overheating

i have a bazooka rsa752hc amp which is 1 OHM stable and thats what im running it at. it pushes my subs really nice for about 30 mins and then it overheats and the protection light comes on. like i said its a bazooka so i can use the C.H.I.L system but it is pretty expensive i was wondering if anybody had any suggestions for a cheaper solution like cooling fans or putting some spacers under the mounting points so that air can flow under the amp. i have a hatchback so i didnt think overheating would be too much of a problem but i guess i was wrong.

where is your gain set?

gain is at about 4/5

well that's probably your problem, the gain is not a volume knob, it's there to match the input sensitivity of the amp to the output voltage of the headunit. Unless you have 1V preouts you should not have your gain up that high