The decision by IMSA’s technical department to award a stop-plus-five-minute penalty to the class-leading Land Motorsport Audi R8 LMS GT3 will be remembered as one of the bolder calls made at the Rolex 24 at Daytona.
Having spent a fair amount of time speaking with the series, team and manufacturer since the ruling was made, the complexities involved are remarkable.
As much as I loathe IMSA’s use of Balance of Performance for its WeatherTech SportsCar Championship series, in this instance, I’m comfortable saying the spirit behind the call was correct – it fit the framework of BoP, which every entrant accepts as part of competing in the series.
But the penalty also exposed an oversight in IMSA’s rulebook, which brought into question whether an actual, printed violation occurred.
At 12:13 a.m., Land driver Jeffrey Schmidt was ordered to pit lane to sit for five minutes as a result of the No.29 Audi spending an insufficient amount of time on pit lane while refueling. It might be the first example where fast pit stops, in a professional series where no minimum time limits are imposed for pit stops, were met with a stiff penalty.
To understand the issue, a glimpse into IMSA’s choice to use BoP as a method to equalize each class is required. Many fans are familiar with BoP in the context of how it applies to the cars in Prototype, GT Le Mans, and in this instance, GT Daytona.
Using GTD as a reference, the low and wide Lamborghini Huracan GT3, with its big V10 engine, competes against the comparatively narrow and tall Porsche 911 GT3 R with its smaller flat-six engine. Both cars cut through the air with differing efficiency, make different levels of horsepower and torque, and weigh different amounts.
Through BoP, IMSA uses a variety of data to try and equalize the on-track performance of Lamborghini and Porsche – and all other GTD cars – through adding or removing weight, aerodynamic settings, through air restrictors that give or take away power, through rev limits, and for the turbocharged cars from Acura, BMW, and Ferrari, boost is increased or decreased in an attempt to give each model an equal chance at winning.
If one model starts to perform outside its demonstrated capabilities – say, one model goes exceptionally faster in the race than it did in qualifying – the series has reserved the right, in its rulebook, to award a non-compliance penalty based on performing better than its BoP should allow.
As the penalty to the No.29 was applied, it was a rare BoP violation that had nothing to do with Land’s Audi and its on-track performance. The speed of delivering fuel into the R8’s 91-liter fuel cell during the first five pit stops was the instigator.
In its effort to balance the three classes on pit lane, IMSA takes live telemetry from the cars to gauge fuel consumption figures as the vehicles race around each track. Using the Lamborghini and Porsche again, if the Huracan’s V10 consumes more fuel each lap than the 911 GT3 R’s flat-six, IMSA would adjust the BoP tables to allow the Lamborghini to carry more fuel on board in its fuel cell.
And since it has a bigger fuel cell to fill, more fuel would be required to fill the Huracan at each stop than the Porsche, which would leave the Lamborghini sitting stationary longer than the Porsche, and that would be a clear disadvantage.
To try and balance the refueling process on the stopwatch, IMSA makes use of refueling flow restrictors. Like an air restrictor that allows more or less air into an engine’s combustion chamber, the refueling restrictors are placed in the hose that connects from the large refueling tanks to each car. For cars with smaller fuel cells, refueling restrictors with smaller openings – to slow the fueling process – are mandated by IMSA. For cars with bigger cells to fill, restrictors with wider openings – to speed up the process – are specified.
Although it isn’t an exact science where every car takes precisely the same time to fill, IMSA’s refueling BoP efforts are intended to level out any obvious refueling time advantages or disadvantages across the various models.
With the refueling restrictor sizes for each model issued in the pre-race BoP technical bulletin, teams install the hose restrictor, which is inspected by IMSA, and then the hose/restrictor is sealed by the series to prevent tampering.
Like the live performance data streaming during a race from each car to IMSA’s computers, the series also places a sensor in each refueling tank to measure the amount of fuel it contains and the speed that fuel enters the car.
