Im trying to understand C rating a bit better and i came across this

I know if you take mah and turn it into a decimal number ( ie 5200mah = 5.2 A)

so if you take amps and multiply by c rating you get how many amps that battery puts out..

so whats the difference between a 6000 Mah 28c lipo and a 4200MAh 40c lipo?

basicaly the c rating is how fast the battery will let power be taken out of the battery so a 40 c will let more power be drawn quicker :wave:

So for racing purposes would the 40 c be better performance wise to give some kind of boost or is it negligable between the two?

C rating is the maximum continuous amps the battery can discharge without damage. How they will perform depends on the motor and even the type of racing being done. A stock motor does not require as many amps so you most likely would not feel a difference with a lower C rating.

But you also have to consider that as a battery discharges, the voltage of the battery decreases. So, comparing the two batteries above, 4 minutes into a race, the 6000mAh battery would have a higher voltage then the 4200mAh pack. But (isn't there always some buts?) considering that in a normal race you would only use about 2000 mAh of the pack, the voltage drop would be negligible.

You didn't say what type of racing you were doing. These things will be much more noticeable in high traction carpet racing and may not even be noticeable in dirt racing.

oo sorry i always forget the details. offroad spec Slash racing and were only using the titan 12 t motor and stock ESC.

Im looking to get more speed but if the am output is the same, then which one would give me more pep/performance.

You will not notice the difference on a stock Slash (I run one). Get the pack that is the least expensive. I've run a 3200mAh 20c and a 5000mAh 40c and notice no difference. The biggest difference in the stock Slash class is a good Titan motor.

what if you were drag racing? which would be better a 3200-40c or a 5000-40c? the 3200 is 3ozs lighter. we are running between a 3.0 to a 4.5 motor

In the case of drag racing, weight is king. You always want to be at minimum weight.