Feb 252015
 

TL;DR:  No.

As the extent of Kyle Busch’s injury Saturday evening at Daytona became evident, Twitter erupted in angry calls for SAFER barriers to be put up on every wall at every track. An interesting division of sides appeared. A small number of people cautioned that simply plastering every track with SAFER barriers was likely to not only not prevent driver injuries, but might actually introduce new problems. Other people accused this group of being insensitive and “stupid”.

Interestingly, the small number of cautionary voices were people like the folks who write Racecar Engineering magazine, people who have been involved with motorsports safety research and people with advanced engineering degrees.

So let’s be really clear here. While I appreciate the passion with which people responded to the accident, opinion has absolutely no place in science and engineering. We work with facts, realizing that oftentimes, we don’t have all the facts we need. In an ideal world, we would have data from collisions at every track in the world, from every angle, with every type of racecar. But we don’t.

It’s fine for fans (and especially for drivers and their teams) to raise their voices and demand more attention to safety, but the average fan (or the average driver) has zero business specifying what those safety measures ought to be. The average NASCAR executive or track administrator doesn’t, either.  Motorsports safety is a constantly evolving research field and luckily, NASCAR recognizes that and works with the top people in the field.

Daytona

Let’s start with the obvious. A bare concrete wall at a track where speeds reach 200 mph is indefensible. To their credit, NASCAR and the Daytona folks promised to rectify that right away. Tire barriers – which are not ideal, but are definitely better than nothing – were up for the next day’s race.

Racetracks originally put up concrete walls to contain the cars and protect the fans. They weren’t there for driver safety. People don’t question the status quo.  It wasn’t until a number of serious accidents in both IndyCar and NASCAR prompted an effort to develop a better wall. I detail the origin and development of the SAFER barriers in my book, The Physics of NASCAR, based on my interviews with the barrier developers. The effort was initiated by IndyCar, but gained momentum when NASCAR threw their support (and money) behind it.

Once the technology was developed and proven, NASCAR mandated SAFER barriers on the outside walls of all tracks. It was a long road to development because it was a brand new (and frankly, counterintuitive) idea and everyone wanted to make sure it would work under as many conditions as possible.

How SAFER Barriers Work

For an overview of NASCAR safety, check out this video I made with the National Science Foundation. Here’s the brief version.

BSPEED_SAFERBarrier_Schematic

The SAFER barrier works by extending the time of impact. It’s much more comfortable to fall on a mattress than a floor because the mattress gives. The mattress absorbs and dissipates energy, so that the energy isn’t dissipated through you.

BSPEED_SAFERBarrier_HitA NASCAR stock car going 180 mph has approximately the same kinetic energy as stored in 2 pounds of T.N.T. When the car comes to a stop, all that energy has to go somewhere. Energy can be dissipated by skidding (friction between wheels and asphalt), light and sound (it takes energy to make that screeching noise and to produce sparks), spinning (energy is used to rotate the car) and deformation (energy is used to crunch or break things).  The key is that you want to dissipate energy any way except through your driver.

A mattress won’t make much difference to a speeding stock car. You need something much stiffer, and that’s the purpose of the SAFER barriers. They’re like mattresses for race cars. They use the energy of the car to deform the barriers and spread out the impact over a longer time. This directs energy away from the driver.

Why SAFER Barriers Aren’t the Only Answer

SAFER barriers save lives and this analysis is meant in no way to diminish their importance. But the inventors of the SAFER barriers would be the first folks to remind us that it takes multiple safety devices, working in unison, to protect the drivers (and the crowds). HANS or hybrid devices, helmets, restraints and the car itself are all part of the equation. You can’t address any one of those elements without considering the others. So here, briefly, are some things to think about.

Kinetic Energy Ranges

SAFER barriers work best in a specific kinetic energy range. I was surprised when interviewing drivers for my book to find that more than one mentioned that hitting a SAFER barrier at low speed actually hurt worse than hitting a concrete wall. But it’s true. The wall works by giving. If you don’t hit it hard enough, it doesn’t give and then it is just like hitting a concrete wall. This is relevant for a couple reasons.
1.  Most tracks host more than one kind of racing series. The kinetic energy scales of those series can vary widely. Any solution has to make the track safer for everyone who races there, not just stock cars.
2. Different tracks have different speeds, so even just within a single racing series, this means different kinetic energies. Compare Martinsville and Daytona, where the maximum speeds are a factor of 1.5-2 different. That means the kinetic energy scales differ by a factor of 2.25-4. That’s a big range. The response of the SAFER barriers can be tuned by using different strength foams and different types of steel tubing – but again, it has to work for all series racing there, not just NASCAR.

Get Off Your Grass

Get rid of the grass. Grass has no business being anywhere in a racetrack that cars could possible end up in.

a. Remember how I mentioned that you can dissipate energy by friction between the tires and the ground? The higher the coefficient of friction between the two materials, the more energy you dissipate. You know what the coefficient of friction is between grass and rubber? Very small. It’s even smaller when the grass is wet. This is why road courses have gravel traps. Huge friction that slows down the cars and hopefully stops them before they hit. (Gravel traps have their problems, notably that it’s near impossible to get out of one once you get in one, and that flying gravel is dangerous and difficult to clean up.)

b. Second, there is a drop off between the asphalt and the grass – a lip on which the car can catch, creating a torque. Check out Elliott Sadler’s crash at Talladega.

When he comes from the grass back onto the track, the roof of the car catches on that lip and starts the car rolling again. If I were a driver or an owner, I would be after every track to get rid of any grass near the track.

The Car Itself

NASCAR has done an amazing job engineering a much safer car than we had fifteen years ago. But the job isn’t done. There hasn’t been a career-ending injury (including death) during a race in any of NASCAR’s three major series since 2001. (Note added. It was pointed out to me that Jerry Nadeau‘s career ended after a very hard hit in 2003 during practice for a race at Richmond.) The injuries we have seen have all been below the knee. Dario Franchitti broke an ankle at Talladega. Brad Keselowski hit a wall testing at Road Atlanta and broke an ankle. Kyle Busch’s injuries from the Daytona crash were to his left foot and right lower leg.

The pedal box and the front of the car need some attention. Can the idea of collapsible steering columns be worked into the pedals? The front of the car is designed to crush (thus dissipating energy) in a crash, but maybe there is a way to refine how the crushing happens and reinforce the driver’s cockpit near the legs. I’m sure the folks at the NASCAR R&D Center are already thinking about this side of the problem.

Perhaps there are driver safety devices than could be developed as well, similar to the HANS device that prevents the head from slamming forward in  a wreck. Maybe there’s a carbon fiber leg brace or similar piece that could provide some extra protection for the driver’s legs in a crash. Of course, anything developed can’t interfere with the driver’s ability to control the car after a crash.

