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      02-26-2014, 08:23 AM   #1
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Adaptive suspension vs coil overs

Now that I've got a better understanding of the M adaptive suspension, was wondering two things.

1. How would it compare to KW? And why.

2. Can anyone speculate on the long term reliability and maint costs of the active susp?

Let me be honest. 90% of my driving will be DD. Probably 95%. But my DD includes some twistys where I can understeer or baby drift safely. I've never had an active suspension. I don't mind a harsh ride, within reason (the fillings in my teeth must stay in).

I know Porsche implemented PASM with the 997's and the 991's have improved on it. I wonder if bmw is on par with them. I haven't tested a 991, but I recently tested a M235 and it stayed pretty planted on fun curvy roads.

Any input appreciated. I thought the adaptive M susp was a no-brainier, but I just don't want the damn thing to break out of warranty and I have to spend $5K to fix it.
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      02-26-2014, 09:20 AM   #2
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Generally speaking, they are pretty reliable, and the performance is improving each generation. If you're talking race track performance, a properly chosen coil-over set up would be better for ultimate lap times, but for the street, there's no question. The ride will be better than a coil-over system and it will perform very well at 8/10's in the twistys.
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      02-26-2014, 09:35 AM   #3
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Quote:
Originally Posted by Racer20 View Post
If you're talking race track performance, a properly chosen coil-over set up would be better for ultimate lap times, but for the street, there's no question.
Hello Racer. You've demonstrated high competency on this topic, so I hope you don't mind a few questions?

First, why do you say a coil-over setup is still the best for the track?

Also, aren't there adaptive coil-overs out there? I thought there were, but maybe I'm mistaken. If there are, what are the drawbacks of these? And if there are not, why not?

Thanks, and Go Blue.
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      02-26-2014, 09:44 AM   #4
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Quote:
Originally Posted by mkoesel View Post
Hello Racer. You've demonstrated high competency on this topic, so I hope you don't mind a few questions?

Frist, why do you say a coil-over setup is still the best for the track?

Also, aren't there adaptive coil-overs out there? I thought there were, but maybe I'm mistaken. If there are, what are the drawbacks of these? And if there are not, why not?

Thanks, and Go Blue.
Kwv3s for 335 were in the 3k range, they had adjustability and had 3 options for dampening etc.. Kwv2s and 3s are track suitable but kwv1 are only for streets. The difference is you have to change the settings from the outside with KW where with BMW it's all controlled within side of the cabin.
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      02-26-2014, 09:52 AM   #5
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Let me clarify:

A track focused coil-over setup will probably be better on the track than a stock adaptive suspension, simply because of the way each was tuned, and the fact that you can have higher spring rates with a coilovers than with the stock system. That same track coilover system would be pretty tough to live with on the street though.

Unless your car sees 50%+ track duty, the optional adaptive suspension is a MUCH better choice.

KW makes a DDC system, but I don't have any first hand knowledge of it's design or performance.
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      02-26-2014, 09:54 AM   #6
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What type of setup does the car have without the optional suspension?
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      02-26-2014, 09:56 AM   #7
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Quote:
Originally Posted by Racer20 View Post
Let me clarify:

A track focused coil-over setup will probably be better on the track than a stock adaptive suspension, simply because of the way each was tuned, and the fact that you can have higher spring rates with a coilovers than with the stock system. That same track coilover system would be pretty tough to live with on the street though.

Unless your car sees 50%+ track duty, the optional adaptive suspension is a MUCH better choice.

