Camaro High Performance Suspension Tuning

8/3/2019 Camaro High Performance Suspension Tuning

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Camaro Subframe Preparation

Thouroghly clean and inspect the front subframe. It may not be necessary to remove the subframe from the car, but that won't hurt. You canreplace the subframe bushings with aluminum or polyurethane, one at a time without having to remove the subframe completely from the car.What you want to do here is reduce or eliminate chassis f lex (between the subframe and the unibody). You may also install subframe connectorsto further strengthen the chassis. Also, by eliminating the potential for flex, you reduce the possiblity of unwanted suspension geometry changesduring hard operation. Weld up any incompletely welded seams in the subframe. For severe use, re inforce the spring seat and the upper controlarm mount.

Camaro Front Suspension Preparation

Replace all control arm bushings with polyurethane, aluminum or bronze. This will prevent deflection under hard cornering and keep the front tiresplanted on the ground. Use high quality ball joints and tie rod ends. Since the lower balljoints are a press fit, tack weld them so they can'taccidently pop out at a bad time. Minimum ground clearance should be 3.5" from the ground to the bottom of the subframe crossmember. Keep inmind, you need to make sure you have enough clearance for bump travel. Bottoming out will cause a massive amount of under or oversteer when

YOU DON'T WANT IT.

I believe there is a steering knuckle that's been tufftrided and allows for the use of the Corvette disc and caliper... I'm looking for the part numberof it.

Camaro Rear Suspension Preparation

Again, replace rubber bushings with polyurethane or aluminum to keep the rear axle positively located and eliminate deflection or spring wrap upunder braking. Secure the axle to the springs via heavy duty U bolts. Rear ride height can be adjusted (lowered) several ways...re-arching the spring (not prefered, as it often can change the springs characteristics)by using lowering blocks (cheap solution, but still not the best) orby having a spring shop make a set of springs with the rate you desire and that has the center line of the front spring eye level with the centerline

of the main spring leaf. This is preferable over lowering blocks since lowering blocks don't do a good job of preventing spring wrapup. You want toallow for 3 inches of suspension travel, measured from the top of the axle to the f loor of the car.

4 w heel Disc Brakes?

While you may be able to find a 2nd gen firebird rear disc brake axle, you can also fabricate a rear axle from a full size (8.875" ring gear) Chevy. You should wind up with a 64.00" rear tread width with zero offset wheels. To this, you can adapt the Corvette disc calipers and rotors. I have notpersonally tried this.(Check into someone like Wilwood or BAER for their rear disc brake conversion kits. I know must kits only fit onto stock 12 bolt housings... eitherway some fabrication will be required.)

Camaro Spring and Sw aybar Selection

See below for adjusting for understeer and oversteer.Quickly put: a slightly understeering car that requires some power to induce oversteer is generally considered well balanced for good handling.

General spring guidelines. Now is a good time to look at my Z28 spring information. See what was available stock, and go from there. UNDER NOCIRCUMSTANCES should the spring and/or shock be allowed to bottom out. This can cause immediate loss of control.

As a general rule or GUIDELINE:Springs: 500 to 600 #/inch front & 200 - 250 #/inch rearSwaybar: 7/8" to 1" front & 7/8" rear swaybar.works well as a starting point.

For high load cornering try:Springs: 750 #/inch front & 300 #/inch rearSwaybar: 7/8" front & 1" rear swaybar

Also see how to tune a suspension via swaybars and springs below.

Other stuff

2nd gen tires and wheels? I know some folx put 17" wheels on their 2nd gen. I've used the standard 15 x 7" wheels with 245 60x15 tires. I likethe car to be balanced on all 4 corners. With an obscenely large tire on the front of the car you run the risk of interference with the steering.

Trimming or removing the bump stops can increase the amount of suspension travel above production limits. You can use bump stops on theshocks to prevent the suspension from bottoming out.

Replace your stock wheel studs with heavy duty wheel studs. I saw a guy lose a $45,000 race car due to wheel stud failure.

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maro High Performance Suspension Tuning http://www.nastyz28.com/pthandle.html

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Alignment and suspension geometryInitial front suspension geometry:Camber: 2-3.5 degrees negativeCaster: 2-3 degrees positiveToe: 1/16 - 1/8 toe out.

The chassis should be set up to allow for equal weight on both front wheels and both rear wheels while the driver (or a couple sacks of concrete)are in the drivers seat. Weight bias can be adjusted via different length spring shackles or by shimming or tr imming the front springs. Measureand make any adjustments with the swaybars disconnected. Upon reconnecting the swaybars make sure they do not preload the chassis.

