BMW M5 Forum and M6 Forums banner
1 - 11 of 11 Posts

·
Registered
Joined
·
59 Posts
Discussion Starter · #1 ·
Hmmm... New development. Passed an 18 wheeler at 200 kph (120 mph), and noticed the car was floating... a lot. After this I tested with a friend at speed, and the M5 comes unglued behind another car at speed (close range).

Apparently disrupting the airflow over the M5 at speed can cause serious problems. Watch your butts


Vapour.
 

·
Registered
Joined
·
3,144 Posts
Not that I have opportunity to drive that fast around here, but I've always wondered. Is that little deck-spoiler really enough? I figured that at the speeds the M5 is designed to do, there should be a more...suitable fix.

--Dan
 

·
Registered
Joined
·
2,009 Posts
The "Venturi Effect" BMW boasts about in designing the Beast must be getting confounded in less than perfect aerodynamic conditions...

"This confidence is reflected in the car's design: an elegantly trimmed waist that increases the Venturi effect and holds the car to the road at high speeds." (bmw.com)

Alps
 

·
Registered
Joined
·
2,009 Posts
The site specifically describes the rear diffuser as such:

"Designed according to the Venturi principle, the bottom fascia reduces lift on the front axle by 50%."

Thoughts?
 

·
Registered
Joined
·
5,239 Posts
I've driven a lot of fast cars. I've never driven one that feels more planted at speed. This tells me that the spoiler and other aero features definitely work, because virtually every other car I've driven gets noticeable lift, especially above 120mph, (hell, many above 90!) and it feels SCARY - like you wouldn't want to have to negotiate ANY turn. The M5 goes through sweepers at those speeds with so much composure it just blows my mind.

That it gets upset in the presence of disturbed air doesn't surprise me - but it is good to know and be wary of.

Dan - suitable fix? You could bolt on a huge wing and rubber ground effects all around. But they will be butt ugly - and they cause more drag which will reduce top speed and mileage. I like the M5 precisely because of what it can do WITHOUT those garrish devices.
 

·
Registered
Joined
·
1,479 Posts
It happens to F1 race cars as well due to disrupted airflow when following another car closely. Moral is don't follow too closely at high speed!!
 

·
Moderator Emeritus
Joined
·
10,698 Posts
there is an often used remark in the manual that applies here-
you cant repeal the laws of physics- so while the M5 is an extremely fine driving machine- perhaps its the *ultimate*
? - it still has to follow the same physical laws as all other objects in our universe. that is until someone figures out how to squeeze it through a hole the size of a human hair and "fold space" then it will really do 0-60 so fast it might even get you to your destination before you left; with no time zone tricks!

ME
 

·
Registered
Joined
·
59 Posts
Discussion Starter · #9 ·
Just to be clear, I'm not complaining


The M5 feels completely planted at speed most of the time. This was just a heads up to those people that don't usually fly down the highway. But.. I have driven quite a few other fast cars that don't respond to turbulence quite as severely.

And I also agree that a silly looking aero kit would spoil my fun, and having an exciting ride is important.

And to that note about physics... I defy physics on a regular basis. Why would I stop now?


Vapour.
 

·
Registered
Joined
·
257 Posts
Not really a beware for the M5 owner. This universal effect happens with all cars, including my last two, a Viper GTS and Porsche 993. In fact, 120mph is hardly bad at all... over 150mph the effects are far more noticeable. What is suprising is that the M5 isn't any worse than "real" sports cars in this area.

Dan
 

·
Moderator Emeritus
Joined
·
10,698 Posts
Good points- it is good to point things out that perhaps some novices might not know.

I am glad the M5 cannot break the laws of physics, it allows me to examine their limits


ME
 
1 - 11 of 11 Posts
Top