KW makes a DDC system, but I don't have any first hand knowledge of it's design or performance.
I go to track often, what do you think about the best option of lowering the car is and keeping comfort? I am not a fan of lowering on springs, I like my coils on e90 but it's set to stiff and it's bone jarring over a bumps.
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      02-26-2014, 10:15 AM   #8
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Quote:
Originally Posted by Racer20 View Post
Generally speaking, they are pretty reliable, and the performance is improving each generation. If you're talking race track performance, a properly chosen coil-over set up would be better for ultimate lap times, but for the street, there's no question. The ride will be better than a coil-over system and it will perform very well at 8/10's in the twistys.
Quote:
Originally Posted by Racer20 View Post
Let me clarify:

A track focused coil-over setup will probably be better on the track than a stock adaptive suspension, simply because of the way each was tuned, and the fact that you can have higher spring rates with a coilovers than with the stock system. That same track coilover system would be pretty tough to live with on the street though.

Unless your car sees 50%+ track duty, the optional adaptive suspension is a MUCH better choice.

KW makes a DDC system, but I don't have any first hand knowledge of it's design or performance.
completely agree with this guy.

there are a few certainties with modifying suspensions

1) if you go cheap on coilovers OR lowering springs only, your car will not only ride worse, but handle worse on anything but the smoothest surfaces. it is CRITICAL to have high quality dampers, AND to have the length of the dampers shortened to compensate for any lower ride height.

2) you must spend money on quality coilovers in order to make the minimum amount of sacrifice possible in your ride quality and handling balance. IMO and personal experience, this means nothing lower than an Ohlins DFV kit. KW v3 is decent, but still will not ride as well on regular roads and be jittery.

Finally, IF the new calibration is anywhere near the new gen PASM in Porsches, it will take one hell of a nice coilover system to handle better. And finding one that will blend ride comfort with handling will be very expensive and probably impossible.

I would NOT go aftermarket on the suspension on this car unless I was willing to spend a lot of money and sacrifice everyday ride comfort. To me, I wont do that because the thing about the m3 that is the best is its blend of DD usability and track prowess.

Quote:
Originally Posted by //M sa View Post
I go to track often, what do you think about the best option of lowering the car is and keeping comfort? I am not a fan of lowering on springs, I like my coils on e90 but it's set to stiff and it's bone jarring over a bumps.
there is none outside of a very expensive coilover kit, such as an Ohlins DFV kit or higher.

I would personally stay stock and then retrofit the soon to come competition package suspension.

If you need it lower than that, buy the most expensive coilovers you can justify and just get ready to deal with a worse ride and more hassle. Depends on the person whether those sacrifices are worth it.

IMO based on my experience with a LOT of suspensions on road and track.
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      02-26-2014, 10:39 AM   #9
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Good to know, thanks Kenny.
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      02-26-2014, 11:32 AM   #10
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I totally agree that going cheap on aftermarket suspension is worthless. I was planning on getting the most expensive set I could afford if I went that route. No point in undoing all that BMW research and development.

In your experience with suspensions, were any with active ones?

Seems like active is the way to go for me, given how I would use the car. Even though active systems have been around for a bit, they seem like they're only relatively recently being adopted for serious sports cars for the masses.

So, glad to hear they're relatively reliable. Intuitively, I just think they wouldn't be, with all the electronics, sensors, moving parts, etc needed. But I know next to nothing about them

Good info guys. I searched around and didn't find too much about this on the web.
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      02-26-2014, 11:54 AM   #11
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Quote:
Originally Posted by KennyPowers View Post
completely agree with this guy.

there are a few certainties with modifying suspensions

1) if you go cheap on coilovers OR lowering springs only, your car will not only ride worse, but handle worse on anything but the smoothest surfaces. it is CRITICAL to have high quality dampers, AND to have the length of the dampers shortened to compensate for any lower ride height.

2) you must spend money on quality coilovers in order to make the minimum amount of sacrifice possible in your ride quality and handling balance. IMO and personal experience, this means nothing lower than an Ohlins DFV kit. KW v3 is decent, but still will not ride as well on regular roads and be jittery.

Finally, IF the new calibration is anywhere near the new gen PASM in Porsches, it will take one hell of a nice coilover system to handle better. And finding one that will blend ride comfort with handling will be very expensive and probably impossible.

