[Navy Horn 16]

I have a 77 "Frankenbird" than I have been working on for the past couple of years. This car was born as an Esprit (though wearing TA front body panels and hood), had a 350 on it's last legs when I bought it, and 2:41 gears. It now has a completely rebuilt 400, Aluminum E-heads via Kauffman, all roller valve train, RPM Performer intake, 3.42 gears (posi), and is running fantastic. To say that I am traction limited would be an understatement.

The next item on my hit list is suspension. This car has none of the fancy WS-6 suspension, though the rear axle did come out of a 79 TA. I have pretty significant body roll when I corner, enough that being hard on the throttle in anything other than a straight line makes me a little uncomfortable. Getting hard on the throttle out of a turn results in enough roll that my rear tire rubs the struts and makes an awful noise.

I received a body bushing kit from my BIL last Christmas, but haven't gotten around to putting it on yet. There are new shocks on the front end. New rubber all around.

My first instinct was to add sway bars, but am second guessing myself. Should the first move to stiffen up an F-Body be sub-frame connectors? Should I do both at the same time? If I go with a sway bar, front or rear first? (wife has me on a budget)

Has anyone used these products, or recommend a better one?
http://www.summitracing.com/parts/up...FdgQgQodV7IAKQ

A bolt in option:
http://www.jegs.com/i/Competition+En...FdM8gQodCZEAEw

The sway bar kits I'm looking at:
Front:
http://www.summitracing.com/parts/hs...w/make/pontiac

Rear:
http://www.summitracing.com/parts/su...model/firebird



Thanks a bunch for any ideas or advice you might have.

[JLMounce]

Get your body bushings installed simply because you have them, but don't expect them to solve your roll issue.

With the car starting life as an esprit, more than likely the spring rate (specifically in the front) is far too soft for the heavier engine package you're now running.

A larger sway bar may help somewhat, but that's kind of the backward approach to suspension engineering. You want your springs and dampers to do the work and fine tune using the sway bar. Not the other way around.

If you like a more stock type ride and stance, I would source replacement springs and leafs from a V8 car. That will likely cure most of your problems.

If you're wanting a modified ride height with greater cornering ability, there are any number of kits, combinations and spring types to choose from.

I am currently running Hotchkis big block springs in the front of my 69 Firebird and their 3" drop leafs in the rear. I've added a half inch tall ball joint to the factory upper arm and currently utilize the factory 11/16th solid sway bar.

I've not begun to test the limit on the car yet, but this setup handles predictably and fairly flat around harder sweeping corners.

In regards to the chassis stiffening, if you're interested in cornering, it's a good idea, it lets the suspension do the work it's supposed to without as much deflection from the chassis itself. However the one thing it may do on an improperly sprung car is make that condition more noticeable.

You'll get better results by doing things in this order.

1. Springs/dampers (include control arm changes in this step if you want to move away from factory control arms)
2. Chassis stiffening
3. Sway bars for tuning balance

As a note, because of how a traditional leaf spring rear suspension works, rear sway bars can sometimes have ill effects. I would opt out of the rear sway bar at first and test your setup. If you find that you need a rear bar, I'd opt for an adjustable sway bar.

As a very general rule of thumb, adding bar in the front provides more traction at the rear. Adding bar to the rear adds more traction at the front.

So going with a large solid bar in the rear can have the effect of creating a car that really wants to oversteer. That's sometimes a good thing, if you're trying to get the car to rotate quickly in an auto-x type setting. It can become dangerous on the street where you want a car to have a more neutral balance that maybe leans towards understeer.

[frbformula]

I used the bolt in sub frame connectors that you posted above with solid body mounts. The sub frame connectors fit really well and I like that you can still take the front sub frame off the car if you need to. I would only do weld in connectors if you never intend to take the sub frame off again. I plan on doing a full resto on my car at some point so I opted for the bolt in ones

[Blued and Painted]

Adding a sway bar to the rear where there was none made a positive world of difference to my A body (coil spring car).

[David Jones]

I found a guy that had the front sway bar / steering box off of a 1978 WS6 T/A and installed the parts on my GTO. I also added a BMR Fabrication rear bar. Replacing 40 year old Esprit springs would help your cause.



Weld in connectors would help.

