[DrPancakes]

Hi all

First post for me, but I've been looking through the suspension forums for a while now. I was wondering if anyone provide some insight into picking the right coilover. I have a 340i xDrive so I'm limited in my selection.

A little bit about my driving:
The 340i is my daily driver. I just got into HPDE due to a recent move, and I can see myself attending 5 HPDE a year since there's 2 repaved HPDE tracks nearby. I'll also probably participate in some autocrossing. As for local commuting, the roads in Michigan are bad, but tolerable. There are the occasional ninja potholes where my current suspension will bottom out. I also walk to work so I don't drive that much each year. My thoughts on my stock EDC suspension are that its comfortable, but I could easily drive with a stiffer setup.

What I'm looking for:
I'd like to invest into something that can handle the track well, and exceeds my skill level as a novice and intermediate driver. I obviously won't be getting into wheel-to-wheel racing, but I do intend to improve my skill and lap times whenever I am at an event. I may participate in some solo time attack events (e.g. autocross), but that'd be about it.

The coilover I'm most interested in is the KW V3. I've seen some debate between the Bilstein B16s and KW V3s, mostly centered around subjective stiffness, and linear vs progressive springs. Does it really make a perceivable difference for a novice/intermediate driver? I'm assuming I could just switch out the stock springs with Swift springs. Lastly, for those with Bilstein B16 and KW V3 coilovers, did you ever feel like you needed something better at HPDE? I'd like to purchase something that I won't be selling off in 1-2 years because they are a limiting factor (that's the impression I got from coilovers like BC Racing). I'm also worried that the sellers market for xDrive suspension components is limited.

I know this is all relative, which has been the troubling part. On the F80 forums, KW V3s seem to be the entry coilover, while TC Kline, AST and AC Schnitzers seem to be the norm. I can't afford any of those...

[marcthedark]

Look into the MSS Kit (Street or Race) as it might be a good compromise for your needs as it will improve the daily and the track experience > Win - Win
https://mss.company/
If after years of experience you grow out of the suspension set up (after doing control arms etc.) then maybe upgrading the adaptive to Bilsteins would do the trick (or Oehlins if you can get by without adaptive)

[FaRKle!]

Originally Posted by DrPancakes

The 340i is my daily driver.

I'd like to invest into something that can handle the track well, and exceeds my skill level as a novice and intermediate driver. I may participate in some solo time attack events (e.g. autocross), but that'd be about it.

I know this is all relative, which has been the troubling part. On the F80 forums, KW V3s seem to be the entry coilover, while TC Kline, AST and AC Schnitzers seem to be the norm. I can't afford any of those...

With your goals in mind, I would really save up for a "by once cry once" setup (probably $3-4k range). I think even if you were going to go to a mid-level setup like KW V3 or B16 you'll end up selling them to upgrade to something else. If you're a person that likes to do their homework to know exactly what they're getting and how it affects their vehicle dynamics I can almost assure you of that.

Your first requirement means that you want a suspension that has smoothness, and composure. You want a coherent feeling vehicle that can handle the various road features experienced in daily driving. Your second requirement means you want a suspension that has excellent control, and that will help improve grip over what you have currently. It has to control quick body motions as well as be able to keep composure over curbing/rumble strips so you can use all the track. Lots of "stiff" setups with overdamped compression and/or rebound run into trouble when going over those features on the track. For example when I had EDC with Shockware the front compression was overdamped, so if I hit curbing on the inside apex of a corner it'd bounce me out.

Beware any mfg that won't provide you with the data to do your homework with. There are some really sloppy companies out there like Bilstein, who use the same springs/damper/coilover for a lightweight 228i as they do a heavy 340i GT. This is one of the most "trusting" customer bases that doesn't demand mfgs "prove it" before buying, and therefore companies can get away with a lot.

[DrPancakes]

Thanks guys. Do either of you have suggestions for xDrive coilovers, or know of manufacturers that are more likely to modify their RWD setup for AWD?

