By on November 3, 2017

“Why can’t we have coolant in the car when we’re racing?” It was getting close to midnight and I was still trying to get the undertray off our MX-5 Cup car so I could drain the distilled water and get coolant into the radiator. There was a bit of a time factor involved; the temperature was scheduled to dip below freezing in the hours to come, and if the water froze in the engine block we would have serious problems. Danger Girl understood perfectly well why we couldn’t let our little Mazda make it through the night without coolant in the engine, but she didn’t quite understand why we didn’t have coolant in there to begin with.

In her honor, and for the enlightenment of every would-be track rat who has been afraid to ask why such-and-such a rule exists, I’ve picked seven slightly opaque trackday or racing rules and explained them below. Even if you never plan to set foot or tire on a road course, this might still of be of interest… or not. What can I say? I tried to get you to click the jump. Click the jump already!

Why can’t we have coolant in the race car? And why doesn’t that rule apply to street-car trackdays?

Conventional coolant/water mixes are extremely slippery when they escape a car and find their way onto the racing surface. It’s a safety hazard to have coolant on a racetrack, so virtually every sanctioning body out there bans its use. Instead, you have to put distilled water in the radiator, usually with something called “water wetter” that raises the boiling point a fair amount.

Why don’t regular trackdays enforce this rule? ‘Cause if they did, nobody would show up. Also, the kind of metal-to-metal collisions that tend to release coolant onto the track are (supposed to be) rare in non-competitive open-lapping days. There’s an exception to this: if you bring your motorcycle to a trackday, chances are that you will be required to run plain water.

Why do I have to have padding on my rollcage or roll bar? It’s really far away from me.

In a crash, your head and body will go places you can’t predict. I have in-car video from when I was hit at Laguna Seca a few years ago where you can clearly see my head move maybe three feet over and hit a rollcage bar. I’ve dented my helmet on rollcage bars before. And both of those incidents were with a five-point harness and a HANS device. In a street car with an add-on rollcar? Expect your head to bounce off it the minute you get into serious trouble.

Why can’t I have floormats in the car? Why can’t I have my phone in its suction-cup holder? Why do I have to empty out the door pockets and center console?

It’s annoying, right? I felt the same way, right up to the moment one of my students had his “un-detachable” cellphone holder detach itself from the windshield over the “ski jump” at Summit Point Shenandoah. Both phone and holder disappeared into the driver’s footwell. The next braking zone was pretty exciting, to say the least. We got off track pronto and pulled the now-cracked phone out from between the brake-pedal hinge and the master cylinder. Anything that can detach in a car during a trackday will detach, and Murphy’s Law says it will end up beneath your pedals.

Why are they making me drive my convertible with the top up? It doesn’t increase the rollover protection.

You’re correct. However, the top will prevent your hands and arms from being forcibly shaved off when you roll the car. We use arm restraints in our MX-5 to prevent just that. Open-wheel racers do the same thing. And don’t think that you’ll just be able to keep your hands in your lap; a high-speed rollover could increase the force tugging at your arms to twenty times the power of gravity, or more. Not to mention the fact that you’ll be a little distracted at the time.

Why would I want an auto racing helmet for trackdays when my organizers are happy to take a Snell “M”-rated helmet? Don’t they provide the same kind of protection?

I have to admit I am the all-time offender for using motorcycle helmets in cars. More specifically, I’ve used my Arai “Oriental” helmet for the last few years of Road & Track’s road-course testing, because it’s extremely comfortable for long periods of time and retains less heat than my real race helmets. That doesn’t mean that you should follow my example. A Snell SA-rated helmet offers fire resistance that you don’t get in an M-rated helmet. That can make a big difference. And although this is not guaranteed to be the case, most auto racing helmets offer more coverage for the back of your head and neck because they don’t have to be usable in a sportbike heads-up riding position. Last but not least, a quality helmet designed for use in a car is usually tested for impact with steel bars… like the ones you’ll find in rollcages.

Why I do have to wear long cotton pants, long cotton sleeves, and closed-toe shoes?

Not every organization requires all three of those things, but virtually all of them require closed-toe shoes for driver and passenger. That’s to ensure that your shoes stay on when you’re exiting the car in a hurry. The requirement for natural-fiber long pants and long sleeves? It’s supposed to give you a critical fraction of a second to escape in case of fire.

Bonus question: Why can’t I take a passenger in the groups below “instructor” or “advanced”?

For the same reason your parents didn’t want you taking your friends around right after you got your driver’s license: you’ll crash the car showing off. Even Formula One drivers are susceptible to his impulse.