[Navy Horn 16]

Lucky for me, the previous owner put the correct springs when he put the 350 in it. I've also done an AC delete on the car and lost a good bit of weight by replacing the iron heads and intake with aluminum. My ride is really smooth when driving normally, and there isn't any bounce when going over bumps. It's only when aggressively cornering that I get the body roll.

Thanks for product review FRB. You make a really good point about being able to remove the bolt on kit if necessary. I think the next step is to get that kit ordered and on the car with the bushings and see where I'm at.

[JLMounce]

Originally Posted by Navy Horn 16

Lucky for me, the previous owner put the correct springs when he put the 350 in it. I've also done an AC delete on the car and lost a good bit of weight by replacing the iron heads and intake with aluminum. My ride is really smooth when driving normally, and there isn't any bounce when going over bumps. It's only when aggressively cornering that I get the body roll.

Thanks for product review FRB. You make a really good point about being able to remove the bolt on kit if necessary. I think the next step is to get that kit ordered and on the car with the bushings and see where I'm at.

That's good news. From the factory these cars are fairly undersprung as it is. A larger roll bar will help a bit for sure, but I would still caution using a rear sway bar. Especially that solid 1" bar that you linked. That is going to add a ton of wheel rate in the rear.

I would recommend this rear bar instead.

http://www.summitracing.com/parts/he...model/firebird

It's a 3/4" solid bar which isn't going to add as much rate as the solid 1" bar and it's also adjustable which will let you tune it to your style of driving.

[JLMounce]

Just for the sake of not confusing the OP, I do want to point out that a rear sway bar functions a lot differently on a coil spring car vs. a leaf spring car like an F body.

The problem is that with leaf springs, the axle itself functions as a suedo sway bar. A traditional leaf spring is anchored to the axle and has no inherent pivot along the leaf's parallel axis. What pivot does occur happens primarily in rubber bushings in the eyelets. This is why you never run solid bushings in the eye of a leaf spring. You'd have near 100% bind during cornering.

The converging four link and coil spring setup of the bigger cars allows the axle to pivot a good deal more before the 4 link starts to bind. As a result using a rear sway bar in this application makes more sense.

That's of course not to say that a sway bar can't help a leaf spring rear suspension. It's just usually not necessary on a street car or hobbyist motor sport cars.

If I was running Global West Cat5 leafs that contain spherical bushings and are designed to allow the axle to pivot, then I'd be more apt to also run a rear sway bar.

[Mike Fowke]

Ditto what JLMounce posted - especially the rear bar. I upgraded my '78 WS6 T/A with Global West springs, del-a-lums, frame connectors, and solid body bushings. The rear bar was beneficial to the stock set up, but it created over-steer with the aftermarket stuff.

Also, solid bushings are recommended with sub-frame connectors. If yours aren't solid, you may want to sell them rather than replace them twice.

You could also save a few bucks with a used WS6 front bar. I doubt there would be a noticeable difference between it and the Hotchkiss bar unless you're going full blown pro-touring.

If you want to save a few more bucks, I still have the factory WS6 replacement springs from my restoration. They have less than 8k miles on them. PM me if you're interested.

[1966socalgoat]

For what you want to do with the car, listen to Crocie!!

[Singleton]

Originally Posted by 1966socalgoat

For what you want to do with the car, listen to Crocie!!

Old post, i'm sure he's figured it out by now....

[Formulajones]

Apparently not. People are asking for updates now. Maybe he'll chime in, since it's been a while he may have formed a solid opinion with plenty of time for some mileage accumulation.

I for one would like to hear how it turned out.

[Bigger is Better]

You didnt mention a budget but if I was looking at an end to end budget solution I would look stiffing the chassis and then increasing the roll/spring rate and front/rear balance.

For the chassis you can get solid frame to body bushings and then the next step would be subframe connectors.

For the roll/spring rate you have a few options. You have some factory options like the WS6 bars (still what I use) but you might have a tough time finding them and there are lots of aftermarket ones now. For springs I would recommend new ones as they are pretty cheap.

Instead of buying from Summit you might want to call a suspension focused shop like Global West, CCP.... I usually recommend Pro Touring F body but they do also sponsor my race car , but seriously they do offer a lot of budget friendly solutions.

