Two Guys Rally

Keeping Drivers Cool [ July 30th, 2008 ] By:Charles Smith

The whole point of keeping a racecar cool is so you can keep the driver(s) cool. There are lots of neat ways that race teams around the globe do it. Here are a few of them:

Cut Back On Layers

This may sound obvious but most racing suits have three or more layers of material to them. Keeping the layers down to a minimum (safety still matters) will allow the air you bring into the car to do its job and cool the driver down. The Subaru World Rally Team cuts that down to 2 layers of outerwear for the really hot rallies. The neoprene underwear still restricts breathability but keeps the drivers safe from fire.

One of the neat things about Rally Racing is that short sleeved suits are allowed in the extremely hot rallies. Many famous world champs have rocked the short sleeves or rolled up sleeves during desert rallies. See Colin McRae and Richard Burns for prime examples.

Drink Lots of Water

Being properly hydrated keeps drivers cool for a few reasons. First of all they can sweat, and if the car is breathing right that sweat can evaporate and will take a large amount of heat away from the driver(s). You will also lose a large amount of water through sweating, especially in the heat of a cockpit.

Your body is mostly water, so any heat your body generates related to general metabolism gets dumped into that mostly water body of yours. Less water means higher temps for the same metabolism (when controlling for the effect of sweat).

Your blood volume is also 80-90% water and so losing water means your blood volume will go down. This makes your heart work harder (oh look more energy release) and you feel hotter for the same temperature. Petter Solberg has said that he and Phil Mills will drink 10 liters of hydration fluid (mostly water and some electrolytes) in a day. That works out to over 1 gallon per person on that day not including the water that is in the food they eat. So drink up before and on race days.

Put Things In Freezers

Put everything you wear in a freezer (except maybe the neoprene) as it will make it a little nicer for that much longer. Your clothes will absorb that much more heat before letting you heat up.

Throw in some towels sprayed with water. Freeze those puppies so when at service, or pre and post race, you can wrap one around your neck and keep cool.

Mix Alcohol and Water

I am not saying drink alcohol, but add water and rubbing alcohol together and keep that chilled in a spray bottle. When you can, spray some on your skin and lots of heat will be pulled away with the alcohol and water (so will the oils in your skin). This works so well that some racecars will put this mix in intercooler spray reservoirs. It really will make that much of a difference.

Drinking alcohol will actually hurt your ability to cool off as it is a diuretic. So that is just one more reason not to drink when racing (besides the many obvious ones).

Neat Technologies Help

A loyal reader Dustin Tarditi reminded me about things like UnderArmor (loved it for lacrosse) and their high tech cousins deemed Cool Suits. Under armor is great for wicking away sweat (and with that heat) from the body and allowing air to do its job.

Cool Suits are even cooler as they will run coolant (water or what have you) from a cooler that is in the racecar (or in the pits) through tubes and across your body. The tubes are zig zagged across your chest and they pull heat away from your body into the coolant (which goes into the cooler).

Newer styles of Cool Suits are focusing on the wrists and palms. Why? Because “in order to cool the body you must cool the blood”, and the blood is a lot closer to the skin around the hands. This is the same reason you treat heat stroke/exhaustion by cooling the hands and feet rather than the whole body (the latter is dangerous as it may make it harder for the body to cool itself as it will bring the blood into the core due to shock). The trick to the new technologies is making them lightweight and not interfere with the driver(s) control of the car.

Keeping Racecars Cool [ July 22nd, 2008 ] By:Charles Smith

While racecars are usually most definitely awesome, today’s weather reminded me they are pretty effing hot inside them. In the quest to save weight (translation: saving time on your laps/stages) common things are kept off the car. Air conditioning is gone, underbody/frame insulation is gone and the lexan windows usually dont roll down. Combine that with the fact that a racecar’s engine runs quite a bit hotter and cars with antilag systems (ALS) have exhaust temperatures above 1000 ºC the car’s interior will be hotter when running. However there are a few tricks to keeping the cabin temperatures survivable:

Air Vents

Racecars have a love hate relationship with air. At really high speeds it slows them down and sometimes even makes them crash, but it also cools their engines. In a similar fashion, it can help cool the cabin and driver(s). Keeping your drivers alive means getting them nice cool air to breath. Good helmets allow the driver to breath and it lets sweat do its work at cooling the driver(s) down. NASCAR likes to use forced air helmets that push air through the helmet, while Rally tends to use open face helmets (very breathable and you can yell at your driver in them).

In order to let a helmet do its job air needs to be getting to the driver(s) from outside. Vents to the cabin are nice for this. Rally cars often have a vent on the top center of the car to let air in through a diffuser so the drivers can breath and cool off. Air also has to exit the cabin, but if your windows are closed how can it do that? Closable vents in the back windows help with getting air out of the car, however in a Rally application I would suggest a filter on them (dust likes to come into the car otherwise). Andrew Comrie-Picard’s Mitsubishi is a shining example of common air ducting.

Window Tint

Sunlight heats up the cabin majorly. Ever been burned by a seatbelt buckle that was left in sunlight on a hot day? I know I have. Tinting a racecar’s windows with reflective tint can reduce any sunlight that is causing the cabin to get real hot. While black tint works to combat cabin temperatures, mirror tint works better (more reflection, less absorption) as it will not radiate as much heat through the glass into the cabin.

Roof Paint

Another way to keep the cabin temperatures from skyrocketing due to sunlight is to paint the roof of the car. The roof of the car is often not seen by spectators, so diverting from your colorscheme is not as big a deal. Painting the roof white will keep it from absorbing as much heat from the sun and further lowering the temperatures in the cabin.

Interior Paint

The interior is exposed to light too! Roll cages and the inside of the car frame make up a large surface that can absorb even more heat. Painting them white keeps them from absorbing as much heat. Plus a consistent interior color makes the car look neater and better organized. Also white shows everything wrong(great trait in a racecar) like: all sorts of leaks including exhaust, cracks and where you dropped your notes pen.

Insulate Exhaust Pipes

Exhaust pipes in racecars get extremely hot. They get way hotter than the exhaust on a street car so there is a lot more heat that comes off of them and into the cabin. Wrapping the exhaust in heat insulation might add a couple pounds, but it might give you a better performing engine. Higher exhaust gas temperatures means higher exhaust gas velocity, and if you’re running a turbo this means a faster spooling turbo. Not only will you get a possible gain in your engine, the cabin temps will drop. A normal exhaust will radiate heat into the metal on the underside of the cabin (a good amount of it too) which will transfer into the cabin. 1000ºC exhaust gas will conduct massive amounts of heat through a thin piece of metal(exhaust piping).

Regardless of what you’re racing doing everything you can to combat high cabin temperature will make your racedays more enjoyable and more consistent. Heat fatigues people, and tired drivers are dangerous drivers. That one, came straight out of a DMV Manual.