Grand Prix Legends Setups
A motley fool explores the setup menu
|
|
Grand Prix Legends SetupsA motley fool explores the setup menu |
What is the point of this page?
|
I'm trying to do my bit to remove the voodoo, uncertainty and guesswork that seems to surround setting up a car, not only in GPL but all other driving simulations (a fair bit of it exists in real life too: just take a walk around the paddock on a club race weekend - you won't know whether to laugh or cry). You know what I mean; just randomly tweaking parameters in the blind hope that the car will suddenly start going much better. I reckon we've all done it; it's how quickly we stop doing it that counts. I'm trying to inject a bit of much-needed science into the process.
Fiddling about with setups is a useful way of getting to know the car, the track and yourself. It helps build awareness. Beginners are sometimes told not to fiddle about with their setups: that's only true if you're hoping that fiddling will make you suddenly quicker. Rather, fiddling will make you gradually quicker. You change a roll bar - you notice something. You change the ride height - you notice something else. Before you know it (well, several months later...) you're very much more aware of what you and the car are doing - making you quicker and more consistent. I've been doing this for years, and I still like to change something on the setup everytime I leave the pits - stops me getting bored with the car and keeps me in the beginner mind.
When you tweak a car, at least half of what you're doing is tweaking the driver's head.
What makes a good setup?
Before you make something 'good', you have to define 'good'. In my opinion, a good setup:
Carroll Smith's chapter on vehicle dynamics: page one, paragraph one, line one: “Grip is what our business is all about. Grip comes from tires, period.”
These little essays form the meat of this section on setups.
The basic approach is to find a baseline setup for each car and then derive track-specific setups from that baseline. In my case, 'track specific' means just changing the final drive ratios, and occasionally the static ride height and wheel rate.
1. Start out by finding, for each chassis, a front/back wheel rate distribution that creates handling that you like. One approach is to start by setting the wheel rate to approximate the weight of the car. For example, if the car has a front/back weight distribution of 40/60%, then set the wheel rate so that you get 40% of the overall rate on the front, and 60% on the rear. You can use these wheel rate lookup tables to help you with this. The front/back weight distribution of the cars in GPL is available here. Thereafter, if something feels wrong, soften the end of the car that isn't working.
2. Then find, for each chassis, a differential setting that creates handling that you like. Use the power-side differential ramp angle to control the amount of power-oversteer, and the coast-side ramp angle to control the amount of dropped throttle oversteer.
3. Set the minimum amount of front roll bar needed to control the roll at the front of the car (you can use the front tire temperatures to judge this) and then set the rear roll bar to give the desired mid-corner understeer/neutral/oversteer handling.
4. The more camber you add, the worse the car handles. The more asymmetric you make the camber, the worse the car handles.
5. Optionally, change the dampers from their default setting of 3/3 (a lot of the time, I find you don't need to do this).
6. Change the static ride height to the lowest setting that is comfortable to drive and keeps the car off the bump rubbers.
7a. All four tires need to be 24-25 PSI (when up to temperature). My baseline is to inflate all four tires to 20 PSI (cold), then make small adjustments to allow for excessive overheating (usually of the front left) or air cooling (usually of the right front). In the 24-25 PSI range, the tires seem to assume their correct shape.
7b. Do not correct handling defects by altering tire pressures. The tires have one pressure at which they assume their optimum shape. If they are set to any other pressure, then you're just giving away grip.
The cars all use the same physical model (or modelettes). Because of the way GPL is implemented, the cars share the same suspension geometry, tire compound, chassis stiffness and a host of other details. All that changes between the cars are variables like mass, mass distribution, CoG location, wheelbase, track width, torque curves and so on. The similarities are such that, if a setup theory works on one car, it will work on all the cars, providing it is a valid theory.
What I'm aiming for in each of the following setups is to create a car with:
The trick is to get the amount of each in balance; for example, there should just be enough power-on oversteer to counter the basic understeer.
I edit setups using Ian Withycombe's simple GPLSetup program, which lets you set weird wheel rates, odd first and second gears, unusual ramp angles and realistically short bump rubbers. ('Simple' is a compliment around these parts.) Download it here. If you want to use 'out of range' values, then you also need to download a small text file called GPLSetup.lmt and save it in the same folder as GPLSetup.exe.
