A lot of thought and huge development has gone into making cars handling better over the years. Suspension Upgrades can come in a number of different components and the overall aims is normally to reduce ride height, to improve the centre of gravity, improve transitional weight transfer rates under acceleration, deceleration and cornering loads.
The ultimate aim is to have a more precise and controllable handling set up, which will result in higher lateral G-Forces while cornering. This helps to bring down lap times on the track or by having a more composed driving experience under extreme driving conditions. With a lower centre of gravity and more aggressive stance, upgraded suspension is a must for any complete performance package.
In many cases these Suspension Upgrades might comprise of a fully adjustable system, where a car can be set up for different tracks and driving conditions. Or to help balance a car's particular handling characteristics, for example a FF (front wheel drive) car's under-steering tendencies. Or even a tail happy FR (front engine, rear wheel drive), over-steering antics.
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If we look at the performance triangle, we can see that Suspension Upgrades have a big impact on Grip and even Aerodynamics.
GRIP AND SUSPENSION:
The suspensions sole purpose is to maximise traction and keep the tyres working at their optimum. This increases available Grip levels and translates into more engine power being used to drive the car forward, increased cornering capabilities and also more effective braking. Any suspension upgrade will result in a net gain in these areas, if the upgrade is well selected and installed and set up correctly. This is where suspension upgrades come into play, having the ability to fine tune and adjust suspension settings, especially in different racing environments.
AERODYNAMICS AND SUSPENSION:
While Suspension Upgrades may not appears to have an effect on the aerodynamic performance of any car, this is far from the true. When Down force is produced it creates a downward load on the tyres, through the suspension system. This effectively pushes down on the tyre and improves grip levels, which in turn increase Acceleration, Cornering and Braking capacities. Spring rates will need to be increased to compensate for this additional loading, as having a setting just for the weight of the car will not be adequate. Otherwise the car could bottom out, which will negate any previous performance advantages.
Even the ride height of the front and rear suspension will have an effect on down force generation, with a rake effect yielding higher levels ( front lower than the rear). With out suspension upgrades, it would not be possible to adjust or fine tune the suspension to maximise this potential.
Suspension Upgrade Components.
The following components will help and you create the ultimate in handling precision:
- Anti-Roll Bars.
- Suspension Bushes.
- Suspension Coilovers.
- Sports Spring and Dampers.
- Strut Braces.
Most modern cars have anti-roll (sway) bars fitted as standard, these suspension components have the job of helping to stabilise the vehicle under cornering loads. It effectively reduces body roll and helps the car to remain level when cornering, helping the suspension to do it's job properly. Otherwise the car's load transfers during heavy cornering forces, may unload the outside wheel too much and as a result, lose of traction will result.
Due to the fact that the anti-roll bar are connected to each wheel on a axle, when one wheel undergoes a bumps on rough terrain. This is transmitted to the other wheel on the opposite side, causing a jarring or waddling effect. With thicker anti-roll bars installed, the effect is proportionate to the thickness of the bar. Increases in bar thickness and speed of the travel, will result in negative handling characteristics.
With too much excessive roll stiffness in place, the inside wheels will lift off the ground during very hard cornering (achieved by configuring an anti-roll bar too thick or adjusted to stiff). This is only possible if the regular spring rate actually allows the outside wheels to handle the much increased transitional loads. This can be used as a advantage with some front wheel drive drive lines (FF car set ups). In fact many front wheel drive production cars will lift a wheel when cornering hard, in order to overload the other wheel on the axle, so limiting the effect of understeer.
Adjustable Anti-Roll Bars:
Suspension upgrades like after market or performance anti-roll bars, give you the ability to adjust the handling characteristics of the car. This can also be done by adjusting the anti-roll bar in the car, these are called blade adjusters. Essentially a lever is located in the car and can be manipulated to adjust anti-roll bars settings.
This can be extremely advantageous for different track conditions, to maximise handling. Depending or the adjustment to the front or rear torsional stiffness bias, it is possible to reduce understeer (reducing front thickness) or decrease oversteer (reducing rear thickness). You can get adjustable blade anti-roll bars (adjustable in the car) or you will have to fit different thickness ones (the thicker the unit, the more torsional stiffness).
Having the ability to reduce body roll through anti-roll bars, it is possible to make suspension adjustments with out the need to reduce suspension stiffness, through spring or damper settings (as this could affect ride quality). Making anti-roll idea ideal for fine tuning for specific handling imbalances.
