BC Coilovers
 

This is a thread for those who may consider buying BC coilovers.

Here we are! I have installed my BC coilovers last week-end. It took me about 5hrs to install them and another 4-5hrs to find the right height and adjust the camber.

For those who might wonder, there is enough stock camber adjustment on the front. I have managed to bring it to spec without any problems. I used a 24inch level on the wheel to find the original camber and I have set the same adjustment to my new set-up. I must have removed the wheels like 100 times (well, at least 5 times) I could have lowered more and still have adjustment left to play with. Also I used a filler gauge between the camber bolt and spindle to be able to set it to the right position at first try on every spring. On the rear I have a little negative camber but I doubt I can do much about it. I was thinking of buying adjustable upper arm but this would push the top of the wheels to the outside and I have no play at all.

My wheels do not rub the fenders under normal driving conditions, even on a rough road but my wife came back with the trunk full of grocery and it rubbed just a bit on the rear at a place that was predictible because of the road condition. I might raise the rear just a little if this happens again.

Positive points: Ride is as smooth as original, Front coilovers can be adjusted for height in 5 minutes each side.

Negative point: Rear camber is not perfect, height adjustment on the rear takes a little longer because you need to drop the A-arm in order to have enough room. (no need to remove the coil spring though). That is 3 bolts: the lower shock bolt, the upper sway bar link bolt and the lower spindle bolt which is a pain in the butt to remove in my opinion.

I would recomand the BC coilovers to anyone who is using his/her car for daily driving and occasional track days. I guess it would be fun to play with the damping in race conditions.

Oh yes end I want to assure everyone, you will see on the photos that my wheel wells are extremely dirty but that is the result of the winter in Canada. Everything is now clean just like brand new

A few photos..

how long can the coilovers go? any weird noise while driving?

Well, I did not extend them yet but I assume I can get a stock height for the winter. I will let everyone know around November.

They can go extremely low, of what I can see on the treads left I could probably lower another 1 to 2 inches, which would be too low with my set-up. I'm running 19 inch wheels with 265/30 on the back and 235/35 on front. At the moment I am at 24.75 inches front and rear (ground to wheel arch). Going lower will bring me some troubles with the road conditions here in Montreal.

No weird noise at all. Just like original ride mate.

Here are some photos of the height as it is right now.

oh nice! how much were they? i want to get new coilovers! lol what front bumper is on your car?

They are $1000, you can look them up on ebay. I think they are actually the cheapest coilovers you can find out there but i had the budget to pay up to $1500. I really chose BC after reading reviews. They are very popular on JDM cars and Subarus etc.. I do not regret my purchase.

Are you running coilovers or lower coil springs?

My front bumper is the new facelift 2012-13 AMG C63. I also have the C63 side skirts and 2012-13 rear bumper with CF diffuser and AMG quad tips. I am just searching for a 2012-13 CF AMG vented hood but I still haven't found what I'm looking for :) I will switch the hood and headlights.

The car looks really nice as is. Based on the side sill gap to floor, mabe a 1-3/4" drop?

Could also increase damping .... 11kg springs take a lot of damping to kill any bounce/overtravel.

Most of the coilover spec's I've checked show that they can't go back to stock height, they typically have have a minimum drop of ~1". Call BC. With all the excess drop available, you might come up with custom spacers that fit on top of the spring's upper seat, about 3/4" thick aluminum.

That's a bit hard to imagine. BC lists the rates at F/R:

7kg / 11 kg, 390 lb/in / 620 lb/in

BC Rates

Assuming that oem is between 200-300 lb/in, that could be real stiff in the rear, ready to give rear passengers a rough ride?

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I am at 24.75 inches front and rear at the moment (wheel arch to the ground). So I have dropped about 1.25 inch I think (I would need to put back my stock wheels on to be exact)

Thanks for your advice, I have set the damping at about 1/3 of of its adjustment (on the smoothest response) on the four wheels. Maybe I can try and turn it a few clicks on the rear. On my first attempt I had set them to the smoothest and it was swinging too much. I was afraid to compromise the ride quality by going stiffer but I think I will try that. I've only installed them last week-end and it's my wife's daily driver so I haven't played with it yet.

Like I said I have not tried to go any higher so I would lie if I said I could get back to stock height. I will find out this fall when I stretch it up. The spacer idea is an option.

As far as the ride I am being honest and it is extremely close to stock quality. This is not my first car with a lowered suspension and my wife was not keen to the idea of dropping her car because of that. I have no regrets on those BC coilovers :)

Front looks perfect, wish the rear was a little lower, but you you can always adjust stiffness to get rid of that rubbing or run a smaller tire next time you need to buy rubber. But looks good! I have BC's on my project car.

I have contacted the Tech Dept. at BC and the guy I spoke with (Sam) told me that BC normally set their height at around 1 inch lower than stock but he could not confirm if it was the case for ou W204. About the spacer idea he answered: «That would be possible but the burden is on you to make it work. I cannot provide any assistance with that scenario.»

So, I will probably need to have CNC an aluminium spacer ring that will fit under the coil spring at its base. It will be a pain in the butt because I will have to remove everything in order to do the mod. I'm not too sure about the rear.. I will need to see what i can do there. The good thing is that I have enough play to bring it back to where I want in spring time, without having to remove the spacer.

