HELP! Front Suspension Woes

[Buick Motorsports]

Hey Guys,

First I will start with the information on the car:

-85 Buick Regal, SBC, T-Tops, 16,000 mile car.
-17x8.5 w/4.47" backspace. 245/45 fronts...275/40 rears.
-Suspension Techniques 1" drop coils
-Napa VST shocks front and rear
-UMI performance tubular rear control arms (poly bushings)
-7/8" front sway bar, no rear sway bar
-seat and front fram braces.
-installed missing body cushions.

Here is my problem, on larger dips in the road the front end seems to float and have an excessive range of travel. This results in the front wheels making contact with the inner fender well just inside the fender lip.

I estimate that the highest point of contact in the well amounts to about 3.5 - 4 inches of total travel. Too much?

I have 1 3/8 front sway bar and a 7/8 rear on order, will this help?

Would a Koni double adjustable shock help the problem? or just create other ones?

Thanks for any input you have.

Jason

[Mean 69]

4" of travel, or even near it, for a performance car is WAY too much (assuming you mean bump travel only). If this is indeed the case, you probably have very, very soft springs, and they are not capable of keeping your front end off the ground over bigger bumps. I am not familiar with the Suspension Techniques springs, but I'd be suspicious.

Sway bar diameters, etc, won't affect the performance of your front suspension in "pure" bump (meaning both front wheels are essentially travelling the same vertical amount over bumps, not in roll).

Shock valving is indeed important, a too-soft shock won't help, but shouldn't be the only cause fo what it sounds like you are describing.

I'd try new front springs. Keep in mind, that a given spring rate for one chassis won't automatically transfer to another of a slightly different design. The motion ratio of the suspension links is very important in determining how a particular spring will affect the wheel rate (which is what you are really concerned with). A really cool thing to do is to go the route that CarlC went, with adjustable "adapters," you can set the ride height far easier without having to cut springs to change ride height (which changes the spring rate as you do!!!). Check the circle track suppliers, such as Coleman, etc.

Mark

[Buick Motorsports]

I had considered that the springs were too soft, but I have not found a spring rate for the suspension techniques springs. I would not know where to start in replacing them. I hope that some of you might be able to help.


I really want to cure this problem,

Mark, I was referring to "pure" bump. What is a reasonable amount of suspension travel for a handling vehicle designed for street use?

The suspension travel by comparison front to rear with me applying the weight...

Front goes from 26 5/8" to 23 1/2"

Rear goes from 26 1/2' to 24 1/2"

these were measured at the fender lip in comparison to the ground.

[Supercharged 86]

Try Moog 5660 springs (probably a little lower than STs). They're a 640 lb spring rate though and should help. I would also get better shocks to help the floating.

[Dust87ss]

The ST springs are ~600# in front and progressive in the rear (~140# to ~160#). I dont think your problem is with the springs, but instead the shocks. The highest rate springs for the front of a G-body were 420#; a lot of replacement shocks cant handle the higher spring rates and then cant perform the way they need to.

Try a set of Bilsteins. Many praises from G-body owner using these shocks.

[Mean 69]

Oooh, something is just not right. You might have gotten a wrong set of springs, perhaps they got mixed up at the factory or something. If you can manually push the front of the car 3" with your own weight, the problem is the springs, period.

Again, I am not sure what the motion ratio of your suspension is, but if you truly DO have 600 lb-in springs, with a typical motion ratios of .6, the wheel rate would be well north of 200 lb-in, and you have two wheels. Unless you weigh 200-lbs x 2 x 3in = 1200 lbs, something is wrong (and if you do weigh 1200 lbs, my apologies). The ability to compress the front of the car this much with a "human" load has nothing to do with the shocks, which is not to say that the shocks might not be a further issue, but they aren't contributing here.

My 69 Camaro has basically the same spring rate, and I would imagine that the fitted rate/motion ratio is pretty similar. I weigh about 185, I just pushed on one corner of my car and it moved right around an inch or so. If you can, take a look the number of coils, the thickness of the coil wire, and the approximate gap between successive coils, in unloaded form if at all possible. You can calculate the spring rate from these variables, it'll at least answer the first order question about the springs being the "right" ones.

Mark

[Buick Motorsports]

Mark,

At this point, I would have to agree! There is no way that I should be able to encourage that kind of motion manually. I can't do this on the rear of the car, not even close!

I'm thinking that maybe I will give the Moog's a try. Unfortunately, I can't get the springs out of the car, at this time, to measure them.

Do any of you g-body guys have the part number for the Bilsteins?

I guess I'm screwed on the ST's, I doubt that I can prove they're incorrect and try to get another set. Chalk this one up to experience.

