pinion size
 

What would be a good pinion tooth count to use with the stock 65t spur for the monster pirate or would i be better off using a new center diff?

What motor kv?

What voltage will it be run on?

What tires, stock or otherwise?

Do you know the front/rear diff ratio? What is it?

With this info I could better recommend a good pinion tooth count.

It's a stock pirate,haven't figured what motor/battery combo yet,thinkin maybe novak ballistic 8 and possibly maxamps.

Cool. Stay away from maxamps, gens ace are good batteries, a lot of people also like the cheap batteries from hobbyking.com.

To figure out a pinion size, you usually shoot for a 40-45mph top speed on monster trucks.

In order to figure out a top speed we need to know the variables mentioned above- tire size, motor kv, voltage, diff ratio.

In my opinion a novak system is a little small for a big monster pirate. My recommendation would be a castle creations mamba monster speed control and 2200kv motor on 6s.

Top speeds can be figured out here> http://www.scriptasylum.com/rc_speed/top_speed.html

Are most of the packs h2o proof?

Any lipo pack would have to be both submerged and have some kind of mechanical failure before water would hurt it.

Unless you plan on driving in a swimming pool you'll be okay. Even then you'd probably be okay.

Water "can" conduct electricity, but it takes some serious voltage and current to happen.

Keep in mind the gap between the positive and negative blades on a deans connector. Almost all waterproof batteries and speed controls are connected with a deans connector, and there is nothing waterproofing the main power connection. Water doesn't "arc" or close the gap between a deans connector. Water and electronics failures usually take time, and it's oxidation that makes components fail, not exposure.

I've ran non-waterproof speed controls many times in water/snow. I just spray them thoroughly with wd-40 (water displacement-40) afterwards so water cannot sit and oxidize components.