One person's suffering is another's joy. Well, you shouldn't really want anyone to have an accident. But if you are behind the wheel of the safety car from MotoGP, there cannot be enough incidents on the track. Only then will the race stewards let the perhaps sharpest M4 off the leash, the BMW has built in the current series so far.
With its huge light organ on the roof and the flashers in the bow, it not only looks like the fire brigade despite its black paint, but it also drives - and actually owes it to a few splashes of water. Finally, the Bavarians are testing a new engine technology in the one-off, with which the performance of the already potent six-cylinder engine is increased from 431 to good 500 PS and with 550 Nm the already lush torque maximum easily climbs over 600 Nm.
"Water injection is the magic word," says Frank van Meel, the new head of M GmbH and tells about the high charge air temperatures, which is why it is not safe to increase the pressure of the turbos. However, if you inject fine water mist into the collector in front of the cylinders, they evaporate in the hot exhaust gas stream, cool it down to 25 degrees Celsius and thus allow the boost pressure to be increased, as well as higher compression and earlier ignition timing, van Meel explains the mechanical engineering professor.
Van Meel admits that this process can also be used to reduce consumption and, in the best case, gain eight percent efficiency. It is not for nothing that the colleagues in the large series are already working on an implementation, for example in one or two. But the M GmbH would not be the M GmbH if it weren't about power and performance. “And we can easily get 50 PS and 50 Nm,” beamed Van Meel.
However, the driver hardly notices anything at first. The mechanics fill the five-liter water tank in the trunk, which lasts just as long in racing as a tank full of fuel. And at the wheel you experience an overstimulation anyway. Strapped in with blue braces, you sit in tight racing shells and just wait for someone to finally call "action".
The fact that the M4 actually chases out of the pit lane on the first test drive on the Salzburgring could be due to the fact that it can breathe a little more freely thanks to the mercilessly roaring sports exhaust and weighs a little less without the back seat. But even in the chicane after the start-finish straight, you think you can feel the fuller torque curve. At the exit of the long Nockstein curve, the M4 looks wide awake and greedy. And when the needle in the rev counter climbs over 5.000 tours for the first time on the long straight line, the water splashes in the intake air have the effect of adrenaline and make the coupé move even faster. Bayern do not want to reveal exact numbers yet. But a bit faster than the 4,2 seconds of the production model, the M4 should already be able to do the sprint at Tempo 100. And 280 km / h top speed should not be the last word for the safety car either.
Although the idea of water injection is not new, it is already known from fighter planes from World War II, was already used in motorsport and was also used in series production for vehicles such as the Fiat Uno or the Saab 99. But after being forgotten for a long time, BMW was the first to dig it out again and would like to drive it forward.
But this is not so easy with this prototype. Because at 18 races on four continents, the safety car is more often on the freighter than on the circuit. And always waiting for a tricky situation, just so that you can unwind a few test kilometers, is not a solution. But if it is up to Frank van Meel, the engineers will soon no longer have to hope for incidents in the race and M GmbH customers will no longer have to wait for the driving experience with the water booster. The Bavarians are working intensively on a series implementation.
And if you speculate with a small series of M3 and M4 in the style of CSL and GTS, the denials turn out to be rather subdued. On the contrary: "It doesn't take two years until we have the technology on the road", hopes van Meel. He has a good laugh. But his engineers could get a little warm at this time. Doesn't matter: You can cool off with a few fresh splashes in the future. They now have enough water on board.
Author: Benjamin Bessinger / SP-X