diff --git a/crates/specialized/rtx-cfd/tests/embedded3_flag_wake.rs b/crates/specialized/rtx-cfd/tests/embedded3_flag_wake.rs
index 55740da..3590779 100644
--- a/crates/specialized/rtx-cfd/tests/embedded3_flag_wake.rs
+++ b/crates/specialized/rtx-cfd/tests/embedded3_flag_wake.rs
@@ -130,7 +130,8 @@ fn flag_wake_on_the_device() {
     let nz = ny;
     let r_edge = h;
     let dt_cfl = 0.3 * h / (U_M.max(2.0 * std::f64::consts::PI * FREQ * AMP));
-    let dt = dt_cfl.min(0.5 * h * h / (6.0 * NU));
+    // `RTX_E3_FLAG_DT_SCALE` scales the step (the dt ladder of the loads).
+    let dt = dt_cfl.min(0.5 * h * h / (6.0 * NU)) * env_f("RTX_E3_FLAG_DT_SCALE", 1.0);
     let period = 1.0 / FREQ;
     let t_end = periods * period;
     let mut solver = Solver::new(