Brabham setup for all tracks (just change the 3rd, 4th and 5th gear final drive ratios):
|
Front
Left Right Steering Ratio: 9:1
20 Tyre Pressure (psi) 20 Fuel: 5 gallons
75 Wheel Rate (lbs/in) 75
3 Bump 3 Transmission Ratios
3 Rebound 3 1st Gear: 7.086:1
-0.75 Camber (deg) -0.75 2nd Gear: 5.167:1
1.00 Bump Rubber (in) 1.00 3rd Gear: 4.185:1
4th Gear: 3.596:1
Toe-in: -0.125 in 5th Gear: 3.235:1
Roll Bar Stiffness: 160 lbs/in
Static Ride Height: 3.00 in
Front Brake Bias: 55% Diff Ratio: 3.100:1
Toe-in: 0.125 in Ramp Angles: 60/60
Roll Bar Stiffness: 80 lb/in Clutches: 5
Static Ride Height: 3.00 in
20 Tyre Pressure (psi) 20
100 Wheel Rate (lbs/in) 100
3 Bump 3
3 Rebound 3
-0.40 Camber (deg) -0.40
1.00 Bump Rubber (in) 1.00 Asymmetrical: N
Back
You can only 'reach' that second gear value by fiddling with GPLSetup's GPLSetup.lmt file.
BRM setup for all tracks (just change the final drive ratios):
|
Front
Left Right Steering Ratio: 13:1
20 Tyre Pressure (psi) 20 Fuel: 5 gallons
70 Wheel Rate (lbs/in) 70
3 Bump 3 Transmission Ratios
3 Rebound 3 1st Gear: 9.817:1
-0.25 Camber (deg) -0.25 2nd Gear: 7.066:1
0.50 Bump Rubber (in) 0.50 3rd Gear: 6.028:1
4th Gear: 5.167:1
Toe-in: -0.100 in 5th Gear: 4.593:1
Roll Bar Stiffness: 200 lbs/in 6th Gear: 4.276:1
Static Ride Height: 3.00 in
Front Brake Bias: 53% Diff Ratio: 3.875:1
Toe-in: 0.100 in Ramp Angles: 45/30
Roll Bar Stiffness: 200 lb/in Clutches: 2
Static Ride Height: 3.00 in
20 Tyre Pressure (psi) 20
110 Wheel Rate (lbs/in) 110
4 Bump 4
4 Rebound 4
-0.25 Camber (deg) -0.25
0.50 Bump Rubber (in) 0.50 Asymmetrical: N
Back
Note the extra clutch and 30° coast side angle in the differential to help stop the pendulum effect of the heavy engine.
The spring rates are critical; 65/100 lbs clearly oversteers, and 75/110 lbs clearly understeers. Try 105/165 lbs (and 4.50" ride height) at circuits where grounding (or bump-rubbering) is a possibility. Maximum roll bars stop the bulky car from rolling soggily in the corners (but you may need to slacken them off a little at bumpy circuits like the 'ring).
The ride height is the same as used by the AI cars, which seems fair.
Cooper setup for all tracks: (just change the final drive ratios):
|
Front
Left Right Steering Ratio: 9:1
20 Tyre Pressure (psi) 20 Fuel: 7 gallons
75 Wheel Rate (lbs/in) 75
3 Bump 3 Transmission Ratios
3 Rebound 3 1st Gear: 7.529:1
-0.75 Camber (deg) -0.75 2nd Gear: 5.812:1
0.50 Bump Rubber (in) 0.50 3rd Gear: 4.994:1
4th Gear: 4.340:1
Toe-in: -0.075 in 5th Gear: 3.838:1
Roll Bar Stiffness: 150 lbs/in
Static Ride Height: 3.00 in
Front Brake Bias: 55% Diff Ratio: 3.100:1
Toe-in: 0.075 in Ramp Angles: 60/60
Roll Bar Stiffness: 75 lb/in Clutches: 1
Static Ride Height: 3.00 in
20 Tyre Pressure (psi) 20
100 Wheel Rate (lbs/in) 100
3 Bump 3
3 Rebound 3
-0.40 Camber (deg) -0.40
0.50 Bump Rubber (in) 0.50 Asymmetrical: N
Back
Vaguely authentic 60/60+1 differential. Wheel rates in front/rear ratio of 3:4 (2:3 makes for an awkward-handling chassis) and set quite stiff, which gives smarter acceleration. Roll bars in 2:1 front/rear ratio just stiff enough to tighten up the handling and reduce the corner-exit power-on snap oversteer problem, caused by the chassis 'flopping over' onto the outside rear. Some front toe-out to give turn-in 'bite'; more toe-out makes the front a bit nervous. Some rear toe-in to reduce power-on corner exit instability. Same amount of toe on front and rear seems to make chassis more predictable. Default dampers. Carefully set camber angles give balanced handling and even tire temperatures on long fast corners. Raise the ride height to 4.00" for the 'ring. Drop it to 2.50" for Monza and other flat tracks. The Cooper has some authentic corner-exit power-on snap oversteer; drive it properly.
