24 Hours at Daytona: Technical Blog
It’s a few weeks since we’ve been back from the 2023 Daytona 24h, and it still feels like an event which redefined, or at least imparted a very different experience of a high profile motorsport event onto us.
Having been to GT World Challenge races, F1 races, Britcar, Le Mans series (Superseded by WEC) and others, all of them were a very different experience to my time in Florida. With this semi-technical blog, i want to run through the race, both from the perspective of an engineer and a spectator, covering some of my experiences and observations over there.
This was the first race of the new GTP class, which is reserved for cars meeting LMDh regulations, so it was the first outing for the Porsche 963, BMW M Hybrid V8, Cadillac V-Series R and the Acura ARX-06. This made it especially exciting.
We were there as guests of Coliseum Media, who were holding the launch event for a product of theirs at the race, and also have a number of other motorsport projects for 2023, so as a first - thanks where it’s due.
The first thing you will notice when you attend an IMSA event is the level of access which fans have. The entirety of the paddock and garage area is open for exploration, which is a sharp contrast to most high level racing over in Europe, where you can’t even get close to the infield area of tracks, let alone paddocks (Take note WEC).
For contrast, at the British GP event in summer 2022, getting to the infield area (where the non F1 paddocks were) required a special pass. This gave access to the 911 SuperCup paddock, but any further into F2/F3 paddocks? Yep, another level of access required. Even with the F1 paddock pass i had, we couldn't even get sight of the cars. You guessed it - pit passes were another level up.
This really presents a barrier for the fan experience and detracts from the enjoyment and spectacle of being next to the most high technology vehicles in the world. Granted, the IMSA attendance is not at the same level as F1 or perhaps WEC, but more could certainly be done.
Horses in Stables:
Ok, so i’m in the paddock on the Friday before the race, the first activity i see is in the GTD garages. Teams had just prepped the cars for final practice and they were starting to form a queue in the paddocks, this is fairly standard, but it’s never a tiring sight to see dozens of high-end race cars in one place, it was also a first opportunity to see the Ferrari 296 GTB, which looked particularly smart.
After the practice sessions were finished, the cars get back to the garages where they are torn down and prepped for the challenge ahead.
Preparations involve visual inspections of bodywork, suspension and powertrain components, checks of bolt torques and replacements of service parts.
Cars at this level have surprisingly short service intervals, standard service items such as oil and filters are required every 5000km (3100miles), same for brake assemblies. Suspension components will be good for only around 10000km (6200miles) and brake fluids etc will be changed after each session.
With the Daytona24 running around 3000 miles, it makes little sense to start the race with used parts, so each car is essentially new in terms of running gear as it arrives on the start grid.
Teams bring an unbelievable amount of spare parts to these kinds of events. After all the preparation time, effort and energy, it would be a big shame for a car to have to drop out because of a suspension, gearbox or brake failure, which is exactly why there will be multiple redundant parts - all teams will run it differently, but 3 of all major items (minus engine and gearbox) is a comfortable number.
The LMP2 & LMP3 area was the same story in terms of final checks and preparations. Being in the garages, just metres away from LMP2 cars which largely had all bodywork removed, there was a whole host of mechanical kit to admire and learn from. I’ve worked with GT3 cars, but not been this close to prototypes, so this was something special.
The underfloor of an LMP2 car gave an opportunity to study front and rear diffuser geometry, which was actually less aggressive than i had imagined, with fairly gentle diffuser angles - enough to generate considerable downforce.
Next was where the real fun began. The GTP (LMDh) cars were grouped at the front of the garages, and i would be remiss if i pretended that my excitement levels weren’t high at this point.
Here i was, an ambitious motorsport engineer, standing close enough to touch the same class of racing cars which inspired me to get into the sport to begin with. These are memories which will stay with me.
Understandably there was a little more secrecy with GTP but it seemed to be more so from the European teams, who i suppose are more used to the WEC atmosphere.
This was also an opportunity to catch up with some connections i have at RLL Racing, who were running the BMW M Hybrid car, so thank you to Kathi and Ricardo for inviting me into the garage. Grateful to be there.
Start your Engines
The race itself was largely par-for-the-course for 24h racing and was well executed by IMSA. The multi-class element always makes things interesting and there were many safety cars, followed immediately by more safety cars as mistakes were made on restarts. It happens.
