M5's traction control 'off' switch nixed for a reason
When Automobile got their paws on a six-speed manual version of the M5, they were none too pleased that BMW's engineers wouldn't allow drivers to fully disable the traction control. At the time, we assumed that BMW's legal boffins pictured overly enthusiastic Americans, stomping the go pedal and promptly winding up in a ditch.
Not so, according to Car. The magazine learned that the M division had no way of controlling clutch plate actuation, which would normally quell the axle tramp caused by the V10's prodigious power delivery. Acceleration times would rise and drivetrain components' lifetimes would fall. Hence, the only conceivable solution was to make the DSC a permanent fixture within the Bimmer's brain.
Still, you can partly disable the system in M Dynamic mode within iDrive (if you dare), but that may not be enough for those who want to test the limits of adhesion of the 285s in the rear.
[Source: Car]
Reader Comments (Page 1 of 2)
Colin Smith 12:08PM (1/27/2007)
It was designed for automatic, so why not stick with it? You only need gears on bends and hills, when a bit of brain activation can be fun; otherwise let the computer do the changing. If BMW believed auto was right for the car, why did they let themselves be led by uninformed fahionistas in NA? Courage of convictions I say; this will only make the company look silly.
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khiem 10:04PM (1/28/2007)
That is complete rubbish! If Mazda can calm down wheel spin during hard launches on the Mazdaspeed 3 by decreasing torque and power in first gear, why can't the M5 think up of something else besides excuses for taking driver control away from the driver. If Mitsubishi can put a launch control rev limit on the Evolution, why can't BMW get back to basics instead of placing the blame on too much power? BMW is just plain lazy and hardheaded to realize some of want total control.
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Brian 12:00PM (1/27/2007)
I highly doubt it was entirely an engineering decision. As it stands the E60 M5 in stick shift form is about as quick to 60 as the old E39 M5 was. Launch control is already neutered on the US market SMG box and the automated manual is still quicker. Obviously the system steps in far too early.
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Brian 12:13PM (1/27/2007)
Also, just a clarification. Does this mean stability control can't be switched completely off? Or just the traction control? If stability control can't be completely killed, then this excuse is nothing short of a flat out lie because traction control alone can quell axle tramp, etc...
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why not the LS2/LS7? 12:22PM (1/27/2007)
Interesting attempt to spin it as just a case of "too much power". Who could argue with that, right?
Except it doesn't make any more power than many other cars which do have a traction control off switch.
For years, people some people have complained about axle tramp on the Corvette and CTS-V. I guess GM should have taken the "fine German engineering" route and refused to allow the customer access to the power in the engine.
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AndyT 12:28PM (1/27/2007)
As the owner of a Mercedes 500E with the same problem (a traction control system without an off switch), I have to say that this is a crappy idea. Sure it proobably safer, but it saps the fun out driving it. Also it make it nearly impossible to get it inspected (even my local dealership can't do an inspection because they cannot perform a high RPM emmisions test without the traction control system kicking in.
Another problem I noticed recently was that in mud, I cannot get any power to the wheels, none, so I am really stuck on the mud rather than in it. I am sure that the technology of controlling the traction has improved greatly since mine was built, but that is my only data point and it sucks.
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Barney 12:39PM (1/27/2007)
I can see BMW protecting themselves from drivetrain problems. Burned out clutchs, snapped ujoints and blown diff's can give them a bad reputation. They obviously don't trust a consumer who wants the manual tranny.
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Barney 3:53PM (1/27/2007)
This is a test only. Do not re adjust your set.
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Kurt B 2:09PM (1/27/2007)
Didn't Clarkson smoke the diff on this car when he took it on their track? I'm pretty sure he raised a caution about this.
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SWP 2:31PM (1/27/2007)
The Corvette Z06 has as much horsepower & more torque than the M5 and it doesn't have this problem. What gives?
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Barney 3:58PM (1/27/2007)
The Corvette Z06 has as much horsepower & more torque than the M5 and it doesn't have this problem. What gives?
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Barney 4:01PM (1/27/2007)
It didn't ALL get posted ...
Trucks have manuals as well and tow more weight. Self protection by BMW? Maybe they think it's low esteem to have someone patch out in their cars.
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John P. 7:34PM (1/27/2007)
Ultimate Driving Machine? No wonder BMW changed their motto, they are now "Sheer Driving Pleasure."
That does sound better to the geezers and old ladies that now buy their cars.
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LPL 7:45PM (1/27/2007)
An independent company... a company full of ideas?
Sounds like they were too concern abaout some Automotive Journalists´opinion on the M. Besides didn´t we learned anything from Ferrari owners, this old folks have more money than experience behind the wheel, and that combination of factor is always bad.
You don´t one good old dad who just cash 401k to crash into a tree in its new M6... dont cha?
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John P. 7:55PM (1/27/2007)
In other news, the Mustang GT's came in 1st and 2nd in yesterday's race at Daytona in front of a bunch of Porsche's and BMW's.
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Pete 8:28PM (1/27/2007)
This is no different than the "Torque Management" GM uses on all their high horsepower LSX equipped cars (C6, Z06, TBSS, GTO), to prolong the life of the transmission and differentials. That much torque, with no where for that energy to be released, will eat gears, clutches, and drivetrain components in short order.
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Eric L. 11:26PM (1/27/2007)
GM is not immune from limiting the powertrain output. In a recent Edmunds test, they found the 365hp 6.0L Silverado had a 4 second lag between WOT and full engine output - probably an electronic limiter to protect the powertrain. I wouldn't be surprised if GM's other high powered vehicle adopt a similar strategy.
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Jon 11:54PM (1/27/2007)
I rolled an E39 540i (there was no DSC) and it seems like about half the E34 and E39 540s ever created have since been totalled. I don't like the "big brother" controls that BMW is usually pretty good about letting you turn off, but all you have to make is one mistake to completely destroy the car (and, possibly, yourself). With 500 hp on tap making that mistake would be VERY easy.
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MikeW 7:15PM (1/28/2007)
The BMW M5 has a speed sensistive differential
The vette and CTS-V have a torque sensitive differential
F1 cars use a speed sensitive differential
The SMG has shorter gearing, and lauch control (not in US market)
so it is purely a legal thing, there is no engineering basis for their claims.
That is like their BS claim that the stripper N52 engine made 215hp@6250 and 185ft-lbs@2750. That would be 180.67ft-lbs@6250, 97.66% of peak torque. That is greater than the real N52, with 3 stage resonance intake manifold, 255hp@6600-202.9ft-lbs, 92.2% of peak torque
http://www.e90post.com/forums/showthread.php?s=ee28e814be1d78b6a530ae2674bd7178&t=37444&highlight=stage
How would a newer, heavier 3 series be faster than the older more powerful one?
http://www.caranddriver.com/shortroadtests/10106/bmw-325i.html
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Marcus 5:04AM (2/17/2007)
I wrecked my 2006 530i on the freeway in the rain and believe it was the traction control trying to correct the car hydroplaning that caused the accident. I was in the #2 lane and moving into the #1 slow lane going 55 maybe 60 mph when the cars rear pitched out no fishtailing the rear end just came around like if you were to pull the ebreak. The car was sliding perfectly in reverse slowly going across all lanes of traffic I started to think for a second that maybe I was going to pull this off without any damage as I slide for close to 1\4 mile in reverse then there it was the center divider so I down shifted and hit the gas witch spun the car so the front hit the center divider and the airbags went off and car pushed of center divider and came back across all lanes stopping in the emergency lane facing the wrong way. I believe traction control is probably great most of the time but in the rain for me this day I think was a bad thing. Has anyone had a problem like mine?
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