Handling issues, Please help!!!!

[ikle]

I am having what I believe is oversteering issues with my car when entering a corner. The rear feels light and unpredictable. The best way to explain this is if you ran really low air pressure in the rear tires and tried to take a corner at 50 mph, almost like driving a fork lift. I am lost on how to correct this, my suspension from front to rear has been entirely upgraded.

Front: Global West uppers with brass bushings for pass side and Del-A-Lum bushings for drivers side
Rebuilt stock lowers with Del-A-Lum bushings and Afco light weight stock replacement ball joints
Kirban stock replacement springs
Bilstein shocks with poly grommets
Moog outer tie rid ends
A/C Delco inner tie rod ends,center link,pitman arm and idler arm
Stock swaybar with greaseable poly bushings and poly grommets on the connecting link
New front wheel bearings

Rear: Metco adjustable upper control arms with greaseable poly bushings and poly bushings in rear end housing
Metco lower control arms with greaseable poly bushings
Detroit Speed adjustable pro touring swaybar
Kirban stock replacement springs
Long pinion snubber
Bilstein shocks
On a side note I had this problem before I installed the Detroit Speed rear swaybar and before I rebuilt the front suspension,my car handled a lot better when I just had stock control arms in the rear with a 1 3/8 Fullthrottle swaybar. What can I do to solve this problem ? Thanks, Kyle.

 

[dsapper]

There are a million ways to correct understeer. Lower your front tire pressure and raise the rear, stiffer front or softer rear shocks, raise your front end or lower the rear, etc. I could go on for hours.

What is the height and width of the front and rear tires, is there a difference in track width because of tires? What is the front and rear ride height? What is your toe in? What is your positive and negative camber setup as?

Without knowing those details my guess would be your swaybar setup even though you said it was there before hand. Bigger sway bar would just make it worse. You need a stiffer swaybar up front to counter act the dse one. Try this, remove the rear sway bar and try again. If it gets better buy a huge swaybar for up front.

 

[ikle]

Dsapper, thanks for the quick reply. If I remember correctly the problem began when I replaced the rear springs and stock rear control arms. It's just not making any seance to me. At the time I was running a stock rear swaybar, so I thought the bigger Detroit Speed swaybar would help. Getting confused.

 

[dsapper]

The bigger sway bar in the rear increases understeer, your going the wrong way. Did the control arms change your ride height? Stiffer rear springs and softer fronts will give you understeer as well. Are your tires old/new? Whats the air pressure? I need some more info but its a fairly exact science not alot to it if we have the right information

 

[charlief1]

This is the exact same thing that you see when it comes to matching a turbo with an engine and everything inside it. To set a chasis up right you need to weigh it first to see where the weight sits. You use all the parts you intend to use but stock springs will help you decide what spring weights to use front to back. What I do see is a mismatch in the sway bars you've chose to use. 99% of the weight is in the front of the car and you got a bar to control the rear.

First thing I will tell you is get the car scaled so you've got front/rear and side/side as well as cross weights. This needs to be done as if you normally drive the car, passengers and all. That will give you a better idea of how the car's sitting and how it will react going straight or in a corner.

I noticed you said "stock" springs from Kirbans. Have you checked to see what rate they've got to make sure they're stock spring rates? One other issue I know of is using "cargo" coils/springs on the rear which have a habit of loading and unloading on acceleration and can cause the rear to kick out in corners.

 

[dsapper]

charlie is right, but I noticed something. In your original post you said stock springs front and rear. Then you said it started after changing your rear springs. Charlie brought up a good point, its very possible if you replaced the rear springs independently of the front ones you have a set of slightly worn front springs and fresh rear springs, that would create understeer and the swaybar situation would just magnify it. Are the front springs new or original? Do you know for sure the springs rates on both of them?

 

[charlief1]

Are the front springs new or original? Do you know for sure the springs rates on both of them?

That was one of the things I was getting at. If you're using "cargo" coils on the back they're variable rate and when you go around a corner the weight transfer will make the rear increase in spring rate. I used variable rate springs in my (long time ago) SCCA car. I also stiffened the fronts up quite a bit and had a good 4 wheel float out of it. I could control the rear with the gas which was exactly how I wanted it. The car would power through a corner really nicely.

 

[ikle]

The front springs are new I installed them 2 months ago, the rears are about 3-4 years old. On Kirbans site it says the rear springs are variable rated springs designed to handle 400lbs more than stock springs. The front springs are stock height and 20% stiffer than stock. I'll post up some more info later on tonight. Thanks for your help guys. Kyle

 

[Chuck Leeper]

Why the long snubber?

