Stock Car Science

OK, this is a minor one to start with, but one that I think could be pretty easily addressed.

The Issue

I’ve written two posts explaining how the drivers determine Pit Road speed (1 and 2), so I won’t repeat here why the cars have tachometers instead of speedometers, and how the gearing choices determine the engine rpm that corresponds too the appropriate pit road speed.

But once you understand how that works, you realize how easy it is for someone to change out the rear-end gear, but forget to put the change into the Excel file they use for figuring out pit road speed and you get Juan Pablo Montoya losing a race he really should have had a shot at winning.

Kudos

I’m trying to remind myself to give NASCAR credit for the things they have done right.  It’s so much easier to criticize the wrong.

The pit road speed limit was instituted for the safety of the pit crews.  Being within five feet of a car going 100 mph+ while changing tires is a recipe for disaster.  The motivating incident for the pit road speed limit was the death of Mike Ritch in 1990 at Atlanta Motor Speedway.  EPSN Classic has been running some old races and it makes me wince to see  the pit crew running out there without firesuits or helmets as cars zip by.

NASCAR gives teams a 5 mph window on pit road speed, so if pit road speed is 55 mph, you can go up to 60 mph without getting a penalty.  If you go 60.1 mph, you are sent to the tail end of the longest line.  So of course, the pit road speed is really 5 mph higher than what is stated because all the teams are trying to go as fast as possible without getting penalized.

Ideas

I would never suggest doing away with the pit road speed limit; however, there seem to be way too many inadvertant violations of that rule that have radicaly changed the makeup of the front runners.  Many drivers use a tachometer with color-coded lights set to come on at predefined rpm values (see an example patent, or the picture below).  But if someone on the crew sets the tach to light up at the wrong rpm, the team is pretty much out of luck – even if the driver was going below the rpm limit he was told to stay below.

Idea 1: Pit Road Rev Limiters.

Rev limiters kick in if the engine is rotating at a higher rate than a certain predetermined rotational speed - they electronically prevent the spark plugs from firing if the rpm limit is exceeded.  Let NASCAR issue the chips the same way they issue the wings and transponders.  Coming down  pit road, the driver switches to the pit-road chip. The transponders already being used to track speed can be used to double check.

Now, there’s a catch here, which is that the rpm limit is associated with being in a particular gear, which is why you hear the crew chief tell the driver something like ‘3400, 2nd gear’.  At some tracks, drivers may want to come down pit road in second or in first, depending on whether they are coming down under green or yellow.  Since you have two ignition boxes, you can only have one pit road speed chip.  And, of course, that eliminates the ability of the engine tuner to use two rev limiting chips to protect the engine.  They sometimes will use one for most of the race, with a second slightly higher-rpm chip in place for use over limited durations or at the very end of the race.

Idea 2 - Cockpit Information Center

NASCAR has the speeds from the transponder data.  Is there any reason they can’t put a piece of electronics in the car that signals when the driver is approaching the pit road speed limit?  Yellow-to-red LEDs?  Or (heaven forbid) a digital display that only reads at and below the pit road speed limit?

The race-safe system allows a series director to throw one switch in the control center when the decision is made to wave the yellow flag.  That switch activates a yellow light in every driver’s cockpit.   Instead of being dependent on the spotter seeing the yellow flag and telling the driver, the racing series can tell the driver directly.  There is no reason cars should be hitting those cars caught up in an accident ten seconds after the first accident happens.

The technology you’d need for an automated system that would turn on a light or display the speed when the driver is at pit road speed is not that much more complicated than the race-safe system.  Get rid of the 5 mph allowance, which is an artifice anyway.  Give the drivers a yellow light when they are within three mph and a red when they are within 1 mph of the pit road speed.  The team will still provide an rpm reading to the driver.  The first time the driver is coming down pit road and the lights come on at a rpm reading he’s not expecting, he’s going to say something to the team and hopefuly someone is going to realize that there may have been a screw up.

At the very least, have NASCAR report measured speeds for each car to the teams during the parade laps when they are ostensibly at pit road speed so teams can compare their calculations with reality.  If there is something systematically wrong on either side (as there seemed to be in at least one Nationwide race in 2009), before the race is the time to find that out.

I understand pit road is supposed to be part of the strategy and the speed & dexterity of the pit crews is part of the race.  Maintaining safety on pit road is the most important thing, but the spirit of the law is significantly more important than the letter of the law in this case.  Being a fraction of a mph over the pit road speed limit ought not to take a driver out of contention for a win.