Based on another thread (below), it seems to me that the front perches sit higher on xDrives. Is this a result of the front axles shifting the coilover position out laterally? If so, would the solution be a shorter springs and a higher perch?

https://f30.bimmerpost.com/forums/sh....php?t=1614674

[Logicoeur]

KWs will fit even if they are for RWD. Just use xdrive endlinks. There have been a couple members here who have fitted them fine with that in mind. BC as well.

[B58 parts]

I have the v3s and they're pretty good. Handling wise they do well to expose the other glaring weaknesses of the chassis. The ride on the street is ok but certainly on the rough side. Your passengers won't exactly complain but they are maybe thinking about it. They are great on the highway and I'm at about 25k daily miles on them and still all good for the time being.

I run the bump full soft up front with the rebound around half way just where it doesn't feel bouncy. The rear about 3/4 stiff and it rotates a bit and is very predictable with the pedal down as awd usually is. Sway bars and a bushing kit kind of have to be done, it's a still a very floppy unconstrained car just now with stiff springs and good shocks.

I had the b16s and couldn't get the front low enough. They were stiffer and I'd say we're better build quality than the kws. No rebound adjustment which is actually very nice to have. I didn't want to spend 3 or 4k but wonder what those options would be like for a DD.

At 36k miles my brakes are nearing the end ... I wouldn't track with the grey msport brakes unless they are newer. They do kinda suck, "lack feel and have no initial bite". I think this car is just too heavy and sloppy to track at all.

[DrPancakes]

I've been looking around at other coilovers now, such as the TC Kline and MCS 2WNR. Any thoughts on buying V3s and switching to swift springs? Or are the dampers just not on the same performance level?

Its hard for me to gauge what is adequate still. I agree with having to only buy one set of coilovers, as opposed to repeatedly buying/selling marginally better products. Would the benefits of a TCKR DA or MCS 2WNR be appreciated by a novice driver?

Originally Posted by YuminNuman

I have the v3s and they're pretty good. Handling wise they do well to expose the other glaring weaknesses of the chassis. The ride on the street is ok but certainly on the rough side. Your passengers won't exactly complain but they are maybe thinking about it. They are great on the highway and I'm at about 25k daily miles on them and still all good for the time being.

I run the bump full soft up front with the rebound around half way just where it doesn't feel bouncy. The rear about 3/4 stiff and it rotates a bit and is very predictable with the pedal down as awd usually is. Sway bars and a bushing kit kind of have to be done, it's a still a very floppy unconstrained car just now with stiff springs and good shocks.

I had the b16s and couldn't get the front low enough. They were stiffer and I'd say we're better build quality than the kws. No rebound adjustment which is actually very nice to have. I didn't want to spend 3 or 4k but wonder what those options would be like for a DD.

At 36k miles my brakes are nearing the end ... I wouldn't track with the grey msport brakes unless they are newer. They do kinda suck, "lack feel and have no initial bite". I think this car is just too heavy and sloppy to track at all.

Have you ever tried your on the track? How did they hold up? I have the THP which came with the M-sport brakes (same m-performance 370 mm fronts though). Didn't experience any brake fade at the track. Runflat tire overheating and decreased traction are my current limitations. I'll likely get new tires and wheels next year.

[FaRKle!]

Would you be interested in a bespoke tuned suspension setup that was priced in the same range ($2-3k) as the B16 and V3s? If so, I'd go with a Fat Cat Motorsports stage 2 build.

[skier_du]

Originally Posted by DrPancakes

I've been looking around at other coilovers now, such as the TC Kline and MCS 2WNR. Any thoughts on buying V3s and switching to swift springs? Or are the dampers just not on the same performance level?

Its hard for me to gauge what is adequate still. I agree with having to only buy one set of coilovers, as opposed to repeatedly buying/selling marginally better products. Would the benefits of a TCKR DA or MCS 2WNR be appreciated by a novice driver?

Have you ever tried your on the track? How did they hold up? I have the THP which came with the M-sport brakes (same m-performance 370 mm fronts though). Didn't experience any brake fade at the track. Runflat tire overheating and decreased traction are my current limitations. I'll likely get new tires and wheels next year.

