1996 - Bmw M3 on 2040-cars

Auto blog

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 i3 REx rated at 117 MPGe, 39 mpg with 72-mile EV range

The numbers haven't made their digital way to the EPA's website yet, but we can now confirm that the BMW i3 with range extender will be officially rated at a combined 117 MPGe with 39 mpg once the battery runs out. That puts the amazing little city car just ahead of the pure-electric Fiat 500e (116 MPGE, combined) and behind the Honda Fit EV (118) and the Chevy Spark EV (119). In the plug-in hybrid category, it's at the top of the class, beating out the Honda Accord PHEV, which is rated at 115 MPGe but is also a much bigger vehicle. The i3 REx also has an official all-electric range of 72 miles and can go another 78 on gas (for a total of 150). When it's not carrying around the extra fuel tank and engine, the all-electric i3 gets 124 MPGe (combined), which is the currently the highest in the US. The i3 EV also has an all-electric range of 81 miles. BMW expects to deliver the first i3 REx in the US this week and delivered the first all-electric version earlier this month. There was a bit of a hold-up on the range-extender version thanks to a delay with getting these EPA numbers. Now that all the bureaucratic boxes have been checked, it's off to customer driveways they go.

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.