nomis3613
Premium
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There are many ways to skin a cat, and even more ways to tune a car in GT4! Here's my thoughts on how to use each setting, all discussion welcomed. This isn't meant to compete with the excellent guides of Scaff, etc (in fact, I used these guides myself) but just throw up some food for thought about the art of tuning...
Spring Rates
I've changed my mind on the best way to use these many times in the past, and reserve the right to change my mind again! These days, I don't use them to reduce under/oversteer in their own right, but rather to balance any other changes. Such as stiffer springs for lower ride height or to keep the balance of spring vs damper vs roll bar strengths similar.
Only adjust in steps of 0.5 or 1.0, and don't go too extreme.
Ride Height
Just used for how a car feels as it moves around on its suspension. Basically if I'm getting sea-sick in a car, down comes the ride height evenly at both ends. Sometime I raise it on bumpy tracks, but just based on a wild guess, nothing scientific.
Can be used to adjust weight balance (hence steady-state under/oversteer), but only where the car has a weight balance problem or normal tuning methods aren't enough.
Damper Bound / Rebound
Start with all settings at 4. Increase front bound or rear rebound to reduce dive under brakes and also oversteer when braking. Increase front rebound or rear bound to reduce squat during and understeer when accelerating.
Like springs, dampers can be used to reduce under/oversteer but given the side-effects I tend to adjust them as a complimentry modification (same as spring rate) to other changes.
Camber
I did acceleration, braking and cornering testing of camber and now I believe that all types of grip are have the same optimum camber angle (unlike reality where you would expect that increasing camber would help cornering but reduce braking and powerdown). I also found multiple peaks on the camber curve (see below- the grip numbers aren't anything real, just used to show relative levels).
The first peak is always slightly lower than the second, but the 2nd peak is really narrow- so if you're a tiny bit off the 2nd peak, you've got less grip than if you'd missed the 1st peak by the same amount. There are more peaks after the 2nd, but they are smaller and even narrower, so not worth worrying about.
A racing car needs less (static) camber than a road car (about 3.0 degrees vs 1.5). Increasing camber increases tyre wear.
So I take a conservative approach and aim for the first camber peak. If tyres at one end are wearing too slowly (and ruining the cars handling balance as the other tyres wear), then increase the camber, even perhaps to values that might normally seem silly.
Camber can be used to adjust over/understeer, but tuning this way is just reducing the overall grip potential of your car, so I only do it in extreme cases.
Toe Angle
Here is the golden secret of tuning: front toe!!! Negative front toe reduces mid- and late-corner understeer. The trade-off is less turn-in, so start with 0 and only use it if you need it, but when the ugly understeer beast raises it's head, ask yourself if it's late in the corner and try 1-2mm of negative front toe.
Negative rear toe can be used to reduce overall understeer. But you will lose a lot of rear grip, so only do it when normal tuning methods aren't enough, and just use 1-2mm.
Stabiliser
Here is where I tune out overall under or oversteer. More stabiliser means less more grip lost over bumps, so start at 3. Then soften the end without enough grip, or stiffen the opposite end.
Stiffen both front and rear stabilisers to reduce body roll, but ask yourself if you've got too much diving under brakes and squat under acceleration, in which case you're best off looking at ride height/spring rates first.
Brake Balance
Don't go below 2 or above 6 at either end. More front brake tames a car that wants to spin under brakes and also reduces stopping distances slightly, more rear brakes makes it easier to turn while braking. Increasing brake setting increases tyre wear slightly, but not enough to matter IMHO.
LSD
More LSD initial or accel reduces wheelspin UP TO A POINT. More LSD initial or decel makes the car harder to turn while braking. Increasing any diff setting reduces agility, so only use as much as you need to.
Start with 0 for everything. Increase accel if you suspect that the INSIDE WHEEL is spinning. Increase decel if the car tries to spin out while braking. Use the initial setting to minimise the difference between accel and decel (otherwise the handling will become unpredictable).
I strongly suspect people use too much diff strength in an attempt to reduce wheelspin. If there is enough power to spin both wheels, then there is nothing the diff can do. So using high diff settings on your high powered car will do nothing to reduce wheelspin, it only makes your car less agile (worse at quick direction changes).
Downforce
Unless you're on an oval track or Circue de Sarthe, I reckon use as much downforce as you can. Who cares if your top speed is a bit slower, you will be exiting the corners faster so you will be quicker for the 1st half of the straight.
Start at max front and rear downforce and work down. More front downforce cures high-speed understeer, rear downforce fixes high-speed oversteer. Reducing downforce slightly reduces tyre wear.
ASM/TCS
Turn them off while tuning, so you can feel what the car is doing! Don't use ASM at all, it works by applying the brakes so it will only slow you down if you're a good driver. TCS can be necessary with high powered or laggy engines. More TCS also reduces tyre wear (for the driven wheels, of course).
