With 36 hours of competition in the books, drivers are getting a good handle on the new Grand Touring Prototype (GTP) cars in the top class of the IMSA WeatherTech SportsCar Championship. As the series heads into a pair of sprint races before the Le Mans break, everyone is getting a good picture of how the cars are performing. Performance alone, however, is one thing; how the cars race each other is another matter.
“I think it’s hard to get ahead,” says Renger van der Zande, driver of Chip Ganassi Racing’s No. 01 Cadillac Racing V-Series.R. “The speeds are higher, but we have to brake a little earlier and the weight is also higher. The minimum speed [in the corner] it’s quite a bit lower, so you can’t really rely on “Let’s go really late and bomb someone.” I think if you bomb someone you’re going straight, you’ll miss the corner. I think with the DPi you could overtake someone on the track because you had a little more downforce, you had a little more speed and minimal grip to get out of a mistake. With these cars, it feels like if you try to brake, you’re actually braking yourself and you’re going to go off the track, so you have to be a little more careful.”
Adds van der Zande’s team-mate Sebastien Bourdais: “I think it’s a bit more difficult to follow very closely. These cars seem to rely a lot on how little downforce they have, which surprised me a bit. But we still saw some passes and some good plays.”
While Acuras, Cadillacs and Porsches have shown some close competition, the finer points of passing with the new cars are still being explored. Jake Galstad/Motorsport Images
Indeed, the Mobil 1 Twelve Hours of Sebring was a good show…until it wasn’t. There was close competition, drivers trying to use traffic to gain or maintain an advantage, and quite a bit of bumping and bumping. Sebring showed that the difference between the cars, and the clear advantage some cars had on certain tracks, can be a thing of the past. For example, Sebring and Long Beach were expected to be Cadillac tracks in recent years, with Acuras doing better on softer tracks where ride height wasn’t as much of a factor. Drivers on both sides feel that the difference is now non-existent or at least very small.
That could lead to a closer race, especially now that Porsche seems to have caught up with Acura and Cadillac, with BMW not far behind. And close racing on the streets of Long Beach usually means contact. Can the GTP cars take it as well as the DPi machines did?
“I think it’s pretty similar to what it used to be,” declares Bourdais. “Obviously, we don’t have a lot of experience to know what the car can handle in terms of lateral contact. But maybe you take less risks now with less little appendages to fly off the car, because they’re cleaner, there’s less around the GTP. As for the suspension, I think it’s at least as strong as the DPi.”
This was put to the test in the closing stages of Sebring, when the battle between the two Penske Motorsports 963 Porsches and the Wayne Taylor Racing Acura ARX-06 came to a head. Coming off the track as the GTP leaders tried to get through GT traffic, Filipe Albuquerque slid around the apex of Turn 3 in the WTR No. 10 Acura and caught the No. 6 Porsche of Mathieu Jaminet. The #7 Porsche, Felipe Nasr at the wheel, hit them both.
“I can tell you one crazy thing: My car was wrecked twice,” says Albuquerque. “First in the front, and then in the second Porsche, a lot. They’ve only changed the front pillars and the nose. It’s good to go. I think that shows how impressive these cars are.”
One thing that has brought a new element isn’t necessarily the car itself, although the way they warm up to the new tires and wear them certainly plays a part, is the lower tire spread. With teams needing to have their tires doubled more often, it makes for an interesting dynamic between the cars doing a second stint in a set and the cars on new rubber.
“As much fun as it can be for the driver, I think it makes the race interesting,” explains Albuquerque co-driver Ricky Taylor in the No. 10 WTR Acura. “At Sebring, a lot of people were out of sequence with each other, doubly so when people were in their early stints. It made it very interesting, I think, at times. And when you have that little bit of grip, it opens up some overtakes. I think for the program was somewhat entertaining.”
Due to reduced downforce, when GTP cars are on old or cold tires, they can actually be slower than GT cars. This can make managing traffic on both sides a challenge, but since the GTPs have more power than their predecessors, passes are usually completed quickly on the straights.
“They’ve lost a lot of performance in the slow-speed corners, and it’s quite noticeable, because that was already the type of corner where the DPI was already very different to us,” says Ross Gunn, driver of the No. 23 Heart of Racing Aston Martin Vantage GT3 in GTD PRO. “And now they have pretty much the same minimum speed. So it definitely makes traffic management different, in some ways a little more complicated. There are definitely ways, as a driver, to drive around that and try to make sure – to make the most of every situation. But it’s certainly a great learning process for both us and them.”
The downforce changes have changed the traffic handling dynamics between the GTP and GT cars. Richard Dole/Motorsport Images
Corvette Racing driver Jordan Taylor recounts an instance where one of the BMW M Hybrid V8 GTP cars came around him, but then was so slow in the corner that Jordan lapped the BMW again in the No. 3 Corvette .So, he says, it makes a GT driver think about getting a little defensive so as not to waste corner time. But others point out that, except in this case of a GTP with old tires, it makes the traffic equation a bit easier.
“The old cars used to corner like they were on rails,” explains Bill Auberlen, driver of the No. 96 Turner Motorsport BMW M4 GT3. “So they would hang around you in the middle of the curves, and always put you in a bad position. Now, they hardly ever corner you because they have their hands full as it is. And in their second stage, they’re slower than us in the corner, so they hold you up. So what it does is it makes it very nice: they come right out to you where you want them to go; once you’re past the braking zone, they get in behind you, wait, and then go onto the next straight. It actually makes interacting with them a lot easier.”
However, the greater power of the GTPs has a downside: a higher closing speed means a quicker decision about where to put the car.
“It’s nice to be able to clear everyone up on the straight,” says Ricky Taylor. “Even though the closing speed is so high there is a level of engagement when you go down the straight and [the GT cars] they are in their own battle. You have to pick a side to go, and especially when there are Ams in the car – they see you, don’t they… you’re trying to read body language from a much further distance and then commit to a side, because La grief of choosing the wrong side and having to get up and move is really greater.”
GTP and GT drivers have now had the opportunity to witness the dynamic at two quite different circuits, and now head to a third variety at the Acura Grand Prix of Long Beach next week. The street circuit has no really fast corners and only a couple of corners at medium speed, so it will be a completely new test for the drivers, but they will come away with more knowledge of how the new GTP cars run.