It doesn't appear the TC Kline makes coil overs for xDrive. For the most part, if a kit isn't for the xDrive, I wouldn't recommend it. It is possible, I did in my e90 with a BC set, but xDrive has shorter shock bodies in the front. This means if the coil over isn't designed with this in mind, you won't get much suspension travel, and that effects ride quality and performance in a negative way. Also, they are (I believe) based on a Koni shock. Or at least they used to be. Koni rides great and performs well. KW is a similar shock design to Koni as well. They also ride similar to Koni. More compliment, while still being firm and controlling suspension movement well.
I have KW V3 on my car and I'm very happy with them. The dual adjustment is very handy to dial in the suspension according to how you want it and use. I track my car several times a year. I've found them to be comfortable on the street, yet fairly firm for the track. If you're hardcore at the track, they may not be enough. You should be able to upgrade to Swift springs. I haven't really heard of it on f series. There may be people that have done it. I've been contemplating it as well. It was common on the E9x series.
However, if MCS has a set that works with xDrive, they're in another level of shock/strut design. More high end and Motorsport derived.
Having had a fair amount of seat time in this car, I thing it's a blast on the track. Few cars can be so great all year in all types of weather, and still blast it on the track. I can keep up with M cars, mustangs and other cars that my 335i xDrive is not thought to be in the same league as. Oh, and brakes are strong. I only have the 340 grey calipers. If your brakes don't feel strong on the track, it may be your pad compound and/or not enough cooling. Bite on the street is definitely a pad compound thing.

[B58 parts]

I haven't tracked the car, it feels too sloppy to me still and wouldn't stack up all that well against other cars I've ran in the past.

More hp for the straight but that's it, so many lighter cars will be all over me in the braking zones, and mid corner my side mirror is touching the ground. I do plan to I just want to be more confident in it first. And I gotta buy a new friggin helmet.

The v3s are a great step forward but the rest of the stock chassis just isn't all there. It doesn't feel point and shoot. But it does have a ton of grip and is a blast when building momentum.

[eleven11]

Check out the KW DDC option, if you're not familiar. I have them on my F31, but I don't track and have it way too low to truly appreciate the capabilities. From my understanding, it's similar to the KW V3. However, it connects directly to the EDC controls. So, it will stiffen the dampers from within the cabin (same rocker you're already using - Comfort, Sport, Sport+). Height is adjustable on the outside. Not the best track option, but a solid daily driver/track combo.

https://www.kwsuspensions.net/products/coilovers/ddc

[cfm56d7b]

Originally Posted by eleven11

Check out the KW DDC option, if you're not familiar. I have them on my F31, but I don't track and have it way too low to truly appreciate the capabilities. From my understanding, it's similar to the KW V3. However, it connects directly to the EDC controls. So, it will stiffen the dampers from within the cabin (same rocker you're already using - Comfort, Sport, Sport+). Height is adjustable on the outside. Not the best track option, but a solid daily driver/track combo.

https://www.kwsuspensions.net/products/coilovers/ddc

KW offers 2 kinds of DDC coilovers: DDC with a dedicated control unit and DDC Plug and Play which use existing Adaptive suspension ECU - literally plug and play. Both are available for your vehicle.

[DrPancakes]

Originally Posted by FaRKle!

Would you be interested in a bespoke tuned suspension setup that was priced in the same range ($2-3k) as the B16 and V3s? If so, I'd go with a Fat Cat Motorsports stage 2 build.

I'll take a look. You wouldn't happen to know which Bilstein shock he typically uses?

Originally Posted by skier_du

It doesn't appear the TC Kline makes coil overs for xDrive. For the most part, if a kit isn't for the xDrive, I wouldn't recommend it. It is possible, I did in my e90 with a BC set, but xDrive has shorter shock bodies in the front. This means if the coil over isn't designed with this in mind, you won't get much suspension travel, and that effects ride quality and performance in a negative way. Also, they are (I believe) based on a Koni shock. Or at least they used to be. Koni rides great and performs well. KW is a similar shock design to Koni as well. They also ride similar to Koni. More compliment, while still being firm and controlling suspension movement well.
I have KW V3 on my car and I'm very happy with them. The dual adjustment is very handy to dial in the suspension according to how you want it and use. I track my car several times a year. I've found them to be comfortable on the street, yet fairly firm for the track. If you're hardcore at the track, they may not be enough. You should be able to upgrade to Swift springs. I haven't really heard of it on f series. There may be people that have done it. I've been contemplating it as well. It was common on the E9x series.
However, if MCS has a set that works with xDrive, they're in another level of shock/strut design. More high end and Motorsport derived.
Having had a fair amount of seat time in this car, I thing it's a blast on the track. Few cars can be so great all year in all types of weather, and still blast it on the track. I can keep up with M cars, mustangs and other cars that my 335i xDrive is not thought to be in the same league as. Oh, and brakes are strong. I only have the 340 grey calipers. If your brakes don't feel strong on the track, it may be your pad compound and/or not enough cooling. Bite on the street is definitely a pad compound thing.