[Marcus SC&C]

Jason,you probably have a compound problem. 1) the shocks are too soft for your spring rate so you`re under dampened. That`s why you can bounce it so easily. Bilsteins (out of the box replacements) will be too soft for your rate also although they`ll be better than what you have now. I`d go with QA1 adjustables set at 6 as a baseline. We`ve used a lot of them and they work really well. You`ll be floored with the positive difference they make! I just installed a set of new direct replacement Koni adjustables. I can`t recomend them. There are no markings on them to indicate what they`re adjusted to and the "directions" are are a tiny pictogram that`s totally unintelligible. I was VERY disappointed. Anyway I would try swapping shocks before you blame the springs (although they may also be part of the problem if they`re out of spec).
Problem 2) the camber curves on the G body are backward. When the suspension compresses the top of the tire kicks out toward the fender. We fix this with our Street Comp packages (in addition to their other benefits) but it`s hard to do anything in this regard with all stock parts.
As a cheap fix you can try a set of Chevy S-10 ZQ-8 lower control arm snubbers. They`re taller than stock and made of a high tech elastomer that gives them a very smooth progressive rate. They also rebound slower than the suspension so they don`t add any rebound rate. They add a little more effective spring rate and reduce that "floaty feeling". We`ve used these a lot too with good results. Nice EASY mod for around $30!
The other thing you can do is check your alignment. If you`re at + something or 0 camber try -1/2 to -1 degree. With the + stock camber curve you can get away with quite a bit of - camber without undue tire wear. More - camber will pull the top of the tire inboard and farther away from the fender. It`ll improve cornering grip a lot too. We do a lot with ProTouring G bodys (I drive one every day!). Feel free to contact me at the shop if you like. Marcus

[Buick Motorsports]

Marcus,

Thanks for chiming in with all that advice. I am familiar with your products and would love the G5.... maybe a little into the future.

As far as the QA1's go, are these the part numbers for the ones you're referring to:

HAL-TC1661P
HAL-TC1914P

I may be in contact with you in the near future. I am really set on having the best handling Buick in this city. I am interested in your Street Comp package as I really want to maintain the tire and wheel combo I have.

Marcus, Email me the shipping cost of the Comp 2 package to Winnipeg, MB R2R 2E2.

As a final note to the g-body guys, the ST front springs are rated at 610 pounds. Got that figure straight from them.

[Mean 69]

Sorry to beat what I feel is a dead horse, but you issue lies in the springs, not the shocks. The shocks determine the RATE of change, not the absolute travel.

A set of springs, properly chosen, are FAR less expensive than a set of shocks, again, properly chosen. I am personally not a big fan of QA1 shocks, others like them, but I have never met a racer that would even consider them. Bilstein's, in the stock valving, if not correct, can be easily revalved from them, they do this stuff all of the time and it is not that expensive. Call Bill Hendorf out here in California (Poway, a suburb of San Diego), he will set you up, and you'll have a FAR better shock than a QA1, albeit non-adjustable, for basically the same price. For a steet car, you don't need to adjust much anyway. If ever. Which you won't.

Again, to stress, if you can manually move the front of the car by 3", by yourself, and you weigh less than 400 lb, you need to look at the springs, FIRST. Better yet, rather than bounce the car, have you and a friend SIT on it. Measure the before and after. This way, you eliminate the shock. One corner is fine. Have her sit on your lap! But, by all means, don't share her weight on the web, if she ever found out, you'll be dead, regardless of how little/much she weighs, it is always a losing proposition.

Fundamentals...
Mark

[Buick Motorsports]

Mark, I will also measure that and post it and get further feedback from both you MArcus.

Jason


Measured the right side:

Startin measure - 26 5/8

125 pounds placed on front corner - 26

214 pounds placed on front corner - 25 3/4

[Mean 69]

Yep, that sounds about right, so I'll retract my statement about the springs being the primary cause.

Mark

[Buick Motorsports]

Thanks for your input Mark. This is a big learning curve for me.

THanks to all of you.

[Mean 69]

No sweat at all, this is how we ALL learn. Keep us involved with your next steps, it'll be helpful to hear what fixes it.

M

[Buick Motorsports]

Hey Guys,


Thanks again for your input on this. I have decided to spend the big bucks go with the QA1's.

I figured that I'd rather spend more now and have the adjustability as my driving dictates.

I will post again once I receive and install them.

Marcus, if you catch this I will be in touch. Your front UCA's will be on my winter mod list.

[Marcus SC&C]

Sorry I haven`t checked in in a while. I think you`ll be happy with the QA1s. Their range of adjustment is huge. Our G-5 car is running 705lb/in front springs and with the shocks set at 1 you can bounce the car all over the place,make the headers scrape,tires hit etc. Set at 3 or 4 they ride nice and soft but nothing hits. At 5 they`re firm but not harsh. At 7 they`re FIRM but livable. At 12 you might as well weld the suspension arms solid. ;) They really let you tweak the car the way you want it. They can even change understeer/oversteer to some extent. Good parts for the money. I`d sell them if QA1 would give us a half decent price on them but you have to be Jegs or Summit to get that. Doh. Marcus