SPO: New Year, Same Old IMSA


Hello Everybody!

‘Tis the first real post of 2018, and oh boy is it going to be an interesting one.

The Roar Before the 24 has come and gone this past weekend and it yielded some…..interesting results. I’ll skip the first few sessions and jump right into the qualifying results.

Full disclosure; I know this is a pre-season test, but results don’t significantly change the BOP for the Rolex.

The Qualifying session was supposed to be IMSA’s attempt to stave off sandbagging, so they can get BOP for Daytona right. The premise was you get to pick your pit and garage locations (for the Rolex 24) before those who were slower than you. Personally, I think this was an excellent idea and I was really looking forward to seeing some close action. However, it is a clearly obvious that a seriously huge nail is sticking out, and I don’t think IMSA will drive it home.

I am of course, talking about the Cadillac DPi. There were evo changes to the base Dallara chassis that the Cadillac uses. These have to be carried over to the DPi, as per IMSA’s agreement with the ACO. However, these were small aero changes. The final change is a new 5.5L V8 replacing the old, 6.2L version. The new engine is supposed to offer IMSA more options for BOP: Let’s let that sink in for a moment.

Cadillac enjoyed a monumental advantage throughout the 2017 season. Winning all but the last 3 races. Until then, IMSA was supposedly trying its best to reel in the GM offering, failing until throwing the anchor out for Road America. The problem was the large amount of torque the 6.2L produced, allowing for crazy acceleration out of the corners. The smaller displacement engine for this year, would in theory, produce less torque and would be more manageable to balance.


The Mazda DPi, as seen at the 2017 Mobil1 Sportscar Grand Prix at Mosport.

Fast forward to the end of the Roar Qualifying: Cadillac 1-2-3-4 and within 0.6s of each other.

The next best were both Acura’s, the fastest of which was 1.1s off of the fastest Cadillac. The problem here is that all the way down in P17 (so the next 12 cars from the fastest Acura) were separated by another full second. This includes both Acuras, Nissans and one of the Mazda DPi’s, as well as a handful of ACO spec Ligier and Oreca LMP2’s. Just outside this zone were the lone ACO Multimatic/Riley LMP2, the CORE-run Oreca LMP2 and the remaining Mazda DPi.

What on Earth did IMSA think it was doing with it’s pre-test BOP!? As a fan I might as well get my Cadillac 2018 Manufacturer Champ hats ordered right now. It’s absurd to think this is acceptable. Again, I realize that this is a pre-season test and that the final Rolex 24 BOP has yet to be released (at the time of writing). Still, historically speaking, there haven’t been significant changes made to the BOP between the Roar and the Rolex.

I’ve had my hand at balancing cars on various simracing platforms and I’ll admit, even in the virtual world, it is not easy. That being said, IMSA has so much data to look at. They are the ones writing the rule books at the end of the day, so they could, in theory, do anything they want. They’ll likely restrict the engine a bit and add weight to the car. This won’t help the torque levels all that much, and the car will still accelerate quite well. Alternatively they could allow less fuel on board and restrict the fuel refill rate, but in my opinion, I don’t think that is the right call.

If you think I’m out against Cadillac, you’d be mistaken. I’d also like to point out that the top 8 were all DPi, and only 2 DPi were in the bottom 10 in class. IMSA keeps the ACO BOP for all LMP2 spec cars as a “baseline” to which the DPi’s are balanced. They had a severe issue where an LMP2 car couldn’t come remotely close to winning a race until Spirit of Daytona won at Laguna (the penultimate race of the season). It’s obvious that this will still be an issue as well in 2018, if these results are of any indication.

Time will only tell if IMSA makes the right call and slow the Cadillacs and bring the DPi’s overall, down to the P2’s levels.

At least there are two other classes to watch! The GTLM class (apart from the BMW’s, which were having a tough time with the new M8) were all within 0.6s, and GTD top 18 were within a full second as well. So we know IMSA can BOP right, just not with Prototypes :/


The Whelen Cadillac DPi, as seen at the 2017 Mobil1 Sportscar Grand Prix at Mosport.

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1 comment on “SPO: New Year, Same Old IMSA

  1. Pingback: Seb12ing: A Long Road Ahead – Steve's Motorsport Blog

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