Went from Swift springs to stock ZCP

[strokemycocktus]

I have just returned to stock suspension setup and wanted to share some thoughts. I bought the car with Swift Spec-R springs and drove it like this for 3 months. I use my car as a daily to drive around town and for some small trips. It is a 2010 ZCP 6MT with EDC.
The main reason for changing the springs back to stock was the car height and problems with my garage driveway - I would scratch my chassis pretty bad every time, which eventually lead to damaged engine belly pan. If not this I probably wouldn't bother and just leave it as it is.
Most people install lowering springs to achieve a better look, and I agree - the car looks pretty damn good with no wheel gap both front and back.

However, I felt from the beginning that the car rides a bit strange. It felt very bumpy and on any uneven road it acted as if it had rubber balls instead of wheels with good suspension. It was hard to get good grip while accelerating in the first gears if the road wasn't perfectly smooth. It felt like the wheels would loose contact with the ground on any uneven surface. Not to mention the wheel hop which happened pretty often when launching the car (even from ~3k rpm).
The car felt very stiff, but it seemed it was just for the purpose of being stiff and nothing more actually, or maybe a way to prevent bottoming out of the dampers. It did not feel any more solid or planted nor did it handle any better than the stock setup.

After the stock springs were installed and the alignment was done, I felt the difference immediately. The car now is planted to the ground regardless the road conditions - slight bumps and holes do not cause half of the car to go airbourne. The front end grips much better, the turn in is better and the car is more predictible overall. It does feel softer, but handles better. I have launched the car a few times and the wheel hop seems to be gone as well. It grips from the 1st gear in WOT even if the road is wet (I am running Continental winter tyres 235 all around).
I think the major reason for this is that the dampers were designed to work at specific range, with specific spring rates and weight distribuiton, which all becomes upset when installing lowering springs, that are stiffer and lower the front more than the back (because wheel gap is bad).
I have seen opinions that lowering springs provide better handling without disturbing the ride comfort. I can believe it would not be much worse than the stock setup if you use the car for some weekend trips on perfectly smooth backcountry roads or on track. For a daily driver to use in a city with rather mediocre roads it is not going to improve anything and rather cause the car to loose contact with the ground more often, which is the opposite of good handling. The lower setup doesn't also seem to be something performance-oriented, as the GTS M3 is just 6mm lower in the front and 2mm lower in the back than the ZCP version, while most lowering springs are -15mm front and -9mm back vs ZCP.

Just wanted to share these observations, in case someone considered springs as a suspension mod rather than a visual mod.

[JsL]

Thanks for sharing that.

How many miles are on your car? It sounds like you may have a blown strut or worn out bushings in the rear. Of course, I'm not discounting your experience and you may drive on some pretty bad roads.

I drive on mediocre/bad roads and my Swift springs are fine. I do agree the ride is stiffer and big bumps seem to be at the stock strut's damping.

When I drive my car hard trough 1st and 2nd, I just get some spin and traction control light like crazy. With Dsc off, I get a lot of spin but no hopping. I'm running a VF620 kit.

[strokemycocktus]

Thanks for your feedback in this matter. I would like to compare my experience with these springs with other users. I definitely prefer my car in the stock zcp configuration, but why not compare some opinions here.
The car has 58k kilometers. The suspension was inspected 3 times during my 4-month ownerwship, first time was a pre-purchase inspection at the dealership (performed by a very professional technician btw), then i took it to the independent workshop i service my car at to have a closer look, and now the 3rd time when changing the springs. Everything is in perfect condition. The only part that needed replacement was the front damper mount bearing.
The roads at my place are quite bad. But regardless, i feel the car is more capable on smooth roads as well. As far as my experience goes, this M3 is my first sports car to be honest, but I have spent quite some time at the race track with my previous 325i on semi slics and ended up running decent laps, so I guess I know the basics.
Comparing grip between stock car and a vf620 can be hard, but isn't a FI car with lots of low end torque less prone to wheel hop? The way I see it is you just set your tires on fire when going wot in low gears, where my car still struggles for grip as it has a chnance to stick with stock power. Stiff springs definitely contributed to the hopping. Maybe solid subframe bushings would have solved the issue.

[b4hand]

I have swift springs but my car has 64k miles on it and it rides like crap. I am replacing them with a full JRZ/Hypercoil setup though.

[strokemycocktus]

64k miles isn't that much I think. Coilovers seem to be the way to go if you want to upgrade the suspension, so good choice I guess. At least I would consider it as the only proper way to lower a car, as it allows you to adjust damp and rebound rates.

[last1left]

Originally Posted by seevin

I have just returned to stock suspension setup and wanted to share some thoughts. I bought the car with Swift Spec-R springs and drove it like this for 3 months. I use my car as a daily to drive around town and for some small trips. It is a 2010 ZCP 6MT with EDC.
The main reason for changing the springs back to stock was the car height and problems with my garage driveway - I would scratch my chassis pretty bad every time, which eventually lead to damaged engine belly pan. If not this I probably wouldn't bother and just leave it as it is.
Most people install lowering springs to achieve a better look, and I agree - the car looks pretty damn good with no wheel gap both front and back.

