Hello Sander, Thank you. I have changed the code but the problem persist:
f = 0 == 824.3733785446891` + (25 (16 + LL)^3)/390224 - (
10625 (16 + LL)^3)/(
97556 ((25 (16 + LL)^3)/390224 +
94.7740978646924` (aa/500 + (16 + LL)/116)^3 +
103.41515070822` (-(bb/200) + (16 + LL)/116)^3)) - (
75819.27829175392` (aa/500 + (16 + LL)/116)^3)/((25 (16 + LL)^3)/
390224 + 94.7740978646924` (aa/500 + (16 + LL)/116)^3 +
103.41515070822` (-(bb/200) + (16 + LL)/116)^3) - WI;
Manipulate[
ContourPlot3D[Evaluate@f, {aa, -10, 10}, {bb, -25, 0}, {LL, 80, 100},
AxesLabel -> {aa, bb, JJ}, PerformanceGoal -> "Speed"], {WI, 50,
200}]