# Anti-Lift/Squat and Acceleration Lift/Squat

Branch ID: 230

Request Number: 80000230

Table 1.
.plt File .mr, .abf File Component Unit Comment
F1 RESULT(1) Not Used Not Used Not Used
F2 RESULT(2) Left Front Anti-Lift or Left Rear Anti-Squat % The resistance to lifting in a front suspension or resistance to squatting in a rear suspension due to suspension geometry during acceleration. In a suspension with 100% anti-lift/squat the moment about the side view instant center due to weight transfer is exactly offset by the moment about the side view instant center due to the acceleration force. See the following equations:
Front Suspensions Live Axles
acx = -(front drive ratio)/2
dtwt = slr*abs(2*acx)/(diff ratio)/track
aczleft = -(cg height)/2/(wheel base) - dtwt
aczright= -(cg height)/2/(wheel base) + dtwt
Orientation A:
dzfleft = acx*(C(3,1)-slr*C(3,5))+acx*(C(3,7)-slr*C(3,11))
dzfright = acx*(C(9,1)-slr*C(9,5))+acx*(C(9,7)-slr*C(9,11))
Orientation B:
dzfleft = acx*(-C(3,1)+slr*C(3,5))+acx*(-C(3,7)+slr*C(3,11))
dzfright = acx*(-C(9,1)+slr*C(9,5))+acx*(-C(9,7)+slr*C(9,11))
dzwleft = aczleft*C(3,3) + aczright*C(3,9)
dzwright = aczleft*C(9,3) + aczright*C(9,9)
left anti-lift = -100*dzfleft/dzwleft
right anti-lift = -100*dzfleft/dzwleft
Front Suspensions Fixed Differentials
acx = -(front drive ratio)/2
aczleft = -(cg height)/2/(wheel base)
aczright= -(cg height)/2/(wheel base)
Orientation A:
dzfleft = acx*C(3,1)+acx*C(3,7)
dzfright = acx*C(9,1)+acx*C(9,7)
Orientation B:
dzfleft = -acx*C(3,1)-acx*C(3,7)
dzfright = -acx*C(9,1)-acx*C(9,7)
dzwleft = aczleft*C(3,3) + aczright*C(3,9)
dzwright = aczleft*C(9,3) + aczright*C(9,9)
left anti-lift = -100*dzfleft/dzwleft
right anti-lift = -100*dzfleft/dzwleft
Rear Suspensions Live Axles
acx = -(1 - front drive ratio)/2
dtwt = slr*abs(2*acx)/(diff ratio)/track
aczleft = (cg height)/2/(wheel base) - dtwt
aczright= (cg height)/2/(wheel base) + dtwt
Orientation A:
dzfleft = acx*(C(3,1)-slr*C(3,5))+acx*(C(3,7)-slr*C(3,11))
dzfright = acx*(C(9,1)-slr*C(9,5))+acx*(C(9,7)-slr*C(9,11))
Orientation B:
dzfleft = acx*(-C(3,1)+slr*C(3,5))+acx*(-C(3,7)+slr*C(3,11))
dzfright = acx*(-C(9,1)+slr*C(9,5))+acx*(-C(9,7)+slr*C(9,11))
dzwleft = aczleft*C(3,3) + aczright*C(3,9)
dzwright = aczleft*C(9,3) + aczright*C(9,9)
left anti-lift = -100*dzfleft/dzwleft
right anti-lift = -100*dzfleft/dzwleft
Rear Suspensions Fixed Differentials
acx = -(1 - front drive ratio)/2
aczleft = (cg height)/2/(wheel base)
aczright = (cg height)/2/(wheel base)
Orientation A:
dzfleft = acx*C(3,1)+acx*C(3,7)
dzfright = acx*C(9,1)+acx*C(9,7)
Orientation B:
dzfleft = -acx*C(3,1)-acx*C(3,7)
dzfright = -acx*C(9,1)-acx*C(9,7)
dzwleft = aczleft*C(3,3) + aczright*C(3,9)
dzwright = aczleft*C(9,3) + aczright*C(9,9)
left anti-lift = -100*dzfleft/dzwleft
right anti-lift = -100*dzfleft/dzwleft
F3 RESULT(3) Right Front Anti-Lift or Right Rear Anti-Squat % See F2/RESULT(2) (above) for explanation and equations.
F3 RESULT(3) Average Front Anti-Lift or Rear Anti-Squat % The mean of the left and right front anti-lift or left and right rear anti-squat.
F4 RESULT(4)

Left Front Lift or

Left Rear Squat

mm/g The front suspension lift or rear suspension squat during acceleration or:
Front Suspensions
left lift = -(dzfleft+dzwleft+aczleft/(tire stiffness))*weight
Rear Suspensions
left squat = (dzfleft+dzwleft+aczleft/(tire stiffness))*weight
F5 RESULT(5) Right Front Lift or

Right Rear Squat

mm/g The front suspension lift or rear suspension squat during acceleration or:
Front Suspensions
right lift = -(dzfright+dzwright+aczright/(tire stiffness))*weight
Rear Suspensions
right squat = (dzfright+dzwright+aczright/(tire stiffness))*weight
F6 RESULT(6) Average Front Lift or Rear Squat mm/g The mean of the left and right front lift or left and right rear squat.