[Camman]

Well, now that I have everything working properly and I've gotten the suspension broken in, I figured I would give a overall review on these coilovers.

I don't have a lot of experience with different suspension setups so I can't say how these coilovers ride compared to the other recommended setups in the same price range (megan, kw/st v1 etc). My previous car (97 Camry), I was on drop springs and tokico shocks, followed by ground control sleeves which did not ride well on those shocks. I was on the springs for a while before getting the sleeves. I went that route so I could have a better drop.

Now onto this car. Since I was not happy with drop springs, I told myself I would do coilovers on the next car, which was this one. I wanted dampening adjustability and I had read many good reviews on the BC's so I figured why not. I had read that they do ride pretty stiff but were not bone jarring. I don't mind a stiffer ride so I pulled the trigger on them. The install was pretty easy and went smoothly. Took about only 3-4 hours roughly.

After the install I took it out on the road and immediately I could tell the car had transformed. It was much stiffer than I imagined but I had also not adjusted the dampers at all so I think it was at 15f and 15r. One thing I noticed was the that the front seemed to have a LOT less travel than the rear. Going over speed bumps the front is not forgiving. The rear is actually very soft going over speed bumps, which confused me since the spring rates are 8kg front and 12kg rear. I guess I don't fully understand how springs and shocks work or the difference between coilovers and multi link systems.

Anyways, I finally got the height dialed in and have done some dampening adjustment. My current setting it 8 from full soft in the front and 12 from full soft in the back. What I've come to find out is that these coilovers are very comfortable if the road your traveling on is not completely torn up. If you travel on roads that are full of big bumps/dips, the coils will not be forgiving. It's not unstable but it is kinda a lot to handle. If the roads are average, it will drive just fine. On my highways, I think it's more comfortable than the old sport suspension. It handles potholes pretty well, too. The sharp impacts are soaked up very well. Better than my old suspension for sure.

I did put these to full stiff, and holy shit, this is waaay too stiff for the streets. Definitely do not recommend going full stiff for the streets lol

As far as handling goes, it has improved dramatically. It's awesome how flat the car stays when taking sharp turns. I'm very happy with how much more confidence it gives me when going into a turn.

Now onto noise, I had some issues with clunking but I found out a sway bar endlink had come loose. Other than that these coilovers are quiet. They don't make a single sound when turning full lock or on rough roads. Road noise hasn't really gotten any louder too. At least not enough for me to really notice.

Overall, I am happy with these coilovers. I can understand why some people will say coilovers are not meant for everyone. These are comfortable but probably too stiff for some people and circumstances. Next thing to see is how well they hold up over time.

I have new control arms and tension struts coming in this week so I'm sure the car will feel even better once those are installed.

Let me know if you have any questions.

P.S. the signature below is the current ride height. The front could go another 1/2inch lower and the back has plenty more room to go lower.

[the dope steez]

Great review, thank you!
I'm in the same boat as just about everyone else, BC/ST coils vs. used KW V1s vs. spring/shock combo...
This was helpful!

[Camman]

Originally Posted by the dope steez

Great review, thank you!
I'm in the same boat as just about everyone else, BC/ST coils vs. used KW V1s vs. spring/shock combo...
This was helpful!

Thanks! I didn't realize I had typed so much lol

Yeah, I'd really like to ride in a car with ST coilovers and one with H&R/Koni setup to see how they ride. Curious to see how ST/KW would handle a rough road with big bumps/dips. I'm betting they would not be very forgiving either. Feel like only a spring/shock combo would shine in this scenario.

[Misty]

Originally Posted by Camman

Thanks! I didn't realize I had typed so much lol

Yeah, I'd really like to ride in a car with ST coilovers and one with H&R/Koni setup to see how they ride. Curious to see how ST/KW would handle a rough road with big bumps/dips. I'm betting they would not be very forgiving either. Feel like only a spring/shock combo would shine in this scenario.

my st coil overs are lowered all the way stiff as fuck. stiff enough to make a drink fly out the cup holder -.-

[Camman]

Originally Posted by Misty

my st coil overs are lowered all the way stiff as fuck. stiff enough to make a drink fly out the cup holder -.-

I think that's because ST/KW lower via the spring collar and not by shortening the shock body like the BC's. So at a reasonable height, ST's probably ride better but lowered all the way, they will have far less shock travel, hence a harsher ride.

