Honda Prelude 1990 Online Reference Owner's Manual page 66

Shifting the 5 Speed (cont'd)
Maximum Allowable Speeds
The speeds shown below are the
maximum at which the car can be
driven or downshifted in each gear
without over-revving the engine:
Recommended Shift Speeds
For best fuel economy, and effective emission control, shift at the
speeds shown for your car:
(2.0 S)
(2.0 Si,Si)