so far.

[David Pozzi]

We have the Hotchkis TVS system on my wife's 73 Camaro. We are pretty happy with it and the car sits about as low as it did before the install because the old springs were sagging. We autocross and open track the car in addition to street use with good results.

The Hotchkis leafs have a long lower leaf like a traction bar that helps stablize the spring, but I don't think it's the most sophisticated leaf setup out there. I'd sure try Chicane67's spring if you can get him to spec one for you. We are just now changing from the Hotchkis rear leaf to a Global West Cat5 because the Hotchkis leaf was just a tad low compared to the front. Some adjustment of the leaf pads or slightly longer shackles would have fixed them, but we wanted to try the Adams front perch mod, and that would have lowered the rear an additional 3/4", so it seemed easier to try the Cat5's. The Hotchkis leafs seem to be better for a tall rear/shorter front tire combo. If your fronts and rears are the same height, the rear looks low.

One tip is, most tuner leaf's will change your pinion angle.

From my tests of the Hotchkis coils and leafs the front is aprox 675, and the rear is 175. We have the GM crate engine 383/425 and have very little traction problems running a Kumho Ecsta MX 285X17 rear tire. I don't know how good our car would be at the drags but ours is not bad off the line with this setup.

I'd get Global West type upper Control arms, the caster they allow you to achieve really helps. Use their shafts, the stock GM shaft's don't really fit their arms.
David

[Bandit]

I think you would be happy with the Hotchkis TVS, depending on how much your stock springs are sagging you might actually end up with a higher ride! My rear ended up maybe an inch HIGHER after swapping in the Hotchkis "lowering" springs, but it greatly improved the overall stance of the car. The spring rates are as Mr. Pozzi mentioned, and very good all-around. They provide a nice street ride. The front only lowered on my car about an inch, maybe less, I assume also because of sagging stock springs/incorrect spring rate for my big block. I still had the Pontiac 301 springs in there LOL!
I can't really speak for the other custom springs out there but if you don't want to go with the TVS I know there are some good options, although it may be a bit more tricky to get other suspension components that are tuned to match.

Before TVS:
https://static1.pt-content.com/images/noimg.gif
After (with TVS installed):
https://static1.pt-content.com/images/pt/2007/01/5782373-1.jpg

Notice the rear actually sits higher now, but the spring rate is much better...

[SHANE 73Z]

David,

The GW Cat5 you are going to run, Do they have a pivot in both spring eyes or just the front?

Also, I am running a setup similar to vaquero. The only weight savings so far are aluminum heads,manifold, wp. I am running Alston Racing welded frame connectors & front structure kit with GW body bushings. In the front I have 500lb circle track coils/adjusters with SC&C upper ams and in the rear are 150lb Afco springs, GW shackle bushings & a Currie Johnny Joint in the front eye. I also have an old set of adjustable Rancho swaybars. I am currently running The Eddy IAS classics, but they will get changed soon.

Shane

[zbugger]

Shane, check out GW's site. They do have a pivot in the front AND the rear. They have a picture of the rear shackle on their site. At least they used to. They've been revamping it and I don't know if they've kept them up.

[David Pozzi]

They have spherical bearings in each eye of the leaf, then "solid" Del-A-Lum (delrin) in the upper rear shackle.

I don't know a lot of the details about these springs other that talking to Doug at SEMA a fiew years ago about them. My wife decided on them and just called them and ordered them, but I had been telling here that's the next thing we should experiment with.

Traction out of corners is NOT a problem with the TVS we at our power levels and tire combo. Maybe we'd need something fancier with more hp and less weight.
David

[71rs]

While the rates of the TVS springs are definitely in the ballpark, the system just results in too much lowering of the car for my purposes. I don't have another inch to give up front - tire clearance and header to ground clearance are already very close. I'd like to go UP an inch, perhaps 1.5", in the rear to get rid of the saggy look and level the car out, and stay where I'm at in the front. With the front springs too low and the rears not having a full-length 2nd leaf to the front eye (for traction bar replacement purposes), it's just not the ideal setup for what I'm looking for.

[Jayco_Automotive]

give martz chassis a call and ask them what would be best after all they are one of the best... or i could ask gary for you if yah want.