Hope all of this helps. Stay tuned for the next installment of this series, where we will tackle the burning question: “Should I run R-compound tires in the novice group?”

[Image: Jack Baruth]

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16 Comments on “Trackday Diaries: All Those (Not So) Stupid Rules, Explained...”

  • avatar

    “Instead, you have to put distilled water in the radiator, usually with something called “water wetter” that raises the boiling point a fair amount.”

    I’m going to be “that guy” as usual.

    Water wetter is sort of a surfactant; it lets water “stick” better to metal surfaces and improves heat transfer by reducing the formation of localized vapor pockets. it doesn’t really raise the boiling point much if at all. The increased boiling point of cooling water comes from the pressure in the cooling system; at a cooling system pressure of 16 psig the water’s boiling point is 260°F. Modern street cars are running 21-22 psig which gets to a boiling point of almost 270°F.

    • 0 avatar
      Jack Baruth

      I appreciate this… maybe I would be better off saying that it reduces the risk of boiling over.

    • 0 avatar

      I’m probably wrong but I had always understood that Water Wetter (or Purple Ice etc) in a car running pure water was less about cooling and more for
      1) Preventing corrosion
      2) Acting as a lubricant for the water pump.
      Normally coolant does both of those things and when it isn’t there something has to.
      Could just be marketing and internet wisdom though.

  • avatar

    And the real reason you want to run water in your track car is that straight water is much better at transferring heat that a mix with antifreeze/coolant. In most Ford owner’s manuals they will tell you that a 50/50 mix is good for most situations but if the vehicle is operated in a hot climate you should use 60% water and 40% coolant to maximize cooling system performance while maintaining corrosion protection.

    The big reason to use water wetter in your vehicle with straight water is the corrosion resistance, not the improvement in heat transfer. Now if you have antifreeze/coolant in the system then the reason to run water wetter is to improve the heat transfer ability.

    • 0 avatar

      yep. water is more or less the best coolant available. not least because of its high specific heat capacity. it takes a *ton* of energy to raise the temperature of water (relatively speaking.)

      that has the useful side effect of being a “thermal buffer;” the cooling water can absorb short-term excursions of maximum engine power without risking overheat. ‘s why a 400 hp Camaro can have a relatively tiny radiator, while a 400 hp Freightliner truck has an enormous radiator.

  • avatar

    Synthetic fibers have a lower melt point than the ignition point of cotton, which ignites at 410 F. A 50/50 blend of polyester and cotton will melt at 350 F., Lycra 340 F., and once melted you can’t “rip” it off of you to stop the burning. The molten mess will continue to burn tissue until it drops below 120 degrees and is harder to remove post-injury. Almost all man made fibers for clothing produce acrid black smoke when they burn, while cotton produces a light gray ash.

  • avatar

    “Why I do have to wear long cotton pants, long cotton sleeves, and closed-toe shoes?”

    You mean I couldn’t wear one of my old DuPont uniforms made out of 100% Nomex? By the way, if you think 100% polyester clothing is uncomfortable, just try Nomex.

  • avatar

    The HPDE group I run with violates most of these rules. The guy who runs things feels more risk factors occur on your daily commute. And I kind of agree with him. On track everyone is doing the same thing, going in the same direction, not using their phones or radio, yelling at the kids or drinking lattes. There are no missed exits or random lane changes. Its a controlled situation, just at slightly higher speeds.

    My biggest worry is people pushing too hard and spinning out in front of me. This has happened to my brother and he had go WAY off track to avoid T-boning a sideways 911 along with the debris field of parts after its owner decided to get a closer look at a tire barrier. I’ve had several guys attempt to out brake me (WTF!?!), miss their brake zone (well duh) and go straight off. They would have t-boned me if it wasn’t for the fact that I’m a conservative track driver and immediately checked up as soon as they appear off line in my side mirror. This only occurs in the advanced/instructor run group (ironically) because that group has no requirement of point-by-passing.

    The only rule we have with ride-alongs is you can’t have passengers when running the Roval (aka using NASCAR 3 & 4 at Homestead) instead of using the standard infield track. Because if things go wrong its the passenger side that hits the wall first, thus the risk to the passenger is higher then the driver.

    To me the closed toed shoes, putting all in cabin items away and removing floor mats are all common sense things. With that said I leave my mats in because they NEVER move, they have hooks/clips that prevent them from going anywhere. In fact I struggle to get them out when its time to vacuum them. There is no way I could drive in open toe sandals. While I don’t have racing shoes I wear a pair of thin, very flexible Sketchers so I have good pedal feel. I find normal sneakers to be too thick and stiff to work the pedals.

