will using a smaller pinion cause my motor to call for less amps?

If your motor is drawing too many amps for your ESC and it's shutting down or overheating or it wants to much from low C batteries and you are cogging as a result, gearing down generally won't help enough, it's a hardware issue that is best fixed with different hardware.

If your question was meant to be phrased more along the line of using amps as a synonym for temperature then the answer is yes and no. A smaller pinion will make your motor run cooler until you go so small that you're driving at full throttle all the time and then the heat will actually increase.

thank you i was trying to figure out a new brushless system for my mini 8ght and can get at best 45amp batteries without modifying the tray. however the motors i am looking at call for 41 amps is a 4amp gap sufficcient?

How many amps a battery can put out is generally expressed in it's C rating, that is amps=C rating*mah so for example, a 40C*3000mah pack should be able to produce a constant 120 amps. Double check the ratings on the packs you're looking at, even for the low mah ratings common to 1/18th car packs, that seems to very lowly rated. Also, check the burst rate. It's usually double the constant rate, whereas a motor is usually rated at it's max amp draw. A motor that is said to draw 41 amps will do so only under max load but a 45amp pack should be able to burst to 90amps - more than enough of a gap to work Ok.

ok thanks, the battery is an 1800mah 25c,50c burst for my losi mini 8ight i know that peolple use the velineon 380 which can call for more than 41 idk the exact amps, but, they all mod the battery tray to fit 2200mah 25c and i could never cut up my poor little losi