YCW Coilovers - Review

[bNks334]

YCW Engineering has been promoting one of their latest developments for the E9x/E8x, Coilovers! Although at first the name may not sound all that familiar, YCW is the parent company of MFactory. MFactory is a brand that has continuously filled gaps in the BMW market with high quality products. They utilize in-house engineering and machining to deliver tailored products at an affordable cost all while working WITH the community.

YCW released their coilovers for multiple platforms simultaneously. Positive reviews are coming in from the BRZ/FRS, Focus ST, 350z, and many other forums!

Link to the official product page: http://store.ycwengineering.com/cata...no/YCW-REF-E87

Key features:
These coilovers provide many desirable features that in my eyes separates them from just about anything close in price:
• Front - Independent height and spring adjustable
• True spherical (pillowball) top mount replaces OE mounts
• Radial spring perch allows spring to spin freely (bind free when steering)
• Integrated camber plate reduces stack height vs adding an aftermarket plate
• Separate Camber (3.5*) and Caster adjustment
• Optional custom spring rates
• Digressive damping
• Meaningful damping adjustment (7 levels)
• Shock covers!
• Adjustable End-links
• estimated min. Front lowering: 40mm with a 4k spring or 7-10mm with a 6k spring vs Msport ride height*****
• estimated min. Rear lowering: 30mm with a 12k spring or 10mm with a 16K spring vs Msport ride height*****

***** resulting ride height will also depend on spring preload and length!!



Unboxing:
The coilovers arrived within a few days of shipping from YCW's west coast warehouse and distribution center. They came well packaged and protected from any damage that could possibly occur during shipping. All aspects were definitely covered in this regard:


Installation and Setup:
The coilover pieces came packaged and assembled as they are to be installed on the car.


Feel free to reach out, or post here, if you need any help. There are plenty of resources already available that can give you a general idea on how to install coilovers:

Tips:
• There is no need to remove the cowl or the strut bar. Simply remove the Torx bolt (E14 Or 11mm) and push the bar out of the way to access the top mount bolts (3x 10mm stock and 3x 12mm YCW).
• Make sure you have an 18mm socket and wrench (ratcheting preferred) to loosen the bolt that clamps the strut into the knuckle
• Use two 3/8” drive bits/adapters to spread the knuckle and free the strut
• Protect your fender with tape (yes you’ll end up chipping paint trying to get the OE struts out)
• Cut the wheel all the way to the opposite direction you’re working on to ease removal of OE struts
• Loosen lower control arms at chassis if you still need more clearance to get the OE strut out. Base suspension requires doing this, but sport suspension should come out without too much fuss. Always re-torque bushing type control arms AT RIDE HEIGHT.
• Have more than one jack handy to line things back up and support the knuckle as you work
• You get adjustable endlinks with the coilovers. Endlinks need to be adjusted as you lower your ride height. The sway bar tabs should be kept in the same orientation to the ground as they were in stock form, or close to it. This should be done with the car sitting at ride height (ramps help here). The sway bar mounting tab will point at something close to 225* or so.

Front:
Use some common sense when installing... things can really only fit together one way. I don’t remember if the left/right front struts were labeled, but the swaybar mounting tab will be in the wrong location if you try to install the struts on the incorrect side. I put 1/4" of preload (spring length measures 6.75") on the spring to keep it tight under droop travel. Springs also lose a bit of height over time. With a 6k front spring, rebound damping feels good to me at about 4/7 - 5/7.

Take note of the camber plate orientation! It can only be mounted one way. My coilovers came with the camber plates installed on the wrong side. It only took a few seconds to swap the plates before installing. i maxed out at -2.6* with the camber plates on the wrongs sides. I can probably get close to -3.5* now. Currently set to -2.9*.


Tire fitment is TIGHT on the E82. In order to gain every mm of possible tire fitment, I found it necessary to upgrade to a custom SWIFT 180mm spring. This moved the spring perch up 40mm (220mm to 180mm spring) and I was able to fit my 17x9 wheels with 255 tires (ET38).


Rear:
Again, use common sense. Things look odd at first because the rear strut is inverted (upside down), but they can only be mounted one way!