The Fallacy of Safe Racing

Motorsports is dangerous. People are killed participating in motorsports – especially at the lower levels, where the safety requirements are much lower than in the high-dollar, high-visibility series. But even in NASCAR, even in F1, even in Indy, there will be serious injuries and – I’m sorry to say – we haven’t lost our last driver to an on-track incident. All you need is that one in a thousand, one in ten-thousand confluence of events.

What Should Fans and Drivers Be Demanding?

Don’t tell NASCAR and the tracks that they should cover every conceivable wall with SAFER barriers and then sit back and congratulate yourself for a job well done.

Consider for a moment the ratio of people whose job it is to make cars fast to people whose job it is to make racing safer.

NASCAR has become so much more proactive about safety in the last years. If I were a driver, I would be lobbying NASCAR to hire more people at their R&D Center focused on safety, and to support more motorsports safety research at universities and industry.

The FIA has an Institute for Motorsports Safety.  It’s a non-profit foundation that centralizes safety initiatives and testing and works to get safety innovations on the track quickly.

Maybe it’s time for NASCAR to team up with IndyCar and the Tudor United Sports Car series and form something similar in the U.S. This isn’t an issue that should come up only after a serious wreck. It’s an issue that needs long-term, on-going commitment and attention. As a fan, I’d pay an extra buck or two on top of a race ticket if that ‘tax’ were earmarked for safety research.

For More:

 

Feb 202015
 

Okay, it obviously does if you’re one of the cars that fails to make the race. But beyond that- given the huge amount of attention that’s been given to the ‘embarrassment’ that was this year’s qualifying – does where you start make any different as to where you finish?

To investigate, I plotted the starting positions against the finishing positions for each race at Daytona. I wanted to do both the July and the February race to see if there was any difference given the different formats of the qualifying (regular qualifying+ duels vs. regular qualifying).

If there were a trend, you would expect a pattern to emerge on the graph. For example, starting position tends to be very important at mile-and-a-half tracks. Although there’s some scatter in the data, there’s a pretty clear trend that the people who start toward the front tend to finish toward the front. Same for the folks who start in the back.

BSPEED_StartingPositionDaytona500

It’s always interesting to look at the points that don’t follow the trend. For example, the point in the upper right circled in red is a car that had engine problems and didn’t finish the race.

The point that is the furthest from the line (furthest defined as the perpendicular distance between the point and the line) is the one circled in crimson and labeled “Harvick”. Despite leading 23 laps, Harvick had axle/hub trouble and spent 30 laps in the garage. His 41st place finish didn’t reflect how good his car was – at least until it broke.

Similarly, the other crimson-circled data points represent cars that ran more than 3 laps down due to problems in the pits, mechanical difficulties, or accidents that didn’t result in the car leaving the race, but did enough damage to require time in the garage or pits fixing the car.

Here’s similar data for Phoenix – it shows the trend even more strongly. If you started well and your name wasn’t Kurt Busch (engine failure), you finished pretty well. If you started in the back, that’s pretty much where you stayed.

BSPEED_StartingPositionDaytona500_2014Phoenix

So if this post is about Daytona, why am I going on and on about Las Vegas and Phoenix?  Well…

I wanted to show you what you were looking for first. And the analogous plot for Daytona is a mess. You might not realize that it means there isn’t a trend if you hadn’t seen data where there was a trend first. So here’s last year’s Daytona 500.

BSPEED_StartingPositionDaytona500_2014Daytona500

 

Again, plotting starting spot on the horizontal axis and finishing position on the vertical axis. I got clever this time – the red shading represents finishing positions that were six laps or more down relative to the winner. The red circles represent DNFs, due either to engine problems or crashes. (Just for comparison – at Las Vegas in 2014, only the last nine positions were six or more laps down.

There’s no discernible trend in this plot. Now you see why I showed you the other one first, right?

But maybe it’s one of those anomalous years, right? Let’s look at the data for the last three Daytona 500s.

BSPEED_StartingPositionDaytona500_CumDaytona

<sarcasm> Oh, yeah. Much clearer.</sarcasm>.

The trend (or rather, the lack of a trend) holds for the last three Daytona 500s and, in fact, for the July races as well.

Drivers and media types tend to talk about Daytona being a ‘crap shoot’. That’s reflected by the fact that where you finish has very little to do with where you start when you’re talking Daytona.

Why? Well, one big factor is that the close proximity of the racing means that you are much more affected by everyone else on the track. You can be the perfect driver, but it you happen to be behind Donny Dangerous and he spins, you have little chance of avoiding being caught up in it yourself. Remember at 190mph, you’re talking traveling a football field in the blink of an eye.

 

 

 

 

Feb 062015
 

There’s a lot of talk about all the rules changes for 2015. The limiting of the horsepower has been a hot topic of discussion, with people suggesting that NASCAR is basically mandating spec engines.  Here’s a couple of things to think about in terms of engines as we get closer to Daytona.

“750 hp Engine” Doesn’t Tell the Whole Story

When someone says they have a 900-horsepower engine, the only thing that tells you is that the maximum power it outputs is 900 hp.  Importantly, power output changes with revolutions per minute (rpm), as shown graphically below.

Engine_Powervsrpm_TwoCars

The power curves for these two cars have the same maximum horsepower, but the range over which they have that horsepower is different.  Let’s say the gearing is such that you’re running most of the race in the 8000-rpm range. Car 1 would have an advantage because (in that rpm range), it has higher horsepower. Car 2’s curve, however, is broader, which means it has a higher horsepower over a broader range.

Tapered Spacers

The big impetus for engine rule changes is NASCAR’s desire to lower speeds (which, it is theorized, will improve racing by lessening the effect of aerodynamics making it hard to pass when cars get close to each other).

There are lots of ways to decrease engine horsepower, but remember that teams have put untold amounts of money into designing and refining the current engines. Designing entirely new engines is a major undertaking, and a risk to mandate without pretty high confidence that lower horsepower will indeed help the quality of racing.

For 2015 NASCAR has gone with the simplest solution: a 1.170 tapered spacer that they expect will reduce power by about 125 hp.

Combustion is the chemical reaction whereby fuel mixes with oxygen and releases energy. It’s very similar to another chemical process called respiration, which is how your body converts food to energy.  In this case, you mix two fuel molecules (C8H18 is octane, one of the hydrocarbons in fuel) and 25 oxygen molecules.

EQ_CombustionBig

 

Remember your chemistry teaching talking about stoichiometry? Stoichiometry is the ratio of molecules, because they only combine in particular ways. If you’ve got four octane molecules, you need 50 oxygen molecules, etc. Combustion demands that exact ratio. The amount of fuel you put in a cylinder depends on how much air you can get in.

That’s how tapered spacers and restrictor plates work – they limit how much air gets into the cylinder, which limits how much fuel you can put into the cylinder, which in turn limits how much energy is produced.

taperedspacer_CUP

A couple people have asked if this is going to have the the same effect as a restrictor plate. No! Fluids (and air is a fluid) travels differently through an orifice (the technical word for a hole) and through a nozzle (which is what the tapered space is).  Don’t believe me?  Here’s proof:

The tapered spacer does change how the air goes into the cylinder and that is something the teams are studying using Computational Fluid Dynamics — and figuring out how to use to their advantage.