I would NOT go aftermarket on the suspension on this car unless I was willing to spend a lot of money and sacrifice everyday ride comfort. To me, I wont do that because the thing about the m3 that is the best is its blend of DD usability and track prowess.



there is none outside of a very expensive coilover kit, such as an Ohlins DFV kit or higher.

I would personally stay stock and then retrofit the soon to come competition package suspension.

If you need it lower than that, buy the most expensive coilovers you can justify and just get ready to deal with a worse ride and more hassle. Depends on the person whether those sacrifices are worth it.

IMO based on my experience with a LOT of suspensions on road and track.
completely agree. I learned this first hand from replacing my stock adaptive suspension on my e92 with KWV3. here are a few observations:

1. the ride quality was way worse. anybody who tells you that the ride quality is similar or better is either smoking crack or driving around on billiard tables. I had the suspension adjusted to its softest setting and it's highest height (which is still a drop compared to stock) because it was just too uncomfortable. only then was it bearable, but when I re-installed the stock setup, I fell in love with the car all over again. so much better from the factory. never again will I tinker with the suspension.
2. don't confuse a car that corners flat with one that handles well. you can always make a car corner flat through stiffening. and cornering completely flat in and of itself isn't necessarily a good thing for handling/speed.
3. lowering the car messes with the suspension geometry and can compromise how the wheels/tires move in relation to the road under cornering loads. this takes a truly expert suspension tuner a long time to perfect, and I think you'd have a hard time making any lowered aftermarket system handle as well as the stock setup. As KP stated, you have to spend big dollars to make it right, and even then you've compromised the daily driveability that makes this car so great.

EDIT: to be clear, coilovers were the only mod I made to my M3 that I thought would enhance performance, but instead made it worse and made the car less enjoyable to drive. the only mod I regretted.

Last edited by Brosef; 02-26-2014 at 12:03 PM.
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      02-26-2014, 11:56 AM   #12
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Quote:
Originally Posted by RocketBoots View Post
I totally agree that going cheap on aftermarket suspension is worthless. I was planning on getting the most expensive set I could afford if I went that route. No point in undoing all that BMW research and development.

In your experience with suspensions, were any with active ones?

Seems like active is the way to go for me, given how I would use the car. Even though active systems have been around for a bit, they seem like they're only relatively recently being adopted for serious sports cars for the masses.

So, glad to hear they're relatively reliable. Intuitively, I just think they wouldn't be, with all the electronics, sensors, moving parts, etc needed. But I know next to nothing about them

Good info guys. I searched around and didn't find too much about this on the web.
they're extremely reliable. they aren't as complicated as you might imagine - it's only the shocks that are different and "adaptive". this isn't like the adaptive suspension on the X5, for instance, that uses active anti-roll bars.
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      02-26-2014, 01:11 PM   #13
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I'm going to order the standard suspension then wait for Bilstein to make this for the F82.
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      02-26-2014, 01:15 PM   #14
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Quote:
Originally Posted by Brosef View Post
completely agree. I learned this first hand from replacing my stock adaptive suspension on my e92 with KWV3. here are a few observations:

1. the ride quality was way worse. anybody who tells you that the ride quality is similar or better is either smoking crack or driving around on billiard tables. I had the suspension adjusted to its softest setting and it's highest height (which is still a drop compared to stock) because it was just too uncomfortable. only then was it bearable, but when I re-installed the stock setup, I fell in love with the car all over again. so much better from the factory. never again will I tinker with the suspension.
2. don't confuse a car that corners flat with one that handles well. you can always make a car corner flat through stiffening. and cornering completely flat in and of itself isn't necessarily a good thing for handling/speed.
3. lowering the car messes with the suspension geometry and can compromise how the wheels/tires move in relation to the road under cornering loads. this takes a truly expert suspension tuner a long time to perfect, and I think you'd have a hard time making any lowered aftermarket system handle as well as the stock setup. As KP stated, you have to spend big dollars to make it right, and even then you've compromised the daily driveability that makes this car so great.

