Horizon 4 Tuning Guide
Part 3 - Off-road Tuning
This part explains how to setup cars to work good for dirt or cross country racing.
Basically this works by altering road tunes as described in part 2 to work better in off-road scenarios.
Generally speaking dirt tunes require a softer and more understeer setup while cross country tunes require a stiffer more oversteer setup as compared to road tunes.
Tires
Dirt tunes require lower tire pressure as compared to road tunes that provides more grip during cornering combined with a slight understeer setup to stabilize the car on corner entry. Cross Country tunes on the other hand require higher tire pressure for improved control during cornering and a slight oversteer setup to improve rotating.
For dirt tunes reduce tire pressure as determined for road tunes in part 2 by 0.5 psi. To achieve a slight understeer setup decrease front tire pressure by 0.5 psi and increase rear tire pressure by 0.5 psi.
For cross country tunes increase tire pressure as determined for road tunes in part 2 by 0.5 psi. To achieve a slight oversteer setup increase front tire pressure by 0.5 psi and decrease rear tire pressure by 0.5 psi.
Front Tire Pressure Rear Tire Pressure
Dirt -0.5 - 0.5 -0.5 + 0.5
Cross Country +0.5 + 0.5 +0.5 - 0.5
Example: Car with road tire pressures 28.5/28.5
Tire pressures for Dirt Tune:
Front Tire Pressure: 28.5 - 0.5 - 0.5 = 27.5
Rear Tire Pressure: 28.5 - 0.5 + 0.5 = 28.5
Tire pressures for Cross Country Tune:
Front Tire Pressure: 28.5 + 0.5 + 0.5 = 29.5
Rear Tire Pressure: 28.5 + 0.5 - 0.5 = 28.5
Alignment
Dirt tunes require a more conservative, slight understeer alignment as compared to road tunes that helps stabilizing the car during cornering. In contrast cross country tunes require a more aggressive, slight oversteer alignment for improved cornering.
For dirt tunes increase front and rear camber by 0.1, decrease front toe by 0.1, increase rear by 0.1 and increase front caster by 0.1 to achieve a more conservative and understeer setup.
For cross country tunes reduce front and rear camber by 0.1, increase front toe by 0.1, decrease rear by 0.1 and decrease front caster by 0.1 to achieve a more aggressive and oversteer setup.
Camber Front Toe Rear Toe Caster
Dirt +0.1 -0.1 +0.1 +0.1
Cross Country -0.1 +0.1 -0.1 -0.1
Example: Car with road alignment settings: -2.0/-1.5/0.0/0.0/5.0
Alignment for Dirt Tune:
Front Camber: -2.0 + 0.1 = -1.9
Rear Camber: -1.5 + 0.1 = -1.4
Front Toe = 0.0 - 0.1 = -0.1
Rear Toe = 0.0 + 0.1 = 0.1
Caster = 5.0 + 0.1 = 5.1
Alignment for Cross Country Tune:
Front Camber: -2.0 - 0.1 = -2.1
Rear Camber: -1.5 - 0.1 = -1.6
Front Toe = 0.0 + 0.1 = 0.1
Rear Toe = 0.0 - 0.1 = -0.1
Caster = 5.0 - 0.1 = 4.9
High Power Cars
For cars with with 400 hp or more power dirt and cross country tunes require additional camber and caster adjustment to account for higher forces on the chassis while cornering. For dirt tunes camber must be increased and caster reduced while for cross country tunes camber need to be decreased and caster need to be increased.
Camber Offset Caster Offset
Dirt +1.0 -1.0
Cross Country -1.0 +1.0
Anti-roll Bars
Dirt tunes require a slightly stiffer, more understeer ARB setup as compared to road tunes hat helps stabilizing the car during cornering and reduce body roll. Cross country tunes require a softer, more overststeer ARB setup that improves cornering,
For dirt tunes first increase ARBs by 0.1 to slightly stiffen the ARBs as compared to road tunes. Then for achieving a slight understeer increase front ARB by 0.1 and decrease rear ARB by 0.1.
For cross country tunes first decrease ARBs by 0.1 to slightly soften the ARBs as compared to road tunes. Then for achieving a slight oversteer decrease front ARB by 0.1 and increase rear ARB by 0.1.
Front ARB Rear ARB
Dirt +0.1 + 0.1 +0.1 - 0.1
Cross Country -0.1 - 0.1 -0.1 + 0.1
Example: Car with road ARB settings: 20.5/19.5
ARBs for Dirt Tune:
Front ARB: 20.5 + 0.1 + 0.1 = 20.7
Rear ARB: 19.5 + 0.1 - 0.1 = 19.5
ARBs for Cross Country Tune:
Front ARB: 20.5 - 0.1 - 0.1 = 20.3
Rear ARB: 19.5 - 0.1 + 0.1 = 19.5
High Power Cars
For cars with with 400 hp or more power dirt and cross country tunes require additional softening of ARBs to account for higher forces on the chassis while cornering. For dirt tunes ARB stiffness must be reduced by 24% and for cross country tunes ARB stiffness must be reduced by 12%.
