Transmission
Sept 11, 2009 6:30:56 GMT 2
Post by ksheppard on Sept 11, 2009 6:30:56 GMT 2
First, some terminology: As I refer to a 'tighter' differential, I will be referring to an increase in the differential lock value. 'Looser' will refer to a decrease in value.
You must first understand what the differential does before you can start adjusting it; The looser your differential, the more independently your rear tires will spin when on or off the throttle. The tighter the differential, the more they spin at the same rate. While not completely accurate, you can exaggerate that a 100% differential is equal to a solid, locked rear axle where both tires are going to spin at the exact same rate. Having a locked axle would not be very beneficial when try to go around a corner since the two rear tires need to travel different distances.
Power and Coast settings are as they appear. The differential settings are adjustable for either on the throttle (power) or off the throttle (coast).
A very loose differential (0 - 25%) will allow the inside and outside tires complete freedom to spin at different speeds. This is helpful in the corners, but can induce both oversteer and understeer for different reasons. When you begin to lose traction with a loose power-differential setting, all drive power is redirected to the wheel that has lost grip, usually the inside wheel. This prevents the outside wheel from losing any more grip and hopefully prevents you from spinning. Our standard passenger cars usually come with a 15-25% differential setting for this very reason... it is safe.
A loose differential may be preferred in some corners where you need to be on the throttle while still deep in the corner (Parabolica at Monza is a great example). Having too loose of a differential can result in understeer because of too much grip. A certain amount of slippage is ideal. It may also lead to oversteer if you begin to break traction with that inside wheel and it begins to spin. Once that wheel begins to spin, it is increasingly more difficult to regain the grip to it, causing more and more oversteer until you are finally facing the wrong direction.
A tight differential (75 - 100%) increasingly prevents the inside and outside tires from independent rotation. This will force the rear wheels to share the workload more and is more suitable for straight line acceleration, such as exiting a tight hairpin or chicane. The downside is that when you begin to lose traction on one of the tires, it forces the other tire to begin to lose traction too. A dragster will have a very tight differential (completely locked axle) as a dragster only needs to focus on straight line acceleration and not any cornering at all.
Again, a tight differential may be preferred for those hairpins and chicanes, but having too tight a differential can result in understeer as both rear wheels are spinning at or near the same rate. This causes the inside rear wheel to 'push' the car into a straighter line, causing understeer. It can also induce oversteer as once you begin to lose traction on either of the wheels the other is certain to follow and a spin is not too far away.
As a rule of thumb; A loose differential is easier to drive as long as you can manage that inside tire from spinning up. It will be more forgiving to accidental loss of grip, but you can easily lose time if that inside tire is constantly spinning. A tighter differential can be less forgiving as you will feel more "snap oversteer" with little time to recover from it. Still, having both wheels working together can be beneficial if you can manage those 'snap' tendencies.
You need to know why the car is under- or oversteering before you can make any differential changes. Is it spinning up that inside tire? Is the loss of grip to the outside tire causing the inside tire to also lose grip? Is there too much grip to that inside tire? These are the questions you need to be asking.
If the track you will be racing on has numerous long, fast, sweeping corners (Barcelona), your setup may benefit from a looser differential setup. If the track is chocked full of chicanes and hairpins (Monza, Montreal) you may want to consider a tighter differential setup to focus on the straight line acceleration and braking. There is no perfect setting, as usual, and you will just have to test different settings to find what is comfortable to you.
The preload settings are fairly straight forward. The higher the value, the greater the differential is preloaded (or "prepared") for the transitions between power and coast. If the car is very twitchy or overreacts as you transition on/off the throttle mid-corner, you may wish to reduce your preload. If you can handle a little twitchy-ness, added preload will help you adjust the car's attitude as you modulate the throttle in a corner.
You must first understand what the differential does before you can start adjusting it; The looser your differential, the more independently your rear tires will spin when on or off the throttle. The tighter the differential, the more they spin at the same rate. While not completely accurate, you can exaggerate that a 100% differential is equal to a solid, locked rear axle where both tires are going to spin at the exact same rate. Having a locked axle would not be very beneficial when try to go around a corner since the two rear tires need to travel different distances.
Power and Coast settings are as they appear. The differential settings are adjustable for either on the throttle (power) or off the throttle (coast).
A very loose differential (0 - 25%) will allow the inside and outside tires complete freedom to spin at different speeds. This is helpful in the corners, but can induce both oversteer and understeer for different reasons. When you begin to lose traction with a loose power-differential setting, all drive power is redirected to the wheel that has lost grip, usually the inside wheel. This prevents the outside wheel from losing any more grip and hopefully prevents you from spinning. Our standard passenger cars usually come with a 15-25% differential setting for this very reason... it is safe.
A loose differential may be preferred in some corners where you need to be on the throttle while still deep in the corner (Parabolica at Monza is a great example). Having too loose of a differential can result in understeer because of too much grip. A certain amount of slippage is ideal. It may also lead to oversteer if you begin to break traction with that inside wheel and it begins to spin. Once that wheel begins to spin, it is increasingly more difficult to regain the grip to it, causing more and more oversteer until you are finally facing the wrong direction.
A tight differential (75 - 100%) increasingly prevents the inside and outside tires from independent rotation. This will force the rear wheels to share the workload more and is more suitable for straight line acceleration, such as exiting a tight hairpin or chicane. The downside is that when you begin to lose traction on one of the tires, it forces the other tire to begin to lose traction too. A dragster will have a very tight differential (completely locked axle) as a dragster only needs to focus on straight line acceleration and not any cornering at all.
Again, a tight differential may be preferred for those hairpins and chicanes, but having too tight a differential can result in understeer as both rear wheels are spinning at or near the same rate. This causes the inside rear wheel to 'push' the car into a straighter line, causing understeer. It can also induce oversteer as once you begin to lose traction on either of the wheels the other is certain to follow and a spin is not too far away.
As a rule of thumb; A loose differential is easier to drive as long as you can manage that inside tire from spinning up. It will be more forgiving to accidental loss of grip, but you can easily lose time if that inside tire is constantly spinning. A tighter differential can be less forgiving as you will feel more "snap oversteer" with little time to recover from it. Still, having both wheels working together can be beneficial if you can manage those 'snap' tendencies.
You need to know why the car is under- or oversteering before you can make any differential changes. Is it spinning up that inside tire? Is the loss of grip to the outside tire causing the inside tire to also lose grip? Is there too much grip to that inside tire? These are the questions you need to be asking.
If the track you will be racing on has numerous long, fast, sweeping corners (Barcelona), your setup may benefit from a looser differential setup. If the track is chocked full of chicanes and hairpins (Monza, Montreal) you may want to consider a tighter differential setup to focus on the straight line acceleration and braking. There is no perfect setting, as usual, and you will just have to test different settings to find what is comfortable to you.
The preload settings are fairly straight forward. The higher the value, the greater the differential is preloaded (or "prepared") for the transitions between power and coast. If the car is very twitchy or overreacts as you transition on/off the throttle mid-corner, you may wish to reduce your preload. If you can handle a little twitchy-ness, added preload will help you adjust the car's attitude as you modulate the throttle in a corner.