08 - Dampers - Suspension Tuning in Forza Motorsport
Keys to Speed presents a multi-part series on how to tune in Forza Motorsport and Horizon. For more tuning guide details visit: https://forzatune.com/guide/the-fully-updated-forza-tuning-guide/ ----- Transcript As discussed in the previous lessons, springs and ARBs control how far the suspension moves. Dampers, however, control how quickly the suspension moves. They also help the suspension settle quicker. If we had only springs controlling weight transfer the car would be constantly bouncing and unstable... This clip shows what a car would do if it didn’t have any kind of damping. Dampers in cars are typically a shock or strut. These types of dampers have a tube with fluid and an internal plunger that moves through that fluid creating resistance. Stiff dampers would be like moving our hand through syrup. Soft dampers would be like moving our hand through water. The syrup is more “viscous” and offers more resistance than water. With dampers we want to tune that stiffness for both compression, handled by bump damping... ...and extension, which is handled by rebound damping. Those are the two important concepts to remember when talking about damping: bump and rebound. You can remember the difference by thinking of how the suspension compresses when hitting a bump. How does the damping stiffness affect the handling of the car? The stiffer the damper, the more it resists movement, and the quicker the suspension will reach a steady state. On smooth tracks, this stiff resistance to weight transfer is desirable, however these settings will not be suitable for bumpy, irregular surfaces. If the overall stiffness of the dampers is set too high for the track, the suspension cannot react quickly enough, and the vehicle will bounce over the bumps. If the bump damping is soft enough but the rebound is too stiff then the tires will not return to the track surface fast enough after going over a bump. Those tires will be momentarily airborne... Tires off the ground are obviously not much use! If the dampers are too soft for the car and track, it will make the car feel unstable and oscillate more than it should as you drive around the track. Dampers are a good way to fine-tune handling without major changes elsewhere and are key to making the vehicle more predictable as it brakes, leans into a turn and then transitions to throttle on exit. It is up to us to shift these damping and other settings for our car as we upgrade it or race on different tracks. As you have learned, dampers will need to be softened when moving from a flat race track to a bumpy street-based circuit and vice-versa. There are also formulas and tuners to help re-baseline your tune as you make upgrades. Check the notes below this video for more information. Generally if we increase or decrease spring stiffness we want to do the same for the damper settings. Just remember dampers control the speed the suspension moves and not the potential length of suspension travel - that function is reserved for the spring rates and ride height. Here are some rules of thumb when tuning dampers... The bump setting will usually be less than (around two-thirds) the rebound setting. Soften the front damping settings to reduce understeer, and... Soften the rear damping settings to reduce oversteer or lift-off throttle issues. Congrats - you have completed this section on controlling weight transfer. You should have a much better idea of what’s happening with spring rates, ride height, anti-roll bars and dampers. In the next section we talk about other ways to improve grip with aerodynamics, brake balance and differentials.
Keys to Speed presents a multi-part series on how to tune in Forza Motorsport and Horizon. For more tuning guide details visit: https://forzatune.com/guide/the-fully-updated-forza-tuning-guide/ ----- Transcript As discussed in the previous lessons, springs and ARBs control how far the suspension moves. Dampers, however, control how quickly the suspension moves. They also help the suspension settle quicker. If we had only springs controlling weight transfer the car would be constantly bouncing and unstable... This clip shows what a car would do if it didn’t have any kind of damping. Dampers in cars are typically a shock or strut. These types of dampers have a tube with fluid and an internal plunger that moves through that fluid creating resistance. Stiff dampers would be like moving our hand through syrup. Soft dampers would be like moving our hand through water. The syrup is more “viscous” and offers more resistance than water. With dampers we want to tune that stiffness for both compression, handled by bump damping... ...and extension, which is handled by rebound damping. Those are the two important concepts to remember when talking about damping: bump and rebound. You can remember the difference by thinking of how the suspension compresses when hitting a bump. How does the damping stiffness affect the handling of the car? The stiffer the damper, the more it resists movement, and the quicker the suspension will reach a steady state. On smooth tracks, this stiff resistance to weight transfer is desirable, however these settings will not be suitable for bumpy, irregular surfaces. If the overall stiffness of the dampers is set too high for the track, the suspension cannot react quickly enough, and the vehicle will bounce over the bumps. If the bump damping is soft enough but the rebound is too stiff then the tires will not return to the track surface fast enough after going over a bump. Those tires will be momentarily airborne... Tires off the ground are obviously not much use! If the dampers are too soft for the car and track, it will make the car feel unstable and oscillate more than it should as you drive around the track. Dampers are a good way to fine-tune handling without major changes elsewhere and are key to making the vehicle more predictable as it brakes, leans into a turn and then transitions to throttle on exit. It is up to us to shift these damping and other settings for our car as we upgrade it or race on different tracks. As you have learned, dampers will need to be softened when moving from a flat race track to a bumpy street-based circuit and vice-versa. There are also formulas and tuners to help re-baseline your tune as you make upgrades. Check the notes below this video for more information. Generally if we increase or decrease spring stiffness we want to do the same for the damper settings. Just remember dampers control the speed the suspension moves and not the potential length of suspension travel - that function is reserved for the spring rates and ride height. Here are some rules of thumb when tuning dampers... The bump setting will usually be less than (around two-thirds) the rebound setting. Soften the front damping settings to reduce understeer, and... Soften the rear damping settings to reduce oversteer or lift-off throttle issues. Congrats - you have completed this section on controlling weight transfer. You should have a much better idea of what’s happening with spring rates, ride height, anti-roll bars and dampers. In the next section we talk about other ways to improve grip with aerodynamics, brake balance and differentials.