2012 - Bmw X6 on 2040-cars

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Is the skill of rev matching being lost to computers?

If the ability to drive a vehicle equipped with a manual gearbox is becoming a lost art, then the skill of being able to match revs on downshifts is the stuff they would teach at the automotive equivalent of the Shaolin Temple. The usefulness of rev matching in street driving is limited most of the time – aside from sounding cool and impressing your friends. But out on a race track or the occasional fast, windy road, its benefits are abundantly clear. While in motion, the engine speed and wheel speed of a vehicle with a manual transmission are kept in sync when the clutch is engaged (i.e. when the clutch pedal is not being pressed down). However, when changing gear, that mechanical link is severed briefly, and the synchronization between the motor and wheels is broken. When upshifting during acceleration, this isn't much of an issue, as there's typically not a huge disparity between engine speed and wheel speed as a car accelerates. Rev-matching downshifts is the stuff they would teach at the automotive equivalent of the Shaolin Temple. But when slowing down and downshifting – as you might do when approaching a corner at a high rate of speed – that gap of time caused by the disengagement of the clutch from the engine causes the revs to drop. Without bringing up the revs somehow to help the engine speed match the wheel speed in the gear you're about to use, you'll typically get a sudden jolt when re-engaging the clutch as physics brings everything back into sync. That jolt can be a big problem when you're moving along swiftly, causing instability or even a loss of traction, particularly in rear-wheel-drive cars. So the point of rev matching is to blip the throttle simultaneously as you downshift gears in order to bring the engine speed to a closer match with the wheel speed before you re-engage the clutch in that lower gear, in turn providing a much smoother downshift. When braking is thrown in, you get heel-toe downshifting, which involves some dexterity to use all three pedals at the same time with just two feet – clutch in, slow the car while revving, clutch out. However, even if you're aware of heel-toe technique and the basic elements of how to perform a rev match, perfecting it to the point of making it useful can be difficult.

BMW calling in 76k vehicles over airbag issues

Vehicles these days are typically fitted with a mat in the front passenger seat that determines whether that airbag needs to be activated in the event of a collision and how it should deploy. But that system doesn't always work, as Mercedes recently found in its SL-Class roadster and as Suzuki did before it with the Grand Vitara and SX4 crossovers. Now a crop of BMW vehicles have befallen the same issue, prompting the Bavarian automaker to cooperate with the National Highway Traffic Safety Administration to issue a recall for the vehicles in question.
The problem affects precisely 76,565 vehicles, including certain the 3 Series (sedan and wagon), 5 Series, 7 Series and X5 crossover families spanning the 2006 and 2007 model years and fitted with a certain type of seat. However, since the parts to repair the problematic components are not currently available, as you can see from the recall notice below, it won't be until March 2014 when local dealers will be able to resolve the issue.

BMW's fuel cell coming after 2020

Honda made news earlier this week at the Tokyo Motor Show by announcing details of the what will be its first production hydrogen fuel cell vehicle earmarked for the US next year. As for BMW? Not so fast. The German automaker might start working on a fuel cell vehicle for one of its larger sedan lines, but don't expect it to see the light of day before 2020, Reuters reports, citing remarks made by BMW executive Merten Jung in Tokyo. Bimmer has been collaborating with Toyota on advancing fuel-cell technology since 2013, but any production vehicle from BMW would take place after that collaboration expires. In fact, one point Jung made was that the BMW fuel cell would be able to go further on a full tank (of hydrogen) than the Toyota Mirai's 300+ miles. Earlier this year, reports surfaced that BMW may have a fuel-cell vehicle ready before the end of the decade, and that it would likely be sold under Bimmer's i brand of advanced-powertrain vehicles. Additionally, this summer, videos started coming out showing a hydrogen fuel cell i8 prototype (a rather sporty one, actually) as well as a 5-series prototype, so getting a handle on BMW's plans for fuel cell vehicles is a bit of a moving target. As for Honda, the Clarity will be earmarked for fleet and business customers in Japan first before marketing starts for everyday drivers. We've got some brief first-hand impressions of what it's like to drive a Clarity prototype here.