The Beachdean Mansell team opted not to compete in this weekend's Spa 1000km to ensure it had no disruptions in the build up to the Le Mans 24 Hours.
Team co-owner Andrew Howard said that he and partner Nigel Mansell, who shares driving duties in the car with his sons Leo and Greg, made the decision last Friday after agonising whether or not to race in Belgium.
"It was a very hard decision," he told AUTOSPORT. "Everyone in the team wanted to race here, we really did, especially the Mansells.
"It had nothing to do with budget, it was just that we felt it was important to focus all our attention on Le Mans. Look at the setbacks that ORECA had last year when Bruno Senna crashed here. We really would rather avoid that kind of issue."
The team plans two tests at Snetterton and Silverstone over the next month prior to Le Mans as it seeks to refine the Ginetta-Zytek's setup and learn as much as it can about the new low-downforce bodywork planned for this year's race.
"Our aim is to make the finish of the 24 Hours, but they have worked very hard on the new bodywork and it looks like it has a lot of potential and we need to make the most of it.
"It's another reason why we are not racing here, we owe it to all those back at Ginetta to work very hard to support them and develop this low-downforce spec as much as we can before Le Mans."