ICE_CFD

The Rules Don’t Say “Your Engine Must Be 770 hp”

NASCAR engine rules address the physical properties of the engine – things like cylinder height and bore, compression ratio, and which materials can be used.  This has always been the case. They control things like rpms and horsepower indirectly via things like gear rules.

So teams actually have a fair number of variables with which to experiment.  The big emphasis is energy efficiency. There are two major energy transformations in the engines: combustion, which converts the potential energy in the fuel to the linear motion of the pistons, and then the linear motion of the pistons is converted to rotational motion.

The conversion processes aren’t perfect. If the air-fuel mixture isn’t right, you don’t get all the energy out of the fuel. This is addressed by specific geometry issues (which controls how the air gets into the cylinder), and EFI mapping.

The other main culprit in energy losses is friction.  In a conventional road car, only about 14% of the energy you put into it actually gets to the wheels. The rest is lost (or used by the air conditioning, power windows, radio, etc.).  Most of the energy losses are in the engine. In a conventional car, 60-70% of the energy loss is in the engine.

Surprisingly, NASCAR (and most race car) engines are more efficient than passenger car engines, due in large part to the use of advanced coatings on engine parts. A typical valve has at least three different coatings – A hard coating on the tip to protect against valve lash wear, low-friction coatings on the stem, and hard coatings on the dome to protect against valve seat recession.

MetTech_ValveFailureThese coatings are often very thin – a hair’s width or two or three. Materials used include Titanium Nitride (that’s what those gold-colored drill bits are coated with) and diamond-like carbon (DLC). DLC has a much smaller coefficient of friction against steel than steel (0.7) or titanium nitride (0.3). DLC has a coefficient of friction on steel of 0.2.

There are companies in the Charlotte area that offer detailed failure analysis of engine parts, like the valve below. They use scanning electron microscopy to examine the parts. The culprit is often the coatings coming off.

Remember back in 2008, when Hendrick Motorsports had a baffling sweep of engine failures? The culprit was the coatings on the cam and/or lifters. They delaminated (i.e. came off) and the small flakes got into other parts of the engine. The clearances between moving parts in a race engine are much smaller and the tiny flakes of coating jammed up the engines, leading to failure.

Teams keep such detailed records of which parts go in which cars that Hendrik was able to track down the batch of parts that failed and ensure they weren’t being used in any other cars.

So if these coatings make engines more efficient, why aren’t they in all our cars?  The usual answer – cost. Coated parts are more expensive and people don’t want to pay extra money for a small improvement in performance/duration. Race teams, on the other hand will spend whatever they can to shave a few more seconds off their time.

So there it is. We’re still nowhere near spec engines, even with the new rules.  I suspect at some point, there will be an engine design initiative, but NASCAR has been fairly respectful for not throwing a zillion changes at the teams at one time.

And don’t forget, we won’t even see the tapered spacer until after Daytona because Daytona and Talladega are still using restrictor plates.

Jan 232015
 

I was at a panel discussion some years ago at a motorsports engineering meeting about materials allowed on the car by different racing series. They had the tech people for IMSA, F1, Indy and NASCAR up there answering questions from the audience.

NASCAR gets a lot of ribbing because compared to, say, F1, we are sort of in the dark ages. See, NASCAR (in attempts to keep cost reasonable) frowns on “exotic materials”. Tubes in the chassis are steel, not titanium or titanium alloys. Exotic is usually a code word for “expensive”.

Someone asked the panel what exactly was meant by “exotic materials”. Robin Pemberton replied

“If you have to ask, it’s exotic.”

Lots of people think that NASCAR requires that all engine blocks be made of cast iron.  That’s actually not written anywhere.  The engine blocks have to be from the manufacturer’s original castings. There is an explicit rule that the engine blocks can’t be aluminum.

Why would you want aluminum?  Aluminum is much lighter. Newton’s Law says that the force the engine provides is equal to the product of mass times acceleration (F=ma). Don’t let people tell you NASCAR is about speed. It’s really about acceleration.

Newton’s law says that if you want a big acceleration, you need a big force and/or a small mass. So anything you can do to lighten up the engine (which sits relatively high in the car) will help your acceleration and your handling.

Ford’s new F-150, for example, replaces steel with aluminum to save weight and thus improve gas mileage. Aluminum has it’s challenges, but since NASCAR doesn’t allow it to be used in the engine block, let’s look at what you might do.

Crystal Structure

Get yourself a pencil and a diamond.  I’ll wait.

The pencil lead is grey, opaque and soft. The diamond is clear, shiny and very hard. But they’re both nothing more than Carbon atoms, with the atoms arranged differently.

800px-Graphite-layers-side-3D-balls

This is graphite (pencil lead). Ignore the colors, they’re just there to show you that graphite is sheets upon sheets of carbon atoms arranged in a hexagonal pattern.  Every ball there represents a carbon atom.

Diamond is a little more complicated. Exact same atoms, but different arrangement (below).

Diamond_cubic_animation

 

Two big differences here to notice. First, each carbon atom in graphite is connected to three other carbon atoms, but in diamond, each carbon atom is connected to four other carbon atoms. This is the reason for the second thing to notice:  Graphite is made of planes of atoms with no connection between those planes. That means that it’s easy to shear (slide off) entire planes of atoms. That’s what happens when you write. The diamond planes are interconnected, which makes it much harder to remove one layer.

Yeah, But What’s That Got to Do with Engines?

NASCAR engine blocks are indeed made from cast iron, but not the cast iron you’re probably used to. A brief lesson on how you make cast iron. You start with iron, which is a very malleable (meaning easily deformed) material. Through millions of years of experimentation, people realized that you could change the properties of cast iron depending on what you added.

In face, if you put small amounts of Carbon in with the iron and heat treat it in a very specific way, the Carbon freezes in graphite flakes, like the picture on the left below. The flakes give the iron a lot of strength, but they also make it brittle. The sharp points on those graphite flakes are very high-stress points, which means it’s easier to start a crack there. If you’ve ever cracked an engine block or a frying pan, you know how that works. Once the crack starts, it keeps cracking. So gray iron, which is what this type is called, is strong, but brittle.

Then some enterprising soul figured out that if you add some magnesium, the Carbon doesn’t form flakes, it forms globs. (Yes, globs is the technical term.) Since there are no sharp points, there’s less stress and less cracking, which is why this type of cast iron is called ductile iron. Ductile being the opposite of brittle. This solves the problem of cracking, but ductile iron is nowhere near as strong as gray iron.

CastIronTypes

Sometime in the 1960’s, someone Baby Bear’ed cast iron. They found that if you added Mg anywhere from 0.007% to 0.015%, you get something spectacular, which is shown in the bottom-most picture. (Credit for the pictures: http://www.atlasfdry.com/graphite-iron.htm)

To set the scale, the bar shown is 50 micrometers. Micro just means millionth. Most human hairs are between 50 and 100 micrometers in diameter. The picture you’re looking at is three or four hair-widths wide.