Chassis Setup & Tuning (Drag Racing)

Traction

Slicks and performance street tires operate at generally higher pressures. Start with 18 - 20 pounds, and adjust up or down by 2 - 3 pounds at atime.

By optimizing starting line technique, you can substantially alter 60 foot times which will cut ET

Work with available traction and establish a baseline before tuning.

Experiment with shift points and launch technique until you have two consecutive runs within .05 seconds.

Car needs to launch straight and steer straight during gear changes.

Manipulate Weight transfer, when car wheel stands or squats

Car Weight

ET, super street, super gas doesn't need to be light weight. this will cost in durability and consistency. The benefit of a light car is it allows you toadd weight where you want it.

Moving ballast is a significant tuning device.

Suspension types A 4 link allows for extra tunability, but is complex, a ladder bar setup is suitable for high nines. Ladder bars with a stick causes violent launchesand produces more roll rotation during gear changes.

Shock absorbers are critical, they allow for chassis reaction no matter what type of suspension is in use.

Shock Tuning (adjustable styles)Front: 90/10 setting provides maximum weight transfer and traction.Rear: 50/50 is for s lick conditions, allowing the body to separate from the chassis and plant the tires. When track conditions are ideal, 70/30 willtake some bite out of car.

Shocks are the best tuning device. Results of a shock change can be confirmed by other tuning changes.

Example: if your car goes quicker when you lighten the rear shock, the tires can take a harder hit, you can confirm this by taking out air inquarter pound increments to reduce the amount of support to the sidewalls.If you keep taking adjustment out of the rear shocks, and the car keeps picking up, you'll run out of adjustment. Keep playing with tire pressure,ballast and launch RPM. Either add a lower gear to multiply the torque or raise the ladder bar, this will hit the tires harder. Remember though, toreturn air to your tires, lower the launch RPM to your baseline and stiffen the shocks so that you've made one change.

Car stiffness is important. Car will react better to tuning changes with a stiff chassis due to flexing caused by the reaction of the suspension. Allfour corners of the car must be braced and the engine and transmission should be secure within the car. This will allow you to tune the car withthe shock absorbers and find out what needs to be done with the rest of the car.

To control pitch rotation at the front of the car, adjust shocks, adjust the amount of suspension travel, or add/remove ballast. At the rear you canraise or lower the ladder bar, move the instant center of car, or add/remove ballast.

When you launch so hard, the rims hit the ground and throw the rear end back up, you need to remove hook from the car. To remove hook, youneed to stiffen the rebound adjustment so that the rearend doesn't separate from the car so fast. With each stiffer setting the 60 foot times pick up and the car improves its reaction time. A bit more air in the tires, moving ballast forward, or lowering launch RPM would help also. Lower the

ladder bar as a final adjustment. Rebound affects how the tires will get hit, bump relates to how the tires will react.

Next move to the front tires. If the car likes stiffer rebound, it will like less front travel to pull the tires out of the lights. If you limit travel to much,the car will dart when it hits bumps. You have to be the worlds best authority on how your car behaves. Use knowledgeable advise andexperimentation with the laws of cause and effect.

****************************************Tires, Gear Ratios, Shocks & TractionSuspension/Chassis tuning & Troubleshooting****************************************

Performance Handling (Road Racing)**** SUSPENSION THEORY BASICS - by P ierre Dupuy

When you get used to taking corners much, much faster than you ever thought possible in your car, with absolutely no perceivable body sway, tiresqueal, or loss of control, you will find it difficult to drive a car with lower handling capabilities - it gets addictive! The right setup will give you this

capability. Some weight & weight distribution, suspension, and handling basics before we get into details of modifications:

1.) Minimize overall vehicle weight as much as possible. With no other changes, the lower a car's weight, the less weight transfer there is in acorner, and the more cornering force a car will generate. A related issue is front/rear weight distribution - the closer to a 50%/50% distributionthis is, the easier it will be to set up the car for maximum cornering. The handling will also be more balanced, predictable, and controllable. Oneeasy way to help distribute weight more evenly is to relocate the battery to the trunk area. There are kits available to do this from a number of suppliers. Be sure you use the best quality, heaviest gauge battery cable possible to avoid increasing electrical resistance and be sure the battery


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width-the width of the contact patch that touches the ground (don't confuse this with section width). The tire manufacturer can get you all thesespecs. This will allow the tire sidewall to remain vertical to allow the full width of the tread's contact patch to touch the road.