[Camman]

Another update: The coilovers have softened up A LOT! I don't have a long commute so I guess it's been taking a while to break in the springs and shocks. I've actually dialed the dampening up some because I like a firm ride and these still feel softer in some ways than my old sport suspension.

I will say that at slower speeds the car is a little more bouncy. It's not bad nor does it really bother me but it's noticeable. Though, I probably can't blame the coilovers because the car is at 110k miles so the stiffer suspension is just exposing the weak bushings that probably need to get replaced.

Once you are on the highway, these things are buttery smooth. All the small bumps are soaked up well. The car will still react more dramatically to big bumps because it has much less droop travel but it is not unstable at all and recomposes itself very quickly. Still consider it more comfortable than the old sport suspension. I'm looking forward to doing a road trip with them.

So if you get these coilovers, they will be fairly stiff for the first 1000-2000 miles but they will soften up considerably and the ride will get much smoother.

Overall I'm very happy with them especially after they have broken in. At first I thought they seemed a little stiff but they are much better now and they make driving so much more fun.

[bNks334]

Motion ratio in the rear is .3x. Basically for every 100 lbs/in you effectively get 90lbs/in in the front and only 30lbs/in. In the rear.

The 8k/12k is not a good spring rate setup for street driving. You needed close to 4k/12k to maintain the stock front/rear suspension frequency bias.

Your front springs ARE stiffer than your rear by quiet a bit. This causes the front to settle faster than the rear when hitting bumps on the streets which can be unsettling. The rear will still continue to oscillate after the front has already settled.

[Camman]

Originally Posted by bNks334

Motion ratio in the rear is .3x. Basically for every 100 lbs/in you effectively get 90lbs/in in the front and only 30lbs/in. In the rear.

The 8k/12k is not a good spring rate setup for street driving. You needed close to 4k/12k to maintain the stock front/rear suspension frequency bias.

Your front springs ARE stiffer than your rear by quiet a bit. This causes the front to settle faster than the rear when hitting bumps on the streets which can be unsettling. The rear will still continue to oscillate after the front has already settled.

Thanks for chiming in!

That definitely makes sense. Though, the front is much stiffer than the rear, it's not bone jarring. I wish I had known this before I ordered the coilovers because I could have gotten custom spring rates at no extra cost. If I decided to do a swift spring upgrade, I'd probably lower the front down to only 6 or 7k and leave the rear at 12k. For now, I can live with the current spring rates. This is only my second car I've owned so this is good learning material for future projects.

[bNks334]

Originally Posted by Camman

Thanks for chiming in!

That definitely makes sense. Though, the front is much stiffer than the rear, it's not bone jarring. I wish I had known this before I ordered the coilovers because I could have gotten custom spring rates at no extra cost. If I decided to do a swift spring upgrade, I'd probably lower the front down to only 6 or 7k and leave the rear at 12k. For now, I can live with the current spring rates. This is only my second car I've owned so this is good learning material for future projects.

This is a very rough estimate, but you have close to 412lb/in up front and 213lb/in in the rear.

That is close to a front frequency of 2.3 (race car) and a rear frequency of 1.7(Close to a stock M3). This is fine on track since you're not exactly hitting bumps, but on the road it throws your suspension out of whack a bit.

Swift springs are a decently balanced F:R setup, but they still have a slight bias toward a stiffer front spring. Not too many aftermarket manufactures seemed to have bothered providing spring rates that are balanced for street driving for the 1-series. Almost all the aftermarket springs are almost 2x as stiff up front.