EDIT: to be clear, coilovers were the only mod I made to my M3 that I thought would enhance performance, but instead made it worse and made the car less enjoyable to drive. the only mod I regretted.
Someone honest about how modding isn't the holy grail.... You sir, deserve a beer on the house.
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      02-26-2014, 01:29 PM   #15
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Quote:
Originally Posted by Alpine F31 View Post
I'm going to order the standard suspension then wait for Bilstein to make this for the F82.
that is not the same thing as the m3's adaptive suspension

that allows for two modes to be used, stiffer and normal. it is not an active suspension setup

the m3's adaptive suspension is an "active" suspension that allows for calibrations and changes in how the dampers react to be made in real time, and at least in PASM equipped 991s, its freaking unbelievable how well it works.

my experience with bilstein products has not been good, and there is a lot of very mixed feedback on that product for older 997 porsches.
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      02-26-2014, 02:02 PM   #16
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Ok, so what I am hearing is that the coil-overs with active dampening aren't electrically adjustable and so they don't integrate with the electronics in the car. That seems like a wasted opportunity. I wonder why they don't design them to plug-and-play with the stock electronics?

That aside, it seems to me that the ultimate aftermarket suspension would have adjustable spring rates (as well as adjustable dampening) so that you can have track and street functions built in to one unit. I guess a fully active suspension could effectively provide that, but I don't know for sure. Weight of the system is probably one trade-off. Or maybe the technology to do it right isn't there yet. Or maybe its just not something enough people want.


Quote:
Originally Posted by //M sa View Post
Kwv3s for 335 were in the 3k range, they had adjustability and had 3 options for dampening etc.. Kwv2s and 3s are track suitable but kwv1 are only for streets. The difference is you have to change the settings from the outside with KW where with BMW it's all controlled within side of the cabin.
Quote:
Originally Posted by Racer20 View Post
Let me clarify:

A track focused coil-over setup will probably be better on the track than a stock adaptive suspension, simply because of the way each was tuned, and the fact that you can have higher spring rates with a coilovers than with the stock system. That same track coilover system would be pretty tough to live with on the street though.

Unless your car sees 50%+ track duty, the optional adaptive suspension is a MUCH better choice.

KW makes a DDC system, but I don't have any first hand knowledge of it's design or performance.
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      02-26-2014, 02:07 PM   #17
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Quote:
Originally Posted by RocketBoots View Post
2. Can anyone speculate on the long term reliability and maint costs of the active susp?
For reliability, you could check up on how the last generation systems from the E9x M3 and E6x M5/M6 have held up. As far as I know, at least with the former, there are no widespread or major problems. For that matter I believe that BMW has been using adaptive systems in the 7 Series for even longer. Even though it's obviously old tech, it still would be interesting to see how they've lasted.
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      02-26-2014, 02:08 PM   #18
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Quote:
Originally Posted by mkoesel View Post
Ok, so what I am hearing is that the coil-overs with active dampening aren't electrically adjustable and so they don't integrate with the electronics in the car. That seems like a wasted opportunity. I wonder why they don't design them to plug-and-play with the stock electronics?

That aside, it seems to me that the ultimate aftermarket suspension would have adjustable spring rates (as well as adjustable dampening) so that you can have track and street functions built in to one unit. I guess a fully active suspension could effectively provide that, but I don't know for sure. Weight of the system is probably one trade-off. Or maybe the technology to do it right isn't there yet. Or maybe its just not something enough people want.
There was one option a few years ago where it had a compressor and you could control it from the inside to 3 set settings, I forgot the name of the product but I know it was really pricey. Someone was selling a used set on the e90 forums for around 5k. I think I will now have to rethink the coils idea. Maybe get 20s to hide the gap until lci comes out lol.
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      02-26-2014, 02:20 PM   #19
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Bilstein has to be the worst company I have ever dealt with ever!

