[Genericf30]

Hi All, I asked this in another thread. Anyone have thoughts on the level of comfort between the BC Coilovers and Koni Yellows with loweredEibach springs?

I am stuck in making my decision as both are around the same price. I don't know much about the BC Racing coilovers and the reviews for it seem all over the place. It seems to have adjustable dampers similar to the koni yellows, not sure how the springs compare to the eibachs and the advantage is the ability raising and lowering of the car. Anyone know how these would compare?

[FaRKle!]

Eibach springs + Koni Yellow dampers should be more comfortable. Eibach springs (166 lbs/in front, 491 lbs/in rear) are much softer than the BC kit (336 lbs/in front, 672 lbs/in rear), and the Eibach spring rates still maintain flat ride where the BC rates don't.

One downside to Koni Yellows is that their adjustability only changes the rebound damping and doesn't increase/decrease compression damping at all. The BCs should adjust both compression and rebound with each click, but you have no idea what force values you're actually setting them to (with Koni you can find the min/max, look for my thread on it).

Another thing to note is that Eibach's springs aren't really much different than the M-Sport springs that already come on the 335i spring rate wise.

[cfm56d7b]

Originally Posted by FaRKle!

Eibach springs + Koni Yellow dampers should be more comfortable. Eibach springs (166 lbs/in front, 491 lbs/in rear) are much softer than the BC kit (336 lbs/in front, 672 lbs/in rear), and the Eibach spring rates still maintain flat ride where the BC rates don't.

One downside to Koni Yellows is that their adjustability only changes the rebound damping and doesn't increase/decrease compression damping at all. The BCs should adjust both compression and rebound with each click, but you have no idea what force values you're actually setting them to (with Koni you can find the min/max, look for my thread on it).

Another thing to note is that Eibach's springs aren't really much different than the M-Sport springs that already come on the 335i spring rate wise.

Agree with FaRKle! advice. Well said.

[brigade24]

you can preserve factory ride frequency (flat ride) with BC racing with the correct spring rates which you can select when you order them. Its just that you may need to go stiffer than you'd like.

BC Racing can adjust the dampers (this is what i was told) for the spring rate you select. I think its good bang for the buck but it is certainly not the highest quality. I have been running my setup for almost 3 years and for the money, they are hard to argue with.

i am warning you now, BC Racing does not have the best customer service. If i were you, KW street comforts is where I would be looking if the car is strictly a street machine...bit more money but its good stuff...im assuming you only wanna do this once.

[Genericf30]

Hi Farkle - thanks for the the recommendation. I read that you can order the BC Coilovers in custom spring rates. If I have BC match the spring rates as you listed would I have a ride that is just as comfortable as the Eibach Springs and Koni Yellows? Just trying to weigh my options, having a hard time deciding between the two.

Originally Posted by FaRKle!

Eibach springs + Koni Yellow dampers should be more comfortable. Eibach springs (166 lbs/in front, 491 lbs/in rear) are much softer than the BC kit (336 lbs/in front, 672 lbs/in rear), and the Eibach spring rates still maintain flat ride where the BC rates don't.

One downside to Koni Yellows is that their adjustability only changes the rebound damping and doesn't increase/decrease compression damping at all. The BCs should adjust both compression and rebound with each click, but you have no idea what force values you're actually setting them to (with Koni you can find the min/max, look for my thread on it).

Another thing to note is that Eibach's springs aren't really much different than the M-Sport springs that already come on the 335i spring rate wise.

[Genericf30]

Brigade - yes you are right I only want to do this once. Did you go with BC Coilover custom spring rates or the one that they sell normally? Farkle mentioned the Eibach spring rates were actually lower so if I have them custom a lower spring rate would it be as comfortable as the Koni + Eibach setup? How do you like your BC Coilovers besides the bad support? Read some threads where they make clunking noises but wasn't sure how true it was. If you could go back would you chose I different option? Just trying to see if they are as bad as some threads make them out to be.

Also I did consider the KW Comfort option, but one it's quite a bit more and two they don't appear to make it for my year and model. I asked Mike from x-ph and he said they don't make it for a 2015 335i xdrive which is weird but I did read my model year was when they switched from the 3 bolt mounts to the 5 bolt mounts.

Originally Posted by brigade24

you can preserve factory ride frequency (flat ride) with BC racing with the correct spring rates which you can select when you order them. Its just that you may need to go stiffer than you'd like.

BC Racing can adjust the dampers (this is what i was told) for the spring rate you select. I think its good bang for the buck but it is certainly not the highest quality. I have been running my setup for almost 3 years and for the money, they are hard to argue with.

i am warning you now, BC Racing does not have the best customer service. If i were you, KW street comforts is where I would be looking if the car is strictly a street machine...bit more money but its good stuff...im assuming you only wanna do this once.

[alohasurftoad]

I think you'll regret getting bc. I havent seen many positive reviews of it, as well as their customer service already mentioned.

I'd do koni yellow or SA, lowered with mild or medium drop eibach springs, or shell out for KW V1

[FaRKle!]

Originally Posted by Genericf30

Hi Farkle - thanks for the the recommendation. I read that you can order the BC Coilovers in custom spring rates. If I have BC match the spring rates as you listed would I have a ride that is just as comfortable as the Eibach Springs and Koni Yellows? Just trying to weigh my options, having a hard time deciding between the two.