[Camman]

Originally Posted by bNks334

This is a very rough estimate, but you have close to 412lb/in up front and 213lb/in in the rear.

That is close to a front frequency of 2.3 (race car) and a rear frequency of 1.7(Close to a stock M3). This is fine on track since you're not exactly hitting bumps, but on the road it throws your suspension out of whack a bit.

Swift springs are a decently balanced F:R setup, but they still have a slight bias toward a stiffer front spring. Not too many aftermarket manufactures seemed to have bothered providing spring rates that are balanced for street driving for the 1-series. Almost all the aftermarket springs are almost 2x as stiff up front.

Interesting. Yeah, my setup drives great on the highways and streets that are properly maintained. It just gets a little crazy when you hit the poorly maintain roads with big bumps and dips. Which there are plenty in Houston. I just make sure to avoid them lol

Just so we're both on the same page, I meant I would get swift springs (with custom rates) to swap out with the bc springs on the coilovers. Sounded like you might have been referring to the swift lowering springs.

Regardless, you have given a lot of good information and I appreciate that.

[zero2sixtyZ]

Originally Posted by bNks334

Motion ratio in the rear is .3x. Basically for every 100 lbs/in you effectively get 90lbs/in in the front and only 30lbs/in. In the rear.

The 8k/12k is not a good spring rate setup for street driving. You needed close to 4k/12k to maintain the stock front/rear suspension frequency bias.

Your front springs ARE stiffer than your rear by quiet a bit. This causes the front to settle faster than the rear when hitting bumps on the streets which can be unsettling. The rear will still continue to oscillate after the front has already settled.

Originally Posted by bNks334

This is a very rough estimate, but you have close to 412lb/in up front and 213lb/in in the rear.

That is close to a front frequency of 2.3 (race car) and a rear frequency of 1.7(Close to a stock M3). This is fine on track since you're not exactly hitting bumps, but on the road it throws your suspension out of whack a bit.

Swift springs are a decently balanced F:R setup, but they still have a slight bias toward a stiffer front spring. Not too many aftermarket manufactures seemed to have bothered providing spring rates that are balanced for street driving for the 1-series. Almost all the aftermarket springs are almost 2x as stiff up front.

This is exactly the info I was in need of. I have FA coils with the similar 8/12k combo, and the rear could be used as a catapult. Could you share the calculations on determining the frequency?

[bNks334]

Matching proper Shock dampening to the springs is said to play an even greater role, and I don't know even know how to even begin to get into that part of the equation lol...

Originally Posted by zero2sixtyZ

This is exactly the info I was in need of. I have FA coils with the similar 8/12k combo, and the rear could be used as a catapult. Could you share the calculations on determining the frequency?

Again, the numbers I threw out there don't mean much by themselves. The below formula can help provide a rough estimate that can be used to quantify the effectiveness of your chosen spring rates though.

Wheel Rate Formula:
Wheel Rate = Spring Rate * (Motion Ratio ^ 2) * Spring Angle Correction

Front:
=> Spring Rate (8k or 448 lb/in) * Motion Ratio (0.960^2) * Spring Angle Correction (unknown)
==>413

Rear:
=> Spring Rate (12k or 672lb/in) * Motion Ratio (0.563^2) * Spring Angle Correction (unknown)
==>213

Frequency Formula:
Here is an easy to use calculator: http://www.racingaspirations.com/app...ncy-calculator

Calculating frequency requires knowing what the corner weight is as well as the sprung weight. I used 765lbs front and 732lbs rear (135i). This probably isn't all that accurate as I just took another users weights, that they posted after getting a corner balance, and I made an estimate as to how much weight to subtract out as un-sprung weight...

