Marshall Pruett photos
Weeks of work by IMSA, the sanctioning body for the TUDOR United SportsCar Championship, Daytona Prototype manufacturers, DP teams and official TUDOR Championship tire provider Continental will be pressed into service during a two-day test starting this Tuesday at Daytona International Speedway.
Right-rear tire blowouts and subsequent flights by the Spirit of Daytona Corvette DP and the Action Express Racing Corvette DP led to an early stoppage of Prototype testing at Daytona on November 19, and having used the time to come up with possible solutions to the issues that were faced, updates will be tried by teams during a co-opted test arranged by DP manufacturer Riley Technologies.
To start, Continental has developed a new rear tire with stiffer sidewalls for teams to evaluate. In concert with elevated tire temperatures, it’s believed the sidewalls of the 2013-spec Daytona tires gave way on the SDR and AXR cars, which then spun and took to the air.
“We have worked to reinforce the rear tires in response to the additional downforce places upon the DP cars,” a Continental representative told RACER. “This is our piece of a very complex puzzle.”
Using a dual-element rear wing and a large diffuser/tunnel addition to the rear of the cars, the 2014-spec DPs carried 60 percent more downforce than the 2013 versions of the car during the November tests. It’s believed the big spike in rear downforce played a role in the elevated rear tire temperatures and subsequent failures, which has led IMSA to craft a testing plan to try running DPs without the diffuser on Tuesday and Wednesday, as well as other aero changes.
“I think the series is still investigating in what happened at the last test; Continental has been working fast to come up with a good solution, and we’ll be trying a few things the series has come up with,” Bill Riley told RACER.
“We’ll try running without the diffuser, which will take a lot of downforce off the cars, and will also help if a car turns backward to reduce the chance of it going airborne. We’ll probably test with it on and off, of course, to get back-to-back comparisons. We’ll do combinations of stuff. We’ll also try the P1- and P2-style cutouts over the wheel arches to reduce pressure there. That will be looked at throughout this test.”
IMSA will keep the new dual element rear wing in place throughout testing and the 24-hour race, along with the pre-existing sidepod tunnels. The cutouts over the wheel arches are expected to become standard for DPs, matching the P2 cars in the Prototype class, and the cutouts are also being called for with the PC cars. The increase in DP horsepower for 2014 remains unaltered.
Whether the diffuser will return to Daytona after this week’s test is a significant question mark, but IMSA has told its DP teams they will be used after the season opener at Daytona. 2013-spec DPs will run without any changes, per a request from IMSA.
The November tests were meant to generate data for IMSA to use in its attempts to performance balance DPs and P2s to set similar lap times while establishing a degree of braking, cornering and acceleration parity throughout each lap.
With the DPs running significantly faster on the stopwatch and on the banking at Daytona, IMSA asked the Extreme Speed Motorsports P2 team to bring one of its HPD ARX-03bs to take part in this week’s test to help with its ongoing attempts to bring the Prototype cars closer together.
The 60 kilos of weight the ESM car was asked to carry in November has been rescinded, and more power will be tried in an effort to reduce a top speed gap of nearly 20 mph to the fastest DPs.
“We’ll test at 900 kilos, and a plus five percent restrictor increase to give more power, and, depending on what happens, we also have the option to run at a different boost target,” said HPD technical director Roger Griffiths. “The restrictor will help us with top speed, but the (extra) boost won’t help us there because we run into the limitations of the restrictor. And no changes on the aero; we expect to run the same Le Mans aero kit.”
ESM will run on Wednesday, only, to help IMSA.DPs and PCs will be asked to follow the wheel arch cutouts found on P2 cars.
A new layer of challenges for Prototype performance balancing could come in the form of removing the new DP diffuser. Lowering the weight of the P2 cars and granting more power and top speed through a restrictor break should bring the cars closer to the 2014-spec DPs that ran in November, but removing the diffusers should only serve to increase top speeds for the DPs.
Wednesday’s running will reveal whether the P2 changes will bring the cars up to the November benchmark, or if more changes will be needed to keep pace with the diffuser-less DPs.
Michael Shank Racing took part in the November tests with his 2014 Riley-Ford EcoBoost turbo, and reported no issues with tires after tuning his suspension. MSR will return to Daytona this week, and is ready to help Continental and IMSA.
“The first thing we’ll do is work through the tires we’ll go through a couple of rounds with them before they let us loose,” Shank told RACER. “We also have some items of our own to work through the flat-shift deal we had and a few others, but tires will be the first priority. Once that’s solved, we’ll work on the aero configuration IMSA wants to see. We’ll run in several configurations and will see what times it produces.
“And, for what it’s worth, it’s not possible for a DP and a P2 to turn the same top speed at Daytona it’s simply not possible, so we need to see how that’s going to be managed. My feeling is we’ll have to have a higher top (DP) speed and they’ll have a higher cornering speed. If we have to run their top speed, we’ll lose in every corner, so we need to see what we can come up with for a meeting at the apex, per se.”
Teams are waiting for downforce targets and a tire testing plan to be provided by IMSA for this week’s test, and as Shank adds, teams have been left to work their way through the changes on their own and as they feel are safe.
“The short answer is no, we will be under our own control on how the test will be run, and yes, I will be exerting a high degree of control on our plan until we feel everything is safe and clear to start running harder,” he said.
“IMSA’s given us some target top speeds to try, but that’s about it. We’ve also gone ahead and installed infrared (tire) sensors on our own; I think everybody has, so we can keep a concerted eye on tire temperatures so we know where we’re at and aren’t caught by surprise on anything.”
Chip Ganassi Racing with Felix Sabates will debut its new Riley-Ford EcoBoost DP on Tuesday, and will also aid the series in the same data capturing process.
Regular CGRwFS driver Scott Pruett is currently recovering from ankle surgery, and reigning IndyCar Series champion Scott Dixon will handle the driving duties.
“Scott [Dixon] has to miss the Roar Before the 24 test, so this was a good chance to get him in and get him some testing miles with the new engine configuration while Pruett is healing,” Ganassi Racing general manager Mike Hull told RACER.
Following the Riley test at Daytona, Chevy DP teams will take to the track early next week. SDR owner Troy Flis, whose team has prepared a new chassis after Richard Westbrook’s violent crash last month, hopes the series comes up with a definitive direction to work toward.
“We’ll be part of the test this week we won’t be running a car, but will be back for the GM test,” Flis told RACER. “Continental has already done a lot of work to prepare a new tire, so that’s really good news, but there’s no firm [DP] rules right now and we’re told they might not be ready until the Roar. That part is tough.
“That’s my biggest concern; will we need to go faster than we were last month, or slower? Are we putting more or less load in the tire? I think the best thing we can do is to be more proactive on things; I wish we were more with my team before what happened last month. Infrared (tire) sensors are illegal in Grand-Am, but I wish we’d brought them anyways. But you learn as you go.”
The latest Daytona test will be filled with more discovery as everyone involved looks to overcome the issues that halted testing last month. Flis, like most of the people this writer spoke with, has faith a positive solution will come into focus.
“Everybody’s pulling together,” added Flis. “GM, Ford, Riley, Coyote, us, Action Express, Continentalwe’ll get through it. We’ll figure it out. It’s just that the target needs to be placed by the series, and we’ll all hit it. If they’re going to place that target where a lot more downforce is being put through the tire, the tire needs to change to handle it.
“If it’s lower downforce, we need to adapt the cars to that, too. We’re all going back a lot more educated and we’ll get a lot more information tomorrow and Wednesday and should be able to develop a better package for everyone.”