IMSA Indianapolis Battle on the Bricks Preview

The 2024 IMSA grid racing at the Battle on the Bricks | Credit: IMSA

The penultimate round of the 2025 IMSA Championship, the Indy Battle on the Bricks, is set for this weekend at the iconic Indianapolis Motor Speedway. For the second time, Indy will host a six-hour IMSA endurance race after returning to the IMSA calendar in 2023.

Qualifying is set to start on Saturday, September 20 3:15 pm track time. The six-hour IMSA Battle on the Bricks race will begin at 11:40 am track time on Sunday, September 21.

All four classes will race this weekend – GTP, LMP2, GTD and GTD PRO – for a total of 53 entries. 12 entries in the GTP class, notably missing the No. 5 Proton Competition Porsche, whose chassis sustained too much damage at the Six Hours of Watkins Glen in June to participate at Indianapolis. 12 LMP2 entries, missing the No. 61 Team Tonis car that debuted last time out. 11 GTD PRO entries, and 18 GTD to finish out the Indy entry list.

The Michelin Endurance Cup races are a whole different animal within the IMSA calendar. Some teams that have found success in the longer format this season are the No. 7 Porsche Penske in GTP, the No. 22 United Autosports USA in LMP2, the No. 1 Paul Miller BMW in GTD PRO, and the No. 27 Heart of Racing Aston Martin in GTD.

In GTP, the No. 7 and No.6 Porsche Penske cars have had immensely successful endurance outings so far this season. The No. 7 car leads the Endurance Cup standings by five points over the No. 60 Meyer Shank Acura, and 7 points to the No. 6 in third place. The No. 7 vitally reached the three hour points threshold before retiring at Watkins Glen with an hour and 20 minutes remaining.

The No. 60 Meyer Shank Acura finished P2 at Daytona after a headline fight for the win in the late stages, and picked up the win at Watkins Glen. While the Penske cars have shown their consistency in the endurance rounds this season, the No. 60 is sure to put significant pressure on them for the win this weekend.

In LMP2, the No. 22 United Autosports USA and No. 43 Inter Europol Competition cars are tied for the lead in the Endurance Cup championship. The No. 22 inherited the win from P2 at Daytona and won at Watkins Glen, while the No. 43 won in Sebring. Alongside Sebring, the Inter Europol team had a great P2 finish at Road America, but has otherwise had some poor luck this season. The United Autosports team has been almost pitch perfect all season, other than their unfortunate first lap incident at Road America that knocked them out of contention for the win. 

The No. 99 AO Racing car should not be discounted this weekend, however. They are currently tied for second place in the Endurance Cup with the No. 04 Crowdstrike Racing and No. 8 Tower Motorsports cars. Their middling results at Daytona and Sebring have now been overshadowed by a P2 at Watkins Glen and two back to back wins following the Glen at CTMP and Road America. The AO Racing team’s current momentum will certainly carry into the Battle on the Bricks.

In GTD PRO, the two Paul Miller BMW cars lead the Endurance Cup standings with the No.1 just four points in front of the No. 48. The No. 1 car has not dominated the endurance races final results, with their best result being P3 at Sebring. However, their consistent front-of-the-pack pace through the middle stages of the races has been their greatest strength. 

The No. 3 Corvette Racing by Pratt Miller has also had a good Endurance Cup calendar so far this year, with P2s at both Daytona and Watkins Glen. They currently sit in P1 in the GTD PRO IMSA standings, and P5 in the endurance standings. Where the No. 1 has succeeded in the middle stages, the No.3 has struggled in that aspect. They will surely look to pick up more mid-race points, vying for the maximum of 5 points at the halfway mark and another 5 for a first place finish. 

In GTD there is a three-way tie for the lead of the Michelin Endurance Cup standings. The No. 27 Heart of Racing Aston Martin, the No. 70 Inception Racing Ferrari, and the No. 21 Af Corse Ferrari are all tied with 27 points. The No. 70 and the No. 21 have –similar to the No. 1– benefitted greatly from mid-race pace points, whereas the No. 27 has consistently finished in the top three of all three endurance races, with a win at Watkins Glen from pole.

The full-season championship-leading No. 57 Winward Racing BMW sits at P7 in the Endurance Cup standings, even after their win at Sebring. Their struggle has been with mid-race pace and failing to cross the 3, 4, 8 hour markers in the top three, which has put them at a disadvantage. However, their pace has been very consistently good as of late with a win at VIR, bar a disappointing Road America P10 outing from pole. 

Although Balance of Performance changes cannot truly be compared between the two six hour endurance races of Watkins Glen and this weekend’s Battle on the Bricks, some significant manufacturer-specific and field-wide changes have been made between the two events. For Stint Energy Replenishment Rate, most of the field received a ~200 MJ/sec reduction since The Glen. The exceptions to this are Acura with a hefty -450 MJ decrease, and Porsche with a 0.475 MJ increase. A notable change for the Porsches can also be found in Maximum Power Speed ≥V2 with a 4.8% increase, where the rest of the field’s changes were in and around 1.5% difference.

There is a very high chance of rain on Sunday in Indianapolis which is bound to effect teams' strategies massively. As we saw in Watkins Glen, a sudden downpour can get the better of even the most experienced drivers on the IMSA grid. This weather complication --whether the storm hits or not-- will have a big influence over the six hours of the Battle on the Bricks.

The race will be available to watch on Peacock, NBC, IMSA TV, IMSA’s official Youtube channel, and IMSARadio.com.