By starting with a known amount of fuel in the refueling tank at the beginning of the race, IMSA’s live level sensor reports back in an instant with how much fuel went into the car at each stop, and how long it took for the fuel volume to change.
As an example during a stop, IMSA will see a change from 300 liters to 250 liters, know that 50 liters went into the car, and the data system will also calculate the time it took for the decrease from 300 to 250 to happen. If the flow rate is clearly faster than the number IMSA has calculated for each model, alarms will be raised.
Keep in mind that while IMSA goes to great lengths to apply BoP to refueling speeds with the fueling equipment on pit lane, if a car has a fuel cell that has been optimized to receive that fuel faster than other cars, the flow rate will increase.
Just as reducing aerodynamic drag will improve top speed, reducing blockages in the car’s fuel cell will improve its refueling speed. It’s an age-old practice carried out by teams in every series where refueling takes place. And some teams are better at it than others.
THE LAND SCENARIO
With the No.29 Land car, IMSA saw figures coming from the refueling tank that said it was taking less time to fill the car than was anticipated. Beyond the refueling flow rate trigger, teams had been informed by IMSA that it had an expectation for each GTD car to sit still for approximately 40 seconds during a full refueling stop.
After the same faster-than-expected phenomenon occurred at the first five stops, which gave the Audi a one lap and 80-second lead over second place, IMSA acted and applied the aforementioned stop-plus-five-minute penalty, which effectively ended its race.
“To measure refueling times, each entrant’s autonomous fuel tank is fitted with a mandated IMSA fuel level sensor and refueling restrictor, which are inspected and sealed prior to the race,” IMSA competition VP Simon Hodgson said in a statement after the penalty was handed down.
“During a standard in-race data review, IMSA observed a consistent and beneficial variance of the No. 29 car’s refueling times compared to the GTD class average. Based on IMSA’s current and past event refueling data, this was deemed to be unacceptable. The entrant was informed of IMSA’s position and a penalty was administered.”
With almost everyone outside IMSA’s tech team oblivious to the reason behind the penalty when it was announced, the first inkling that it was related to the refueling tank came from pit lane.
“It means our refueling time is shorter than [IMSA] calculated,” Land told IMSA Radio. “We are every time a bit quicker, but we follow the regulations. We are fine. IMSA has a calculated refueling time for our class, it’s around 40 seconds, but we did nothing out of the regulations, but we are quicker than the calculated time so we are penalized five minutes.”
A quick look at the timing and scoring information prior to the penalty shows the No.29 was, without question, the fastest GTD car from the time it crossed the pit-in beacon to when it crossed the pit-out beacon.
Using the GTD race-winning No.11 GRT Grasser Lamborghini (above) as the control, its first seven pit stops took between 1m27.3s and 1m33.1s. This accounts for driving the length of pit lane at 37.3mph, stopping, refueling and possibly changing tires and a driver, and then driving away and out at the same 37.3mph limit.
As Land reiterated, the refueling portion is, by IMSA’s decree, expected to consume approximately 40 seconds of the overall time on pit lane.
The No.29, on its first seven visits, took between 1m13.0s to 1m22.7s. Even the Audi’s slowest stop was almost five seconds faster than the best the winning Lamborghini could manage. Multiplied over those seven stops, the Land entry was killing the competition every time it drove away from its pit stall.
Other entries dipped into that sub-1m20s range, but only on rare occasion. In the case of Land Motorsport, its pit stops were significantly and consistently faster than the other GTD competitors, which was the exception, and IMSA took notice. After serving the penalty, and dealing with different issues, the No.29 Audi rallied to place seventh in class, three laps behind the GRT Huracan.
BUT WAS IT CORRECT?
Where the conversation takes an interesting twist is in the point raised during the race by Audi Sport.
Using the statement from IMSA’s Hodgson, the series did not declare the No.29 had used an illegal refueling flow restrictor to achieve its faster-than-expected refueling speeds. To reinforce that notion, Land also said the correct 29.0mm restrictor was installed, Hodgson said each tank’s restrictor was inspected and then sealed, which ensured compliance.
