Compthis

iTrader: (1)

I have BC coilovers on swift springs. My drivers front suspension has developed a dull knock when going over small bumps at very low speeds. At higher speeds 40km/hr and higher, the sound goes away. I removed the top components and torqued to spec. The suspension does not appear to be leaking when I had a look at it on a hoist. I made a few video clips to capture the noise its making.

first clip is one I made in car

second clip is one I made with the phone sitting directly on top of damper corner.

Any suggestions are welcomed......

Kojak77

Is the spring pre-load OK?

Compthis

iTrader: (1)

The more I investigate this issue, it appears to be a common problem with the BC coilover. I'm going to email BC racing and see what they can do. All roads lead to a faulty cartridge.

ISFPOWER

iTrader: (20)

its easy

Compthis

iTrader: (1)

I brought my car to a friends house who has a hoist. He took it apart and did exactly that, nothing fixed. The more I search, it appears to be a common issue with the brand and a simple cartridge replacement will do the trick. I emailed BC USA, hopefully they can shed some light.

lobuxracer

iTrader: (2)

You're expecting a lot from a low end piece. Tein is no better. If you want something to deliver, you need to look at Ohlins or Penske. The video alone is enough to make me not want to waste a dime on cheap shocks. While BC might call this good, it's total crap and in no way represents a good way to adjust preload on any suspension device. All it does is sets the bar very low for failure.

kauaian

iTrader: (18)

^^ well said! They're cheap coils setup for all show and no go.

Compthis

iTrader: (1)

I agree, they are garbage... I bought these because I never thought the car would see a track. I was originally looking to have a better ride than stock which I got. No more jumping out of the seats with the factory suspension. But give the BC's some track time and good night. Come to think of it, the problems with these coilovers developed before even seeing the track. I'm almost sure I have the same knock in my passenger rear, it's just not as obvious as I have the front corner drowning out the rear corner. Just disappointing. I've been looking into the ohlins but what I've read in past threads, there is no true application for our F as of yet correct me if I'm wrong.

FIGS

iTrader: (11)

The knock issue is usually the upper bushing compression. The center crush tube is just a hair too short for the amount of torque you can put on the nut. So an impact driver (not impact wrench) but something with a much lower torque limit is required to get the stack to compress into the tube. The second thing that sometimes happens is the circlip on the shaft sometimes rolls over which prevent the stack from compressing as well. BC''s are still the best bang for the buck and can be very reliable if this issue is resolved. I think most of the time when people change the spring cartridge, they are reassembling the shock, so it has a tendency to resolve itself just from the re-compression of the bushing.

We just received the Ohlins R&T setup that we have been working on for the past 3 1/2 years Friday. This includes spring rates appropriate for the F as well as new valving. Testing this coming week and might get out the the track on Friday.

I8ABMR

Figs to the rescue !!

Compthis

iTrader: (1)

If all the parts were designed and built with the right tolerances, there should be no issue. The fact that I'm having this issue with two corners is a testament to an inferior product. The only thing I'm getting out of the buck I spent is the bang. In my case, their suspension has a 50% failure rate. I had the suspension professionally installed by Defcon Racing who did every other modification to my car flawlessly. Days later, I brought the car to suspension expert Scott Murfin at http://www.canalignment.com/ who is the chief instructor for the Ontario Time Attack series where he made his adjustments to the suspension and aligned my F to make sure I didn't cut corners. That visit cost me $400 alone. I've emailed you regarding the issue numerous times, your customer service is great, no complaint there. You've offered me trouble shooting tips but nothing has worked. This suspension failed before a year of use and what's worse, the car was stored for 5 months of the year. So within 6 months of road use I'm left holding the empty bag. Ultimately it's my fault for buying a cheap product, you get what you pay for.......I've tried everything you told me through email and even what you just posted. Nothing works.....

The only thing I can suggest at this point is if you can create a video showing step by step what you want me to do so there is absolutely no way I'm missing a thing. It would be greatly appreciated.

scamsel

ha, not to laugh at your situation in any way, but that line made me lol

FIGS

iTrader: (11)

I will work on something this week, or come up with a solution myself. I don't make much on these either, but they are the best solution for the price point but I do not expect people to "deal" with anything like this. I agree that is something was properly designed it would not have these issues, but I think its more of an assembly shortsight than purely a design spec.The rubber durometer is just a little too high for the gap it needs to compress and fill. So its a false torque issue. It is also possible its another issue that is internal to the shock, but I find it to be less likely given such a short use and given the spring should be doing so much of the work as we spec them.

as with any part, labor and setup are so far out of the scale of the original product in cost that if you are going to go to these lengths, you likely should invest more in the shocks anyway. I deliver alignment specs that any shop should be able to hit and really beyond that is a few damping settings that you set to your preference and ride height. If you are going to do a serious setup, you want more adjustment in your shocks anyway, at least divorced compression and rebound adjustment. So my advice to anyone on a budget is just consult with me first on setup targets and I will get you very close. In most cases hiring a high profile or high end shop really will not get you much further than piece of mind as there are just not that many settings to tinker with, likely even less from a professionals perspective so you might both be frustrated for no reason..
Mike

Compthis

iTrader: (1)

Thanks for your response, I appreciate you spear heading this. I just want to include a picture I took today to also show how much of the adjustment collar I'm using. With the car sitting as high as it is, and running 16k fronts, premature wear on the damper should not be an issue. With the factory wheel on factory spec tires sitting on the ground, the floor to fender measurement is 26-5/8". So that's no where close to "slammed" as one may say.