If I had found this, I would have called it “micro-coral”. You get some of the flat flakes of gray iron, which provides the strength, but the edges of the flakes are round (like ductile iron). This cast iron is just right. It’s not as strong as gray iron, but it also doesn’t crack as easily as ductile iron.

This is called Compacted Graphitic Iron or, if you’re German, Gusseisen mit Vermiculargraphit.  I’ll abbreviate it CGI.

And CGI is the “exotic material” NASCAR teams use for engine blocks. You can have a comparable strength with less weight. CGI engine blocks are especially useful in V-shaped engines because that area between the two cylinder banks (the two edges of the ‘V’) has to take a lot of stress.

You may wonder why, if we knew about this material in the 1960’s, it’s taken so long to use it for engines. The reason is because of the very fine control over the amount of Magnesium added. It has to be controlled to within a few thousandths of a percent. A change of just one one-hundredth of a percent can drop the tensile strength by 25%. A person in a lab can exert this much control, but if you’re going to make this in a production facility, you need computers and computerized manufacturing.

This Week’s Semi-Gratuitous Colorful Picture for Moody

The pictures I’m showing you are Scanning Electron Micrographs. Instead of using light waves, we use electrons to make the image. Light can be thought of as a particle or a wave. So can things like electrons, protons, neutrons, etc.

Electrons have a much smaller wavelength than visible light, which means electrons can “see” things our eyes have no chance of seeing. Color doesn’t really mean anything when you’re talking electrons because color refers to a range of wavelengths that our eyes are capable of seeing.

But, of course, that doesn’t stop scientists from artificially coloring their images to make them clearer to explain or, sometimes, just because you can. So here, from The Telegraph, is an artificially colored scanning electron micrograph of a flea done by a gentleman named Steve Gschmeissner. He’s got everything from cells to bugs to plants.

SEM_Flea

And yes, there are a lot of scientists who buy images like this to frame and put on their walls. I have x-ray images of calla lilies and eucalyptus in my living room.

But no bugs.

 

 

Jan 092015
 

Welcome back from the holiday shut down. December in the U.S. is like August in Europe. Everyone you need something from is gone. I’m happy to be back to the regular grind.

Forty-three days till the Daytona 500. The shops are buzzing with activity as everyone adjusts to another new rules package. The engine folks are working overtime dealing with the changes there. The only thing that’s slowed down is planning for on-track independent testing, since that’s been eliminated this year. But more time in the wind tunnel, on the seven-post machine, at the computers.

Pit crews have a number of new issues to deal with this year and they stem from NASCAR’s decision to eliminate the tradition of having one official in each pit box during pit stops. Starting this year, they’ll rely on cameras to provide information about any infractions and calls will be made from a central location where all the camera feeds are monitored.

This change necessitates some compromises. Some rules will be easier to enforce via the cameras, while others will be more difficult. As the NASCAR Insiders point out, one of the less-enforced rules is that teams can’t be on the ground in their own pit stall until their enters the pit box immediately behind theirs.   The Insiders note that when NASCAR tested the system in 2014, they found that this rule was routinely violated, but called by officials only when the violation was blatant.

funny gifs

The gif above come from:  http://www.gifbin.com/988955 and it’s there to illustrate that one of the violations that will be more difficult to enforce with the video system is whether all the lugnuts are on tightly or not. Here’s the verbiage from the 2014 rule book.

Where tire(s)/wheel(s) are replaced, all lug nuts must be installed before the car leaves the assigned pit box area. When a NASCAR Official detects a violation, the car must return to its assigned pit box for inspection.

200610Lowes_TireCloseUpIf a lugnut ends up on the ground instead of on a wheel, that’s pretty obvious and officials would require the team to bring the car back in. (No one ever ‘inspected’ the tire – they just put a lug nut on the lug.)

NASCAR uses a five-stud configuration for their tires. Some sports cars and open-wheel cars using a single, central stud, but NASCAR likes to stick with things that look more like what we have on our cars.

As a side note, one of the disadvantages of the five-lug system is that when a lug nut gets away from the pneumatic air wrench (which spins it pretty quickly), it behaves very much like a bullet when it goes flying. Most people who have spent time on Pit Road have been hit by a flying lug nut. It hurts. Without proper head and eye protection, a flying lug nut could do some real damage.

Teams do everything they can to make getting tires on and off the car as fast and fail-proof as possible.

NASCAR_lugs

Notice that you see hardly any thread once the lugs are on. The rules require that the first thread must be visible when the lug nut is installed. The remainder of the lugs are smooth and the outmost portion rounded to enable the wheels to slide on quickly and the lugs to tighten fast. Teams are experimenting with different types of air guns to try to speed up their pit stops.

The lugs are mandated to be solid, one-piece heavy duty 5/8 inch diameter with 18 threads per inch. The lugnut itself is required to be one inch (OD) and a minimum of 0.650 inches thick.  So, if there’s 18 threads per inch and the width of the lug nut is 0.650 inches, then there are (18 x 0.65 = 11.7) just about 12 threads in play.

Yes, teams have been caught boring our the lug nuts so that there are fewer threads that have to catch, which means they go on faster.

The obvious question is: “How many lug nuts do you actually need to hold the wheel on?”  I asked a former tire changer. He gave me a big grin. His answer?

Two. But they have to be the right two.

The two next to each other won’t work very well. Two approximately across from each other would be better. Three would be even better. Two lug nuts aren’t ideal, but five is probably overkill.

Which brings us to the people questioning whether this is a really bad idea on NASCAR’s part because it encourages the teams to do something unsafe – possibly to skimp on making sure that every last lug nut is one-hundred-percent, absolutely positively tight as it can be. Teams will cheat a little now that they’re not being watched, which means we’re likely to have safety issues with wheels coming off.

It’s true that teams may not be as paranoid about making sure they don’t do something they could get called for. But the penalties have been called primarily for missing lugnuts, not those that aren’t completely tightened because that’s very difficult to see – camera or in person.

Plus, it’s in the team’s interest not to leave the lugs loose. If one is noticeably loose, you’re likely to develop a vibration in the wheel and that causes not only a potential problem with the wheel, it can totally freak out a driver into thinking he’s about to have a flat.

We’ve seen tire changers signals to the crew chief that they are afraid they missed a lug — even when the official didn’t see it or call it. A crew chief may call a driver back to check, just because a crash could knock you completely out of a race while checking will only set you back a lap or maybe two.

The rule I’m far more concerned about in terms of safety is that NASCAR will not allow one team to help the team in the next box from over the wall. The origin of the rule is to prevent one team (say a team in the Chase) from getting essentially an extra pit crew member, or allowing their pit crew to go faster because they’re got a safety net in the form of someone else corralling their stray tires.