I threaded in the rear strut approximately 35mm. This measures 9 1/4" as seen below. Bump travel and droop travel in the rear have been sufficient on the street at around 2” in each direction. With a 16k rear spring, rebound damping feels good to me at about 6/7. adjust the rear strut length to produce the desired bump/droop distribution. This is important to ensure the rear doesn't take a set on the bump stop too quickly in roll. When this happens, spring rate goes to infinate quickly and the rear will abruptly loose traction. Try to ensure the front will engage the bump stop first.


Here are some comparison shots between YCW and stock:


Rake:
A stock M-sport E82 (17" wheels) sits at 580mm in the front and 572mm in the rear. That creates a larger front wheel gap than the rear (visually) with the car appearing to sit almost .25” higher than the rear. However, actual rake, as measured by ground clearance at the side skirt, is around .25" (The rear sits slightly higher than the front despite the wheel gap showing the opposite). I maintained a small rake angle with my ride height settings. More rake can make the car more playful (rotate).

Ride height:
With the 4k 180mm SWIFT springs installed, ride height and suspension travel were a bit low for my taste and performance goals. I was able to get a maximum ground clearance up front of about 3.75". I then tried dialing in .5-.75" of pre-load up front to maintain a higher ride height which produced 4.25" of ground clearance up front. As mentioned in later replies below, I then added a spacer between the camber plate to add another .25" of ride height resulting in around 4.25." However, this resulted in coil bind over large potholes with the shorter 4K SWIFT 180mm springs installed. I ended up moving back to a 6K 180mm spring which got me to about 4.25" up front. I also lowered the rear of the car by reducing the rear spring load a bit from the pictured measurement. The car now sits at 4.25/4.625" for about 3/8" rake.

E82 stock ride heights:




Excuse the dirty car:



Things that can affect ride quality (bounce):

Spring rates:
One of the drawbacks of a McPherson front suspension is that the camber curve has a tendency to go positive as the chassis compresses under load (braking/cornering). One common way to offset this is by running a stiffer front spring rate to prevent the front suspension from ever compressing in the first place. While this may work, people tend to increase the front spring rate more than the rear. This upsets the natural frequency bias of the front and rear springs. This imbalance will not produce a flat ride when the car settles over bumps and the car will feel bouncy.This imbalance in spring rates will also affect handling behavior. Most notably, an increase in mid-corner under-steer.

Motion ratios and corner weight can be used to see how effective a spring is after taking suspension dynamics into consideration. The motion ratio of the E82/E90 dictates that the front and rear springs should be kept at close to a 1:3 ratio (this is over-simplified... not an exact ratio) to maintain wheel frequencies that will produce a flat ride. The further you deviate from this 1:3 ratio the more out of sync your springs will be as they oscillate (bouncy feeling) and the more specifically tuned your damping will need to be to handicap it.

Here is a spreadsheet I put together that you can use to get a starting point on how stiffly sprung you want your car to be. I personally shot for ~2Hz which is right around that 6k/18k mark. The spreadsheet also includes a tab that converts between kg/mm and lb/in. You’ll need to play with the sprung weight per corner for your particular vehicle to get ROUGH estimated spring frequencies and then further tweak the handling to your liking: https://drive.google.com/open?id=1VR...8UvX7BwusPj5yw

My personal take on it is that spring rates, and more importantly effective wheels rates, should generally be matched to the amount of grip your tires can generate as well. Total wheel rate should take into consideration all sources of stiffness from sway bars to binding suspension components. There is no sense in running race-car like spring rates of 2.5HZ+ if you drive around on 205/50 all-seasons. You simply won’t generate enough mechanical grip to make use of the springs. With that being said, your coilovers do restrict what rates you can run as well. If you go too soft, you'll run out of suspension bump travel. Go too stiff, and you'll have all bump travel and no droop travel (people lifting wheels).

A 6k/18k rate works well for these coilovers. I personally may move to 8k/20k in the near future to get a better bump/droop travel distribution and ride height adjustment (back to stock with 0 pre-load).

