In some ways, the edgy Michelins go with the car. The 750R is more brutal and aggressive. It’s no less sophisticated under normal driving conditions, but it’s clearly more primal near the limit. And that’s only enhanced by its ripping-100-yards-of-cardboard exhaust note. Chapman finds the 775B to be softer and more compliant as it rotates around the driver rather than the more pointy, nose-first corner-entry feel from the 750R.
“In the TPC 775B, I always felt it was underneath me,” he says. “In the (AWE) 750R, I sometimes felt like I was a hair’s width away from getting way sideways,” he explains, indicating that he found the quicker reflexes of the AWE 750R more intimidating on these roads. That said, he admits a preference for the deft initial turn-in offered by the 750R. We are in agreement here, as I prefer to be more involved in a street car, and perfection does not always go hand-in-hand with one-with-the-machine immersion in the driving experience. The driver is more responsible for the outcome of every maneuver in the 750R, and I like that.
Even so, when pressed to pick one, Chapman gives a slight nod to the 775B for spirited road driving, finding it more manageable at the limit and easier to catch. I prefer the 750R better for its more involving driver experience; to me, TPC’s 775B lacks a bit of…what was that old VW commercial?…Fahrvergnügen.
We agree to head back to VIR’s 3.27 miles to let the cars duke it out, with AWE holding the barest of advantages.
Our comparo ramps up a few notches with the participation of an obviously enthusiastic David Murry. He promises to bring considerable experience and talent to the driver’s seat, even in the midst of the bustle of his first David Murry Track Days event. Also, the addition of a Traqmate data-acquisition system will yield objective measures of performance. Murry is first behind the wheel of the 750R, so I grab the keys for the 775B. After a few laps, we’ll switch.
AWE specifies Sport on and PSM off for the track run — and that’s how Murry goes out. Entering some corners hard, he triggers the 750R’s ABS, causing PSM to intercede even though it’s off. He has no complaints about that, though, feeling that, with PSM on, some unwanted slide angle might be reduced. The PCCBs display noticeable front brake bias as delivered, which Murry says hampers deceleration a bit by overworking the front tires, causing them to overheat. The pedal gets a bit soft after a couple laps, and Murry suggests that a different proportioning valve might be a simple cure for track work with an experienced driver. I wonder, though, whether a few other tweaks might be in order first, as great braking feel can often be found with improved chassis setup.
Heading out in the 750R, I find it has less body roll than the 775B. It feels good in the corners until it reaches the actual limit. At that point, it’s challenging to maintain your desired slip angle because the drop in grip as the tires slide is significant, scrubbing off a bit of speed and costing you time in the corners. Also, its suspension is a little harsh over bumps and curbs, upsetting the car just enough to briefly lose grip and more time. This is likely due, in part anyway, to the Sport Cups’ at-the-limit characteristics.
Remember how the 775B felt faster, lighter, and all-around more powerful on the street? In the experienced hands of David Murry, that starts to make sense. It’s down to turbo-lag characteristics. It isn’t a huge difference, but it’s enough of one to be noteworthy. Says Murry: “The 750R builds boost at low rpm but is very hard coming on,” says Murry. “It was nice to have that power down low but a bit hard to drive.”
At the top end, the 750R loses boost earlier than the 775B. When the 750R’s boost drops during shifts on the straight it recovers more slowly than the 775B, interrupting acceleration as boost rebuilds. So even though the 750R has good power in the lower range, it is more difficult to modulate in corners and it falls off with each shift. Ultimately, this costs it both while exiting corners and on the straights.