However, I felt from the beginning that the car rides a bit strange. It felt very bumpy and on any uneven road it acted as if it had rubber balls instead of wheels with good suspension. It was hard to get good grip while accelerating in the first gears if the road wasn't perfectly smooth. It felt like the wheels would loose contact with the ground on any uneven surface. Not to mention the wheel hop which happened pretty often when launching the car (even from ~3k rpm).
The car felt very stiff, but it seemed it was just for the purpose of being stiff and nothing more actually, or maybe a way to prevent bottoming out of the dampers. It did not feel any more solid or planted nor did it handle any better than the stock setup.

After the stock springs were installed and the alignment was done, I felt the difference immediately. The car now is planted to the ground regardless the road conditions - slight bumps and holes do not cause half of the car to go airbourne. The front end grips much better, the turn in is better and the car is more predictible overall. It does feel softer, but handles better. I have launched the car a few times and the wheel hop seems to be gone as well. It grips from the 1st gear in WOT even if the road is wet (I am running Continental winter tyres 235 all around).
I think the major reason for this is that the dampers were designed to work at specific range, with specific spring rates and weight distribuiton, which all becomes upset when installing lowering springs, that are stiffer and lower the front more than the back (because wheel gap is bad).
I have seen opinions that lowering springs provide better handling without disturbing the ride comfort. I can believe it would not be much worse than the stock setup if you use the car for some weekend trips on perfectly smooth backcountry roads or on track. For a daily driver to use in a city with rather mediocre roads it is not going to improve anything and rather cause the car to loose contact with the ground more often, which is the opposite of good handling. The lower setup doesn't also seem to be something performance-oriented, as the GTS M3 is just 6mm lower in the front and 2mm lower in the back than the ZCP version, while most lowering springs are -15mm front and -9mm back vs ZCP.

Just wanted to share these observations, in case someone considered springs as a suspension mod rather than a visual mod.

Different shocks like bilsteins with the swifts would of worked well.

[Redd]

Car was over sprung. Really stiff springs really only work on perfect roads like the race track.

[Solo_M_Tech]

Im 30k miles on my H&R springs and ZCP shocks (116k on the car) and I don't have any of the issues noted in the OP's post. Car feels just as planted as the stock ZCP springs, just lower.

[benchan78]

while i haven't tried swift springs, i have had coilovers, and i found that when lowering the front too much, the front end wants to dive into any bumps/dips which results in a stiff and unstable ride. also, the braking is adversely affected because there's more weight transfer to the front and thus more brake dive.

i think we hear different opinions because we all drive on different quality roads. in area with lots of bumpy roads, this is really noticeable, but if driven on smooth roads, it's much harder to detect these effect on the chassis. i'm now using dinan springs with bilstein b6 edc shocks, and i find them to work pretty well. the dinan springs lower the car 10mm all around, without lowering the front too much.

[strokemycocktus]

Originally Posted by benchan78

i think we hear different opinions because we all drive on different quality roads. in area with lots of bumpy roads, this is really noticeable, but if driven on smooth roads, it's much harder to detect these effect on the chassis

That's probably the biggest factor here. I am sure I wouldn't really notice much if the roads in my whole country were not that crappy. Anyway, I will say it again, I like the car much much more with stock ZCP springs when it comes to handling, it has much more grip during turn in and in hard cornering. When I want it to be stiff as hell I just crank the EDC to sport which in ZCP locks the dampers 100% in the hardest setup.

Originally Posted by benchan78

i'm now using dinan springs with bilstein b6 edc shocks, and i find them to work pretty well. the dinan springs lower the car 10mm all around, without lowering the front too much.

I have checked these springs and this looks really good. Dinan definitely knows how to adjust the suspension for best performance, especially with their bump stop set. They lower the car 0,5" which is 12,5mm, but I gues this is over the standard M3, so basically their springs are about the same as the competition pack.
Are Bilstein B6 shocks an improvement over the stock BMW ones, or just a cheaper replacement?

[pbonsalb]

The stock shocks have very limited travel, so running shorter springs -- even soft ones -- without additional changes reduces the already limited travel. The changes people make compensate for most of the drop of mildly shorter springs, but cannot compensate for significantly shorter springs. The changes are cutting down the upper strut mount guide tubes and changing to E36M3 bump stops. I did both of these mods to run H&R mild springs.

The better approach, especially now that stock struts and shocks are 5-10 years old on these cars, is to change to Bilstein B6 or B8, with B8 being the better choice for shorter springs. Or, if you need to go even lower because you are already very fast on the track or just want to look cool, try coilovers since they preserve shock/strut travel.

I am now on Bilstein B8s -- bought a used set for $200 and think they are great. New strut mounts with full length guide tubes and the bilstein struts have internal bump stops so no changes there. With my mild H&R springs, I could have run B6, but the B8 were available. Some say the only difference is the B8 have slightly shorter internals and are designed for lowering springs, and that the valving is the same as the B6.