Rear shock mounts:
I strongly advise you take installing coilovers as an opportunity to overhaul your rear shock mounts. Here is a quick clip of how poorly the stock mounts handle stiffer spring rates:

You can see how much the stock mounts flex and I am only putting my body weight on the bumper. This will create a sensation of “bounce” since the motion is not being damped by the strut.

Pretty much the best/cheapest solution I found was MONROE shock mounts carried at a local auto parts store (Pepboys). These mounts are made of a hard rubber instead of foam the stock mounts are made of. I could instantly feel the difference in the strut damping once I got these mounts installed.

Monroe 907984 & 907985:


Tires:
Stiffer spring rates shift load to your tires which have a spring rate of their own. If you are going to up your springs rates significantly then you’re going to want to look at what tires you’re running and how stiff the sidewalls are. To demonstrate the effect of tire construction on suspension feel, here is a comparison video showing the sidewall deflection of a winter tire vs the sidewall deflection of a summer tire (200tw category). The soft sidewall winter tire results in a bouncy ride as the sidewall deflection is un-damped:

Winter Tires at 40psi:

Summer tires at only 30psi:

Alignment:
Alignment is going to be mandatory after installing coilovers. As with everything suspension related, alignment settings are a trade-off.

Camber: Front -1.5 to -3.5*
Rear -1.5* to -2*

Dialing in static negative camber up front helps offset the dynamic change in camber that occurs under load that I talked about earlier. This allows the car to corner flatter, but it also reduces straight line stability. Typically, you want a bit more camber up front (1* or so more) to help offset dynamic camber loss in ROLL due to the McPherson front strut. More front camber and less rear camber can help make the car a bit more playful. Personally, I think anything over 3* is excessive for a car that still sees street use. Most professional racing classes running full Pirelli slicks don't even allow more than -3-3.5* of camber. I also keep rear camber around -1.8* as a trade-off between cornering and reducing rear straight-line traction.

Toe: Front 0*
Rear .3* total (.15* per side)

Toe is the same deal as camber. Toe-in (positive toe) aids in straight line stability. Front toe-out can aid in agility/turn-in, but, the car will feel darty/twitchy on the street. Increased toe settings will increase the RATE of tire wear since the tires will be pigeon toed and "dragging" down the road. Again, it's a trade-off. The Mcpherson front suspension toes-out as it compresses, so, 0* up front works well for me as a dual purpose car. I kept a little toe-in (positive toe) in the rear for straight line stability and increased traction on acceleration. Slight front toe-in is best for street cars because of the stabilizing feel.

Caster: 7-8*

Caster is fairly high on a stock car as is. For that reason, I did not dial in any additional caster when installing the coilovers. Caster can also impact the camber curve as it alters the steering axis inclination. Alignment sheet came back at 7.3* with the camber plates pushed as far forward as they can go. Some of the affects of caster are steering effort and the wheels ability to return to center. Some people run closer to 10*.

Driving Impressions:
Just to note, these coilovers use linear springs and digressive damping. The ride on the street IS NOT going to feel like stock or some other coilovers. Coilovers in this price range, like ST, use progressive spring rates and standard damping.

These coilovers have been fantastic. Not only have they held up through their first Northeastern winter, but they provide a phenomenal improvement in performance and adjustability over a standard strut and spring pairing. The damping adjustment provides a wide range of rebound that adequately damps the 4/12k and 6K/16K springs rates I have tried. Resulting ride height and bump/droop travel distribution can be tweaked with slightly higher spring rates like 8k/20k. The bump stops are also very short and aggressive (stiff). They are a true bump stop and not a "spring helper" that stock struts use. I moved to E46 M3 bump stops to provide for a more progressive spring rate in roll rather than an abrupt increase in spring rate as the car took a set on the bump stops.

YCW has been excellent to work with throughout the test phase of the coilovers. I get a response within a few hours of emailing them. If anyone is considering buying any of the other mid-tier BMW suspensions, I highly suggest they look to YCW first and TRY to find a reason not to buy the YCW instead. You’ll be hard pressed to find another vendor that offers the same features and functionality for less.

