Flex-a-Form Fiberglass F-body springs

[CarlC]

For those interested there is a new section on my webpage that shows the new 250 #/in Flex-a-Form fiberglass rear springs. They have been modified to use a spherical plain bearing system (similar to CAT5) on each end.

[Taylor1969]

For those interested there is a new section on my webpage that shows the new 250 #/in Flex-a-Form fiberglass rear springs. They have been modified to use a spherical plain bearing system (similar to CAT5) on each end.

Carl,

I planned on purchasing rear springs soon and would like to know if you can go into a little more detail on what is necessary to complete this setup.

Did you purchase directly from flex-a-form? Can I purchase the rear cat5 bushings from GW and put them directly into these springs? I am looking to drop the car as well. What does the ride height look like with these springs? Are Qa1 12 ways the best shock to get with this setup?

Thanks,
Chris

[CarlC]

Did you purchase directly from flex-a-form? Yes, it's the only way.

Can I purchase the rear cat5 bushings from GW and put them directly into these springs? No. As noted on my website the spring eyes must be bored to fit the spherical bearing housing.

I am looking to drop the car as well. What does the ride height look like with these springs? 14 1/2" from the center of the axle to the bottom of the fender lip. Another 3/4" - 1" lower is possible by flipping the spring eyes over.

Are Qa1 12 ways the best shock to get with this setup? I don't know, but a friend has the same setup with adjustable QA1's and it seems to work well. I don't know what the on-track reliability of QA1's are.

[Mean 69]

Very cool, Carl, and as always, thanks for the open and candid feedback.

The spring rate seems pretty high, and I read that you felt it rode smoother than the softer Gulstrand springs, which is cool. How was it in terms of putting the power down though? I run quite a bit softer rate on mycar (different suspension, as you know), and with tighter springs there is more of a tendancy to spin the tires on corner exit, etc. Just wondered if you had an impression on that specific attribute. I was a little surprised that there was a bit more lateral movement, I wouldn't have guessed that.

Mark

[Lowend]

I'm curious to know what you are using for shocks?
In my experience fiberglass springs need massive amounts of damping, more than an off the shelf shock can offer

[CarlC]

Mean,

Corner exit is similar to the previous springs. For low-speed exits, like many at SOWS, I have to be careful not to overpower the tires during acceleration. Higher-speed corner exits still exhibit quite a bit of aft weight transfer (see the pic on the Alcino's Bachelor Party post in the Racing Events section). It squats close to 2-1/2" in that photo.

The shocks are Bilstein AK2074. I need to call Bilstein and talk to someone about having them re-valved, if needed. So far, they work pretty well. Lap times are the best so far, and the track temperatures were 40* warmer than the previous best. Same setup on the car except for the spring change.

[rattus]

Carl,
Thanks for the info. I'm curious why you chose Flex-A-Forms over Hyperco's composite leafs (as they offer 250 lb/in leafs)?.

Another thing: Does you Flex-A-Form offer higher (than 250 lb/in) spring rates?

And finally, could you give some more detail on the parts you used to construct the spherical bearing ends?

[CarlC]

Hyperco's were my first choice, but the spring eye does not appear ridgid and does not completely encapsulate the bushing. The FAF ends are a very beefy alumunum extrusion and can be bored from 1.555" to 1.600" to fit a GW CAT5 bushing.

For spring rates you will need to talk to George at FAF directly.

All of the parts in my setup are hand-made except for the bearings. QA1 offers a bearing that is ideal and is reasonably priced. There are plenty of others available in the industrial power transmission world that will work as well.

I do have an Excell spreadsheet that I used to make a drawing. I can send it to you if you would like, but in all honesty after the time and materials cost I would rather buy the parts from GW. There's a lot of machine time, some fairly precise bore diameters, and anti-corrosion coatings required to get things right. Either way, the spring eyes need to be bored with a boring head to match the bushing housing diameter. With all of the parts needed to do the job + eye boring you're looking at close to $800 total.

[Steve68]

Carl, Gulstrand can revalve Bilsteins for you, FYI,

[chicane67]

The shocks are Bilstein AK2074. I need to call Bilstein and talk to someone about having them re-valved, if needed. So far, they work pretty well.

Something like..... 250/90 would work with that rate. Looks like its time to give Shane a call and mail a package to Poway.

[Steve68]

Tom whats Poway?

[chicane67]

Poway California.

And BTW, Guldstrand will pretty much only do the valving that they know for their own, known spring rates. Anything custom, rate to damper, is going to be handed to Mr. Hindorf via Shane. Its much easier to cut out the middle man in this situation.

[alcino]

How much are those spherical bushings from globalwest? I found pics of them but they seem to be part of "cat 5" spring package. Do they sell them seperatly? I guess I could call them, but thought I would ask here.

Did you get a chance to ride the Flex-a-forms with the original bushings to compare the ride to the sphericals?

[Mkelcy]

How much are those spherical bushings from globalwest? I found pics of them but they seem to be part of "cat 5" spring package. Do they sell them seperatly? I guess I could call them, but thought I would ask here.

Global West website listings for first generation Camaros:
"Part # 115SH ----- This a category 5 bearing and shackle kit. It converts your stock system over. Cost $460.35"

[Stu Seitz]

By going from a solid bushing, in both front and back, to a spherical bushing in the rear and a solid in the front. Would this require a sta bar in the rear?

[wendell]

I think the reduction in roll stiffness from a monoball in the REAR spring eye is going to be marginal and won't require a sway bar.

[6'9"Witha69]

Carl, good to see you got those in and had some fun on them. Since the day you showed them to me I have been thinking about doing the same.

[Steve68]

Tom, I see, yes I understand cutting out the middle man,

[CarlC]

I did not try the springs with the standard, as-supplied bushings. Frankly, the as-supplied bushings were terrible. The diameter that fits into the spring eye was "customized" with a belt sander to fit. For me this did not matter since it was decided to go with the spherical bushing from the get-go.

The bushings are installed in both ends of the spring so roll bind is basically gone. Anti-roll bar requirements will depend on how the car is set up, but I went this route to get rid of the Hotchkis bar, which has a low effective rate but helped the car a bit.

GW will sell just the bushings separately. I already had the upper GW del-a-lum bushings and shackles so all I needed were the spring eye bushings. Doug sold these to a friend of mine for $350. If the advertised CAT5 kit has the frame del-aa-lums as well, it's a pretty good deal.

[rattus]

It appears that Global West will no longer sell the spherical bearing kit (they say they're only available w/ their Cat5 springs).

However, Deaver Springs offers these:

http://www.deaverspring.com/BajaBushing.htm