Eagle setup for all tracks: (just change the final drive ratios):
|
Front
Left Right Steering Ratio: 13:1
20 Tyre Pressure (psi) 20 Fuel: 7 gallons
120 Wheel Rate (lbs/in) 120
3 Bump 3 Transmission Ratios
2 Rebound 2 1st Gear: 7.529:1
-0.75 Camber (deg) -0.75 2nd Gear: 5.812:1
0.50 Bump Rubber (in) 0.50 3rd Gear: 4.994:1
4th Gear: 4.340:1
Toe-in: -0.100 in 5th Gear: 3.838:1
Roll Bar Stiffness: 180 lbs/in
Static Ride Height: 3.75 in
Front Brake Bias: 54% Diff Ratio: 3.100:1
Toe-in: 0.100 in Ramp Angles: 45/30
Roll Bar Stiffness: 170 lb/in Clutches: 1
Static Ride Height: 3.75 in
20 Tyre Pressure (psi) 20
160 Wheel Rate (lbs/in) 160
3 Bump 3
4 Rebound 4
-0.50 Camber (deg) -0.50
0.50 Bump Rubber (in) 0.50 Asymmetrical: N
Back
85° on the power side is unstable on grass, and can cause snap power-on oversteer, hence the 45° power-side angle. If the front wheel rate is (relatively) any harder, I can't feel the grip at the front during corner entry. If the roll bars are any softer, the chassis starts to wallow and fall over during corner entry. If the ride height is any lower, the car hits the bump rubbers under acceleration out of slow corners (e.g. Rouen/New World).
Lotus setup for all tracks (just change the final drive ratios):
|
Front
Left Right Steering Ratio: 13:1
20 Tyre Pressure (psi) 20 Fuel: 7 gallons
80 Wheel Rate (lbs/in) 80
3 Bump 3 Transmission Ratios
3 Rebound 3 1st Gear: 7.529:1
0.00 Camber (deg) 0.00 2nd Gear: 5.288:1
0.50 Bump Rubber (in) 0.50 3rd Gear: 4.340:1
4th Gear: 3.753:1
Toe-in: -0.100 in 5th Gear: 3.382:1
Roll Bar Stiffness: 180 lbs/in
Static Ride Height: 3.25 in
Front Brake Bias: 53% Diff Ratio: 3.100:1
Toe-in: 0.100 in Ramp Angles: 45/45
Roll Bar Stiffness: 180 lb/in Clutches: 1
Static Ride Height: 3.25 in
20 Tyre Pressure (psi) 20
120 Wheel Rate (lbs/in) 120
3 Bump 3
3 Rebound 3
-0.00 Camber (deg) -0.00
0.50 Bump Rubber (in) 0.50 Asymmetrical: N
Back
Again, a mixture of understeer and power-on oversteer (trail-brake until you get the nose pointing inside the apex, then start feeding in the power).
You can change the wheel rates to anything you like, so long as they are in the 2:3 front/back ratio. For example, you might need 130/195 at Spa.
Honda setup for all tracks (just change the final drive ratios):
|
Front
Left Right Steering Ratio: 13:1
19 Tyre Pressure (psi) 20 Fuel: 4 gallons
200 Wheel Rate (lbs/in) 200
3 Bump 3 Transmission Ratios
2 Rebound 2 1st Gear: 10.172:1
-0.25 Camber (deg) -0.25 2nd Gear: 6.838:1
0.50 Bump Rubber (in) 0.50 3rd Gear: 5.507:1
4th Gear: 4.798:1
Toe-in: -0.125 in 5th Gear: 4.198:1
Roll Bar Stiffness: 200 lbs/in
Static Ride Height: 2.50 in
Front Brake Bias: 52% Diff Ratio: 3.875:1
Toe-in: 0.125 in Ramp Angles: 60/60
Roll Bar Stiffness: 200 lb/in Clutches: 1
Static Ride Height: 2.50 in
20 Tyre Pressure (psi) 20
200 Wheel Rate (lbs/in) 200
3 Bump 3
3 Rebound 3
0.00 Camber (deg) 0.00
0.50 Bump Rubber (in) 0.50 Asymmetrical: N
Back
In order to counteract that great lump of an engine hanging off the back of the Hondapig, I've made the rear really soft (relative to the front). To counteract that, I've increased the rear roll bar. Hence, 200/200 lbs for the wheel rate and 200/200 lbs for the roll bar.
| Static ride height » |
|
|