[MFactory]

Thank you for the detailed writeup

[bNks334]

Latest Update:

Swapped out the SWIFT 4k springs (178mm) for SWIFT 6k springs (178mm). I also raised my front and rear ride height to 22". This provides for a more ideal suspension geometry. The rear A-arms sit just about parallel to the ground. The front-end could probably be lowered another 1/4" to get the front arms to be parallel to the ground. I also had it aligned to 2* negative camber.

Yes, I have wheels gaps still. It is unsightly, but that is where the suspension should sit.

The car plowed like a pig at an autocross yesterday. It was horrible. The pavement was also terrible and dirty, but that doesn't change that the car was ALL understeer. I had to use the throttle to power over-steer to get the car to rotate. I was essentially drifting around.

I conclude that a 27mm front sway bar combined with 6k front spring is just TOO STIFF relative to 16k rear springs and no rear sway bar. Maybe things will change when the temperature rises a bit more. It was cold at 50-60f and the RS3's weren't providing much traction. Again, that doesn't change that the car was plowing like crazy.

I was MUCH happier with 4k/16k. No, not an even F:R ratio (4k/12k), but the 27mm bar made up for the lower front roll resistance provided by the 4k springs. Problem with those rates were that my ride height was too low. Next weekend I'll try running with the front swaybar disconnected and see how it feels.

I also have the damping set to 7/7 front and 6/7 rear to reduce bounce on the street. Maybe I'll trying reducing front damping to something like 5/7 before I disconnect the swaybar.

Update: 7/7 front damping was indeed too stiff. I am at 6K/16k and 5/7 F 6/7 R right now. I'll remove the sway bar at the next event if the car still pushes.

[deesea]

Awesome. Thanks for the update. Been referencing this guide for some time.

How did the 4K pair with the 27mm H&R FSB? Primarily around the understeer department? Also curious what you mean by the 4K being too low. Did you mean that in order for the arms to be at their "optimal" position, the car had to be lower?

I've been thinking of upping to a E92 M3 hollow one (26.5mm all around). A slight increase in stiffness.

[John_01]

I suggest trying to lower the front ride height to get more grip and less understeer. It works because the front roll-center will become lower. Its kind of similar to using a softer front sway bar. It may also help you take a tighter line on corner exit because the front roll center is typically too high when the car pitches up as you accelerate.

The other solution may be changing to a E92 or E93 M3 Front sway bar. (as noted above )

[bbnks2]

This is my experience with setting up an E9x/E8x:

Both cars came with a soft setup off the factory floor for comfort. What's the quickest/cheapest solution? Throw some big sway bars on it! This is the first thing everyone seems to do including myself. This would be known as a soft spring big sway bar setup. There are positives and negatives of this setup which you can google yourself, such as ride over uneven pavement.

Problem #1: While changing the front sway bar is easy, you can't really get to the rear bar to upgrade it and dial things in with trial and error... So, it's not really feasible for a majority of us to use the soft spring big bar approach.

The solution would be to run a stiffer rear spring rate to achieve the same goal of reducing ride height changes under acceleration/braking and decreasing body roll. This leaves the stock swaybar in place with a stiff spring soft bar setup.

You would now have two different setups on the car. You would have a soft front spring (comparatively) and big front bar (such as 4k w/ 27mm) and a stiff rear spring with a soft bar (such as 16k w/ stock bar).

This created problem #2, ride quality. The front of the car was comparatively softer than the rear in all situations other than cornering. The front of the car dove under braking, and rose under acceleration, more than the rear.

Problem #3 was that a 4K spring didn't provide for much bump travel (1in or so vs 3" of droop travel) or ride height adjustment up front. The car sat pretty low at 21.25" or so going off memory until I put in a .25" spacer. Not bad, but not good for winter since this is my daily.

Given the above, I've moved toward a stiff spring small bar setup through my trial and error.

***** All the above is subjective and dependent on personal preference and other suspension factors such as tires... *****

Originally Posted by deesea

How did the 4K pair with the 27mm H&R FSB? Primarily around the understeer department?

That setup performed well. I really liked how the car handled with 4k/16K and the 27mm bar. I did not think it was an ideal setup though for some of the above reasons.

Originally Posted by deesea

Also curious what you mean by the 4K being too low. Did you mean that in order for the arms to be at their "optimal" position, the car had to be lower?