 

[charlief1]

The front springs are new I installed them 2 months ago, the rears are about 3-4 years old. On Kirbans site it says the rear springs are variable rated springs designed to handle 400lbs more than stock springs. The front springs are stock height and 20% stiffer than stock. I'll post up some more info later on tonight. Thanks for your help guys. Kyle

Get a bigger front sway bar and put regular springs in the rear. That should help get rid of the issue. The chasis is unbalanced.

 

[Heg87t]

Why the long snubber?

I wondered about this also. Is it contacting the rear end housing and unloading the suspension? Put a little grease on the snubber and see if it transfers to the housing.

Are the Global West front upper arms for the stock spindles or B-body?

 

[ikle]

Get a bigger front sway bar and put regular springs in the rear. That should help get rid of the issue. The chasis is unbalanced.

charlie, which rear springs do you recommend, looking to maintain stock ride height, also will a 1 3/8" front swaybar get it done if so should I go with a hollow or solid bar. Thanks Again, Kyle.

 

[ikle]

I wondered about this also. Is it contacting the rear end housing and unloading the suspension? Put a little grease on the snubber and see if it transfers to the housing.

Are the Global West front upper arms for the stock spindles or B-body?

I am going to remove the longer stubber and replace it with a stock one, the Global West G-Plus uppers are for stock spindles, their Negative Roll arms are for B-body spindles.

 

[ikle]

charlie, which rear springs do you recommend, looking to maintain stock ride height, also will a 1 3/8" front swaybar get it done if so should I go with a hollow or solid bar. Thanks Again, Kyle.

Charlie the solid front swaybar is 1 5/16 not 1 3/8 sorry, Kyle.

 

[dsapper]

Get the large helwig sold front swaybar. You will need a fairly beefy piece to compensate for the DSE one you have. As for the springs, it depends on what the spring rate for your front ones are.

 

[charlief1]

charlie, which rear springs do you recommend, looking to maintain stock ride height, also will a 1 3/8" front swaybar get it done if so should I go with a hollow or solid bar. Thanks Again, Kyle.

For stock ride height get MOOG 5600 front and MOOG 5379. If you want to get a stiffer set of springs then get MOOG 5658 front and MOOG 6377. The second set will lower the car 1" overall and help handling. If you want a lighter spring on the front you can use MOOG 5608 springs for a softer ride than the 5658's. If you get a new front sway bar the hollow are lighter and do the same as the solid ones, they just weigh less.

 

[ikle]

OK correct me if I am wrong, understeering is when the rear of a car turns to quickly when making a turn, similar to how it feels when driving a forklift. This can be caused by the spring rate to high in the rear or to low in the front, or to stiff of a shock in the rear or to soft of a shock in the front. Also the rear of the car to high or front to low, to big of a swaybar in the rear or to small of a swaybar in the front, to wide of a tire in the rear or to narrow of a tire in the front, or to low of tire pressure in the rear or to high of a tire pressure in the front. Or a combination of these, correct. Thanks for your help, your information is greatly appreciated, Kyle.

 

[dsapper]

Understeer means the front end of the car comes out. Oversteer means the rear of the car comes out. Honestly for spirited street driving I like a bit of oversteer. Understeer is just dangerous.

There are tons of things that affect both of those, the ones I listed are just some of the easier ones. Good news is your dealing with a fairly well known platform. In your case your rear swaybar choice and springs (on paper) would give almost anyone oversteer. Like I said, dissconnect your rear sway bar and drive it then tell us how it feels.

 

[scot w.]

Ikle,

Did you get your rear sway bar from us?
What size is the DSE rear bar? 1" or 1-1/8" ?
Where are your sway bar end links located? Which hole (first or second)?
1" rear sway bar rate adjustments - Front hole = 722 lb/in Rear hole = 947 lb/in
1-1/8" rear sway bar rate adj. - Front hole = 1084 lb/in Rear hole = 1422 lb/in

What size Bar and where your end links are located will make a big difference as you can see above...

.

 

[ikle]

Ikle,

Did you get your rear sway bar from us?
What size is the DSE rear bar? 1" or 1-1/8" ?
Where are your sway bar end links located? Which hole (first or second)?
1" rear sway bar rate adjustments - Front hole = 722 lb/in Rear hole = 947 lb/in
1-1/8" rear sway bar rate adj. - Front hole = 1084 lb/in Rear hole = 1422 lb/in

What size Bar and where your end links are located will make a big difference as you can see above...

.

Scott its a 1 1/8" bar with end links located in the first most forward hole. I had this problem before I installed the DSE bar when I was running the stock bar.