But, the danger of a tire rolling out of a pit box and being punted by a car is significant. Tire plus wheel is seventy plus pounds. A flying tire can literally kill someone one. NASCAR is going to be more rigorous about ensuring that pit crew members  stay in control of the tires until they are more than half way back to the wall (where, in theory, they wouldn’t roll out into the path of an oncoming car), but I would really hate to see a case in which someone hesitated to stop a tire that ended up posing a threat to the people on Pit Road.

The NASCAR Insiders suggest that there are likely to be a plague of penalties in the first couple of races as the teams adjust to the new enforcement criteria. As usual, they’ll adapt quickly, but keep an eye on Pit Road for the first couple races of 2015.

In only 43 days!

And since I know Moody will be disappointed at the lack of colorful graphics, I’ll leave you with a New Year’s present. When you were toasting in the start of 2015, you probably weren’t paying a lot of attention to the bubbles in your bubbly. Well, a couple fluid dynamicists in France have made a career of studying bubbles and they provided some neat diagrams showing how fluid dynamics works in champagne.

ChampagneFluidDynamics

I, of course, will have to procure a couple bottles of champagne so I can check this out myself…

Dec 122014
 

The primary motivation for all the changes to the Chase format was to up the excitement factor – the “game seven moments” as NASCAR brass put it. While the fact of the matter is that you can’t guarantee excitement, all the machinations put in place definitely increased the stakes of the chase races.

I’ve heard a lot of people say that the increased stakes spurred the drivers to be more aggressive and that resulted in better racing.  To be sure, we had a couple notable off-track incidents. It’s pretty surprising when Matt Kenseth loses his cool. But what about on-track?

Lead Changes

I started thinking about how you would measure that.  My first inclination was to look at lead changes. If drivers are being more aggressive, there ought to be more lead changes in Chase races than in other races. Now, comparing this is a little tricky.  You can’t compare a Talladega (where the ever-shifting lanes of cars trade the lead, resulting in hundreds of lead changes) to a Martinsville or a Charlotte.

But there are eight tracks in the Chase that have races earlier in the season.  What about them? I looked at how many lead changes there were at each track in the Fall, then compared that to the Spring. Kudos, as always to racing-reference.info for putting all this data at my fingertips. I took the difference, so that a negative number means that there were more lead changes in the Spring and a positive number means there were more lead changes in the Fall.

For example, At Loudon, there were 18 lead changes in the Spring race, but only 10 lead changes in the Fall race, so you get a bar going down of magnitude (18-10=) 8. Surprisingly, For all races except Texas, there were the same or MORE lead changes in the Spring race.

BSPEED_ChasePlayoffFormat_2014

This, of course, led me to wondering. Could it be that perhaps drivers were being less aggressive during the Chase? So I looked at tracks with two races but neither one of them in The Chase. I added them (and made the graph 3D because it looks cooler that way). The last five races (the ones on the right) are non-Chase races.

BSPEED_ChasePlayoffFormat_SFALL

 

So regardless of the race being in or out of the Chase, the first race at a track routinely (with one exception) has an average of seven more lead changes than their latter-season counterpart races. The only difference (and it’s very minor) is that there are an average of 4.75 fewer lead changes Fall vs. Spring in Chase races and an average of 10.4 fewer lead changes in non-chase races.

Finally, I thought it might be helpful to look at the same data for the year before, where we didn’t have the playoff format.

BSPEED_ChasePlayoffFormat_2013vs2014

And it’s pretty much the same story. There are fewer lead changes in fall races than spring races in 2013 as well.  Recall that the races where cuts were made were Dover, Talladega and Phoenix, and there’s no big standouts there either.

So if you want to quantify racing quality by lead changes, you can’t really make a case that the new format led to more aggressive or better quality racing to any great extent.

I looked at a couple of other parameters as well. I tallied up the number of accidents in each race, counting true accidents as well as spins, but not debris, competition or drunk-people-sitting-on-catchfence cautions. I then compared those Spring vs. Fall. In chase races, there was an average of one more accident in the Fall than the Spring and in non-chase races, there was an average of just about one more accident in the Spring than the Fall. Over the course of the season it average to just about zero, but remember that these are very small numbers of races, so you can’t read too much into the statistics. There would have to be some overwhelming difference in numbers to be convincing.

Next up – looking at Driver Finishes to see if they’re driving more or less aggressively.

Nov 202014
 

One of the biggest changes NASCAR has instituted for the 2015 season is eliminating individual team testing at any tracks. In 2014, teams were limited to four tests and were not allowed to test at tracks that were included in the schedule.  NASCAR may run some limited tests, but they won’t be having the week-long marathon that was Daytona Speedweeks.

Given the intensive schedule in February, most teams are happy to be losing the Daytona tests. A lot of focus for one race – and a race in which the probability that the car comes home in one piece is vanishingly tiny.

Will It Save Teams Money?

Even though some teams will amp up other types of testing, eliminating sending a dozen people and a car out to a track will most likely result in a net savings of money.  NASCAR’s done a good job lately talking with the teams and most teams were in favor of the new rule.

Perhaps more important than the dollars saved is the time and energy of the team members. The season is already 36 points-paying races, plus the week before Daytona and All-Star week. That’s a lot of time to be away from home.  Even when they are  in Charlotte, the team members are at the track enough that they don’t really have time to be “at home”. They get to sleep in their own beds, which is nice, but it’s still pretty intense work.

A lot of NASCAR crew members simply burn out. It’s fun being part of a traveling circus – for a little while.  But eating out all the time, getting irregular sleep and dealing with the stress of the race weekend takes its toll. Once you start having kids, or a crisis at home, being on the road becomes a huge barrier to living the rest of your life. There are a lot of former crew chiefs who are very happy working out of the shop.

The few at-track tests that will be allowed will be run by NASCAR, and one assumes that they will schedule those immediately before or after race weekends, which again will minimize transportation costs, although it’s another day away from the shop for the participating crew and the driver.

Types of Testing

You can divide “testing” into two broad categories:  testing with the driver and testing without the driver.  NASCAR has historically come at it from both sides, hoping they’ll meet in the middle.  The testing rule has effectively taken away a lot of the tools on one side with the intent that tools from the other will compensate.

Remember that NASCAR’s goal isn’t so much keeping the status quo. It’s ensuring that whatever the rules are, they don’t give one company a huge advantage over the others.

So here’s my breakdown:

BSPEED_TestingTaxonomy2

You’ll notice the driving simulators are in a different color – that’s because that’s the only type of ‘testing’ that really involves only the driver. Teams are trying to use this tool in a more scientific way (see my blog on the Ford tech center, for example), but it still doesn’t address the communication between the team and the driver – which I happen to think is one of the most critical aspects of driver-involved testing.

 

With Driver vs. Without Driver

Some properties of a car are driver independent.  Drag is never a good thing, so any testing that shows you how to lower the car’s drag is useful and requires absolutely no input from the driver.  Similarly, downforce is almost always good, so changes that increase downforce are also good and will be the same, regardless of who’s inside.