Originally Posted by YuminNuman

I haven't tracked the car, it feels too sloppy to me still and wouldn't stack up all that well against other cars I've ran in the past.

More hp for the straight but that's it, so many lighter cars will be all over me in the braking zones, and mid corner my side mirror is touching the ground. I do plan to I just want to be more confident in it first. And I gotta buy a new friggin helmet.

The v3s are a great step forward but the rest of the stock chassis just isn't all there. It doesn't feel point and shoot. But it does have a ton of grip and is a blast when building momentum.

Looked more at MCS. Didn't realize pricing is the shock only.

I called KW in the meantime. I mentioned I was looking into the V3 for my daily and intended to use them for occasional track use. The tech suggested KW CS's instead due to accelerated degradation for the V3 from autocross. Then they realized they didn't sell any for xDrive. At this point I asked how many track days per year is tolerable for the V3. Apparently 0. The V3 is a street performance coilover only. Kind of bummed. I was under the impression the construct was similar to the clubsports (aside from valving and spring rates). Make also me wonder how much life my OEM suspension really has left. They already have 53k miles on them.

I emailed TC Kline and AST to see if their suspensions work with xDrive. The AST 5100 looks more promising to me with their modular design. I guess I'll look at the Bilstein Clubsports at this point as well. Anyone have any experience with these?

The 340i felt pretty capable to me during the HPDE. My biggest gripe was the steering felt vague. I was hoping some coils and maybe new bushings would help with.

[Logicoeur]

I'm surprised no one has mentioned Fortune Auto 500s yet. They are well revered in the JDM world, and are a bit cheaper than KW street comfort. You can customize them as well. Camber plates and swift springs are standard with them. They have them in varying x-adjustable shocks as well as 100% race ready inserts. I would give them a look.

https://shop-fortune-auto.com/produc...ries-coilovers

[skier_du]

From what I've researched, the design of the KW club sport is very different from the V3. They are designed to last longer in the auto-sport area and perform at a higher level. However, just because the V3 go on track doesn't mean they'll fall apart. I think the potholes around the NYC area will do far more damage than half a dozen track weekends a year. Plus I've spoken to other people who have them on their street cars and also tracked the V3 occasionally. They loved the V3 for its all around performance. Personally, I'm not looking to I get 5-10 years out of them. More like 2-3 and I'd be happy. Living where I do most shocks don't last longer than that with no track time. Better part of a year and they still ride great so far.
Comes down to budget and desired use. If you have the budget and the patience to wait, some of the higher end companies will build a set for the xDrive and your desired us. I choose the V3 because they were the best all around option without having to wait months and at a reasonable price. Also I don't like the ride of the high pressure Bilstein shocks (they were one of the only other decent choices without paying twice as much). Not to mention there really just aren't as many xDrive options at the moment.

[Logicoeur]

The clubsports also have an external reservoir to keep the shock oil temps down. Else those seals will go quick. If you are really adamant, BC makes one, but never did for the f30. They should be able to custom make you a set. Same with Fortune Auto if you give them a call.

This is also the first I've heard that the V3 can't be taken on the track. Why would you need 2 ways adjustable shocks just for the street???

[skier_du]

Originally Posted by Logicoeur

The clubsports also have an external reservoir to keep the shock oil temps down. Else those seals will go quick. If you are really adamant, BC makes one, but never did for the f30. They should be able to custom make you a set. Same with Fortune Auto if you give them a call.