Their products are unreliable. I had a B16 coil system specific for Porsche PASM and it came with cut wire at top and Bilstein wouldn't replace it because evidently my vendor wasn't an authorized dealer...never mind it was a sealed brand new box...my vendor had to eat the 800.00 for the single coil that I had to get and Bilstein at first wouldn't even sell a single.

I would never buys another Bilstein product ever again....the Porsche guys have had horrendous probs with Bilstein products with pins snapping off and Bilstein trying to blame it on install error...and drop link snap off all the time with this product also.
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      02-26-2014, 02:23 PM   #20
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I was doing some digging, and from what I could gather, additional cost, weight (on the order of ~100 lbs!!), and lack of technology were limiting factors early on for "air ride" type active suspensions from, say, Caddy, Benz, Lexus. Those were for very different types of cars, but still... That was a tiny bit of my concern for active suspensions: complexity, (weight), and reliability.

It seems like the aftermarket suspensions either don't have active setups, and require a disabler to trick the OBC so it won't throw error msgs, or do not integrate into the electronics of the car. The second part sort of makes sense. I would think the algorithms for the active suspensions were developed with specific equipment, and a specific car, in the case of M3/M4, in mind, and were designed to have the whole system work synergistically. So to upgrade, you might need to change the whole system, including the computer, if it's a discrete unit.

Two side notes:
anyone venture a guess on the additional weight, if any, of the active setup?

And has anyone changed just the springs in an active suspension and the whole system still worked well, or even better?
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      02-26-2014, 03:11 PM   #21
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Quote:
Originally Posted by //M sa View Post
There was one option a few years ago where it had a compressor and you could control it from the inside to 3 set settings, I forgot the name of the product but I know it was really pricey. Someone was selling a used set on the e90 forums for around 5k. I think I will now have to rethink the coils idea. Maybe get 20s to hide the gap until lci comes out lol.
I think this is the product you are referring to, http://www.praxissuspension.com.
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      02-26-2014, 03:20 PM   #22
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Quote:
Originally Posted by mkoesel View Post
Ok, so what I am hearing is that the coil-overs with active dampening aren't electrically adjustable and so they don't integrate with the electronics in the car. That seems like a wasted opportunity. I wonder why they don't design them to plug-and-play with the stock electronics?

That aside, it seems to me that the ultimate aftermarket suspension would have adjustable spring rates (as well as adjustable dampening) so that you can have track and street functions built in to one unit. I guess a fully active suspension could effectively provide that, but I don't know for sure. Weight of the system is probably one trade-off. Or maybe the technology to do it right isn't there yet. Or maybe its just not something enough people want.
Quote:
Originally Posted by RocketBoots View Post

And has anyone changed just the springs in an active suspension and the whole system still worked well, or even better?
no, that is not correct

these aftermarket suspensions are not active at all. they are simply systems that may have two "modes" that can be controlled electronically, using the same controls as the OEM system. so basically, imagine a "normal" and "sport" mode.

the oem adaptive systems are active systems, which are constantly adapting to road conditions and making on the fly adjustments AND have multiple modes in which they do this. they are far more advanced than the OTS systems that claim to be "electronic".

and unfortunately not, substituting the springs only will make the system perform like garbage. it would probably be a good idea to read some articles on suspension setup and geometry.

the springs are bad for three reasons. one, the OEM setup calibrates the shock length and travel length to the spring height, allowing for a specific amount of suspension travel. two, the suspension geometry and alignment are specific to a certain ride height range. three, the shocks are calibrated for a specific spring rate, which will be different than the aftermarket springs.

adding aftermarket springs on OEM shocks, or any shocks that are not shortened and re-valved to account for the new spring heights and rates is an absolutely horrible idea and will perform much worse than stock
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