    I also violate the motorcycle helmet rule too due to comfort. However if you think about it wearing a helmet without a HANS device is just as bad. If you have a harness instead of the standard 3 point belt then a HANS should be mandatory. The harness will hold in you place while your head (with the extra helmet weight) will… well I think you can figure it out. I wear a full face helmet with a visor. My brother switched to this style after one day a rouge piece of tire rubber flew into his car and hit his shoulder. It left a bruise! So I think shielding your face / eyes is VERY important. When I first started doing HPDE I wore long pants and long sleeves for general skin protection (glass/fire) but this is South Florida where for 9 months out of the year pants and sleeves is just asking for heat stroke.

    One rule not mentioned is windows must be down. This to allow point-byes and to keep any broken glass contained within the door frame vs flying all over the car. If it starts to rain we can put the windows up, but I just pull into the pits to be safe. My Z is too challenging in the wet to drive aggressively.

  • avatar

    “Why do I have to have padding on my rollcage or roll bar? It’s really far away from me.”
    I recall a MVC where an unrestrained back seat passenger was killed when her temple struck the unused seatbelt buckle.

    “Why can’t I have floormats in the car? Why can’t I have my phone in its suction-cup holder? Why do I have to empty out the door pockets and center console?”
    All of those little items become projectiles. Floor mats can become the equivalent of a “crazy carpet” on an icy hillside. I was at a low speed MVC where the passenger was found crumpled up partially under the dash.

    “Why are they making me drive my convertible with the top up? It doesn’t increase the rollover protection.”

    No one has the strength to resist centrifugal force.
    Very common to see limb injuries in side by side quad crashes for this very reason.

    “Why I do have to wear long cotton pants, long cotton sleeves, and closed-toe shoes?’
    Burns are obvious but one can literally have their feet torpedo out of those open toed shoes. I was at a fatality where a person struck by a car while wearing roller blades and the roller blades were sitting neatly on the ground at the point of impact.

    People tend to have zero clue as to the forces involved in even a low speed crash.

  • avatar

    i did a couple of lapping days on a local smaller track a few years back. we had all the same rules except we were allowed passengers, which I never thought about but makes sense because: The one time I went off track was when I had a guy friend with me. (My wife rode with me once but nearly cried so I couldn’t push it.) After a some warm up laps I told him I was gonna push it, which I did and I found the limit of my front tires in a corner braking zone and being a novice (and not stupid) I merely under-steered into a grassy runoff area. waited for traffic to clear and drove to the exit with my tail between my legs.

    we also had the windows down rule.

  • avatar

    Regarding removing suction cup holders and everything else not bolted down, what gives with journos driving on track with cameras and mics stuck to almost every surface available? I’ll pick on Winding Road, for example. Is this a rule more specific to competitive events than open lapping?

    Interesting article and great comments, especially the conversations about only water for coolant and cotton vs synthetics.

  • avatar

    I worked in a hospital burn unit for a while. It’s astonishing how well cotton clothes protect people from fires. Synthetic melts, and the melted synthetic sticks to skin. I’ve seen folks with > 70% body surface area third degree burns – with no burn whatsoever, not even first degree, where they were protected by cotton underpants, which are pretty thin.

  • avatar

    There’s a reason synthetic fibers aren’t allowed in historical reenactment, and it’s not just authenticity. Keep in mind all those women doing American Civil War (Rev War, etc.), tending the campfire and cooking, in those big, voluminous skirts.

  • avatar
    Matt Foley

    Bonus Bonus Question:
    I have an NA Miata. If I drop $700 on a Hard Dog Hard Core Double-Diagonal Roll Bar (including padding, cover, and shipping), spend a Saturday installing it, and show up at an HPDE with an SA2010 rated helmet, will I be allowed to run? Or will somebody produce a broomstick and tell me I’m half an inch too tall, or my helmet is too old?

    • 0 avatar

      Depends on the group doing the event. I’ve run with one group that checks everything. They actually make your car go thru a real tech inspection to ensure it meets every last rule. For example (and not mentioned by JB) your battery should have a cover over the positive terminal and 2 bolts holding it in place. However my normal group has self tech – so you just fill out a form, sign it and you done. Nobody checks anything, its your responsibility to ensure your car is safe. And our Miata guys are allowed to run with the top down. Most of them go top up, but I believe that is for aero reasons.

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