But a lot of the magic in setting up a car is finding out what your specific driver prefers for specific conditions at specific tracks. Someone who comes from a dirt-track background has very different preferences than someone who grew up racing open-wheel cars on asphalt.

All drivers want more grip, but different drivers can make do with different levels of grip in different places along the corner. The really successful long-running crew chief/driver combinations (Chad/Jimmie, notably) work because the driver and crew chief have learned how to communicate. The driver can express what the car is doing and the crew chief knows how to change it so that it favor his driver.

What They’re Losing

This will be one of the few seasons where teams have no say in where and when they test. This eliminates their opportunity to strategize. When there were no rules regarding numbers of tests, you did as many tests as you could afford. You might test at places you were historically good at to optimize your changes of winning, or you might test at places you normally didn’t run well at so that you could get better.

When numbers of tests were limited, teams had to strategize. For example, some teams decided to make sure they were really good at one of the three races in a each segment of the chase eliminations. If you won one of those races, you were automatically in. And just about everyone who was in the Chase wanted to test at Homestead. Now those choices are out of the teams’ hands entirely.

Goodyear will run tire tests – but they aren’t promising they’ll include everyone. Tire tests exist for Goodyear to get the information they need to produce a good tire. That goal is often at odds with the information the teams would like to get from testing. Goodyear prefers 3-5 cars in a test.  You need one from each manufacturer at a minimum to ensure fairness, but you don’t want too many voices providing feedback because it becomes impossible to get detail.

Goodyear also has drivers and teams they like testing with. Some drivers are better at providing the kind of feedback Goodyear would like. And, frankly, some teams are just easier to work with than others. If you mandate that every car running the full season get to participate, that disadvantages Goodyear – which means disadvantaging the rest of us.  That kind of scheme means more Chevrolets test than the other brands, simply because there are more Chevrolet cars.  But if you limit the test to one or two teams per manufacturer, then some Chevy teams will be disadvantaged because there won’t be enough slots for everyone.

NASCAR-run tests are the best shot most teams will have to get real testing with the driver in the car.  The tests will be open, so everyone has a shot at participating. The disadvantage is that NASCAR decides the tracks. Given history, NASCAR is likely to hold tests at tracks that have been repaved, or for which there are new tires. Helping teams perform in the Chase is not part of their strategy.

Although both tire tests and NASCAR-run tests will allow the driver and crew chief additional practice at communicating, drivers who are changing companies and/or crew chiefs are the ones who will suffer most from this testing ban. The crew chief-driver relationship is critical. I maintain that one of the reasons Tony Stewart struggled the first part of this year (I’m talking before the accident in New York) is that his time out of the car with the broken leg the year before interrupted his developing the routine week in-week out relationship you need with your crew chief.

If I were Rick Hendrick, for example, I might put Keith Rodden (Kasey Kahne’s new crew chief) and Kasey in an XFINITY Car (that still sounds weird) just to give them some quality one-on-one time during an actual race. Because the cars are different, not a lot of specifics will transfer; however, the practice in driver giving feedback and crew chief adjusting is absolutely critical. Those lower-level series may be the only opportunity some drivers get to forge a bond with a new crew chief.

Without the Driver

I’m going to cover each of these techniques in a little more detail over the break, but for now, suffice it to say that the type of information you get from a technique like a seven-post rig or a wind tunnel is much more general. Yes, the particular car being tested will have the setup (springs, shocks, etc.) that the driver favors, but you’re missing the crucial component of the driver telling you how it feels.  All the charts and graphs in the world do not compensate for having a driver’s butt in the seat.

Below is what the underside of a seven-post rig looks like.  The four large pillars make the tires go up and down. You program the movements of those pillars based on sensor data you collected from on-track testing. The quality of the results go up the better input data you have. If you have data from a couple years ago, or data from the car with a different driver, you’ve lost some fidelity, some precision.

BSPEED_7PostRigUnder

And the unfortunate fact is that we just don’t know enough about reality to be able to replicate it in our theories. A wind tunnel has a huge advantage over a computation fluid dynamics simulation because one of the hardest things to simulate in a computer is turbulence (shown below, in red just because turbulence looks way cooler in red.)

FordFusion_Turbulence

Will The New Rule Level the Playing Field?

One of the claims I’ve heard people make is that banning on-track testing will help the smaller teams. Let’s start by saying that there are very few teams that are single-car operations anymore. Not because a given company has more than one car, but because manufacturers are doing a better job sharing information between their teams. So the question of one-car vs. multi-car really isn’t a relevant as it used to me.

The question of smaller vs. larger teams, however, is very relevant. Anyone can book time at a wind tunnel, but with time running $1200-$1700 an hour, smaller teams will spend much less time in the wind tunnel than teams with higher budgets. Larger teams have their own seven-post rigs, so they can run 24/7 if they are so inclined.

But even if NASCAR limited wind tunnel time and even the amount of computational fluid dynamics calculations you can make, it still wouldn’t be even. Smaller teams pay less. They generally have less-experienced crew and smaller R&D divisions. If you gave everyone exactly the same amount of data for their cars, the smaller teams would not gain as much as the more experienced teams.

RCR has (at last count) five Ph.D.-level people on staff.  The whole point of getting a Ph.D. is that you are being trained not to implement things that are already known, but to figure out things no one else knows. That is the level at which teams are analyzing this data. If I want to work at SpaceX or Orbital Sciences developing the next alternative to the Space Shuttle, there is a very well-defined path I take.  I train for eight to twelve years, learning as much as I can about what we already know. Then I strike out and try to learn things we don’t know.

There isn’t a Ph.D. level program in race car engineering in this country. The folks who are working in the industry have created their own set of knowledge and boy, is it proprietary. Their experience isn’t in books. So even if a team suddenly got a windfall and can hire smart people, they have to find a way to pull them away from the existing teams. I’ve got a Ph.D., but I couldn’t walk into a race team and help them. It would take me months, maybe years, to understand what they’re doing and what they know before I’d be able to make a contribution.

I think the upshot is that the new rule will keep things pretty much the way they are already, with the exception that teams with new driver/crew chief combinations are going to be at a disadvantage because of the lack of on-track testing.

 

 

Nov 072014
 

Flared side skirts became an issue when social media started noticing them somewhere around Kansas. The fact that the most obvious example of this was on the 2 car and Brad Keselowski is rapidly taking over from Kyle Busch as most-love-to-hate driver in NASCAR may have brought the issue to the fore faster.

The side skirts (or ‘vertical extension panels’) help seal the bottom of the car to the track. This picture, of the 2013 Toyota Camry, shows the clearest example of the side skirt because you can see the line where the side skirt joins onto the side of the body. The cutout is for the jack – if there were no pit stops, there’d be no reason for the cutout. The side skirts help funnel the air that does get under the car smoothly out, and they keep air from coming on on the sides.