The transitions from day-night-day really does make things interesting from an engineering point of view and as expected the temperatures throughout the race varied quite a lot. The race started at around 15 °C, fell to just below 10° during the night, but the following day was around 25 °C.
For the cars, this means the tyres work very differently during certain portions of the race, not only requiring adaptation in pit strategies, but even requiring changes in setup to maintain the chassis balance in a place which is comfortable for the driver. I’ll come back to this later.
As i posted up by Turn 1 for an hour or so in the ‘morning after the day before’, it was really quite interesting to observe the different ways in which each of the 4 car classes (GTP, LMP2, LMP3 & GTD) approached a lap.
In the braking phase of the corner, clearly the higher aero cars were able to brake later, but what was quite a contrast to see is the different lift and coast approaches amongst the hybrid GTP cars.
They were all clearly on different fuel saving and regeneration strategies and one of the cars in particular was lifting around 50m earlier than the others.
Corner entry was also a very different story for each of the classes. Different lines were cut by the high aero cars which are more averse to bumps and sliding, whereas the GTD cars are distinctly more ragged, attacking the bumpy sections of the corners and handling them with a little less finesse, it even looked scrappy at times. Very different solutions to a race car.
It’s always surprising to see the finish results after 24 hour races and this was not different - The top 4 finishers in GTP were separated by just 12 seconds.
A similar story for LMP2, but this time, first and second were separated by 0.016 seconds!!
At this level, it’s not just about the cars. The preparation by the mechanics, every pit stop, every refuelling stop, every driver change and each and every calculation which was executed by those teams had to be razor sharp, for the entirety of the 24 hours.
This is exactly the magic of motorsport for me and why a big part of my ambition in this space is to engineer at 24 hour races. The element of human endurance and organisation is really admirable to me. Sprint racing is a very different engineering activity.
Post race is another part of the event in which the differences between IMSA and the European events manifested themselves.
The pit area opened for non-team personnel, so that was an opportunity to go and learn something - observing the box setups each team had, how they managed race logistics and so on. Very insightful.
Cars returned to the garages post-race, and to my surprise, some of the GTP cars were there with rear covers removed - is this the engineers equivalent of an all you can eat buffet?
The BMW was especially interesting here. The suspension concept was largely as expected. With an inboard arrangement, two roll dampers and a heave damper, as well as the associated springs and anti-roll bars (blades).
The anti-roll bars are driver adjustable, which is key to fine tune the balance of the car mid-race - for particular corners/sections of the track, or to keep on top of the tyres as they age.
As i mentioned earlier, this is a tool which can also be used to offset the change in balance experienced as the track temperature changes and the tyres find themselves in different areas of the operating windows.
What was definitely unconventional, was something which looked like a device on the heave spring used to adjust rear ride height.
At a track like Daytona, where there is a somewhat technical and low speed infield section followed by some very high speed speedway, having the capacity to raise and lower the underbody unlocks the capability of reducing drag and downforce where it’s not needed on the high speed sections, whilst providing high downforce where drag isn’t so important.
I didn’t see if this was on the front axle too, but that’s a neat solution which has some similarity to the ‘weight jacker’ which RLL Racing will be intimately familiar with on their IndyCar.
All fascinating stuff, but the real fun was at the tech inspection.
To ensure the cars conformed to regulations, it’s common for all events to have inspections of a selection of the finishing cars. The tech inspections are NOT usually open for public viewing.
Not a whole lot to say here, a picture tells a thousand words.
The regulations in LMDh allow a reasonable amount of freedom in the aero, so each car had a subtly different approach to reaching the drag and downforce levels and a different expression of creativity. In engineering there are many ways to arrive at the correct answer.
It really isn’t often you get a clear look at all the fine technical details of technology like this. Fair to say i got carried away, in fact so carried away i stayed too long in conversations and missed my flight back to the UK that evening and ended up in Canada, but that’s a story for another day..
Missed flights aside, it was a trip which will mean a huge amount to me for years to come. One day when i’m trackside at the Daytona i’ll look back at this blog with a lot of appreciation and achievement.
I don’t often write blogs, perhaps that gives you an idea of how highly i rated this experience. Congrats to Eric and the rest of the IMSA team who were all a part of the trip.
I arrived back in the UK full of inspiration and motivation for 2023. If the mind can see it, you can achieve it.
Pleasure to meet everyone i met, and congratulations to IMSA for another successful Daytona24.