What does new suspension really do over EDC?

[8600RPM]

Tailing off my BBK thread, I am trying to understand components that go into tracking a car since I've started tracking.now I can clearly see how more negative csmber is needed or helpful to eliminate pushing through corner.

However driving my 2013 zcp edc in sport suspension the thing is very flat and it seems to handle perfectly with very neutral manners at the limit of grip and slightly beyond

Now what do putting in a new suspension do better besides the adjustability of csmber ? Can you take a turn with more objective grip? Faster through turns?

Just not seeing where edc is not really good but I want to understsnd!

[roastbeef]

I wondered the same thing when I started tracking. I'm glad I held out, because now I understand why I need suspension and where exactly the benefit is. I'm not at my car's limit, but I'm getting more experienced and I'm able to see the oem zcp suspension's weak points.
It's in the valving.
The car's ability to transfer weight becomes more efficient and it handles bumps more efficiently. The car is able to maximize contact with the ground throughout the suspension cycle. There are others that will be able to describe this better than I can.

[NoCarrier]

I'm by no means an expert, so I'll offer my layman's perspective until an expert shows up. While there is a noticeable difference in the three modes of EDC, the limitation of the system is that it only adjusts the damping of the shocks and doesn't change ride height or spring rates. From the factory the M3 is meant to be a road car first and foremost, because only a small handful of M3s actually see track time. For a car's suspension to be optimal on the track it's going to be significantly lower and stiffer than a road car, and BMW doesn't want to sell a car with a suspension mode that could be described as "bone jarring" and doesn't clear speed bumps. And it's just not really possible to have a car that is perfectly dialed in for the track and yet still comfortable around town.

If you buy a set of coilovers they allow the ultimate in fine-tuning, so you can get the perfect spring rates, you can set the ride height exactly where you want it, and you can have dampers that are two or three-way adjustable. But again, for every step you take towards track performance (stiffer spring, lower ride height), the less practical the car is. And when you really start getting serious about suspension you start swapping out rubber bushings for poly or solid ones, and that's when things really get uncomfortable. I had aftermarket suspension on my e46 and it was a total blast on the track, but it scraped over every speed bump or driveway and it was not a pleasant ride on the street.

If you're not experiencing any limitations with the stock suspension, then don't upgrade it! Spend the money on driving instruction or safety gear. As you gain more experience you may start to uncover weaknesses in the suspension, and at that point you could consider an upgrade.

I found the stock EDC suspension to be weak on small tight road courses. In situations where you're flicking the car back and forth quickly it's just too heavy of a car to be nimble on the stock suspension. Like roastbeef said, it's about weight transfer. If the car were lower and stiffer it wouldn't lean over so much in turns. But the car is new to me and I don't see the suspension as a top priority right now.

[redpriest]

More grip in turns, ability to put the power down sooner in a turn. I've seen people with upgraded suspensions drop 4 seconds in a technical lap.

[bigjae1976]

An upgraded suspension will generally react faster and the dampers will tolerate higher spring rates. Therefore you reduce weight transfer and increase overall grip. For example, a stiffer suspension will reduce the amount of weight transferred in a left turn to the right side. So you've got more grip on the left side which allows for better turn in and more throttle application.

Also, there should be a designed increase in suspension travel which will improve performance. I think this is the biggest benefit since I feel like the rear is bouncing off the bumpstop on exit.

More ability to tune the balance of the car with spring rates and damper settings.

With that said, the OE non-EDC dampers are pretty darned good. My only complaints was the car was hard to balance in any quick side to side transition. Wasn't a huge issue if you're willing to give it a bunch of throttle and drift a little bit.

I could definitely see how a well thought suspension could be a significant upgrade.

[Z K]

If you take your M3 through some tight twisty roads, you'll see the failings of the stock suspension. No need to even go to a track. The suspension is lazy and reacts slowly.

The stock suspension is built to be comfortable and appeal to a wide market of people - most of which are looking for a commuter car to get to work in. The "Sport" mode doesn't do anything other than make the car more uncomfortable. It feels "stiff" because it has more dampening but you'll actually lose traction on rough roads because of it. In many cases the non-EDC suspension is better for performance.

The main thing the stock suspension lacks is rebound. The rebound is too slow to react to bumps on the road. Hit a fast series of bumps and you'll see the suspension compress for the first one, and then stay compressed over the other bumps. The shock doesn't rebound fast enough to uncompress for the next bumps. You lose traction over the road as the wheels lose contact. Lower spring rates for comfort also mean the car will have more body roll and reacts slower because of the weight shift. This problem is worse with the "Sport" mode because it makes the compression stiffer but doesn't change rebound at all. You have even less grip and control. Why doesn't BMW make rebound faster? Because it'll be uncomfortable.

