[snellemin]

7S is 29.4V charged up and 25.9V at rest when nearly depleted.

For dragracing you have the wrong setup. You want to reduce weight on your vehicle, so adding more batteries will just weight you down and loose the race. Acceleration is key here and not top speed. You are not doing a 300ft speed run, but a 132ft dragrace.

Get rid of you 51t spur and swap in the 47T. Launch control is key to winning with these big cars and not the abundance of power. Remember it's only 132ft. My A123 "low powered" GTP kept up and won races against more powerful cars and buggies.