Front: wetweight * frontweightdist / 2 - 105
Rear: wetweight * (1 - frontweightdist) / 2 - 135

Front Frequency (calculated directly to Hertz) => SQRT((386.4 * 413 lb/in. wheel rate) / 765 lbs. sprung weight) / 6.28
==> 2.3hz

Rear Frequency => SQRT((386.4 * 213 lb/in. wheel rate) / 732 lbs. sprung weight) / 6.28
==> 1.68hz

Some sources:
http://performancetrends.com/Definitions/Wheel-Rate.htm
http://www.truechoicekoniracingservi.../worksheet.pdf (shows how to calculate frequency in cycles per minute, which then need to be converted to hertz)


Other considerations to take into account when trying to balance your setup would be things such as, sway bars, bushings, control arms and anything else you've done to the suspension.

[zero2sixtyZ]

Replaced the rear springs to 14k, with much better results and stability. Half week with the car settling and the car doesn't bounce as much at higher speeds. Will most likely have rear struts revalved over winter to match springs even though FA stated +/-2k would be decently within range.

[whyzee125]

Originally Posted by Camman

Thanks! I didn't realize I had typed so much lol

Yeah, I'd really like to ride in a car with ST coilovers and one with H&R/Koni setup to see how they ride. Curious to see how ST/KW would handle a rough road with big bumps/dips. I'm betting they would not be very forgiving either. Feel like only a spring/shock combo would shine in this scenario.

Maybe I had a bad experience, but I always discourage people from going the ST/KW v1 route. I had them on my ZHP and wasn't happy with them at all. Glad to hear you're liking the BCs, I'd certainly choose them over the ST's.

[Camman]

Originally Posted by zero2sixtyZ

Replaced the rear springs to 14k, with much better results and stability. Half week with the car settling and the car doesn't bounce as much at higher speeds. Will most likely have rear struts revalved over winter to match springs even though FA stated +/-2k would be decently within range.

I was actually going to do the opposite at some point and lower the front down to 7k or even 6k and then I can turn up the dampening. Feel like the 8k does not like when the dampening is under 15clicks. And when it's at 15 or higher, then it's just super stiff. I'm going more for comfort versus handling where raising the rear to 14k is definitely smart.

Originally Posted by whyzee125

Maybe I had a bad experience, but I always discourage people from going the ST/KW v1 route. I had them on my ZHP and wasn't happy with them at all. Glad to hear you're liking the BCs, I'd certainly choose them over the ST's.

Oh really? Aren't they progressive springs too? I know to lower you lower the spring perch down which shortens the shock travel so the lower you are the less travel distance you will have.

[zero2sixtyZ]

Originally Posted by Camman

I was actually going to do the opposite at some point and lower the front down to 7k or even 6k and then I can turn up the dampening. Feel like the 8k does not like when the dampening is under 15clicks. And when it's at 15 or higher, then it's just super stiff. I'm going more for comfort versus handling where raising the rear to 14k is definitely smart.

How soft was the rear suspension on your setup if you pushed down on the trunk area? Was it noticeably bouncy while standstill?

[Camman]

Originally Posted by zero2sixtyZ

How soft was the rear suspension on your setup if you pushed down on the trunk area? Was it noticeably bouncy while standstill?

I mean you can push it down some with your hands(by hands I mean you're full body weight) unless the dampening is turned up. If it's turned up, it will not move. But I wouldn't say the rear is bouncy at all.

[Eagle1oh7]

So are these the ER-line with the external reservoir?

[Camman]

Originally Posted by Eagle1oh7

So are these the ER-line with the external reservoir?

Nah, these are the standard BR Series.

[vincentvthaile]

Hey guys, love the thread! I am about to purchase BC BR coilovers with extreme lows as well but i am not sure what spring rates to get for a smooth ride on the streets and still stiff so that it won't kill me on bumps! pls let me know what you think!

[bbnks2]

Originally Posted by vincentvthaile

Hey guys, love the thread! I am about to purchase BC BR coilovers with extreme lows as well but i am not sure what spring rates to get for a smooth ride on the streets and still stiff so that it won't kill me on bumps! pls let me know what you think!

4k/12k? really depends on your make an model as some weight more than others.

[Digitalize]

Depends on what sort of ride height and fitment you want too.