Fortune Auto might do it. I called them when I was looking for coil overs. They don't make them for xDrive and don't recommend using their RWD sets for the awd. They might make some if someone sends them measurements or can bring their car to them to be a Guinea pig. I've had BC coil overs before. They're ok. But not great either. KW and Bilstein are major steps up as far as shock and valving design go.

[Logicoeur]

Originally Posted by skier_du

Fortune Auto might do it. I called them when I was looking for coil overs. They don't make them for xDrive and don't recommend using their RWD sets for the awd. They might make some if someone sends them measurements or can bring their car to them to be a Guinea pig. I've had BC coil overs before. They're ok. But not great either. KW and Bilstein are major steps up as far as shock and valving design go.

Shit. I didn't notice they weren't for xdrive. I was seriously considering them for a set. I've done BCs before with swift. They weren't bad and I was pretty low in that Audi. But I had gone from stock, to $400 FK coilovers, to BC+Swift with new lower arms and adjustable upper arms. It was a huge jump in comfort in comparison.

[FaRKle!]

Originally Posted by DrPancakes

I'll take a look. You wouldn't happen to know which Bilstein shock he typically uses?

Shaikh can work with just about any monotube Bilstein. So you can buy a new/used set off B6, B8, B14, B16, or H&R coilovers (Bilstein is their OEM). If a set of used B14s is going for $700 or less on these forums (which isn't too uncommon) that's a great starting point for a donor set.

Bilsteins are well built with good materials and from the get go have a digressive piston. You want a digressive damping curve to avoid having too high compression/rebound forces at high speed. Lots of companies advertise "digressive piston" or "linear piston" because it "sounds impressive" and customers don't know what it actually means. There isn't really any reason to go with linear pistons.

One thing you will want to do is your homework on spring rates and frequencies. I think targeting a 1.5-1.6Hz front (and appropriate rear frequency to achieve fast settling/flat ride) is probably a good choice. Of course if you want to go more "racecar" you can go higher. Check out Shaikh's youtube channel (Suspension Truth) for a wealth of information on suspensions.

With some of the options you've been talking about, it seems like an FCM stage 3 build might even be in your budget...

Originally Posted by Logicoeur

I'm surprised no one has mentioned Fortune Auto 500s yet. They are well revered in the JDM world, and are a bit cheaper than KW street comfort. You can customize them as well. Camber plates and swift springs are standard with them. They have them in varying x-adjustable shocks as well as 100% race ready inserts. I would give them a look.

https://shop-fortune-auto.com/produc...ries-coilovers

I looked into them when I was considering suspensions. I think their "customization" is pretty limited, and the fact that they recommended the exact same spring rates for the wagon as the sedan when I submitted a custom inquiry said to me they don't know this platform very well. Heck, they even recommend the same spring rates for 6cyl and 4cyl models... When I did a frequency analysis on their setup not that long ago for a 340i they had some stupid freq imbalance with like 2.35Hz front and 1.75Hz rear. That's going to require overdamping to prevent pitch.

[Logicoeur]

Originally Posted by FaRKle!

Shaikh can work with just about any monotube Bilstein. So you can buy a new/used set off B6, B8, B14, B16, or H&R coilovers (Bilstein is their OEM). If a set of used B14s is going for $700 or less on these forums (which isn't too uncommon) that's a great starting point for a donor set.

Bilsteins are well built with good materials and from the get go have a digressive piston. You want a digressive damping curve to avoid having too high compression/rebound forces at high speed. Lots of companies advertise "digressive piston" or "linear piston" because it "sounds impressive" and customers don't know what it actually means. There isn't really any reason to go with linear pistons.

One thing you will want to do is your homework on spring rates and frequencies. I think targeting a 1.5-1.6Hz front (and appropriate rear frequency to achieve fast settling/flat ride) is probably a good choice. Of course if you want to go more "racecar" you can go higher. Check out Shaikh's youtube channel (Suspension Truth) for a wealth of information on suspensions.

With some of the options you've been talking about, it seems like an FCM stage 3 build might even be in your budget...