Some companies such as Ohlins (OEM on Pagani, Lamborghini and others) have the technology to make a fast rebound shock without compromising suspension comfort... but its expensive and the shocks need to be rebuilt every 30k miles. BMW and most of their customers wouldn't want to pay for those costs.

Here's how a Ohlins DFV shock works:


vs a conventional shock like the M3 suspension:

[M3 Number 86]

better suspension will also soak up bumps a lot better so even if you're hitting all kinds of berms, the car doesn't jar and jump around like it would on sport+ setting.

so you get stiffer but also more compliant suspension.

[FogCityM3]

ZK is spot on IMO..the lack of rebound in EDC is the key flaw. The whole goal of the suspension is to keep the tires gripping the tarmac as much as possible, so when you go over a bump or take a turn, it is critical that the wheel that is pushed up off the ground gets pushed back into the tarmac. BMW cheapened out with the EDC with compression adjustability only and minimal rebound change only to give the illusion of more grip when it just largely prevents body roll giving you more of a go-kart type feel but not doing much in terms of improving tire contact with the pavement at all times. When you have a double adjustable suspension, it becomes very obvious that the rebound adjustment is the larger determinant of grip (and most compression adjustments for the track are actually recommended to be on the softer side, while rebound is more on the aggressive side) and the larger determinant of ride quality.

As others mentioned, it definitely helps with transitions and furthermore enables the rear wheels to stay in contact with the tarmac in turns....you will notice it will help you with carrying more speed and grip out of corners.

[Richbot]

You need some ass time in a car with decent dampers on it to understand. EDC is a dim-witted setup that doesn't react quickly enough (compare to GM's MR setup which is like a magic carpet over bumps especially on power). And even when EDC does work "right" its adjustment range doesn't allow enough rebound damping. Also, the stock suspension, especially the ZCP setup, is designed and usually does corner on the bumpstops. The EDC dampers don't have enough rebound damping to control the suspension once it's down on the stops. It seems flat because it's riding on the ginormous stock bumpstops as soon as it's taken a set.

I miss my MCS 2-ways every time I drive my car. Next time I have the suspension apart, good dampers are going back on. The stock SACHS/ZF stuff is "good enough" but once you experience what a good damper can do for a car,'s behavior you never want to go back. Better ride, better handling, better stability over big hits and dips, everything is just better. And you don't have to stick super stiff springs on the car to reap most of the benefits of aftermarket suspension. Yeah the much stiffer (300% stiffer than stock is the norm for the front, 50% stiffer in the rear) springs make the car handle better on the track and are nicer to tires, but using conservative springs with good dampers is the best way to make the car awesome all the time.

[///Mobbin]

Originally Posted by Richbot

You need some ass time in a car with decent dampers on it to understand. EDC is a dim-witted setup that doesn't react quickly enough (compare to GM's MR setup which is like a magic carpet over bumps especially on power). And even when EDC does work "right" its adjustment range doesn't allow enough rebound damping. Also, the stock suspension, especially the ZCP setup, is designed and usually does corner on the bumpstops. The EDC dampers don't have enough rebound damping to control the suspension once it's down on the stops. It seems flat because it's riding on the ginormous stock bumpstops as soon as it's taken a set.

I miss my MCS 2-ways every time I drive my car. Next time I have the suspension apart, good dampers are going back on. The stock SACHS/ZF stuff is "good enough" but once you experience what a good damper can do for a car,'s behavior you never want to go back. Better ride, better handling, better stability over big hits and dips, everything is just better. And you don't have to stick super stiff springs on the car to reap most of the benefits of aftermarket suspension. Yeah the much stiffer (300% stiffer than stock is the norm for the front, 50% stiffer in the rear) springs make the car handle better on the track and are nicer to tires, but using conservative springs with good dampers is the best way to make the car awesome all the time.

I'm 90% there on picking up MCS 2-ways, appreciate the write-up!!

For a DD what spring rates would you go with?

[MasterP]

Originally Posted by ///Mobbin

I'm 90% there on picking up MCS 2-ways, appreciate the write-up!!

For a DD what spring rates would you go with?

It's not the rates that matter - it's the shocks for DD use.

I could DD my E92 and I'm at 896F/1008 (16K/18K) and my ride is firm but doesn't crash over bumps. AST 5300 doubles with remotes and I had the valving set for my rates.

You want the right spring length for the ride height you'll be using also. I prefer mixing mains and tenders vs just using a single main. Everyone has a different opinion on this.

