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Discussion Starter · #1 ·
7am shift this morning, left my house at 6:15. Temp 54. Hit RT128, which was blissfully deviod of traffic - and let it rip.

There is just something special that happens with these cars at speeds over 100mph. The whole feel of the car transforms. Averaged between 95 and 130mph (for a brief spurt). Felt amazing!!

Is it my imagination, or does the E46 become more stable at higher speeds? The handling seems more precise too. Are some aerodynamics coming into play??
 

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geomax said:
Is it my imagination, or does the E46 become more stable at higher speeds? The handling seems more precise too. Are some aerodynamics coming into play??
No, it's not your imagination. The car has a different personality at those speeds. I had a brief encounter over 110 a few weeks ago. The suspension seemed to hunker down and it felt like i was riding on rails. I'm sure there's some aero effect but I think it's mostly chassis dynamics. It's very comfortable at that speed. Maybe too comfortable on US roads.

Kinetic energy = 1/2 m v^2. Wouldn't want to hit something or have a problem in that stratosphere.
 

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Double Bimmers
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Re: Re: FAST commute

ObD said:
No, it's not your imagination. The car has a different personality at those speeds. I had a brief encounter over 110 a few weeks ago. The suspension seemed to hunker down and it felt like i was riding on rails. I'm sure there's some aero effect but I think it's mostly chassis dynamics. It's very comfortable at that speed. Maybe too comfortable on US roads.

Kinetic energy = 1/2 m v^2. Wouldn't want to hit something or have a problem in that stratosphere.
At a PTG open-house, I remember Tom Milner telling us... "all BMWs have lift". Wings and spoilers help to counteract the lift but we are never going to have net downforce.
 

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Discussion Starter · #5 ·
Re: Re: Re: FAST commute

CD-55 said:


At a PTG open-house, I remember Tom Milner telling us... "all BMWs have lift". Wings and spoilers help to counteract the lift but we are never going to have net downforce.
So what accounts for the distinct feel at higher speeds? Some people have mentioned "chassis dynamics" - what exactly is this??
 

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I can't comment on the physics effecting the feel of the the E46 at 100+ MPH, but I can testify to the feel as well.

The last time I drove my car over into mainland Europe, I drove non-stop from western Germany (Bitburg), through Luxemburg, and on into Brussels. I don't recall the exact mileage, but I held the speed to 100~105 for most of the way (except for speed zones at the borders) and it felt like I was driving my Accord at 75. It was dead solid on the road with none of the twitchy or floaty feeling you get in other cars at higher speeds.

In fact, my wife who is deathly afraid of going over 85, never looked up from her book for most of the trip I described above.:D
 

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Double Bimmers
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Re: Re: Re: Re: FAST commute

geomax said:
So what accounts for the distinct feel at higher speeds? Some people have mentioned "chassis dynamics" - what exactly is this??
Ever driven a motorcycle (sport-bikes also have no down force) 100 MPH? The faster you go the more stable it feels. I takes a lot of force to get it to turn when you are going that fast. My guess is the force of the wheels spinning and the rake of the steering work the same way for a BMWs at high speed.
 

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OMGWTFBBQ
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Re: Re: Re: Re: Re: FAST commute

CD-55 said:


Ever driven a motorcycle (sport-bikes also have no down force) 100 MPH? The faster you go the more stable it feels. I takes a lot of force to get it to turn when you are going that fast. My guess is the force of the wheels spinning and the rake of the steering work the same way for a BMWs at high speed.
Steering rake is something that I've never thought about WRT cars, but it can't be the same as on bikes, can it?

OTOH, momentum does create straightline stability which will account for a lot plus a little bit of play in on center steering (autobahn sneeze factor) will enhance that feel. Combine that with what you want to believe :p and you have a car that feels very good at high speed.
 

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Some comments on chassis dynamics:

I'm no suspension expert, but here's my take on the subject from an engineering perspective:

The car chassis is a classic "spring-mass-damper" system, designed to allow up and down movement of the wheels while keeping the car body as stable as possible. The spring rate, wheel/brake/control arm mass, and the damping rate can be varied to optimize the response for a given frequency. As a car goes faster, the frequency of the bumps being input to the system (as the car rolls over dips, bumps, etc.) increases. The E46 cars (especially with the sport package) have a high spring rate and a low un-sprung mass, thanks to aluminum control arms, aluminum wheels, etc. This combination allows the wheel to move up and down rapidly when the car is going fast, and thus impart a minimum of movement to the body.
 

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OMGWTFBBQ
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mg-ca said:
This combination allows the wheel to move up and down rapidly when the car is going fast, and thus impart a minimum of movement to the body.
Which translates not to stability, but numbness...IOW, Buick (shudder)
 

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I don't mean to imply that the E46 isolates the driver from road feel like a Buick does. As we all know, the road feel at high speed is excellent!

Stability is enhanced by having the wheels follow the bumps, dips, and contours of the road as quickly and accrately as possible. Buick suspension does not move quickly enough at high speed to maintain the same degree of constant-force contact with the road.

Again--I'm no suspension expert, but FWIW those are my thoughts on the subject.
 

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Davis? cows?...what cows?
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....for some reason....mine feels sort of floaty at those speeds....

i have Dunlop sp 8000 tires which i put on 4000 miles ago or so...

what can be the problem? :dunno:
 

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hah ! Yea it feels reallll comfy I bet. Until Something JUMPS IN THE ROAD liek flying debris and you have to slam your brakes and watch in desguist as the DSC Pumps your brakes back n forth jerking your car around. all of a sudden all the weight that was so comfy comes CREAMMING towards the front of the car EVERYTHING S A BLURRRR AHHH *SKIRRRTTTTT* *BOOM*


*later that day*
Hello, Im jhonnie pie in the sky for fox news . It seems we have a bmw that thought he was the king of the world again becuase he drives a german 40,000 dollar car now he is dead god bless his soul.:eek:


I drive fast too! but this is the message everyone sends to me when I post somethin like this so I thought Id keep the trend goin ! lol
 

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Bimmer? said:
hah ! Yea it feels reallll comfy I bet. Until Something JUMPS IN THE ROAD liek flying debris and you have to slam your brakes and watch in desguist as the DSC Pumps your brakes back n forth jerking your car around.
Actually it's the ABS not the DSC that modulates your braking
 

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in_d_haus said:


Actually it's the ABS not the DSC that modulates your braking
is it? Because when I turn the dsc off The brakes dont keep locking and unlocking locking and unlocking with it off it may just lock and stay locked which is better in some cases. when you turn the dsc off des it also turn off the abs?
 
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