ARB Stiffness Offset
Dirt -24%
Cross Country -12%
Springs
Dirt tunes require a slightly softer, more understeer suspension setup as compared to road tunes for more grip and to stabilize the car during cornering. Speed tunes require a slightly stiffer, more oversteer suspension setup for improved control and cornering.
For dirt tunes first decrease front and rear springs slightly by 0.5 as compared to road tunes. Then for achieving a slight understeer setup increase front springs by 0.5 and decrease rear springs by 0.5.
For cross country tunes first increase front and rear springs slightly by 0.5 as compared to road tunes. Then for achieving a slight oversteer setup decrease front springs by 0.5 and increase rear springs by 0.5.
Front Springs Rear Springs
Dirt -0.5 + 0.5 -0.5 - 0.5
Cross Country +0.5 - 0.5 +0.5 + 0.5
Example: Car with road spring settings: 567.15 / 365.14
Springs for Dirt Tune:
Front springs: 567.15 - 0.5 + 0.5 = 567.15
Rear springs: 365.14 - 0.5 - 0.5 = 364.14
Springs for Cross Country Tune:
Front springs: 567.15 + 0.5 - 0.5 = 567.15
Rear springs: 365.14 + 0.5 + 0.5 = 366.14
High Power Cars
For cars with with 400 hp or more power dirt and cross country tunes require additional softening of springs to account for higher forces on the chassis while cornering. For dirt tunes spring rates must be reduced by 24% and for cross country tunes spring rates must be reduced by 12%.
Spring Rate Offset
Dirt -24%
Cross Country -12%
Ride Height
Dirt and cross country tunes generally require maximum ride height for increased suspension travel while cornering and increased stability during acceleration and braking. Dirt tunes additionally require a slight understeer setup to stabilize the car while cornering while cross country tunes require a slight oversteer setup for improved cornering.
For dirt tunes set front and rear ride height to maximum possible values and then decrease rear ride height by 0.1 to achieve a slight understeer setup.
For cross country tunes set front and rear ride height to maximum possible values and then decrease front ride height by 0.1 to achieve a slight oversteer setup.
Front Ride Height Rear Ride Height
Dirt set to max set to max - 0.1
Cross Country set to max - 0.1 set to max
Example: Car with road ride height settings: 4.0 / 5.0, max ride height 5.5/5.8
Springs for Grip Tune:
Front ride height: 5.5
Rear ride height: 5.8 - 0.1 = 5.7
Ride height for Cross Country Tune:
Front ride height: 5.5 - 0.1 = 5.4
Rear ride height: 5.8
High Power Cars
For cars with with 400 hp or more power dirt and cross country tunes always require maximum ride height front and rear for maximum stabilization of the car.
Dampers
As with springs dirt tunes require a slightly softer and more understeer damper setup for more grip and stabilization during cornering as compared to road tunes. Cross country tunes require a stiffer and more oversteer damper setup for improved control and cornering.
For dirt tunes first decrease front and rear dampers slightly by 0.1 as compared to road tunes. Then for achieving a slight understeer setup increase front dampers by 0.1 and decrease rear dampers by 0.1.
For cross country tunes first increase front and rear dampers slightly by 0.1 as compared to road tunes. Then for achieving a slight oversteer setup decrease front dampers by 0.1 and increase rear dampers by 0.1.
Front Rebound Rear Rebound Front Bump Rear Bump
Dirt -0.1 + 0.1 -0.1 - 0.1 -0.1 + 0.1 -0.1 - 0.1
Cross Country +0.1 - 0.1 +0.1 + 0.1 +0.1 - 0.1 +0.1 + 0.1
Example: Car with road damper settings: 7.5 / 7.2 / 4.5 / 4.3
Dampers for Dirt Tune:
Front rebound: 7.5 - 0.1 + 0.1 = 7.5
Rear rebound: 7.2 - 0.1 - 0.1 = 7.0
Front bump: 4.5 - 0.1 + 0.1 = 4.5
Rear bump: 4.3 - 0.1 - 0.1 = 4.1
Dampers for Cross Country Tune:
Front rebound: 7.5 + 0.1 - 0.1 = 7.5
Rear rebound: 7.2 + 0.1 + 0.1 = 7.4
Front bump: 4.5 + 0.1 - 0.1 = 4.5
Rear bump: 4.3 + 0.1 + 0.1 = 4.5
High Power Cars
For cars with with 400 hp or more power dirt and cross country tunes require additional stiffening of front dampers to account for higher forces on the chassis while cornering. For dirt tunes front rebound and bump must be increased by 2.5 while for cross country tunes front rebound and bump must be increased by 1.5.
Front Damper Offset
Dirt +2.5
Cross Country +1.5
Brakes
Dirt tunes require more braking force on the front and a higher braking pressure as compared to road tunes for improved braking and stabilization before corners. Cross country tunes require more braking force on the rear and a lower brake pressure for improved braking while turning (trail braking).