I had to raise the car up! The general consensus is that an ideal ride height puts the control arms parallel to the ground. Lowering any further is not functional. The car sat pretty low with the 4k spring. Moving to the 6K increased static ride height. This moved the shock into a more effective position improving available bump travel.

I am at 22" ride height now (E82) and this is how the rear arms sit:


I still scrape getting onto the alignment rack with this height. 21.25-21.5" looked fantastic (no wheel gap), but it was just too low. The lower arms were beyond parallel to the ground. The car also almost got stuck on the alignment rack at that height. I bottomed out on the side skirts.

Originally Posted by deesea

I've been thinking of upping to a E92 M3 hollow one (26.5mm all around). A slight increase in stiffness.

As stated previously, the 6k spring combined with a 27mm (solid) sway bar was too much even with 16k rear springs. The car pushed way more than expected. I may go back to the stock front bar since the 6k/16k rates I have now already results in a stiffer front (understeer) than rear.

My personal suggestion would be to stop throwing money at the car. What do you plan to achieve by running a stiffer front sway bar? I would choose a balanced spring rate like 5k/15k and then check tire wear! Still rolling over the side wall too much? Try bumping up tire pressure a few psi and maybe adding a bit more negative camber (2* or so works well). Still rolling over the sidewall too much (very unlikely)? Try running the slightly stiffer sway bar... I just happened to already have the 27mm bar installed from when I was on stock suspension and it actually helped reduce roll with those soft spring rates...

An E92 M3 bar is something like 7% stiffer than stock. A solid 27mm bar (H&R) is something like 52% stiffer. Huge difference between the two.

https://www.turnermotorsport.com/t-t...-e92-sway-bars

[bbnks2]

Originally Posted by John_01

I suggest trying to lower the front ride height to get more grip and less understeer. It works because the front roll-center will become lower. It’s kind of similar to using a softer front sway bar. It may also help you take a tighter line on corner exit because the front roll center is typically too high when the car pitches up as you accelerate.

The other solution may be changing to an E92 or E93 M3 Front sway bar. (As noted above)

I will definitely be going back to a stock bar and checking tire wear! I'll make adjustments from there to determine if I even need a bigger bar at all (unlikely).

22" ride height front and rear actually results in 3/8" or so of rake. I will be dropping the front down to 21.75" though to increase rake a bit more.

The car actually came stock with an 8mm higher front ride height than rear ride height which resulted in close to 0 rake to induce understeer (580F [22.8"]/572R [22.4"]).

[deesea]

Originally Posted by bbnks2

This is my experience with setting up an E9x/E8x:

Both cars came with a soft setup off the factory floor for comfort. What's the quickest/cheapest solution? Throw some big sway bars on it! This is the first thing everyone seems to do including myself. This would be known as a soft spring big sway bar setup. There are positives and negatives of this setup which you can google yourself, such as ride over uneven pavement.

Problem #1: While changing the front sway bar is easy, you can't really get to the rear bar to upgrade it and dial things in with trial and error... So, it's not really feasible for a majority of us to use the soft spring big bar approach.

The solution would be to run a stiffer rear spring rate to achieve the same goal of reducing ride height changes under acceleration/braking and decreasing body roll. This leaves the stock swaybar in place with a stiff spring soft bar setup.

You would now have two different setups on the car. You would have a soft front spring (comparatively) and big front bar (such as 4k w/ 27mm) and a stiff rear spring with a soft bar (such as 16k w/ stock bar).

This created problem #2, ride quality. The front of the car was comparatively softer than the rear in all situations other than cornering. The front of the car dove under braking, and rose under acceleration, more than the rear.

Problem #3 was that a 4K spring didn't provide for much bump travel (1in or so vs 3" of droop travel) or ride height adjustment up front. The car sat pretty low at 21.25" or so going off memory until I put in a .25" spacer. Not bad, but not good for winter since this is my daily.

Given the above, I've moved toward a stiff spring small bar setup through my trial and error.

***** All the above is subjective and dependent on personal preference and other suspension factors such as tires... *****



That setup performed well. I really liked how the car handled with 4k/16K and the 27mm bar. I did not think it was an ideal setup though for some of the above reasons.



