If you feel that your QuickSilver responds too fast or clears your search field too quickly, you can do these steps to adjust them until you feel satisfied.

1. Go to QuickSilver Preference Pane
   

   

2. Move your mouse under Command tab
3. At the second half of "Command" tab, there are many settings you can choose
   

   

4. Read this manual for reference

Explanation
Row Height	Setting up row height for other matches found
Show other matches
Never	Only appear as you key in ↓
Immediately	Appear as soon as QuickSilver finds a result
Delayed	Appear 3s to 5s after result found
Spacebar behavior
Normal	Space acts as space
Select Next Result	Space acts as ↓, Spc acts as ↑
Jump to Argument Field	Space acts as ⇥
Switch to Text Mode	Space acts as .
Show Item's Contents	Space acts as /, Spc acts as /
Switch to text mode	If no match is found - tick it to enable
Time slider
Reset search after	Automatically clear your typing after a few seconds (0.5s to 3.0s), tick to enable
Wait before searching	Delay of searching after you type your first letter (0.0s to 0.5s)