Thanks for reading,
Simon
Spring Rates
I've changed my mind on the best way to use these many times in the past, and reserve the right to change my mind again! These days, I don't use them to reduce under/oversteer in their own right, but rather to balance any other changes. Such as stiffer springs for lower ride height or to keep the balance of spring vs damper vs roll bar strengths similar.
Only adjust in steps of 0.5 or 1.0, and don't go too extreme.
Ride Height
Just used for how a car feels as it moves around on its suspension. Basically if I'm getting sea-sick in a car, down comes the ride height evenly at both ends. Sometime I raise it on bumpy tracks, but just based on a wild guess, nothing scientific.
Can be used to adjust weight balance (hence steady-state under/oversteer), but only where the car has a weight balance problem or normal tuning methods aren't enough.
Damper Bound / Rebound
Start with all settings at 4. Increase front bound or rear rebound to reduce dive under brakes and also oversteer when braking. Increase front rebound or rear bound to reduce squat during and understeer when accelerating.
Like springs, dampers can be used to reduce under/oversteer but given the side-effects I tend to adjust them as a complimentry modification (same as spring rate) to other changes.
Camber
I did acceleration, braking and cornering testing of camber and now I believe that all types of grip are have the same optimum camber angle (unlike reality where you would expect that increasing camber would help cornering but reduce braking and powerdown). I also found multiple peaks on the camber curve (see below- the grip numbers aren't anything real, just used to show relative levels).
The first peak is always slightly lower than the second, but the 2nd peak is really narrow- so if you're a tiny bit off the 2nd peak, you've got less grip than if you'd missed the 1st peak by the same amount. There are more peaks after the 2nd, but they are smaller and even narrower, so not worth worrying about.
A racing car needs less (static) camber than a road car (about 3.0 degrees vs 1.5). Increasing camber increases tyre wear.
So I take a conservative approach and aim for the first camber peak. If tyres at one end are wearing too slowly (and ruining the cars handling balance as the other tyres wear), then increase the camber, even perhaps to values that might normally seem silly.
Camber can be used to adjust over/understeer, but tuning this way is just reducing the overall grip potential of your car, so I only do it in extreme cases.
Toe Angle
Here is the golden secret of tuning: front toe!!! Negative front toe reduces mid- and late-corner understeer. The trade-off is less turn-in, so start with 0 and only use it if you need it, but when the ugly understeer beast raises it's head, ask yourself if it's late in the corner and try 1-2mm of negative front toe.
Negative rear toe can be used to reduce overall understeer. But you will lose a lot of rear grip, so only do it when normal tuning methods aren't enough, and just use 1-2mm.
Stabiliser
Here is where I tune out overall under or oversteer. More stabiliser means less more grip lost over bumps, so start at 3. Then soften the end without enough grip, or stiffen the opposite end.
Stiffen both front and rear stabilisers to reduce body roll, but ask yourself if you've got too much diving under brakes and squat under acceleration, in which case you're best off looking at ride height/spring rates first.
Brake Balance
Don't go below 2 or above 6 at either end. More front brake tames a car that wants to spin under brakes and also reduces stopping distances slightly, more rear brakes makes it easier to turn while braking. Increasing brake setting increases tyre wear slightly, but not enough to matter IMHO.
LSD
More LSD initial or accel reduces wheelspin UP TO A POINT. More LSD initial or decel makes the car harder to turn while braking. Increasing any diff setting reduces agility, so only use as much as you need to.
Start with 0 for everything. Increase accel if you suspect that the INSIDE WHEEL is spinning. Increase decel if the car tries to spin out while braking. Use the initial setting to minimise the difference between accel and decel (otherwise the handling will become unpredictable).
I strongly suspect people use too much diff strength in an attempt to reduce wheelspin. If there is enough power to spin both wheels, then there is nothing the diff can do. So using high diff settings on your high powered car will do nothing to reduce wheelspin, it only makes your car less agile (worse at quick direction changes).
Downforce
Unless you're on an oval track or Circue de Sarthe, I reckon use as much downforce as you can. Who cares if your top speed is a bit slower, you will be exiting the corners faster so you will be quicker for the 1st half of the straight.
Start at max front and rear downforce and work down. More front downforce cures high-speed understeer, rear downforce fixes high-speed oversteer. Reducing downforce slightly reduces tyre wear.
ASM/TCS
Turn them off while tuning, so you can feel what the car is doing! Don't use ASM at all, it works by applying the brakes so it will only slow you down if you're a good driver. TCS can be necessary with high powered or laggy engines. More TCS also reduces tyre wear (for the driven wheels, of course).
Thanks for reading,
Simon