You can order them with different spring rates (the lowest they offer is 5kg/mm 280lbs/in), but their and your definition of "dampers are revalved for the springs" might be different... Unless you know the actual damping curve, you can't say a whole lot for comfort, or know the rebound bias.

I still don't think a BC setup with different spring rates will be quite as comfortable as a Koni. Being a monotube damper, most companies increase the gas force beyond what's necessary, and that hurts comfort. Twin-tube designs (like what Koni uses) don't need as high gas forces. Additionally, the higher BC spring rates naturally won't isolate as well as lower ones.

[brigade24]

Originally Posted by Genericf30

Brigade - yes you are right I only want to do this once. Did you go with BC Coilover custom spring rates or the one that they sell normally? Farkle mentioned the Eibach spring rates were actually lower so if I have them custom a lower spring rate would it be as comfortable as the Koni + Eibach setup? How do you like your BC Coilovers besides the bad support? Read some threads where they make clunking noises but wasn't sure how true it was. If you could go back would you chose I different option? Just trying to see if they are as bad as some threads make them out to be.

I went with a custom rates from BC...I believe it was 6kg front 18kg rear. Since comfort is important to you I would not recommend those rates. I doubt the BCs will be more comfortable than a Koni/Eibach setup. BCs really focus onlow ride height which requires very stiff damping. the Koni/Eibach set up may be more appropriate for you.

For my application, my experience with BCs has been good. my application is motorsports, autox etc so I am hard on the car and they have held up fine. They are rebuildable which is important for me. I had the clunking noise...it occurred three times, once was a loose sway bar end link, another was was a loose top nut and the last was a loose collar causing the spring to move up and down. Since rectifying all that, I havent had any clunking noise since...

If I could go back, I probably would have gone with Bilstein setup. They were out of stock so I went with the BCs...for what I paid, I am happy with them. I ran koni shocks before the BCs and they were amazing for soaking up the bumps but i was on stock springs so it was still very rolly polly, lots of rebound and no compression but it was very comfortable.

[Gen13 F36]

BC coils as Farkle said... are monotube, the area the gas and oil occupy inside the chamber are the same is limited which mean less area for shocks to travel during compression (unless you make the shocks tube longer or have reservoir) hence company increases gas pressure so not to bottom out. This is why they are bumpy

[vtown]

Originally Posted by FaRKle!

Another thing to note is that Eibach's springs aren't really much different than the M-Sport springs that already come on the 335i spring rate wise.

Really? I was thinking of replacing my M-sport suspension with koni SA and eibach springs...but I dont really need to lower the car more. I would like the look, but The lip already drags occasionally. I was under the impression that the dampers would be better matched to the eibach's. Not true? Maybe i just keep the stock springs?

[FaRKle!]

Originally Posted by vtown

Really? I was thinking of replacing my M-sport suspension with koni SA and eibach springs...but I dont really need to lower the car more. I would like the look, but The lip already drags occasionally. I was under the impression that the dampers would be better matched to the eibach's. Not true? Maybe i just keep the stock springs?

Yes, the Eibach spring rates for the kit Eibach recommends for the 335i aren't much different from M-Sport rates. They're ~5% stiffer front and ~1% in the rear. You can go to a stiffer Eibach kit for another model if you want.

You could always just change your dampers, but I have no idea how the M-Sport dampers compare to Konis.

[vtown]

Originally Posted by FaRKle!

Yes, the Eibach spring rates for the kit Eibach recommends for the 335i aren't much different from M-Sport rates. They're ~5% stiffer front and ~1% in the rear. You can go to a stiffer Eibach kit for another model if you want.

You could always just change your dampers, but I have no idea how the M-Sport dampers compare to Konis.

huh. I've got to believe they are better....the m-sports feel very under damped and pretty floaty on rises and dips in the road / speed humps.
Of course if i do this and its not much different I'll be pissed

[Genericf30]

Thanks for all the comments, had another question what is the consensus on bumpstops if I went with the rwd eibach springs and koni yellows? Do you cut them, leave them alone, or buy specific replacement ones now that you have lower springs?

[FaRKle!]

Originally Posted by Genericf30

Thanks for all the comments, had another question what is the consensus on bumpstops if I went with the rwd eibach springs and koni yellows? Do you cut them, leave them alone, or buy specific replacement ones now that you have lower springs?

I'd go with shorter ones like F8x. You particularly want to make sure you have enough unrestricted damper travel in the rear, which will affect ride comfort a good amount.

[Genericf30]

Originally Posted by FaRKle!

I'd go with shorter ones like F8x. You particularly want to make sure you have enough unrestricted damper travel in the rear, which will affect ride comfort a good amount.

Hi Farkle, thanks it's been years since I've lowered a car with springs and remember how I always had to make a guess at how much to cut the bumpstops so buying shorter ones will make it easier. Just want to make sure I have the right f80 part # is it 31336859768 for the front and 31337847662 for the rear?

[FaRKle!]

Originally Posted by Genericf30

Hi Farkle, thanks it's been years since I've lowered a car with springs and remember how I always had to make a guess at how much to cut the bumpstops so buying shorter ones will make it easier. Just want to make sure I have the right f80 part # is it 31336859768 for the front and 31337847662 for the rear?

Yes.

I recommend when changing your suspension you jack the knuckle/wheel carrier to ride height and measure how much distance you have till bump stop engagement.

I've been playing with that even as recent as this weekend.