I dont understand any of these. Al I know is they affect front suspension geometry and there are different settings for them for different applications. Maybe if i understand them, I can change them on my car for better handling.

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1983 Firebird
TH700R4 Auto
Small Block 400
LG4 ECM, Intake, Carb, Distributor, etc.
Soon to be non-computer.
Clarion Head Unit 45X4
2 Pioneer 400W 12" Subs
Third Gen Performance
"A four cylinder is half an engine."

 

Caster is the angle of the axis the front wheel turns on. Imagine the fork on the front wheel of a crotch-rocket motorcycle. They're not far off from straight up-and-down. Now imagine the fork on a Harley cruiser. It's more laid back, and when you turn the wheel sharply, it almost lays down sideways rather than turn. This is the same concept on your car. It's controlled by moving the upper strut mount forward and backward.

More caster give better high-speed control and the car tracks straighter, but the tires wear oddly and you can't turn as sharply. Of course this is talking about at extreme degrees, but you get the idea (I hope). On the rods I worked on, we'd lay the caster way back because the cars were so light, didn't have power steering, and ran a solid front axle, so this gave them great handling on the highway.

Camber is the angle the rotating axis of the wheel is on. If you look at the front of the car, hopefully your wheels are straight up and down (or maybe the top angles in a little bit for performance). Here comes the example: You know those wheelchairs in the hospital? Big bulky things, huge back, big fold-up footrests? The wheels are straight up-and-down when viewed from the front. Now think about the custom wheelchairs that paraplegics use (especially if they race or play sports). Sort of the IROC of wheelchairs. Notice the wheels are angled so that the top is closer together than the bottom. On your car, it's controlled by the upper strut mount moving left or right.

Less camber (negative) gives your car better cornering, but causes the tires to wear more on the inside (and looks stupid at extremes IMO).

Toe is the relationship between the distances the front of the wheels are together. Er, how much they're turned in. Just think of your toes. Turn them in so your heels stick out and that's the same. Obviously, you want both wheels to roll parallel, with the front just slightly closer. You control toe-in with the tie-rod sleeves.


[This message has been edited by Jza (edited July 09, 2001).]

 

Nice descriptions, Jza. A little different from the usual ones.

Ward - could you give some info about what aspects of handling you'd like to improve or what type of driving you'd like to help out? For example, settings that would work well at an autocross would not be the hot setup for a daily driver.

Norm


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1979 Malibu w/some cornering tweaks and a few other interesting things

[This message has been edited by Norm Peterson (edited July 09, 2001).]

 

Well i dont really plan to drag race my car, but I want it to handle the streets the best possible. Right now the suspension is all stock, and a little worn, and it doesnt handle so good. I have ALOT of body roll, and in hard turns, i have oversteer.

------------------
1983 Firebird
TH700R4 Auto
Small Block 400
LG4 ECM, Intake, Carb, Distributor, etc.
Soon to be non-computer.
Clarion Head Unit 45X4
2 Pioneer 400W 12" Subs
Third Gen Performance
"A four cylinder is half an engine."

 

While I am by no means an "expert", perhaps this explaination will make it clearer.

1. CAMBER is the inward or outward tilting of the wheel from the vertical. If the tire is straight up and down, or perpendicular to the ground, you will have 0° camber. When the top of the wheel tilts inward at the top, you'll have negative (-) camber and when they tilt outward at the top, positive (+) camber. Of course, if they are tilting too much inward at the top, then the inner side of the tire will wear excessively, tilting too much outward (positive camber) at the top will wear too much on the outer edges of the tread.

2. CASTER is the tilting of the front steering axis (at the top) either forward or backward from the vertical. A backward tilt is positive (+) and a forward tilt is negative (-). Caster will affect the directional control of the steering but will not affect tire wear. Think of it this way. Positive caster is when the lower ball joint is ahead of the spindle, or pulling the spindle. Caster will be negative when it is behind the spindle, or pushing the spindle.

3. TOE is a measurement of how much the front of the wheels are turned in or out from a straight ahead position. When they are pointed straight ahead, toe will be 0°. This is what the factory calls for on my 1991 Camaro. When the wheels are turned in (toe-in), toe is positive, turned out, negative. Of course, excessive toe in/out will increase tire wear. Generally, the tires should be pointed slightly inward (toe-in or positive)

As was posted elsewhere (recently), the following measurements are often used for third generation cars driven aggresively.

CAMBER: -0.5° (wheel top tilted inward)

CASTER: +4.5 (struts will be almost all the way back, lower ball joint ahead of spindle)

TOE: + 1/16" (wheels slightly turned in)

If the vehicle is driven moderately, you may want to adjust camber to ~ -0.2° to -0.3°. You can "fine-tune" these measurements based upon abnormal tire wear. Look for too much inner or outter tread wear after several thousands of miles.

I make my own adjustments will excellent results. This was discussed several weeks ago - you can search it in this section if interested. There are good tools made specifically for a "do-it-your-selfer" that'll help you do an accurate and professional job, although I acheived good results using commonly available items.

 

Well i dont really plan to drag race my car, but I want it to handle the streets the best possible. Right now the suspension is all stock, and a little worn, and it doesnt handle so good. I have ALOT of body roll, and in hard turns, i have oversteer.[/QUOTE]

Sounds like you'd benefit from Z28 springs and antiroll bars. They are quite a bit stiffer (some might say harsher, too – what's the condition of the roads in your area?). Actually, both the front and rear bars come in several different diameters, and GM also tinkered with the spring rates over the years. Mounting the bars in poly bushings and using poly bushed endlinks will also help. Beyond that you can replace the axle end bushings in your lower control arms (LCA's) with poly. Leave the chassis end bushings alone, unless you intend to use either 4th Gen 1LE bushings there (I think they fit, but I'm not 100% sure). And then there are subframe connectors and strut tower braces to stiffen the chassis itself.

You may start to hear all kinds of suggestions to use box section LCA's or box your existing LCA's and put poly in both ends. Don't do it. While those mods are OK for the dragstrip, they work pretty much opposite to what you are seeking in street use, tending to give you even more oversteer than you have already. I might as well reference a thread over at www.camaroz28.com for more info, it's on the autocross & road race forum, titled "LCA's binding". It's 4 pages long, so you might prefer to print it out.

Some of it may be a function of how fast you feed in throttle while you still are under fairly high lateral g's. With that 400 you have to be gentle squeezing down on the gas coming out of a hard corner, certainly you have to be smoother than what you could get away with if/when you only had an LG4 under the hood. A bit more rear tire would help, too.

Norm