2.) If you car oversteers too much (the front of the car wants to steer into the turn too much, you have too much rear roll stiffness.and may alsoneed to adjust tire pressure What is happening here is that the rear tires have a higher "slip angle" than the front tires, causing the tail of the carto slide out of the turn and aim the nose too much into the turn. Try increasing rear tire press / reducing front tire pressure, or some combination,and adjust roll stiffness as detailed below:

a.) To decrease rear roll stiffness: - installing softer anti-sway bar bushing materials (see discussion under anti-sway bar part of suspensionsection) - decrease anti-sway bar stiffness - decrease spring stiffness

b.) You can also increase front roll stiffness to further correct oversteer by: - substituting harder anti-sway bar bushings (as discussed in the

anti-sway bar section ) - increasing front anti-sway bar stiffness (install new anti-sway bar) - increasing front spring rate - install stiffer springs.

Handling - Objectives

Handling comes down to one thing: Traction, and not just traction during cornering.A good handling car will be predictable and easy to controlunder cornering, braking, acceleration, on all sorts of roads, and in all sorts of conditions. As with anything, this means you need to compromise orbalance the chassis for the majority of conditions the car will be operated under.....Street vs. Racing - Ride vs. comfort.

Understeer vs. Oversteer

Most cars are designed to understeer, which is when the car approaches a corner it wants to keep going straight. If you enter a turn too fast thefront end will slide and turning the steering wheel is useless, so you'll have to slow down and turn into the slide. This is also known as "push".

Oversteer is the opposite, where the rear end wants to slide out from under the car while the car continues to turn into the curve. This is knownas "Loose".

Most cars are designed to understeer so a normal driver can instinctively control the car. In a race situation, oversteer is prefered because a gooddriver can control the car easier and corner faster.

To reduce understeer you add oversteer to the car by:

Increasing front tire and wheel sizestiffen the rear springsincrease front tire pressure.increase rear stabilizer bar.

Summary: You want to set the car up to oversteer. I repeat this because if you run out and spend $$$$ on a larger front swaybar, you're actuallyadding more understeer to the car, which you are (supposed to be) trying to get rid of.

Wheels and Tires

The only thing attaching your car to the road surface is the tire. Therefore, the tires are the key to a good handling chassis. A poor driver with

good tires can outrun a good driver with poor tires anyday.

Again, compromise is necessary due to the conditions the car will be driven under.

Shocks

Shocks dampen the actions of the springs.For the ultimate in tunability, you want adjustable shocks. These are expensive and if you don't know what you're doing, a waste of money. Sinceyou're reading this they may be beneficial. Street shocks are designed to provide most of the dampening force on the rebound, i.e. when the tireis going back down towards the road after it hits a bump. This makes for a smooth ride. Performance shocks usually dampen at a 50/50 rate,rebound vs. compression. This improves handling at the cost of a firmer r ide. Nitrogen gas shocks are the prefered way to go. Adjustable shocksallow you to tune for compression or rebound, depending on the road conditions.

Swaybars and Springs

Swaybars or stabilizer bars twist when a car leans during a turn.

If your car doesn't have a rear swaybar, PUT ONE ON. This will be the most significant handling improvement you can make for little money.

By switching to polyurethane, you effectively make your bar think it's 20-25% larger in diameter due to reduced deflection which rubber mounts.This will also speed up the bars reaction time.

Springs hold the car up. They'll also rattle your teeth if they're too stiff. Use swaybars to TUNE your ride while maintaining softer springs if youneed to drive on the road. Shortening springs lowers the car, which lowers the center of gravity. If you go too far, your car will bottom out eitheron the road or on the suspension, so pay attention.

Other TipsWeight distribution - balance. Less weight = less effort to accelerate/decellerate.

Alignment & steering (deflection, scrubbing off speed).

Chassis reaction time/ bushings/bracing

Brakes You want your car to be fast as hell, but the brakes are an important part of any cars overall handling package. If I can drive deeper into acorner, get on the brakes for a shorter period of time and get back onto the gas quicker than the other guy, I will be faster in the long run. Thebiggest problem with brakes is HEAT. When brakes overheat they will "fade", where you need to press the brake longer and/or harder to get thecar to slow down.


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Camaro High Performance Suspension Tuning

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