IMSA’s technical bods will be looking for a lie down in a quiet and darkened room post the Rolex 24 Hours at Daytona – The latest post Roar technical bulletin issued by Scot Elkins’ team relays a raft of Balance of Performance changes to the GTLM and GTD runners, these changes looking set to apply for one race only as the powers that be look to keep abreast of relative performance:
GTLM
There are no changes announced for Aston Martin, Corvette or BMW
Ferrari 458 – The Ferraris (Risi and Krohn) get a 15kg weight break (1230kg) and a larger restrictor (up 0.6 mm to 40.6mm)
Porsche 911 RSR – The factory entered, Core AutoSport run cars get 15kg more weight (1225kg), but they do get a increase in size to their air restrictors (2 x 29.6mm)
SRT Viper GTS-R – The big snakes get a 30 kilo weight break (down to 1250 kg) and a larger (120l) fuel load than the IMSA E85 runners.
GTD
There are wholesale changes and clarifications to the GTD field, unsurprising with such a wide range of new machinery on parade.
Aston Martin V12 Vantage GT3 – TRG’s Astons get a 22 kilo weight break (1236kg), and are dealt 2 x 47.0mm air restrictors (an increase from the Roar). The Astons also get a marginally larger front tyre.
Audi R8 LMS – The Audis get a fuel tank reduction (down from 90 to 86 litres and a rev limit break (200rpm up to 8600)
BMW Z4 GT3 – The BMW gets a 15mm smaller rear Gurney flap (down to 10mm) and a 50mm higher rear wing. it gets the same fuel tank reduction as the Audi (86 litres), and the same new front tyre as the Aston.
Ferrari 458 Italia – The Ferraris get changes more or less across the board – a near 30 kilo weight break brings the 458s down to 1280kg but the Ferraris will be breathing through much smaller restrictors (down a full 5mm to a pair of 50.5mm items, but will be allowed to rev to 8200rpm .
The Ferraris gets a 37.7 mm lower rear wing and the 85 litre fuel tank capacity
Porsche 911 GT America – The squadron of new Porsches have their weight limit confirmed at 1215kg (35 kilos up) and the 911s get the smallest fuel load in the class – 85 litres. There are changes too for the rear wings of the new Porsches, 70 mm lower and 25 mmm closer to the rear bodywork
SRT Viper GT3 – The new Viper is anther runner that sees changes from the Roar – it will run with larger (2 x 45 mm) air restrictors and the same reduction in its Gurney flap as the BMW (down 15mm to 10mm) but with a 300rpm rduction (a rumbling 6000rpm) The Viper gets the same new front tyre as the Aston and BMW and it gets the biggest fuel load in the class (95 litres)
