IMSA: GTD, GTLM Roar BoP changes revealed

IMSA: GTD, GTLM Roar BoP changes revealed


IMSA: GTD, GTLM Roar BoP changes revealed

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Technical specifications for the GT Le Mans and GT Daytona classes have been distributed ahead of next month’s Roar Before the 24 test at Daytona International Speedway. Entrants in the TUDOR United Sports Car Championship’s GT categories will run under the Roar Balance of Performance guidelines as the technical team from IMSA looks to gather data on each chassis in order to lock down its specification heading into the Rolex 24 at Daytona.

As IMSA revealed last year, heavy penalties will be levied on teams or manufacturers caught sandbagging – intentionally running at a slower speed to skew the data in the hope of receiving a more advantageous BoP:

“In accordance with Article 2.11 of the IMSA Sporting Regulations and Supplementary Regulations for the TUDOR United Sportscar Championship, it should be noted that the performance levels exhibited at the pre-season ROAR before the 24 test will define the expected performance level for the Rolex 24 Race Event the bulletin. Any performance which is outside of the expected level shall be penalized accordingly during or after the Race Event.”

Based on the final BoP figures at the end of the 2014 season in GTLM, the following adjustments have been made for the Jan. 9-111, 2015 Roar test:

Aston Martin V8 Vantage: Aston Martin Racing will be allowed to fit its low-drag Le Mans-spec splitter “bubble” and to run without dive planes. A 15mm reduction in rear wing Gurney height from 15mm to no Gurney has been made.

BMW Z4: BMW Team RLL will take 25 kilos off its cars, reducing the coupes to 1230kg. The BMW V8 engines breathed through two 30.2mm air restrictors to close the season, and will receive a slight bump in air flow (and power) with a move to a pair of 30.5mm restrictors. A 15mm reduction in rear wing Gurney height from 25mm to 10mm has been made, and altogether, the weight loss, power increase and downforce reduction should aid the Z4’s limited top speed at Daytona compared to last year’s race.

Corvette C7.R: Corvette Racing will take 25 kilos off their cars, reducing the coupes to 1230kg. The Corvette V8 engines breathed through two 29.5mm air restrictors to close the season, and with a notable power deficit late in the year, they will receive a solid jump in air flow/power with a move to a pair of 30.1mm restrictors. A 15mm reduction in rear wing Gurney height from 25mm to 10mm has been made. The C7.Rs went into the final race of 2014 sharing the highest class weight with BMW, and had the most restrictive engine air limitations. By the numbers, the overall changes to the factory Corvettes are the greatest in the GTLM class heading into the Roar.

Ferrari F458 Italia: Risi Competizione will have a slight air restrictor break, moving from a single 40.9mm unit to a single 41.2mm device. The Italian coupe is the only GTLM car heading into the Roar with a decrease in rear wing height, which moves down 50mm.

Porsche 911 RSR: The 2014 Rolex 24 GTLM class-winning Porsches will test with 5 kilos removed, lowering the mid-engined cars to 1220kgs, and will retain the increased splitter dimensions used to close the 2014 season.


Aston Martin V12 Vantage: As one of the fastest GTD cars—at least in qualifying trim—late in the season, The Racer’s Group will add nine kilos to their British coupes, testing next month at 1245kgs. A 15mm reduction in rear wing Gurney height from 25mm to 10mm has been made.

Audi R8 LMS: A win by Paul Miller Racing at the season finale was the first victory of 2014 for the German coupes, but across the entire championship, the R8s struggled in a few areas. A notable restrictor increase will see more air reaching the V10 engines, as its pair of 42.0mm restrictors has leapt to twin 47.7mm units. The R8s were in need of a downforce increase, and it has been received with a spec 72-inch Crawford DP rear wing. The previous wing was 60-inches. Dual dive planes on each side of the R8’s nose are also permitted to balance the spike in rear downforce.

BMW Z4: Turner Motorsport won the 2014 GTD title with a car that received continual BoP penalties throughout the season, and with the Vita4One team expected to race at Daytona, the German outfit could have a favorable experience on its TUDOR Championship debut thanks to a 50 kilo weight reduction, dropping the car to 1245kg. A big air restrictor break, up 19mm from 65mm to 84mm for the single unit, is also listed. Based on the limited performance displayed by Turner’s Z4 on its TUDOR Championship debut at Daytona, these Daytona-specific concessions should solve any disparities that previously existed.

Dodge Viper GT3-R: Like the Audi R8, the Riley Technologies-built Viper GT3-R will also move to the spec Crawford DP rear wing, although unlike the Audi, the American V10-powered coupe will see a change in Gurney height, losing 10 mm as it moves from 20mm to 10mm.

Ferrari F458 Italia: The GT3 version of the F458 was a championship contender prior to the last round of BoP changes during the 2014 season, and a few breaks, starting with a 15 kilo weight reduction that brings the sleek coupe down to 1305kgs have been made. A 100 rpm increase to a maximum of 8250rpms has been granted, and the required use of the GT3 body kit for Daytona has also been implemented. A taller front Continental tire has also been permitted, moving from a 305/650R18 to 305/680R18

Porsche 911 GT America: The most popular GTD car of 2014 will test with a 15mm Gurney reduction, lowing from 25mm to 10mm, and teams will be allowed to adjust the front wheel arch Gurney.​


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