Foul weather racing
Racing in wet conditions is an occupational hazard for the uk & protecting your gear is a must if you want to survive the day without failures or do not want to costly a season.
Radio gear always put reciever in a ballon this will help keep out any moisture. Silicone any holes where the wires come through & lids prior to any final to make box water tight.

Engines & air filters, Invest in a wet weather filter as its a must if there is standing water. Two versions shown here one being the Edit filter the second a GT85 cap does just as good a job & will keep out most of the water keeping the foam dry, also consider duck tape to make simple covers. Oil up both inner & outer foams this will also help repel the water.

Other simple methods to stop water being forced in is a spur gear guard this stops water from being sprayeed all around the internals.

Fuel tank & lexan guard stops that direct channel through the fuel filler hole to the air filter.
Prior to any wet race when body is fitted spray entire car with WD40 or GT85, this will help save moving parts & help prevent ingress of water. It also repels alot of the mud & stops it from sticking for a period of time.
When cleaning avoid using a compressed airline or at least near the bearings as it will push the moisture into the bearings. It will also be necessary to check pivot pins during intervals between heats & finals as the plastic can often swell making it bind on the pins. After the meeting strip the car down removing the diffs, drive shafts, bearings, engine, pivot pins radio gear & dry all of this off. The Engine it is advisable to strip it down & dry it out as water will get in, re lubricate it & re assemble otherwise engine internals will corrode.