senor honda

IMSA Cadillacs are too fast....more is done to make them slower.
Anyone considering that good drivers have something to do with it?



IMSA Cadillac slowed again with Long Beach BoP

By Marshall Pruett / Images by LAT

IMSA's unwavering efforts to slow Cadillac's DPi-V.R prototype have continued into the next WeatherTech SportsCar Championship round at Long Beach. Following two consecutive wins by the new Daytona Prototype international model in the hands of Wayne Taylor Racing, IMSA has hit the DPi-V.R with three Balance of Performance restrictions ahead of the April 8 street race.
Following a post-Rolex 24 at Daytona BoP adjustment to slow the Cadillacs for the official series test at Sebring, and a second BoP adjustment to pull back on the pair of Action Express Racing DPi-V.Rs and the lone WTR entry for the recent 12-hour race, IMSA's technical department, led by Simon Hodgson, has applied a third round of BoP adjustments to the three Dallara-built prototypes since Jan. 29.

In a new twist, Hodgson's team has gone beyond the standard methods of adding weight or restricting air to the engine in order to increase its lap times – at Long Beach, the Cadillac teams will be forced to use taller first and second gear ratios chosen by IMSA to eliminate the car's low-rev torque advantage.

With its big 6.2-liter V8 engine pitted against the smaller turbocharged 4- and 6-cylinder DPi engines chosen by Mazda and Nissan for its DPis, the Cadillac's natural torque and acceleration attributes have given the AXR and WTR cars an advantage exiting the slower corners. Saddling the Cadillacs with long first and second gears at a twisty street course like Long Beach – with its famous final hairpin – should neutralize most, and possibly all, of the acceleration advantage.
The DPi-V.Rs have also lost an additional two liters of fuel cell capacity (down to 66 liters) and the time it takes to refuel the Cadillacs has been lengthened once more with a loss of 0.5 mm to its refueling hose restrictor.
Counter to the Cadillac DPis, the pair of Mazda RT-24Ps and Nissan Onroak DPis have been given turbo boost increases for Long Beach, with the Mazda's 2.0-liter engines receiving a stronger corner-exit punch from 2000-7000 rpm (its redline is 8900 rpm), and Nissan's 3.8-liter powerplant getting a full-spectrum increase from 2000-7600 rpm. The Tequila Patron ESM-run Nissans also lost two liters of fuel capacity (down to 78 liters).
The final change for the Prototype class went to the Riley/Multimatic MK30 WEC LMP2 chassis, which had the speed of its refueling slowed through a loss of 2.0mm to its refueling hose restrictor.
GT Le Mans also received numerous changes as Porsche's 911 RSR has been awarded 10 kilos of ballast (22 lbs), BMW's M6 GTLM and Ferrari's 488 GTE have been given top to bottom boost increases, and to go with its new ballast, Porsche has also forfeited some engine power with a 0.3mm reduction to its air restrictors.
Completing the changes to Porsche, IMSA added a third and fourth level of BoP restrictions for Long Beach by removing two liters of fuel capacity (down to 94 liters) and making a sizable adjustment to its refueling speed by slowing the fuel entering the cars with a loss of 5.0mm to its refueling hose restrictor.
The last changes to GTLM came in the form of a 3.0-liter fuel cell increase for the BMWs (up to 108L), a gain of one liter for Ferrari (up to 87L) and a slight increase in refueling speed for the Italian car with a 0.5mm aid to its hose restrictor.
In GT Daytona, every single model scheduled to compete at Long Beach has had BoP changes performed by IMSA, and in some cases, three or four modifications per brand have been made.
Starting with power or weight manipulations, Acura's twin-turbo NSXs have been given more top-end boost from 6000-7500 rpm; the pair of Lexus RC Fs have lost power with the removal of 1.0mm of air restrictor flow; the Sebring-winning Mercedes-AMG model has been handed a 10-kilo ballast increase and shares in the RC F's pain with the same removal of 1.0mm of air restrictor flow; Porsche's 911 GT3 R will race with a favorable 20-kilo weight reduction (44 lbs).