Anti-roll bars are normally constructed from a U shaped piece of steer or aluminium and connects the left and right wheels together. When the right and left wheels move together, the anti-roll bar rotates around it's mounting points and will not bend. If the wheels do move relative to each other, then the anti-roll bar with be subject to torsional forces and made to twist. This twisting motion, resists the tendency of the suspension components to roll the car in corners. When you have different thickness’s, or a adjustable set up; this ultimately affects the amount the ant-roll bar will counteract this forces.
Often a overlooked component in the suspension system, is the suspension bushings or bushes. These are devices which can help isolate vibration and noise, transmitted from road during travel. Overtime factory fitted rubber bushes can become tired and worn out, from the constant contact with heat, cold and motor oils. This deterioration of the suspension bushes, can result in a adverse affect on the handling of a car and could affect Camber, Caster and even Toe settings. Due to the structural integrity of the factory fitted rubber bushes becoming sub standard over time.
The suspension bushes work by separating the faces of two metal objects and allowing a certain amount of movement through the components, under a damping effect. This movement allows the suspension parts to move freely and when travelling over a large bump, will minimise the transmission of noise and small vibrations through to the chassis of the vehicle, helping to stabilise handling and improve ride quality.
Factory fitted rubber bushes are a potential weakness in the suspension system, upgrades are available which are made of more durable materials like polyurethane.
Upgraded suspension bushes, have a more durable construction and can increase suspension stiffness and effectiveness. Improve tyre life, also they provide a more precise and reliable platform to mount you upgraded suspension components on.
If you are considering upgrading your suspension system, suspension bushes are definitely worth considering to maximise your suspension´s performance potential.
The term Coilover is short for the description of Coil over Strut and once fitted to a vehicle, will look similar to a McPherson strut set up. But don't be fooled by appearances, as this suspension upgrade has its origins in Motorsport.
Due to the complex way the suspension has to work over a number of different surfaces and tracks, engineers had to come up with a fully adjustable solution.
With Coilover installed and depending on the exact features of the unit on offer, it is possible to adjust Ride Height, Stiffness and Damping settings on the car. The general rule is the more expensive and feature rich your upgraded component has, the more complex and difficult it will be to get the correct set up.
It is normally recommended for the Coilovers to be professionally set up once installed. A process called Corner Weighting can be applied to make sure each corner of the vehicle has a similar weight diagonally from back to front. This process takes into account that during the manufacturing process cars are not made to have equal corner weights, due to the location of different components. With Racing cars, the whole weight distribution can be played around with, but with Road cars, normally spare wheels or batteries are the only things that can be moved around for maximum effect.
Weight savings and more durable construction are a few of the other benefits on offer with this suspension upgrade type. These units can range from mid level pricing up to the pinnacle of the top levels of Motorsport. Research your application well, as the wrong selection could be overkill for a medium focused project and will cost financially as well add to the complexity of a correctly set suspension system.
Sports Spring and Dampers.
Sport springs and upgraded dampers are a common performance option available to help increase suspension performance. These are normally none adjustable, but offer a lower ride height (25mm to 60mm) and firmer, sportier focused suspension set up over some compromised factory fitted items. But with most things, the more you pay the more features are available.
Any fast road or track car will benefit from sports springs and dampers, with the added bonus of having a stronger and more durable component fitted. Weight savings and more robust construction are some of the performance advantages on offer.
Ideal for a any project on a budget, as these are normally more cost effective then suspension coilover units, there are normally lots of different ranges of units available for your specific make and model.
Don't dismiss sports spring and dampers on performance potential, as many Motorsport applications and range topping models use this type of unit to provide precise and focused handling characteristics.
Strut braces are a suspension device which can be used to help with stabilising and improving rigidity for better handling. Located on the top and bottom of the front suspension mounts, they can also be located over the rear suspension mounts.
Normally constructed from stainless steel (available in other materials), these bolt on upgrades make strut braces a easy and effective suspension upgrade. They work by helping to keep a constant relationship between the suspension components, which are subjected to torsional loads under cornering forces. This in turn aids the other suspension components, to stay fixed and not be subjected to chassis flex.
Due to structural flex in the body, under these extreme loads, suspension can wander and might not be fully optimised. Fitting Strut braces will let the suspension components do their job fully with out the added stresses from structural twist. Fitting a roll cage has a similar effect of keeping the chassis stiff and firm, as well as greatly increasing structural strength.
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