I looked into them when I was considering suspensions. I think their "customization" is pretty limited, and the fact that they recommended the exact same spring rates for the wagon as the sedan when I submitted a custom inquiry said to me they don't know this platform very well. Heck, they even recommend the same spring rates for 6cyl and 4cyl models... When I did a frequency analysis on their setup not that long ago for a 340i they had some stupid freq imbalance with like 2.35Hz front and 1.75Hz rear. That's going to require overdamping to prevent pitch.

Well a lot of these manufacturers do the same, with little to no detriment to ride quality. Why not just order the springs you want instead? They provide that option. I, also, dont doubt that if they were a popular option here, and got many custom orders they'd have the data to suggest better spring rates for people, else they'd have to do the work upfront themselves. They're a lot more popular in the jdm world than in Bavaria, so it makes fiscal sense to not make the investment upfront, here . In any case, they're still a good option if you know what you are doing with the customizations. If only someone in VA could be a testrat for a week or two lol. I'd also tell them that KW shocks, and BC shocks fit both rwd and xdrive without hitting anything in use. Those would be good measurements to work off of.

[DrPancakes]

Originally Posted by Logicoeur

KWs will fit even if they are for RWD. Just use xdrive endlinks. There have been a couple members here who have fitted them fine with that in mind. BC as well.

Originally Posted by Logicoeur

The clubsports also have an external reservoir to keep the shock oil temps down. Else those seals will go quick. If you are really adamant, BC makes one, but never did for the f30. They should be able to custom make you a set. Same with Fortune Auto if you give them a call.

This is also the first I've heard that the V3 can't be taken on the track. Why would you need 2 ways adjustable shocks just for the street???

Probably has to do with their lifetime warranty. I'm still considering the V3s, but looking around a bit more.

Originally Posted by FaRKle!

Shaikh can work with just about any monotube Bilstein. So you can buy a new/used set off B6, B8, B14, B16, or H&R coilovers (Bilstein is their OEM). If a set of used B14s is going for $700 or less on these forums (which isn't too uncommon) that's a great starting point for a donor set.

Bilsteins are well built with good materials and from the get go have a digressive piston. You want a digressive damping curve to avoid having too high compression/rebound forces at high speed. Lots of companies advertise "digressive piston" or "linear piston" because it "sounds impressive" and customers don't know what it actually means. There isn't really any reason to go with linear pistons.

One thing you will want to do is your homework on spring rates and frequencies. I think targeting a 1.5-1.6Hz front (and appropriate rear frequency to achieve fast settling/flat ride) is probably a good choice. Of course if you want to go more "racecar" you can go higher. Check out Shaikh's youtube channel (Suspension Truth) for a wealth of information on suspensions.

With some of the options you've been talking about, it seems like an FCM stage 3 build might even be in your budget...




I looked into them when I was considering suspensions. I think their "customization" is pretty limited, and the fact that they recommended the exact same spring rates for the wagon as the sedan when I submitted a custom inquiry said to me they don't know this platform very well. Heck, they even recommend the same spring rates for 6cyl and 4cyl models... When I did a frequency analysis on their setup not that long ago for a 340i they had some stupid freq imbalance with like 2.35Hz front and 1.75Hz rear. That's going to require overdamping to prevent pitch.

I've looked more at Fat Cat, and it is an interesting option. My only concern is he's in California. Not sure how easy it would be to setup the dampers properly from across the country. Still reading through his site though.

I contacted fortune auto. Doesn't sound like they're going to make an F30 xDrive system anytime soon. TC Kline might be able to make a custom set. Guess I'll be doing more research before I commit to anything soon.

[FaRKle!]

Originally Posted by DrPancakes

I've looked more at Fat Cat, and it is an interesting option. My only concern is he's in California. Not sure how easy it would be to setup the dampers properly from across the country. Still reading through his site though.

It's really not an issue. Shaikh has done lots of setups for people he's never met in-person. The only extra logistics to work out are shipping your dampers (and maybe springs) to/from him. If the springs have known rates, they likely don't need to be sent.

Some "pre-work" that you'd normally have to do (like getting motion ratios and measurements) are already done for you from my and other F8x/F2x vehicles Shaikh's done. For vehicle weight and distribution, those figures are published (and part of his info form asks how much driver weight to expect and if there's typically more people/load that needs to be considered too).