Audi & BMW to follow Lexus in offering 8 Speed Autos
#1
Audi & BMW to follow Lexus in offering 8 Speed Autos
Luxury car makers are always trying to top each other with each new generation of vehicles, and recently the battle for supremacy has moved to the arena of transmissions. In 2001, BMW added a six-speed automatic to its 7 Series sedan, and then Mercedes upped the ante with a seven-speed two years later. Currently Lexus holds the crown with its eight-speed unit in the LS sedan, but now BMW and Audi are fighting back, and according to reports will offer eight-speed transmissions as early as 2009.
Both automakers are apparently looking to ZF to develop the transmission technology, and the German company says that due to longer gear ratios its unit will offer 14 percent better fuel-economy than a regular five-speed auto. With the U.S. CAFE standards looming and stricter emission regulations coming for Europe as well, the ZF transmission is seen as a way for luxury brands to make their powerful sedans more efficient.
Due to cost the eight-speed will only be offered in top-line models at first, but should make its way across each automaker's lineup as it becomes more affordable. BMW is supposedly readying the unit for its new 7 Series in 2010, and will add it to the surprisingly popular X6 SAC as well. Speculation is that Audi could make the transmission available in the A8 and Q7 SUV by 2009, as well as Ingolstadt's answer to the Mercedes CLS, the new A7 four-door coupe.
For its part Mercedes is sticking with seven speeds for the moment, though the company's head of passenger car engines and powertrains has said that adding an eighth is certainly possible. Some may feel that eight-speeds aren't really necessary for everyday driving, but as fuel-economy standards tighten, anything that can improve the efficiency of large, powerful luxury sedans is welcome. The only question is if an automaker raises the stakes with a nine-speed unit, how long will it take for the competition to follow suit?
Both automakers are apparently looking to ZF to develop the transmission technology, and the German company says that due to longer gear ratios its unit will offer 14 percent better fuel-economy than a regular five-speed auto. With the U.S. CAFE standards looming and stricter emission regulations coming for Europe as well, the ZF transmission is seen as a way for luxury brands to make their powerful sedans more efficient.
Due to cost the eight-speed will only be offered in top-line models at first, but should make its way across each automaker's lineup as it becomes more affordable. BMW is supposedly readying the unit for its new 7 Series in 2010, and will add it to the surprisingly popular X6 SAC as well. Speculation is that Audi could make the transmission available in the A8 and Q7 SUV by 2009, as well as Ingolstadt's answer to the Mercedes CLS, the new A7 four-door coupe.
For its part Mercedes is sticking with seven speeds for the moment, though the company's head of passenger car engines and powertrains has said that adding an eighth is certainly possible. Some may feel that eight-speeds aren't really necessary for everyday driving, but as fuel-economy standards tighten, anything that can improve the efficiency of large, powerful luxury sedans is welcome. The only question is if an automaker raises the stakes with a nine-speed unit, how long will it take for the competition to follow suit?
Where are the noobs that bashed Lexus for offering this first. :troutslap
#3
Originally Posted by SeCsTaC
Where are the noobs that bashed Lexus for offering this first. :troutslap
As the article points out the gain from a 5AT to the 8AT is only 14%. From most current 6ATs the gain would be in the low single digits and for MB there'd be virtually no gain from their 7AT. MB could gain 1-2% in fuel mileage (about the same gained by an extra gear) by just reprogramming their existing 7AT. This is mostly marketing BS.
#6
Yes, especially the way big displacement V8/V10/V12 engines burn gas zooming on the highways. They want the tallest gear ratio as possible to save gas. The CAFE fleet mileage rule is getting tougher and tougher.
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#12
Originally Posted by Ken1997TL
8 gears IMO is only necessary for engines that have over 500 ft pounds of torque AND a wide torque curve.
#13
Just for reference, the Lexus LS460 is the first car in the world with a computer-controlled eight-speed automatic transmission. The 4.6L-V8 is rated at 380hp and 367ft-lb of torque. The most amazing part is the fuel economy which is 27mpg EPA highway and 19mpg EPA city.
There's no cylinder de-activation, no electric hybrid motor. It's all the 8-speed transmission helping the hulking car to achieve this very respectable fuel economy numbers.
There's no cylinder de-activation, no electric hybrid motor. It's all the 8-speed transmission helping the hulking car to achieve this very respectable fuel economy numbers.
#16
#20
The article writes:
"Both automakers are apparently looking to ZF to develop the transmission technology, and the German company says that due to longer gear ratios its unit will offer 14 percent better fuel-economy than a regular five-speed auto."
But the Germans do not say what is the % of improvement over a 6 speed or even a 7 speed box. Bottom line I think 8 speeds it's just too much.
"Both automakers are apparently looking to ZF to develop the transmission technology, and the German company says that due to longer gear ratios its unit will offer 14 percent better fuel-economy than a regular five-speed auto."
But the Germans do not say what is the % of improvement over a 6 speed or even a 7 speed box. Bottom line I think 8 speeds it's just too much.
#23
I think a car with an 8-speed auto and cylinder deactivation would bog at highway speeds running on only 4-cylinders at ~1000-1300rpm, wouldn't it? I know the transition from running on 4-cyls to 8 is almost seamless now, but still.
Really is overkill, but someone will probably do a 9-speed for the hell of it in the future. and IIRC they still can't build CVTs that are strong enough to handle a engine with a lot of torque (350+ lb/ft) someone correct me if I'm wrong?
Really is overkill, but someone will probably do a 9-speed for the hell of it in the future. and IIRC they still can't build CVTs that are strong enough to handle a engine with a lot of torque (350+ lb/ft) someone correct me if I'm wrong?
#25
Originally Posted by Dan Martin
Have they given up on CVT's, or does the thought of a CVT just not sound sexy enough to the luxury crowd?
#26
Assuming they can build one to handle the loads, CVT should stay around not because fuel efficiency but because of cost - there's very little in term of parts in a CVT compared to say a 6AT. You know Nissan is all about cost cutting and they wouldn't be so big on the CVT if it didn't save a buck.
#27
Originally Posted by biker
Assuming they can build one to handle the loads, CVT should stay around not because fuel efficiency but because of cost - there's very little in term of parts in a CVT compared to say a 6AT. You know Nissan is all about cost cutting and they wouldn't be so big on the CVT if it didn't save a buck.
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