xA6x Celica Chassis Suspension
Before I begin, here is a little basic information on the Celica suspension. All of the xA6x Celica chassis use a MacPherson strut style suspension with sway bar up front. There are two styles of rear suspension: the GT models got a solid (live) axle rear suspension, while the GT-S received a double semi trailing arms style independent suspension. Both styles use shocks, coil springs and an anti-sway bar.
The GT-S rear double semi-trailing arm style suspension while a very effective independent suspension has one major issue. Due to the geometry of the arms on the rear crossmember there is an inherent negative camber problem when lowered. Negative camber being how far the tops of the wheels are tilted in (measured in degrees). This can be good for sharp handling but makes it more difficult to transfer large loads of power/torque to the road, not to mention it's bad for tires. The independent rear end also has a tendency to squat (and increase negative camber) during a hard launch, whether lowered or not. This makes it more difficult for the wheels to transfer power. Squat can be helped with stiffer springs and dampeners.
The GT solid axle rear suspension is good for planting the power to the ground, but it does not handle as well.
All suspensions respond well to lowering, to a certain degree. No matter what you drive cornering will be improved by lowering the weight and thus, center of gravity. Even a decrease in 1" will greatly improve road handling. On the xA6x Celicas lowering is accomplished by shortening the springs from the OEM length. The front end can go as low as you want, though you may need camber plates and/or strut spacers after more than around 1.5". This is because the camber curve is altered by the change. Strut spacers can be used to return the camber curve to its original perfection. The GT rear axle can go very low too, but the GT-S independent suspension will start to have problems after around a 1.5"' decrease. I am still trying to figure out a reasonable way to remedy this problem but don't expect anything anytime soon. You may need to get shorter shocks and/or struts for more than 1".
Using stiffer springs will provide a great response increase. How stiff you want your springs is a matter of taste and what you use the car for. Naturally you will want stiffer springs for an autocross machine than a daily driver. The best brand for springs was Eibach, but they discontinued the old Celica line a while ago. But they still make the 1982-86 Toyota Supra line. The rear springs will fit a Celica GT-S independent suspension, but the front springs will be to stiff. The front of the car would literally sit up. So if you run coil overs up front you should be able to use Eibach Supra springs out back, on a GTS. But if you need a complete set you are basically left with the custom shops. One that is often recommended is Coil Spring Specialties (CSS). Or King Springs in Australia.
The best shocks/struts is a matter of personal choice. Whatever you get I would recommend adjustable shocks, that way you can fine tune your suspension to what you need. Some good, recommended brands are Koni, KYB, Tokico and Gabriel. There are many places to get these brands. Just about any real retailer should be able to set you up. I would recommend Classic Car Garage as a good source for Koni's.
Anti sway bars (often referred to as stabilizer bars) are simple devices to transfer pressure from one side to another during cornering. A thicker, stronger bar will allow less body roll than a thinner one. So thicker anti-sway bars is an obvious upgrade for any car. Unless you really know what you are doing you should always change anti sway bars as a set (front and rear) at the same time. If you don't, you could make the car unstable. Addco would be my recommendation because cops use them, you can get these from Cyberspace Automotive Performance. But Koni's are a much better deal, look to Classic Car Garage for those.
This chassis does have a slight tendency to flex under extreme conditions. So structural reinforcement is always a good idea. A set of strut tower bars will significantly improve responsiveness. A properly executed roll cage set up is also said to help. Mass produced strut tower bars produced by Cusco and ToySport are available from ToySport. Cusco makes rear strut tower bars for the 1982-86 Toyota Supra, these will fit a 1982-85 hatchback Celica. But if you want a really stiff chassis you would be better off getting a custom made set. Use a 3-point brace up front (strut to strut to firewall).
Coil overs are a great way to fine tune your ride at will and look cool at the same time. These consist of a spring mounted on a adjustable brace over a strut. Front adjustable coil over's are available for the 82-85 Celica though Ground Control, a very recognized name brand. They use Eibach springs too! Gary M. has successfully implemented a custom rear coil over set for his 1983 GT-S. He worked closely with Ground Control to make a MacPherson strut with coil over setup that replaces the original shocks. In the end he had to install it upside-down, but it works. For more information click here.
Polyurethane bushings are a huge improvement over the stock rubber bushings. They are stronger and they last longer. The reduced flex improves ride control. Just be sure to use generous amounts of the prelube substance. It is generally agreed that the best manufacturer of polyurethane bushings is Energy Suspension, these are available through Cyberspace Automotive Performance.
The last common upgrade I will address is camber/caster adjustment plates. These are plates that you install at the top of the strut that allow fine tuning of the camber and caster. Camber is a fairly easy concept for most people but caster is more of a mystery. Camber is simply how far in or out the top of the wheels are tilted. Caster is the angle of the axis of the struts on the ball joints. This is the axis the wheels turn on. Anyway, these plates allow you to control the alignment of your front wheels. This is incredibly useful to perfect the handling of your car. Camber plates are available from Cusco via Cyberspace Automotive Performance (part #145410A) and Ground Control. I am told the Cusco plates don't require any cutting.
Suspension Parts/Manufacturers List
- Custom Made
- Coil Over (front) with Eibach (rear)
- Energy Suspension
- Suspension Techniques
Anti Sway Bars
Strut Tower Bars
- Cusco (Front and Rear)
- ToySport (Front)
- GAB (Front)
- Custom Made
Coil Over Set
Camber/Caster Adjustment Plates