They found the performances of the LMP2 and DP cars that form the field to be uneven during pre-season testing.
One modification IMSA introduced aims to limit the power of the Daytona Prototypes with a small diameter air restrictor. The sanctioning body also reduced the fuel capacity of the LMP2 cars from 75 to 72 litres, in order to make their stints shorter.
"The balance wasn't quite close enough, so what we are doing is making a very slight power reduction to the DPs to try to close the gap a little bit to the P2s," said Scot Elkins, technical boss of USC sanctioning body IMSA, is quoted saying by Autosport.
"We had a relatively significant lap time difference and we also had a difference in terms of top speed, so hopefully the power adjustment will compensate for that a little bit."