They are not known for their technical capacity ... likely a few people that know what's up and a bunch of clowns. Clown#1 promised a working special run of Mazdaspeed6 BC's, not a std set-up in their catalogue at the time. By the time I was involved, I found that they had taken a typical race set for a similar car, with short travel, and stuck in the relatively soft rate springs that were promised. A total mismatch in spring and damper travel => hard bottom out on a regular basis.

Unfortunately BC is not like H&R and others, who specify the approximate drop range. H&R Coilover Drop Range. So you have some design work to do.

I'd call them again, and say you need the details of these parts, unless they gave them to you already. They should tell you what the minimum thread engagement is at the front, and a similar spec for the rear. Next find the motion ratio (MR) and square it. So if the spring location from the lower arm pivot at the chassis is 18", and the similar location out to the tire center is 22", then the sq of the MR is (18/22)^2 = .67 . That means .67 inch reduction in the spring length will give 1" drop at the tire. Then you can find the true minimum drops.

A multi axis programable cnc machine is not required for a 1 off set of 4 spacers, nor is 6061-T6 aluminum, nor is body fit bolts or tight tolerances since this piece is a static addition to the frame or lower control arm. From your photos, it looks like the spacers will go at the very top of each BC assembly.

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ill trade you my megan coilovers +400 if you need cash :)

Yes well on the front coilovers the top plate is the OEM. It will be easier to put a spacer on the bottom of the coil spring because it sits very flat and the part will be smaller. All I would need is a 1 inch thick flat washer that will sit right Under the coil spring.

I don't think I will need my Trigonometry class to do that :-) thanks for your help!

Cheers mate!

You are right, spacer on small, flat bottom of spring, up front. But at the rear, should go on top to avoid the lower, contoured seat.

At the rear, you adjust the rear shock length based on the drop. Might have to do a little figurin' to see the effect of the spacer on that adjustment.

Have fun in the sun!

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I hear you, this makes sense. Cheers mate!

From the length of the threaded cylinder and spring perch in the rear, I was thinking that much of the threaded portion would be usable without having to halfway uninstall the units. Would it be any better if you reversed the setup and put the spring perch at the bottom instead of hidden at the top where it's hard to reach? I have seen that done and it worked, so I'm curious as to if that would allow you to adjust the rear perches/height without removing anything-- like a properly designed coilover system would use. Unfortunately, this is a major flaw I see in many of them. Very disappointing :crazy:

I have decided to leave it just like that for the winter. I bought a spare car to drive in the snow storms and my C350 drives just fine Under normal winter conditions even lowered..

I have had my front fender wells modified to give it more clearance because I ended up with cracks last fall. (fiberglass fenders) Now I could even go lower without rubbing but I like the look as it is now and it is more ''wife friendly''

I've got my new 2013 C63 Hood at the paint shop and new 2013 C63 headlights ready to install so my mod will be completed to the 2013 C63 look all around in a few days. Looking forward to the new look :-)

Do the threads on the rear spring perch stick out above the rear suspension beam? I'm trying to determine if you set these to the top, would they then be ride height adjustable without disassembling half the suspension?

Mind taking a pic from below with them installed and the car on the ground as it sits?

Thanks for taking the time to put this thread up. It is very informative.

See photo attached. It shows you how tight it is to move the wrench. If it is something that you want to play with quite often it is a pain in the butt...

Sorry my photo ended up sideways for some reason.

Thanks
 

Thanks for posting the pic, really appreciate that!!! So from the pic I guess the threaded perch goes at the top in the rear not at the bottom like the bilsteins. And it looks like if you choose a higher ride height, it is indeed adjustable while installed on the car and you do not need to dismantle any part of the suspension to make adjustments (even if it's hard to get in there at least it's not impossible). That's just what I wanted to know. Looks like you could go higher just by the threads remaining to resolve your rubbing problem?

Do you remember if the rear spring is flattened on both ends where it seats to the suspension or if you can still use the mb spring seat spacer with these like the stock springs use?

Yes you could go a little higher but you have to remember that when you play with the spring adjustment you need to play with the shock accordingly.

If I remember well, one side is harder to adjust than the other but the shock is in the way. You will see by yourself.

The rubbing on the rear is only in extreme conditions where I hit a huge bump on the road at high speed. Thouh I have found out last night (after questionning myself about it) thay it seems to be the plastic in the inner wheel well that makes contact with the tire.

Just to follow up on this I have talked to BC tech support and verified that the rear spring is flat on one end where it sits on the perch but like the OEM spring on the other end. What this means is that you can also gain additional height back because the top of the spring is seated on the OEM spring pad which comes in 4 different thicknesses. So far these coilovers are very well thought out.

Can you or any other owners comment on how stiff they will go? I asked the tech about the range and he said it had a very wide range of adjustment but that's not very conclusive.

Also I had him give me some measurements on the springs and damper bodies which I will have to dig up and post here.

Finally, we discussed the Swift Spring updgrade which seems like a lot considering it adds 30% more in cost. However, after reading about swift springs it may be worth it- they have better memory retention, last longer with less deformation, are made in Japan, and manufactured with a unique process and material. Even though it's a lot percentage wise, it's not a large dollar amount considering the value the BC's are IMO.