I had to raise the car up! The general consensus is that an ideal ride height puts the control arms parallel to the ground. Lowering any further is not functional. The car sat pretty low with the 4k spring. Moving to the 6K increased static ride height. This moved the shock into a more effective position improving available bump travel.

I am at 22" ride height now (E82) and this is how the rear arms sit:


I still scrape getting onto the alignment rack with this height. 21.25-21.5" looked fantastic (no wheel gap), but it was just too low. The lower arms were beyond parallel to the ground. The car also almost got stuck on the alignment rack at that height. I bottomed out on the side skirts.



As stated previously, the 6k spring combined with a 27mm (solid) sway bar was too much even with 16k rear springs. The car pushed way more than expected. I may go back to the stock front bar since the 6k/16k rates I have now already results in a stiffer front (understeer) than rear.

My personal suggestion would be to stop throwing money at the car. What do you plan to achieve by running a stiffer front sway bar? I would choose a balanced spring rate like 5k/15k and then check tire wear! Still rolling over the side wall too much? Try bumping up tire pressure a few psi and maybe adding a bit more negative camber (2* or so works well). Still rolling over the sidewall too much (very unlikely)? Try running the slightly stiffer sway bar... I just happened to already have the 27mm bar installed from when I was on stock suspension and it actually helped reduce roll with those soft spring rates...

An E92 bar is something like 7% stiffer than stock. A solid 27mm bar (H&R) is something like 52% stiffer. Huge difference between the two.

https://www.turnermotorsport.com/t-t...-e92-sway-bars

Thanks for the detailed response. YCW also mentioned that with the 4K/12K set-up won't really need to run larger sway bars. I might still do a stiffer hollow bar (perhaps a hotchkis one) if I need it.

It's a double duty car, but I'd love to tighten up the car a bit more and eliminate a lot of the understeer I faced on my last track day...the car just ploughed forward on every corner.

[bbnks2]

Originally Posted by deesea

Thanks for the detailed response. YCW also mentioned that with the 4K/12K set-up won't really need to run larger sway bars. I might still do a stiffer hollow bar (perhaps a hotchkis one) if I need it.

It's a double duty car, but I'd love to tighten up the car a bit more and eliminate a lot of the understeer I faced on my last track day...the car just ploughed forward on every corner.

I know I provided a lot of info and it's hard to summarize the main takeaways.

The only time a bigger front sway is used to reduce understeer is if dyanmic camber loss is causing the front end to lose grip. A bigger sway increases roll stiffness (so does stiffer springs) and prevents camber change from occuring in the first place. This allows the tire to corner flatter therefore increasing front end grip and reducing understeer. Go too stiff and you'll just dial in understeer with the bar, as I've done.

First steps to reduce understeer before messing with the sway bars is to:

1) Stiffen spring rates but in a 1:3 ratio. Stiffer springs serve to increase roll resistance. Keeping the supension from compressing will prevent dynamic camber change from occuring during cornering and therefore increase front end grip by allowing the tires to corner flatter.

2) Square up your tires (reduces understeer caused by the staggered stock 225/245 setup)

3) Reduce front ride height relative to rear and aim for .5" - .75" of rake (reduces understeer dialed in from factory ride height of 580/572mm)

4) Dial in -1.5* to -2* static negative camber (offsets dynamic camber loss under cornering loads taht may still occur even with stiffer springs) and 0 toe up front (helps aid turn in vs running stock toe-in settings).

Doing the above should pretty much eliminate any understeer without needing different sway bars. Afterall, the car is already well balanced as is. Understeer is just dialed in by BMW through the above items (number 2-4).

[ianc]

Hey guys,

Nice thread and huge effort by bNks to start; thanks!

I'm interested in installing those Monroe strut mounts, but I can't think off the top of my head what's required there. I installed Koni sports and Eibach springs about six years ago, but haven't touched them since.

Do the rear shocks have to come out to install them? Can you give me a brief summary of the install procedure? Thanks!

Edit: - Found this thread over at E90 post which explains everything, so no need to bother...

http://www.e90post.com/forums/showth...=Monroe+907984

ianc