From both statements, we know that restrictor tampering was not the source of the infraction. It leaves the short refueling process as the main culprit, and that’s where Audi zeroed in on a tough question for IMSA to answer.
If 40 seconds is the approximate time teams are meant to spend refueling, and taking less than 40 seconds on a regular basis is considered a violation, where in the rulebook – the one that so tightly governs every aspect of IMSA competition – does that 40-second rule exist? As Audi and Land rightfully argued, it can’t be found in the rulebook because it isn’t documented in print. “It’s an unwritten goal,” an IMSA spokesperson told RACER.
It’s tricky situation to consider. Where the 29.0mm metal refueling restrictor is a hard, specific piece that can be measured and complied with by the Land team, the same can’t be said for IMSA’s verbal ’40 second’ rule. It begs the question of, if a rule isn’t written, how can a team be in violation of IMSA’s rulebook?
In a follow-up exchange, the same IMSA representative elaborated on their original statement.
“This penalty was called due to the unexpected observed performance of the fuel flow rates,” they said. “And IMSA applied an appropriate penalty per the Sporting Regulations.”
No one is questioning the speed advantage Land used to its benefit during those early pit stops. But it is worth asking if and when verbal rules should be considered valid when intricate rules are written into existence for use by each team and the series itself to govern its events. When teams can be penalized for breaching unwritten rules, the outrage expressed by Audi and Land is easier to understand.
THE ACTUAL RULES
Although the specific ’40-second/fuel flow rate’ infraction does not exist in IMSA’s rulebook, the series did cite the two rule numbers that allowed it to penalize the No.29 entry.
As supplied to RACER by IMSA, the first is Rule 2.1 from the BoP section: “In order to maintain competitive equivalency between Cars within each class and between classes, IMSA may, at its discretion, utilize an adjustment method during each season (BoP).”
The second, which is a catch-all, is found in 2.7: “…manipulates the performance, or displays a level of performance above or below the expected result in any Session may be penalized to the full extent listed in Art. 57.”
Rule 2.7 is how IMSA opened the door to hit the Land Audi with its penalty. But it also relies on the same undefined ‘expected results’ phrasing that is completely subjective.
Adding to the confusion, looking at Article 57, IMSA’s table for penalties, there is nothing listed for a refueling-related performance advantage. Frankly, there’s nothing even close to it, nor will you find a stop-plus-five-minute penalty for anything other than turning extra laps during a red flag or after the checkered flag has waved.
There is, however, the all-powerful Rule 1.1 in Art. 57, which gives IMSA the freedom to penalize however it deems necessary:
“Except when the Race Director/Supervisory Officials determine there to be extenuating circumstances, these standard minimum penalties are assessed for the RULES violations listed in the table below.”
We’ll assume the refueling speed advantage was deemed an ‘extenuating circumstance.’ The matter of the rulebook and all the bulletins that followed leading up to the race failing to contain the ’40-second/refueling speed’ rule is still an issue.
How exactly did the Land Audi out-perform the entire GTD class, and the other Audi R8 LMS GT3 fielded by Magnus Racing, in the Rolex 24 pits? And was it done legally?
Let’s start with the question of compliance.
After the race, IMSA announced all cars, including the No.29, passed technical inspection. The fuel cells in the No.29 Audi and the No.44 Magnus Audi were also impounded and inspected by IMSA to search for irregularities and illegalities. None were found.
“[The No. 29’s fuel cell] was inspected and it cleared tech,” the IMSA spokesperson confirmed.
Land’s refueling tank, IMSA-mandated refueling restrictor, and the fuel cell inside its car that received the fuel was, with absolutely clarity and confirmation by the series, legal from start to finish at the Rolex 24. How, then, was a performance advantage created?
Through intensive work by the team, and painstaking efforts to try different internal fuel cell configurations that were tested and tested until the optimal arrangement was found, the team came up with the perfect fuel flow conditions inside the Audi’s fuel bladder.
