IMSA – Old Tech Versus New, Who Has the Edge at Sebring?

As with the elimination of the split in North American open wheel racing, the joining of Grand-Am and ALMS is anything but a smooth merger. The open-wheel racing scene didn’t have the equivalency issues that the TUDOR United SportsCar Championship is facing as the Panoz DP-01 that the Champ Car World Series was using never saw use in the Indy Racing League, now known as the IndyCar Series. Both CCWS and IRL teams were mandated to use the same Dallara chassis, and still are. By contrast TUSCC teams may use either a Daytona Prototype chassis designed for low-tech and therefore presumably low-cost or an LMP2 chassis designed for competition on the World’s largest sports car stage, the 24 Hours of Le Mans. We saw in pre-season testing at Daytona how the first attempts to simply bolt on more aero elements to generate greater downforce lead to extreme instability and tire degradation. A lot of the teams, in fact, were very agitated with the constantly changing aero rules leading up to the Rolex 24. Just check out some of the quotes in Gordon Kirby’s post-Daytona The Way It Is article.

What many feel the league was attempting to do, and apparently was successful in doing, was to insure that a Daytona Prototype entry won the overall victory at the Rolex 24. I don’t think it was much of a stretch for this to happen, however, as the LMP2 cars were not designed for the high-banks of Daytona. Certainly, Circuit de La Sarthe is pretty wide open with the huge Mulsane Straight and the long straights leading into Indianapolis and out of Arnage, but most of the circuits on which the LMP2 chassis competes are tight, technical, twisty affairs. The DP cars look to have their full aero packages back for Sebring, but that’s not the only issue. Whenever you generate more downforce, you are going to need to make compensating changes to the suspension. Here in lies a huge challenge for the DPs if they are to remain the top prototype class at Sebring. With the old airport circuit being significantly bumpier and twistier than Daytona, there’s a legitimate concern that a DP car may not come out on top.

Racer Magazine’s Marhsall Pruett published a nice write-up about potential changes to the DP suspension, and there were a couple of things that stood out in my mind. First, the DP chassis cannot be long for this world in it’s current state if the series is to be viable in the long-term. Second, it is very clear that the league does indeed wish the DP class to remain the top class overall. What officials have been contemplating is the fitting of a third front damper to moderate the pitch of the car under braking and through bumps. IndyCar fans will remember Penske using this to great effect on street circuits such as Long Beach and St. Petersburg. The third damper couples the left and right front in such a way that they behave close to normally under independent bound and rebound, but behave much more stiffly under braking when both left and right dampers are being compressed. This allows a car to run a lower ride-height with spring and damping rates suitable for a bumpy surface without risking putting the nose of the car on the tarmac under hard braking. The LMP2 cars were designed for this, the DP cars were not.

Right now, the league officials are undecided on whether to modify the DP cars in preparation for Sebring or to eliminate the third front damper from the LMP2 cars. Personally, I’d love to see a situation where the DPs and the LMP2s were on par over the course of the season but with different tracks playing to the different strengths of the two platforms. I remember fondly the days of the Audi LMP1s doing battle with the Penske Racing LMP2 Porsche Spyders and Andretti Green Racing LMP2 Acuras. On the longer, more wide-open circuits, the turbo diesel LMP1s from Audi ruled, but on the tighter confines of a street race, the lighter LMP2 cars had the edge. It was nice to see great differences in design while maintaining competitiveness. I think that our new blendified (to borrow a term from the open-wheel reunification) sportscar series could learn from their not too distant past.

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One Thought to “IMSA – Old Tech Versus New, Who Has the Edge at Sebring?

  1. The last paragraph is dead on, exactly what IMSA should be aiming for and the best we could ask for in 2014.

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