[Navy Horn 16]

Thanks everyone. My Brother-In-Law was smart enough to get me the solid body bushing kit. I'll check out those sources for the subframe connectors.

The guy that sold me the car has an extra set of WS-6 sway bars in his barn, so those are found.

Thanks again for all the info and knowledge. I originally thought rear-sway bar ahold be first. Sounds like that will be last (if at all).

[CROCIE JR]

No F body car I have ever built, raced, tuned or street driven had the rear bar removed. Lap times are fact, personal feel is subjective. A 7/8" chromoly rear bar and a 1 3/8 solid chromoly front is my choice for all street and auto cross cars. Spring rates in the 480-520in/lb in the front and 115-144 in/lb in the rear. Koni reds or KYB whites. Subframe connectors and solid bushings make the car noisy inside and from all customer feed back plain "annoying." Dont do it. Have you seen f body chassis deflection data? Frequency analysis? Soft springs and big bars are king on the street. BTW this has been tested, proven and for what its worth published in magazines. Winning!

[Will]

^^Ditto.

Swaybars will do the most to correct body lean for the money spent while doing the least to alter the ride characteristics. They are also easier to install than springs.

Springs will definitely help ultimate handling, but for a relatively cheap and very easy to install remedy that will have a huge effect without killing ride quality get some beefy bars on there.

Good shocks would be my next upgrade (I've had excellent results with Koni reds - I don't like the KYBs. I hear Bilstein are also very good). Again, much easier to install than springs and will make a big difference.

If, once you have the bars and shocks, you find the car has too much nose lift/dive on acceleration/braking or still isn't handling up to what you would like, get springs.

Control arm and leaf spring bushings are also a good upgrade. Body bushings and subframe connectors aren't going to make a huge difference.

[Navy Horn 16]

So, now we have distinctly different camps.

The first group says bushings, sub-frame connectors, sway bar (rear last).

Now I'm hearing that putting in a rear sway bar where there currently isn't one at all is probably the best first step.

Fun.

Well, I went ahead and ordered the rear sway bar. Mostly because it is what I can afford right now and I can install it myself, and there isn't anything there right now.

I'll report back in a week or so once it is on.

[Formulajones]

Originally Posted by Navy Horn 16

So, now we have distinctly different camps.

The first group says bushings, sub-frame connectors, sway bar (rear last).

Now I'm hearing that putting in a rear sway bar where there currently isn't one at all is probably the best first step.

Fun.

Well, I went ahead and ordered the rear sway bar. Mostly because it is what I can afford right now and I can install it myself, and there isn't anything there right now.

I'll report back in a week or so once it is on.

I don't think you'll regret it. After all, GM figured all the TA's and Formula 2nd Gens should have rear bars. Worked okay.

I was never into G-machine stuff. I like good ride quality, with decent handling, enough to feel comfortable. My 70 Formula is all stock stuff suspension wise, with poly subframe bushings. I do also have poly bushings in both front and rear sway bars, No sub frame connectors, original 50 year old springs front and back and stock type shocks. The ride quality is nice, handling is as good as I feel it needs to be for a daily driver. Fun to drive through the mountains and at least gives a sense of some stability and predictability. Won't win an autocross contest but that's not the goal anyway. For a 3800 lbs. car it's acceptable IMO as GM delivered, and I have nearly zero money in the suspension.

Try jumping in the 56 nomad for a ride around the block and when your done the Formula will feel like a little slot car LOL

[android 211]

It isn't until you replace the subframe bushings that you will realize how much the body was flexing. If the front springs have been replaced with something stiffer and you like the ride height then replace the front bar with a TA 1 1/4" piece. GM used 1 1/8" after 1974 except on WS6 cars which got the thicker one. The rear bar was only 3/4". I'd source TA replacement springs all around. 70-74 was lower and stiffer. '75 up was softer due to owner compliants about stiff ride. I thought my '72 was real stiff until I was going over 70 then it seemed appropriate.

[CROCIE JR]

After many years making these cars pull .95-.98 G on sticky street tires and over a G with race tires, none of them had sub frame connectors. You are not going to be anywhere near those numbers with your set up. I have built cars with roll bars (4 point) in conjunction with sub frame connectors and made for a horrible (subjective terminology) street car. So if any of you guys have actual data lets hear it.