Although the maximum fuel capacity on board the Audi was set at 91 liters by IMSA for the race, every fuel cell in every WeatherTech Championship car can hold more fuel than the maximum allowed by the series. It’s the same in every racing series, to be honest.
If the Audi has a fuel cell capable of holding 100 liters, and IMSA decrees 91 liters as the R8’s maximum for the event, teams like Land and Magnus would rely on a few popular choices to fill the cell with objects that take away the extra nine liters of capacity. Some use hard plastic balls, which displace a certain volume, and others use blocks that can be molded in different shapes.
Think of it like filling a 12-ounce glass with ice cubes. Without the cubes, the glass will hold all 12 ounces from a can of soda. Fill the glass with ice cubes, and you’d be lucky to get six ounces into the glass. The same principle applies here with inserting items into a fuel cell to comply with the maximum fuel allowed.
If, by chance, a team like Land used blocks that were positioned in specific, tested places in the cell, and had shapes that provided the least amount of turbulence – drag – when the fuel started flowing in from the refueling hose, the cell would reach its 91-liter maximum faster than the other cars.
It’s a basic case of working with the R8’s fuel cell to come up with the fastest way to ‘pour’ fuel into the car, akin to finding the perfect locations for those ice cubes to get the soda into the glass long before everyone else. Land’s efforts produced refueling times said to be in the 35-second range, and with the team also placing a heavy emphasis on completing its tire changes faster than ever, time was shaved there as well.
The final component that led to the minimal time spent on pit lane during those early stops came from the byproduct of rocket-fast tire changes. With the team able to pull the air jack and drop the car sooner than most of its rivals, the Audi sat lower to the ground, which helped increase refueling speeds due to the use of gravity.
Combined, the Land team aced every phase of its pit stops, and it was plain for IMSA to see. So how did the team manage to comply with the 40-second/fuel rate expectations after the penalty? An easy solution was floated: The refueler would stay connected to the car for 40 seconds at each stop. That request, to my surprise, was denied.
To avoid running afoul of the fuel flow issue, the Land team would need to slow its refueling rate, and despite lacking real-time data to aid in this venture, the person controlling the refueling tank’s shutoff valve – commonly referred to as the ‘dead man’ valve – had to change the practice off pulling the lever to open maximum flow into the hose, to partially closing the valve – throttling down the flow rate manually. It was an imprecise method, but it worked. No further penalties were given.
Although the Audi and all of IMSA’s homologated cars have schematics that detail aspects of how the fuel cell must be assembled, IMSA’s rulebook for the GTD class does not provide instructions on where those balls or blocks must be placed. It is, as Land found, open for interpretation and exploitation.
Reportedly, the Magnus Audi team did not make the same efforts as Land to optimize its fuel cell, and took somewhere between two and three seconds longer per stop to fill the No. 44 R8. It points to one team within the German brand’s IMSA customer base finding an open area to maximize.
Per Rule 9.13.3, the GTD rules say “Entrants may use blocks or balls to achieve maximum fuel cell capacity.” The only written warning covers efforts to cheat the IMSA-mandated fuel capacity set for each race: “Any device, system, or procedure designed to increase, even temporarily, the total fuel storage capacity beyond the maximum is prohibited.”
And that’s where the story comes to an end.
The cell was legal, the tank and restrictor were legal, and through some nebulous wording, Land’s crafty work was turned from a nearly two-lap lead to a deficit of two laps or more in an instant. If only hard rules existed to facilitate the penalty that was given.
Moving forward, I would not be surprised if the BoP tables for the next round at Sebring, and all rounds afterwards, carry written refueling time targets for teams to use as official rulebook compliance items.
I would also expect a highly definitive fuel cell configuration document to be produced by IMSA or Audi to make sure a Land-style flow advantage becomes impossible achieve after Daytona.
What’s the lesson here? Doing too good of a job – even when the series agrees it was 100 percent legal – isn’t acceptable within the constructs of a championship that relies on BoP.
I mourn the dying concept of building a better mousetrap.