2013_Camry_Side

Side skirts are made of a durable rigid plastic — except for one spot on the right side of the car near the tail pipe area. The rationale for this is that exhaust pipes get very hot. Although plastics are indeed the material of the future, plastics that are really, really heat resistant also tend to be expensive and harder to work with.

The plastic from which the side skirts are made is pretty rigid. You can cut it and bend it a little, but you really can’t monkey with it too much.  Except for that metal part, near the right rear wheel.  You know… this part:

NASCAR_2014_FlaredSideSkirts

Flaring out the right rear of the side skirt started out being done by a couple of teams and now you can find most all of the teams doing it.  So now for the burning questions.

Is it illegal?

Nope. NASCAR hasn’t fined or taken points from anyone for doing it.

Is it happening accidentally?

A lot of internet pundits initially claimed that this was the result of hard racing, no ride-height rule, and drivers racing on the apron, where the possibility of banging the car on the track is maximum. But not when it’s happening to so many cars and happening every week.

And then video appeared that showed jackmen pulling out the skirt during pit stops – right in front of the NASCAR officials overseeing the pitstop.  So no, it’s not happening by accident.

Is it really an advantage?

There have been a number of times in the garage where a team started doing something goofy just to see how many other teams would copy them. There are some cases I know about where teams made a modification they’d seen other teams make without understanding it — but they also had their engineers figuring out whether it was doing anything. If one of the backmarker teams had started doing this, I doubt anyone else would have noticed, unless that team all-of-a-sudden improved.

NASCAR does have a history of allowing something and then cracking down on it when it becomes too blatant, so the first teams doing this knew they might get their hand slapped.

The argument people have made is that it changes the balance of aerodynamic force. you’re providing a couple more square inches for air molecules to slam into. In this case, I doubt there’s much of an effect down the straightaway (especially with the rear-end skew), but it probably does help a little in the corners.

It certainly isn’t hurting the cars, or teams wouldn’t be doing it.

Why are they only doing it on the right? If it increases downforce, wouldn’t you do it on both sides?

They can’t do it on the left. The left-side skirt is entirely plastic and you can’t bend it. Plus, the issue here is really in helping the car turn, so you wouldn’t want to make the same change on both sides.

Should NASCAR prohibit it?

BenHur

First, let’s note that this has been going on for much longer than most people realize.  Like most things in NASCAR, it starts with one team sticking their nose out a little (or their skirt out a little) and escalates until it’s a big enough effect that those of us sitting at home notice.

It’s not like NASCAR hasn’t been aware of what’s going on.

The main reason I can see for NASCAR stepping in is that a sharp piece of metal sticking out at wheel height has the potential to turn Phoenix and Homestead into the Roman Colosseum.

Not that anyone would purposely try to cut someone’s tire down, but it makes bumpin’ and bangin’ a very different proposition.

Here’s the problem. It’s going to be tough to police. And I don’t say that just because Jeff Burton said it and he’s almost always right. It is possible for the skirt to get bent and banged by (for example) a tire being pulled off at an angle, or contact on the track.

The NASCAR pit officials can’t see everything. Their primary job during pit stops is to make sure the wheels aren’t going to come off again. Do you want them to take their eyes off the tires so they can check what the jackman is doing? Maybe with the electronic pit officiating coming next year, that will be possible.  Not this year.

NASCAR’s Sprint Cup Series Director Richard Buck told popularspeed.com

“I will say the garage is comfortable with how we’re managing it right now.  It’s the same for everyone. That’s how we try to manage everything — that it’s the same for the big teams as it is for the little teams.”

NASCAR has done a really good job not knee-jerk reacting to things. They tend to wait and see how things evolve. When they threaten to get out of hand, NASCAR makes a rule. This happened with the skewed-out rear ends a few years ago. It got to a certain point and then it got silly.  The cars couldn’t even get up on the rails for tech. When NASCAR made the rule, it had all the details – how much they would allow, how it would be measured.

I wouldn’t be surprised if they do something next year, but don’t expect anything to happen in the next two races – unless there’s a catastrophic accident that can be linked back to the flared side skirts.

And on a chemical note…

I always tried, as a teacher, to find analogies to help my students understand scientific concepts.  For example, my mental picture of “potential energy” is of a cat about to pounce or a sprinter on the blocks the second before the gun starts the race. You can see the energy ready to go in the tensed up muscles and once they move, you can see the kinetic energy (energy of motion).

Last Sunday at Texas, I got another one.

A catalyst is a chemical that initiates or speeds up a chemical reaction, without taking part in said reaction itself. All I need is a good video from Texas to make my point now.

That, or chemists everywhere should start referring to catalysis as “Harvicking”.

 

 

 

 

Oct 172014
 

Every year at this time, we hear that Talladega is a wild card because “Anyone can win”.  Which, of course, made me wonder — can anyone win?

Who Wins Races?

Let’s start by looking at who wins races in general. I analyzed the last three years and everything we have so far for this year and put it in a table. Why a table? Because tables help you see your way through all the numbers.  What I was interested in was trying to find a correlation between who wins and how “good” a driver they are, as determined by how high they finish in the standings at the end of the year.

The number in each box is the percent of all wins run by drivers in the top 5, top 10, top 15, top 20 and the Chase.  Note that I discarded some situations, like Brian Vickers, who won a race in 2013, but sat out much of the season due to illness and finished 78th in points. Same thing for Hamlin and Stewart, neither of whom ran all the races that year, but won a race.

Note that the new rule – that anyone who wins is automatically in the top 16 is going to invalidate this type of an analysis in the future because someone who would’ve finished lower in points gets boosted up by the win.

Year T5 T10 T15 T20 Chase
2011 44.4 63.9 83.3 91.7 77.8
2012 48.6 88.6 94.3 100 88.6
2013 61.8 70.6 91.2 94.1 85.3
2014 35.5 71.0 96.8 100 100

Here’s a gratuitously colorful graph of the same data, just for Moody:

BSPEED_PercentWinsByFinishingStatus

The take-away message:  It is very unusual for a driver who ends the season outside the top 15 to win a race. In fact, for the last three years, more than 70% of the races are won by the top ten drivers. (And I don’t know about the goofy perspective Excel uses in those graphs.  It makes it look like the numbers for 2013 and 2014 are less than 70% – but they’re not. I promise.)

But What About Talladega?

If Talladega really is an ‘equal opportunity racetrack’ in terms of winning, then the stats ought to look very different over the years. I analyzed Talladega races all the way back to 1990, which is almost 50 races. You know what? It’s not that different from the average.

Year T5 T10 T15 T20 Chase
2011 44.4 63.9 83.3 91.7 77.8
2012 48.6 88.6 94.3 100 88.6
2013 61.8 70.6 91.2 94.1 85.3
2014 35.5 71.0 96.8 100.0 100.0
Talladega 44.7 72.3 91.5 95.8

The stats are almost identical relative to every other race track out there. Out of the 47 races I included, only two were won by drivers outside the top twenty.

