LeMons at Le Mans – Part 2


3: Speaking of hauling ass, Dan Binks says the Corvettes break 200 mph FIVE TIMES during every lap of the Le Mans circuit!

4: Wait, did I say one of the alternators? Yeah, it turns out A.C.O. rules dictate that the car must be able to start itself or else it isn’t considered to have completed this test of endurance. This means if the car dies on track, it has to re-start and limp itself home, and even when it’s in the pits, it has to start itself. No push starts allowed.

That means one simple charging system failure could end the race. Or an engine that’s hard to hot start could drain the battery, or overheat the starter and lose the race. To prevent a boneheaded loss like this, the Pratt and Miler Corvettes run two completely separate redundant charging systems (I’m not sure where the other alternator is) and two starters mounted on the front of the transaxle, below.

le mans in the pits

5: With only enough fuel to run for about 45 minutes, fast pit stops are absolutely critical at LeMans. With over 30 pit stops on average, saving a second in every stop could easily gain you a position. To save that second, the fuel system is rigged with a clever array of electronics. This carbon fiber honkus (below) is the fuel tank vent. The filler is on the other side of the car and looks roughly the same. Both have a big spring loaded flap that gets pushed open by the fuel jug (or vapor jug) and a one-way check valve downstream to keep fuel from sloshing out, but to let air in as fuel is used. 

le mans in the pits

Ok, that’s all expected. The cool bits are the fuel level sensor (on the vent side of the tank) that activates lights on both sides of the car when the tank is full. This way everyone on the crew knows immediately when fueling is done (just like LeMons, they aren’t allowed to touch the car during fueling). The lights mean no time is wasted yelling at each other.

There’s also a switch wired to each of those flappy doors on the filler and vent that activate a solenoid that interrupts the starter. This way the driver can sit with his finger on the stater button and as soon as the fuel and vent jugs come out, the car starts automatically. Again, nobody has to yell at anybody.

6: Oh yeah, the engine:

le mans in the pits

It’s an LS somethingorother, just as you’d expect. It starts out as a production block, but get’s a high-dollar makeover, just as you’d expect. It makes lots of power, but not as much as you’d expect, because of these things:

le mans in the pits

This poor bastard has to breathe through two 28.8mm restrictors! Imagine if this thing was carbureted and breathing through a 2-barrel carb with 29mm venturies. This is why everything else in the car is more interesting than the engine.

The plenums, as you can see, are huge. This, naturally, is in an effort to get a little air snuck past those restrictors under braking so there will be a fraction of a second of free breathing before the engine is choked again. This works, so naturally the A.C.O. has strict limitations on plenum volume. I’m not really sure what that limit is, but I’m pretty sure you’re looking at a picture of it.

7: If you wanna go geegaw over sexy race hardware, take a look at these AP Racing calipers (look down). The GT cars run cast iron rotors, so we aren’t talking about brakes that cost as much as your Ferrari, but we’re still probably talking about brakes that cost as much as your WRX. Interestingly, the carbon ceramic brakes on the LMP cars are not any better at stopping. Instead of a braking advantage, the expensive brakes give a weight and aero advantage. They’re much lighter than iron rotors, and they run hotter, so they don’t require as much brake ducting. Ducting air through brakes causes drag, so hot brakes are an aero advantage.

le mans in the pits

Note how massively thick the brake pads are, and as a result, how massively wide the calipers are (the pistons and bores have to be deep enough to keep working even when the pads are worn down to nothing, and that’s what dictates caliper width).

Also note the intricate machine work to shave every last ounce from the highly-optimized caliper structure, and the sexy dry-break fittings that let the team hot-swap pre-bled calipers onto the car without introducing any air into the brake hydraulics.

8: Logistics.

So how exactly do two All-American Corvettes find their way to France? Turns out it isn’t easy. The race cars are trucked from Detroit to Chicago where they catch a Virgin Atlantic flight to London. Each plane only has enough room for one Corvette (who knew there was even that much room?) so it takes two days to get both cars across the pond.

When they arrive, they’re loaded into their very own transporters, already packed with tools and spares, that were shipped (by boat) ahead of time. They then have the challenge of driving massive American semis through the french countryside. Having just driven a small SUV through the French countryside, I can imagine what hell that must be. Apparently there is a fair amount of bumping into hard objects placed too close to a too small roadway for such a massive vehicle, but the damage done to the transporters (and the hard objects) is less of a hassle than trying to re-pack and re-organize everything into Euro-sized trucks. 

9: Check out the track map on the steering wheel so the drivers don’t get lost!

le mans in the pits

Also, who knew Grant, the same company that made the $30 Pep Boys steering wheel in my vinyl-topped shoebox of destruction, also made wheels like this?

10: Oh yeah…

le mans in the pits

Did I happen to mention that all this little LeMons love fest happened to be around the car that went on to win the Le Mans GTEPro class the next day? 


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