This week’s three-day IMSA test at Daytona International Speedway will feature approximately 30 cars from all four WeatherTech SportsCar championship classes, and in a new twist, the series will do more than just try to collect performance balance data to use them for the month of January. Rolex 24 at Daytona.

The main focus for IMSA’s Friday-Sunday outing is the new application of torque sensors to the supercars in its GT Daytona and GT Daytona Pro categories. Implemented by IMSA in 2023 on its Grand Touring Prototype hybrid cars, the series extends the deployment of torque sensors beyond the GTP to include all GTD models in 2025 as a method to improve BoP information gathering and steering methods for its based field on the GT3.

Torque sensors serve as miniature chassis dynamometers attached to the rear axles that provide constant performance information—horsepower, torque, and throttle curve data are among the key channels—to serial via telemetry and highlight any associated BP violations that are detected by sensors. .

With such a big difference in the looks of its GT entries from Aston Martin, BMW, Corvette, Ferrari, Ford, Lamborghini, Lexus, McLaren, Mercedes-AMG and Porsche, IMSA’s technical staff will rely on torque sensors manufactured by Magcanica to balance better. front engine model range with turbocharged inline sixes, naturally aspirated and front engine turbo V8s, mid engine turbo V6s, mid rear engine flat sixes, naturally aspirated V8s and mid-engine turbo and naturally aspirated mid-engine V10 from track to track.

With its BoP modeling for each car as a parity-creating tool, manufacturers are given performance cornering parameters to play with, and with torque sensors, the series can track each car’s engine power and corner-to-corner acceleration figures every turn. The sensors also act as electronic referees, flagging any violations of BoP limits set by IMSA as they occur.

The decision to carry over the same torque sensors from GTP to its GTD and GTD Pro cars also means that the series brings exceptional familiarity with the use of the units in competition, but this is not the case for the majority of GT teams and manufacturers in the WeatherTech paddock Championship. , which is why the series is using the November test at Daytona as an opportunity for its GT participants to learn about the sensors during the many test sessions.

“One of the main things we were trying to achieve was the ability to bring GTD and GTD Pro cars to the racetrack, to give manufacturers, teams and IMSA an opportunity to see this new technology integrated into their cars,” Matt . Kurdock, IMSA’s director of engineering, told RACER. “It’s a fundamentally different way of regulating the powertrain and we felt it was a significant enough change to the technical regulation that it would be beneficial to provide the opportunity to get the cars on track with adequate time to resolve any issues beforehand. to the Roar Before The 24 .

“Not only will some of these systems be used for the first time by some of the teams, but we also have to make sure that all the monitoring and tuning electronics work together with the updates that the manufacturers have made. cars. We like to call it a ‘systems integration test’ and we will then have the opportunity to work throughout the event to resolve any issues that arise. But also, if there’s anything IMSA or the manufacturers need to address before the noise, there’s plenty of time to look into it.

With the adoption of torque sensors in the two GTD categories, IMSA will drastically alter its usual engine BP adjustment techniques to align vehicle performance, along with the introduction of a new two-level BP table.

“When we did this before, we were adjusting the power through the air restrictors and increasing the limits based on the engine speed and setting the maximum fuel capacity,” Kurdock said. “Those three things fall by the wayside now, and we’re going to tune the power to a maximum power curve, defined not only as a function of engine speed, but we’re going to implement something called two-stage power.”

Based on the shape of the car – some being low, while others are tall – or the different ways their respective architectures produce power, the GT car lineup has strengths and weaknesses inherent to each IMSA circuit.

At Daytona, for example, a waist-high Ferrari 296 would be more likely to easily slice through the air and reach a higher top speed on the long straights than a chest-high sedan like the BMW M4, and with the new BoP in two stages. dealing with power, the second stage settings can help address any advantages or disadvantages as the cars approach top speed.

The first stage, where naturally aspirated engines provide instant acceleration while turbocharged engines need an extra moment or two to spool up and deliver big power and torque, is where IMSA will address any innate differences .

“We will have one power curve up to a certain vehicle speed and then another power curve potentially on some cars after a certain vehicle speed,” Kurdock continued. “And the idea is to better regulate how the cars achieve their lap times and give us more tools in the toolbox to get parity in acceleration and top speed and things like that. So we will implement this in GTP as well. And if you look at the BoP tables that I’ve published, they’ve been redefined along those lines to have two-stage power. That’s another thing we’re going to try.”

The two-step BP approach was used by IMSA’s European counterpart.

“This is not the first time it has been used; The World Endurance Championship used that,” Kurdock said. “And we think that, especially when we go into a very power- and traction-sensitive racetrack like Daytona, it’s going to give us more capabilities in what we can do to balance the cars.”

Once IMSA’s GT field has a full understanding of how the torque sensors work, Kurdock says the focus will shift to the governance side of the technology once the new season gets underway.

“Torque sensors are less monitoring tools and more tuning tools,” he confirmed. “So if a power limit were to be exceeded, there are tools running in the IMSA logger that will quantify that and notify us in real time via telemetry, and there could be penalties associated with that.”

Another new area of ​​surveillance will be implemented with the GT’s torque sensors – one that is borrowed from GTP hybrid cars to dictate the time interval between pit stops.

“For us, it’s a tool that will regulate the power output and also regulate the length of the stint, because we use maximum time energy, as we use it in the GTP, to control how teams are able to achieve these stint length targets. all these different platforms,” Kurdock said. “As proven in the GTP, it still comes down to what the driver does in terms of how they are able to use traditional fuel-saving strategies. They also work to save energy.

“So we expected to see the same benefits of that regulation as it applies to GTD, where we’ve had a very wide range of engine group and engine combinations, which for years, we can see that not all, not every engine has the ability to save fuel. in the same way, and it wasn’t just down to the driver. The car was a factor. So with the maximum energy system and using the torque sensors to calculate energy, we feel it really puts the extension of stint length back into the hands of the driver and less the inherent technical advantages of one engine configuration over another. “

More traditional BoP testing will take place for IMSA’s GTP and LMP2 cars, and in another first, a non-LMDh car (all GTP models from Acura, BMW, Cadillac, Lamborghini and Porsche are built to LMDh regulations) will do the WeatherTech Championship. the debut of Aston Martin Racing’s Valkyrie, which conforms to the looser LMH rules that Ferrari and other marques used in the WEC’s Hypercar class.

“We felt it was important to give them the opportunity to get on the circuit,” Kurdock said. “It’s an opportunity to also see the new Aston Martin Valkyrie at the IMSA event and make sure that our systems integrate well with that car, that our control processes can be tested on that car as well. And it’s the first time an LMH will run in the GTP. So there are some differences in the technical regulations and some of the procedures we have to use to make sure the car is running within the regulations.”