Jamie McMurray – 2009 Fall (22)

David Ragan – 2013 – Spring (28)

I omitted the Spring race in 2009 because the driver (some guy named Brad Keselowski (?)) only finished in 38th place – but only ran 15 out of the 36 races. So if you’re currently running below 20th place, you’ve got less than a 5% chance of winning.

Even the year Michael Waltrip – the patron saint of teams hoping for an upset at a plate track – won, he finished 15th.

Wait a Minute… That Can’t Be Right

We all remember David Ragan winning Talladega and Daytona and Trevor Bayne winning the Daytona 500.  Is it true that if you’re not in the top 15 and you’re going to win, it’s likely going to happen at a plate track?  Let’s look at the exceptions.

Year Driver Finishing Rank Track
2013 Martin Truex, Jr. 16 Sonoma
2013 David Ragan 28 Talladega
2012 Joey Logano 17 Pocono
2012 Marco Ambrose 18 Watkins Glen
2011 Trevor Bayne 53 Daytona
2010 Regan Smith 26 Darlington
2010 Paul Menard 17 Indy
2010 Marcos Ambrose 19 Watkins Glen

This year Aric Almirola won Daytona, and I’ve left that out because we don’t know where anyone is finishing yet. He could be 15th or better still.

But even if you counted him, not even half of the “upsets” take place at restrictor plate tracks.

But I swear I remember all these times…

I gotta tell you. I sweated this one out. I have looked at Dega Data for two straight days because I knew there had to be something interesting in there.

And I finally found it – but it runs counter to all my intuition. This is one of those things scientists have to be very, very careful about – not letting our expectations get in the way of reality. If you expect to see something, you’re more likely to see it.

So why does everyone think anyone can win Talladega?

It’s not at all surprising – it’s called the von Restorff or isolation effect. It’s named after a woman named Hedwig von Restorff (1906-1962), a psychiatrist and children’s doctor who conducted a set of memory experiments and found that an isolated dissimilar item surrounded by otherwise similar items would be better remembered.  In other words, it basically says that when something stands out as being very unusual, we tend to remember it.  For example, consider two lists

A B
9 TCE
21 GTS
3 JWN
16 PDY
QXK QXK
5 RWV
13 MTX
8 LEB
54 DVQ
3 PYN

The same three-letter sequence is in both lists. If I showed you the lists, then took them away and asked you what you remembered, you’d remember the letters better if I’d given you the A list than if I’d given you the B-list.  We tend to remember the unusual. And there’s a reverse effect, in that you may actually remember less about the things that don’t stand out.

Now if only I could wipe Michael Waltrip’s last dance (and 70’s mustache) out of my memory.

Oct 032014
 

@NASCARRealTime, @TheOrangeCone and @CircleTrackNerd had an interesting dialog when the 2015 rules were announced. They were debating whether the track records that are now standing are going to be essentially locked into history. The debate ended with an appeal to me and Goody’s Headache Powder. TwitterConvo_TrackRecords

When the Gen-6 car was introduced in 2013, new track speed records were established at 19 of 32 qualifying sessions. Yes, that’s more tracks than we run, but the record at Martinsville, for example, was broken in the spring and again in the fall. Another way to look at it is that out of 20 tracks where there was an opportunity to break a track record (meaning we exclude Dega and Daytona because their records are pre-restrictor plate, plus rainouts) – it happened at 16 places.

Why? The primary change was the much lighter car – they took 150 lbs off relative to the Gen-5 car while maintaining the same engine power and increasing downforce.

That changes in 2015, as one of the new rules NASCAR announced is a 1.170″ tapered spacer that will reduce power by about 125 hp. Gene Stefanyshyn (senior vice president of innovation and racing development for NASCAR) expects this is only going to decrease speeds by no more than 3-4 mph in most instances.

That seems like a weird trade off, right? 125 hp = 3-4 mph? Well, that’s because the engine isn’t the only place they’re making changes. They’re going to decrease the spoiler size to six inches, which will take away about 300 lbs of downforce, but will also reduce the drag on the car.

Here’s the theory: racing on ovals is won and lost in the corners. The primary impact of horsepower (all other things held equal) is determining maximum straightaway speed. In the corners, you’re not (except for plate tracks) using all the horsepower you have – you’re more limited by your lateral grip, which is determined by downforce.

Any driver can mash the gas coming down the frontstretch. What makes a difference is how soon they get off the gas/onto the brakes coming into the corner and how soon they get onto the throttle coming out of the corner. Let’s say you have to slow to 180mph to make a corner. It makes a difference when you start braking if you’re going 210 mph vs. going 200 mph.

You may actually be able to take the corner faster if you aren’t slowing the car down quite so much. A number of the drivers and NASCAR officials have stated that slowing down the cars a little (and remember, we’re talking 3-4 mph) should give drivers more options in the corners and thus make for more exciting racing.

But What About the Records?

Yes. A lot of records were broken in 2013. But a number of those records have been broken this year. The overall trend of pole qualifying times is up. Even when a rules change or a track change decreases the qualifying time, the next year, it starts creeping back up. I plotted qualifying times for a couple tracks to show this. Everyone’s been talking about these records being broken as if the speeds were stuck and then suddenly they jumped up. Not at all.

TrackPoleSpeeds_Charlotte2

So here’s Charlotte.  There are year-to-year oscillations, but the overall qualifying times have ben nothing but increasing.  On average, over the last twenty years, they’ve increased by about 0.7 mph each year.  So let’s assume that speeds are down across the board by 3 mph. In four or five years, they will likely be right back where they were before. You see a big jump in the slope of the curve (how fast it’s getting larger) from Gen 1 to Gen 2, but after Gen 2, it’s been pretty consistent.

I put each of the car generations on the graph to see how much difference changing car models actually made, but the track condition also makes a huge difference. Let’s blow up the last twenty years.

TrackPoleSpeeds_CharlotteRecent2

So there was a big jump after the 1994 repave. Then remember 2005 when we all learned a new word: levigation? They diamond ground the track, which made it very rough. Pole speeds jumped and the fall race that year was an unmitigated disaster, with tires blowing left and right. They did a formal repave in 2006.

And if you really want to see what a different track surfaces make, take a look at Kansas.

TrackPoleSpeeds_Kansas

After the re-pave, the pole speed jumped from 176 mph to 191 mph. There’s almost no history to rely on, but the following year, the fall speed was 4.3 mph slower than the spring speed.

In addition to major changes in the track, you get year-to-year oscillations due to things like weather and the tires Goodyear provides. One of the goals for the new set up is to allow Goodyear to make grippier tires that wear out faster, which could have a big impact on qualifying and (more importantly) racing.

So are the track records safe?  Probably for a couple of years.  But I’m not betting for much beyond that. The guys designing the race cars are just too clever to let little things like rules keep them down. The impressive thing is going to be if they figure out how to make the cars faster while also making the engines more reliable and longer lasting.

A final note. In the end, we judge drivers on race wins and championships. Poles may help you win a race, but I guarantee you if you give a driver a choice between a win and a pole, they’re going to choose the win.

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