I don't actually DD (solid diff/trans/engine mounts) it but I do drive it to the track and back and for track upkeep I can't or don't want to do myself.

[///Mobbin]

Originally Posted by MasterP

It's not the rates that matter - it's the shocks for DD use.

I could DD my E92 and I'm at 896F/1008 (16K/18K) and my ride is firm but doesn't crash over bumps. AST 5300 doubles with remotes and I had the valving set for my rates.

You want the right spring length for the ride height you'll be using also. I prefer mixing mains and tenders vs just using a single main. Everyone has a different opinion on this.

I don't actually DD (solid diff/trans/engine mounts) it but I do drive it to the track and back and for track upkeep I can't or don't want to do myself.

Thanks for the input, any idea if MCS or JRZ will set the valving for the spring rates?

[dogbone]

Originally Posted by ///Mobbin

Thanks for the input, any idea if MCS or JRZ will set the valving for the spring rates?

In general, JRZ does not keep pre-assembled suspension packages laying around on a shelf waiting for an order. Each purchase is custom made to order in Holland. They can set things up like valving, spring rates, camber plates, length of remote oil lines, whether you have quick disconnects in the rear, etc., however you ask. Now maybe some large US vendor could purchase like 10 generic sets that would be pretty much fine and put them on a shelf so you can get them real quick, but I would not normally buy JRZ that way. I would be patient and get what I want.

It's the same with an OS Giken diff. You can purchase a physical unit that is generically setup and shipped from Turner. Or, you can purchase a unit through Turner and pay an extra $100 for a fully custom diff setup that is setup specifically to your car and is shipped from OS Giken's Los Angeles shop. You actually have a conversation with the OS Giken techs to tell them about your car--the weight, power, tires, tracks you go to, aero, driving style, etc. I did the latter and it was great.

These are boutique purchases. Get boutique setups!

[///Mobbin]

Originally Posted by dogbone

In general, JRZ does not keep pre-assembled suspension packages laying around on a shelf waiting for an order. Each purchase is custom made to order in Holland. They can set things up like valving, spring rates, camber plates, length of remote oil lines, whether you have quick disconnects in the rear, etc., however you ask. Now maybe some large US vendor could purchase like 10 generic sets that would be pretty much fine and put them on a shelf so you can get them real quick, but I would not normally buy JRZ that way. I would be patient and get what I want.

It's the same with an OS Giken diff. You can purchase a physical unit that is generically setup and shipped from Turner. Or, you can purchase a unit through Turner and pay an extra $100 for a fully custom diff setup that is setup specifically to your car and is shipped from OS Giken's Los Angeles shop. You actually have a conversation with the OS Giken techs to tell them about your car--the weight, power, tires, tracks you go to, aero, driving style, etc. I did the latter and it was great.

These are boutique purchases. Get boutique setups!

Interesting how customizable both of these can be, thank you for the info. It looks like I have some more research to do!

[MasterP]

Originally Posted by ///Mobbin

Thanks for the input, any idea if MCS or JRZ will set the valving for the spring rates?

I'd know what direction i would be going before picking rates and valving. Sometimes you get lucky and your base rate and valving has enough range you can go up and down rates marginally without a need to revalve. I timed my recent rate change and revalve with my rebuild and overhaul.

If you're using DOT R Comps like NT01 and R888/R you don't need the higher rates you could use with DOT slicks, and Full slicks. factor in if your going to use aero or not and that also plays into the spring rates you go with. Sway bars and where you like to run them is another element. I prefer higher spring rate to running the bars stiff and using the sway bars as a fine adjustment.

In the high end shock game custom or to your spec is the way to go. Contact inertia Laboratory. they're in dallas and they stock and service JRZ, MCS, etc. They already have a database of customers so they may already have a recommendation based on your setup and preferences.

[SYT_Shadow]

Contact a shop who really knows what they're doing, like BW, and who sells both setups.

I'm considering selling the JRZ 2WNR I have sitting in a box and buying the MCS 2WNR setup instead

My JRZ spring rates are 600/800. The MCS are 600/900 or 700/1000 for a more track oriented setup.
700/1000 sounds like a lot for the street, but I do not drive my track car on the street except to go to the track. Race seats are too uncomfortable for any realistic DD activity



By the way OP, my 2013 ZCP EDC also feels very good at the track, but real track suspensions have 2-3x stiffer springs and shocks that can handle those rates, so it must make a massive difference

Like the BBK, I don't think most of the people equipped with 'coilovers' are making good use of them. You can be really fast with stock suspension, but a good driver will be faster in a car with good suspension