For dirt tunes move more braking force to the front by decreasing front brake distribution by 1% as compared to road tunes and increase brake pressure by 4%.
For cross country tunes move more braking force to the rear by decreasing front brake distribution by 1% as compared to road tunes and decrease brake pressure by 4%.
Brake Distribution Brake Pressure
Dirt - 1% +4%
Cross Country + 1% -4%
Example: Car with road brake settings: 52% / 125%
Brakes for Dirt Tune:
Brake distribution: 52% - 1% = 51%
Brake pressure: 125% + 4% = 129%
Brakes for Cross Country Tune:
Brake distribution: 52% + 1% = 53%
Brake pressure: 125% - 4% = 121%
High Power Cars
For cars with with 400 hp or more power dirt and cross country tunes require reduction of brake pressure to account for higher forces on the chassis while braking. For dirt tunes brake pressure must be decreased by 20% while for cross country tunes brake brake pressure must be decreased by 10%.
Brake Pressure Offset
Dirt -20%
Cross Country -10%
Differential
Dirt and cross country tunes generally require lower accel and higher decel settings as compared to road tunes for improved stability during cornering. Dirt tunes additionally require a slight understeer setup while cross country tunes require a slight oversteer setup.
For dirt tunes first decrease accel by 24% and increase decel by 40%, then to achieve a slight understeer setup decrease accel by 1% and increase decel by 1%.
For cross country tunes first decrease accel by 12% and increase decel by 20%, then to achieve a slight oversteer setup
increase accel by 1% and decrease decel by 1%.
Accel Decel
Dirt -24% - 1% +40% + 1%
Cross Country -12% + 1% +20% + 1%
Example: Car with road differential settings: 74% / 75%
Differential for Dirt Tune:
Accel: 74% - 24% -1% = 49%
Decel: 75% + 40% + 1% = 100% (max)
Differential for Cross Country Tune:
Accel: 74% - 12% + 1% = 63%
Decel: 75% + 20% - 1% = 94%
FWD cars
For FWD generally adjust only the front accel, keep front decel always at 0%.
AWD cars
For AWD generally adjust only the front accel, rear decel and distribution, keep front decel always at 0% and rear accel always at 100%.
Gearing
Dirt tunes require overall longer gearing and tighter gear ratios as compared to road tunes for better utilization of the engines powerband in lower gears that allows to better attack and accelerate out of corners. Cross country tunes require overall shorter gearing but longer gear ratios for better utilization of the engines powerband in higher gears that works better when attacking obstacles.
For dirt tunes decrease the final drive by 1.0 and increase gear ratios by 0.2 as compared to road tunes . For cross country tunes increase the final drive by 1.0 and reduce gear ratios by 0.2 as compared to road tunes
Final Drive Gear Ratios
(Race Transmission)
Dirt -1.0 +0.2
Cross Country +1.0 -0.2
When using sport transmission for dirt tunes first decrease the final drive by 1.0 and then increase final drive by 0.2. For cross country tunes first increase the final drive by 1.0 and then decrease the final drive by 0.2.
Final Drive
(Sport Transmission)
Dirt -1.0 + 0.2
Cross Country +1.0 - 0.2
Example: Car with race gear box and road gearing: final drive 4.38, gear ratios: 2.89/1.99/1.49/1.16/0.96/0.78
Gearing for Dirt Tune:
Final Drive: 4.38 - 1.0 = 3.38
Gear ratios: 2.89/1.99/1.49/1.16/0.96/0.78 + 0.2 = 3.09/2.19/1.69/1.36/1.16/0.98
Gearing for Cross Country Tune:
Final Drive: 4.38 + 1.0 = 5.38
Gear ratios: 2.89/1.99/1.49/1.16/0.96/0.78 - 0.2 = 2.69/1.79/1.29/0.96/0.76/0.58
Aero
Generally dirt and cross country tunes require lower downforce as road tunes.
For dirt tunes reduce front downforce by 15% and rear downforce by 30% as compared to road tunes. For cross country tunes reduce front downforce by 30% and rear downforce by 60% as compared to road tunes.
Front Downforce Rear Downforce
Dirt -15% -30%
Cross Country -30% -60%
Example: AWD car with standard Forza race aero kit, road aero settings 220/220 (max / min)
Downforce for Dirt Tune:
Front Downforce = 220 - 15% = 187
Rear Downforce = 220 - 30% = 220 (min)
Downforce for Cross Country Tune:
Front Downforce = 220 - 30% = 154
Rear Downforce = 220 - 60% = 220 (min)
Example: RWD car with standard Forza race aero kit, road aero settings 110/441 (min / max)
Downforce for Dirt Tune:
Front Downforce = 100 - 15% = 110 (min)
Rear Downforce = 441 - 30% = 309 (min)
Downforce for Cross Country Tune:
Front Downforce = 100 - 30% = 110 (min)
Rear Downforce = 441 - 60% = 176