[strokemycocktus]

But those are for non-EDC cars right? I mean I know you can just shut the controller to have no errors, but the functionality is gone then anyway.
I have only seen B6 for EDC and they were priced at around 60% of the OEM cost. I am curious if they perform better than new OEM shocks. Plus how they would work with ZCP setup.

[Richbot]

GTS standard ride height isn't much lower because it's still a road car IMO, but it's on coilovers, see eg the M4GTS "track" configuration that is significantly lower

The hot ticket for performance is to get the car as low as possible while still maintaining compliance over bumps. The thing people continue to screw up is failing to damp and address travel appropriately, which is why dropping the car with no other changes usually means you're going to make the car worse

[Richbot]

Originally Posted by Redd

Car was over sprung. Really stiff springs really only work on perfect roads like the race track.

The swift springs are only about 80% stiffer than stock IIRC up front, and not much stiffer at all in the rear (in other words, not stiff enough to lower the car as much as they lower the car and still keep the suspension from hammering the bumpstops over every pebble) the problem when people report this kind of thing is usually the car was too low with no other changes and pummeling the bumpstops. No surprise going up 5/8" makes the car behave better when a ZCP car only has about 3/4" of bump travel to begin with before it starts touching the bumpstops...

EDIT: Yup, Front -1.0" drop, 279lbs/in; Rear -0.7" drop, 670lbs/in (from Swift's web marketing materials, ride height change for base car). That's about 99 lb/in more up front and 70 in the rear vs. stock. Smaller change in rate compared to, for instance, what is by all accounts a nice-riding setup on the Ohlins R&T (342 lb/in up front, 784 rear) for instance, but the Ohlins strust is easily adjusted to maintain bump travel.

I agree doing the B8's with some changes to bumpstops would probably make the Swifts work ok, I have a pair of the rears going on the car this winter to see how I like them

[benchan78]

I think the B6 EDC shocks perform similarly to the stock shocks, but they go better with lowering springs because the bumpstops are smaller on them, and so the car has more bodyroll if you keep stock springs on. if I could do it all over again, I would just keep everything stock, especially if you have the ZCP package. BMW knows how to tune their cars best.

[strokemycocktus]

Originally Posted by benchan78

if I could do it all over again, I would just keep everything stock, especially if you have the ZCP package. BMW knows how to tune their cars best.

My thoughts exaclty. That's what I did and I couldn't be happier with the setup. IMO it's either good coilovers or keeping everything stock. Bilstein dampers are probably a quality replacement and may work with lower springs, so could stock dampers with some mods (I read sth about e36 bump stops and cutting the mounts - sounds a bit ghetto to me), but I don't find it as good as a complex system that was designed together from the start.

[Z K]

Originally Posted by Richbot

The swift springs are only about 80% stiffer than stock IIRC up front, and not much stiffer at all in the rear (in other words, not stiff enough to lower the car as much as they lower the car and still keep the suspension from hammering the bumpstops over every pebble) the problem when people report this kind of thing is usually the car was too low with no other changes and pummeling the bumpstops. No surprise going up 5/8" makes the car behave better when a ZCP car only has about 3/4" of bump travel to begin with before it starts touching the bumpstops...

EDIT: Yup, Front -1.0" drop, 279lbs/in; Rear -0.7" drop, 670lbs/in (from Swift's web marketing materials, ride height change for base car). That's about 99 lb/in more up front and 70 in the rear vs. stock. Smaller change in rate compared to, for instance, what is by all accounts a nice-riding setup on the Ohlins R&T (342 lb/in up front, 784 rear) for instance, but the Ohlins strust is easily adjusted to maintain bump travel.

I agree doing the B8's with some changes to bumpstops would probably make the Swifts work ok, I have a pair of the rears going on the car this winter to see how I like them

+1

Any lowering on stock shocks means you're riding the bumpstops a lot. The stock suspension just doesn't have enough shock travel to allow for lowering.

Best bet is to use coilovers that have a reduced shock body length to maintain shock travel when lowering.

[derbo]

Out of curiosity did you perform an alignment on the swift before the swap?

[strokemycocktus]

No, but the car was aligned by the previous owner about a half year before i bought it. Wasn't done at the dealership though, and it was not as perfect as it is now comparing both alignment reports (one or two values were out of spec). But I am not sure if it is possible to properly align a car lowered that much, without further modifications.

[BOOF-M3]

Out of curiosity what is your month build on your car OP? You must have one of the earlier 2010 ZCP cars?

[strokemycocktus]

According to VIN info it's 06-2010, but all legal documents I have say 01.01.2011 lol. I don't really get this, as by the end of 2010 the car has visited the dealership twice and had some miles on it.

[pbonsalb]

Originally Posted by seevin

(I read sth about e36 bump stops and cutting the mounts - sounds a bit ghetto to me)

Very few people call Dinan’s mods “ghetto” — usually Dinan is pretty good on the engineering since it guarantees factory warranty