I'd like to ask for recommendations for front spring rate. The car is a steet car with good handling as a goal. The roads in the area I live tend to be rough. So I can't go too high on the spring rate.

I am also going to use either Landrum or AFCO adjusters. In the past I have had just way too much fun getting the correct ride height. graemlins/clonk.gif

I was thinking of a 550 lb spring, but am concerned about ride. The roads here are so bad that there are some I won't even take my 1st or 3rd gen on. But like all good motorheads I want a good handling and cornering vehicle.

Thanks in advance,

Bob.


Engine/drivetrain:

SBC
aluminum heads
aluminum intake
headers
manual transmission
A/C system, factory

Battery mounted in trunk
Sub frame connectors
Solid body mounts, lowered

Front Suspension:

Bilstein shocks
guldstrand mod
VSE spherical bearings (lower A arm)
VSE nyloc upper arm bearings
VSE sway bar (1-1/4"?)
poly frame bushings (on sway bar)
heim ended end links (on sway bar)
HD center link
tubular tie rod adjusters
disk brakes (11", D52 caliper)


Rear Suspension:

Bilstein shocks
3 leaf spring (240-260 lb), Betts GP
VSE sway bar (to be adjusted as required)
Del-a-Lum spring eye bushings
aluminum drums on brakes

Rims/Tires:

Currently a 15x7 with a P225-60R15 Comp T/A

Since tire manufactuers are phasing out performance tires for 15" rims I'll probably be going with a 16x8 rim with a KDW tire.

[ 04-22-2004, 02:43 PM: Message edited by: a67 ]

since your roads are so bad, I'd usually say to try a Moog #6308 which is 380 lbs/in.
AFCO makes a larger inner dia coil adjuster #20191, that is more compatable with large dia shocks like the QA1. A spring rate of 400 lb would be nice. AFCO does not list a 9.5" tall X 5" dia coil spring below 500 lbs, but they should be able to make a pair for you. They are stock shape on the bottom end, flat on top for the "hidden" adjuster.

A spring in the 550 range is real good if the roads are kinda average, 650 or so will be good for severe use like autocross and open track events, not bad at all on good roads, probably too stiff for your use.

Just remember with the softer springs, you will have more wheel travel and can't have the car too low or it may bottom out. The larger wheels and much better KDW tires will cause more G forces to be achieved, so your car will pitch and dive more. The sway bars will tame down the roll, as Herb's system is designed around soft springs and stiff bars anyway.
David

http://www.afcoracing.com

Well Bob, with the rear spring rate you are going to be running, I wouldnt even think about bolting a rear sway bar onto it. Atleast not with the soft front spring rates you are considering.

The Bett's springs are to be used with a chassis that has at least 400 ft/lbs/tq rear wheel and I would say at a minimum of a 550 to a 600 front. Anything less and you'll be swapping ends through corners, as it will most likely oversteer badly when driven fairly hard through a turn. So bad I think, that you'll need a fair amount of toe-out to compensate.

If ride quality is your main concern, I myself would run a 550 with the rear springs you have, but I wouldnt run the rear bar.

Dave, Tom, good input, thanks. Yes, that rear bar just may be a problem. I had planned to leave it off with the install of the new springs/shocks (the front & rear springs & shocks are being replaced, all the other listed suspension goodies have been in place). I've once before 'adjusted' the rear bar by grinding it flat on two sides. With the mono-leafs and stock VSE bar the rear of the car liked to get loose. Without the bar the car didn't want to turn.

Once back together and have a chance to drive the car I'll decide what to do with it. Can either leave it off, or grind it down even more. All depends upon the balance.

Don't quite have 400 ft/lb/tq/rw but am close to that. I am going to go with the adjusters as posted (thanks Dave) and the 550lb spring. That same number came up in both posts.

It's funny about the Betts GP, I jumped on it quickly and didn't even think about the rate until later. I then emailed Ken and inquired about it. What a forehead slapping moment that was. . .

Bob.

Bob,
From what you already have, and haven driven the Bett's springs, I think you will have a very nice ride. I think you will find that don't need the sway bar just as Tom says. The little bit of driving I have done has shown the rear to be a little free. I used the Moog 6041 springs and cut them to about 600-615 lbs/in. I may end up cutting them a little more. Anyway, it sounds like you have the right components to make this car work well.

Good luck.
Ken

Update: have the 550# fronts springs in with the AFCO adjusters and Bilstein shocks. No rear sway bar (left it off).

This rocks! smile.gif

The ride is much better then I expected. To tell the truth I think it is better then the original springs and shocks (6-cyl spring w/Gabrial Strider shocks).

I could even see using a 600# spring with no qualms. It really rides and handles that nicely. And the adjusters. . . the only way to go. Won't do it any other way. So easy to adjust the ride height and level the car.

The front springs conclude the suspension update. This winter the car received the Betts rear springs with bearing type bushings (all 6), the front 550# AFCO springs w/adjusters and Bilstein shocks all around. Good for another 20 years graemlins/thumbsup.gif

Bob.

Thanks for posting the results!
One important variable is the A arm bushing material. Polly bushings make the suspension act stiffer because they have "stiction" (Herb Adams quote). Good shocks are important too.
David

Dave, your welcome. About the poly bushings, I put polygraphite lower A-arm bushings in my '92 Camaro and am sorry that I did. They are stiff, not compliant at all. Some day I'll do some bearing type bushings for it.

Again the '92, I even did the rear trailing arms up by boxing them and using poly bushings. Just did not work out, too much bind as the rear articulated (or tried to) over bumps.

Pulled them off and used tubular steel trailing arms with kevlar/teflon raced heim ends (QA1's). Now that works!

The '67 (back to the '67 f-body) will now corner so quickly I have to watch out for vertigo. It's going to take a little time to get used to it again. Now if other drivers would just stop trying to follow me through the curves. . .

Bob.

Yo Bob....can ya post a pic or... ten? I would love to see what the ride height came out to be one those who used the Betts springs.

Glad to hear your input. It is nice to see someone else getting to enjoy their ride as much as the rest of us..!! graemlins/thumbsup.gif

a67,
I would list two sets of spring rates, one for Delrin type bushings, and another for Polly bushings if I could ever figure out how much to allow for the polly bushings! graemlins/clonk.gif

As I've said here before, I've got a buddy with a 69 Z/28 who has had polly forever in the front A arms and they squeak LOUD when he jacks it up in the pits to change tires. He open tracks the car and it feels like he has 700 lb springs in front, or even stiffer, but he has stock ft coils. The suspension is all bound up and will barely move!
I told him to change out the bushings but he doesn't want to "mess with it"! graemlins/clonk.gif

He is having fun with it as-is I guess.
David