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BC Coilovers Question - Height adjustment, Not long enough?

Joined
21 October 2015
Messages
234
Hi Prime,
So I had time this weekend to start on the BC coilover install. Might be stupid question or not, but I may be missing something. Hoping someone here can shine some light on this. So from previous coilover install (on other vehicles), I usually take off the oem shocks and compare the new coilovers to match the height. Once I adjust the coilover to the height of what was previously there, I would go ahead and install it in place. This way, I can see the height from the wheel to fender. After that, I would adjust the height of the coilovers to my personal preference (lowered or needed more gap, etc.) So I took out the front oem shocks (has eibach springs with OEM shocks) and compared the new BC coilovers. I adjusted the height of the BC coilovers but it wouldn't go further enough?
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Current height OEM shocks with Eibach springs

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My understanding is, loosen part C and twist lower spindle to adjust height. Correct?

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It would not go down any further. If I adjust the lower spindle to all the way to bottom, I still have about 2" off compared to the OEM shock. I want to match the oem shocks first before I adjust how low I want the car to be. Looking at the top photo of the car, the OEM shock with eibach spring is about one/two finger gap. I'm worried that if I install the BC coilover the way it is, it might be too low.

Please let me know what you think or if I'm missing anything. I don't want to adjust the upper collar as it might alter the preload of the springs.

Thanks!
 
How preloaded are the springs? They should be loaded just enough so they don't move. If it is loaded too much, you will lose your shock travel.


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I did not adjust the preloaded springs so it should be loaded at default.
 
BC coilovers are made for extreme lowering.
You must make sure that you do not adjust the thread of the shock past the small eyehole in the shock mount. The only option you have to raise the car is by adding a ton of preload to the spring.
 
BC coilovers are made for extreme lowering.
You must make sure that you do not adjust the thread of the shock past the small eyehole in the shock mount. The only option you have to raise the car is by adding a ton of preload to the spring.

That does not sound right at all. You should not have to adjust the preload of the springs. If you alter the spring load, you will change the settings on your preloaded springs which will cause bad shock travel. Which will make your ride really stiff.
 
That does not sound right at all. You should not have to adjust the preload of the springs. If you alter the spring load, you will change the settings on your preloaded springs which will cause bad shock travel. Which will make your ride really stiff.
Your telling me... Which is why I sold my BC coils. They are made for lowering and nothing else in my own opinion. But there are some people who really like them. However,,, you can buy longer threaded shock bodies from BC America for 100 dollars per shock. But even at the the highest height on BC coils, your already extremely low...
 
**UPDATE**

I was totally wrong... Installed the BC and had a huge wheel gap between rim/fender. I guess BC coilover sit much firmer than OEM. Didn't have to go down that much on the lower spindle. Now, I just need to adjust height and should be fine. Thanks all.
Do not adjust spring preload. Leave it alone, just unlock perch C and adjust height.
 
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BC coilovers are made for extreme lowering.
You must make sure that you do not adjust the thread of the shock past the small eyehole in the shock mount. The only option you have to raise the car is by adding a ton of preload to the spring.

Wow..........some really bad info right here..............be careful who you take advice from around here.....................
 
Wow..........some really bad info right here..............be careful who you take advice from around here.....................

I don't think that is bad info. If the shock is already threaded down as far as it can go, the only option to get the height higher is add preload. Which was recommended to me to do by [MENTION=16531]stuntman[/MENTION] and was all I was explaining. I'm not claiming to be an expert either. But that's cool, it is easy to disagree from reading some things here.
 
I don't think that is bad info. If the shock is already threaded down as far as it can go, the only option to get the height higher is add preload. Which was recommended to me to do by [MENTION=16531]stuntman[/MENTION] and was all I was explaining. I'm not claiming to be an expert either. But that's cool, it is easy to disagree from reading some things here.

We can agree to disagree...........I know you had a bad experience with them. I'm not and never had said that BCs are the best but for the money they're a great deal. Oh and BTW I was killing it again at autox at Sonoma Raceway yesterday with my BC coilovers...............and had a smooth drive home afterward...................
 
The stiffer spring rate and less droop (rebound) travel of the BC is why your ride heights ended up being similar despite the shorter free length of the BC.

You can adjust the ride height by the lower collar or by changing the "preload" of the spring. As you Change the spring perch height (preload) you will change the compression and rebound travel of the damper (lower spring perch = less compression travel & more droop/rebound travel, and vice-versa).

0.02
 
Do you know how much of the damper body is suppose to be screwed into the lower bracket at the minimum? In other words what's the highest you can go?

Can you insert 1/4"? 1/2"? 1"?

Answered my own question. Took apart my Ohlins to find out. Looks like more than an inch needs to be in the bottom bracket as determinedby the machined mark/line.

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It's been a while, but I believe the BC instructions said to leave at least 10 mm of thread in the lower perch cup for safety. When Kaz installed them, he noted that at maximum, the BC coil was still about 10 mm shorter than the factory 1991 ride height. He was considering adding urethane spacer plates to the top mount to make up the difference. Don't know if he ever did that. As for performance, you can read my BC thread, but I never felt like they were a bad performance option. I was turning around 2:10 lap times at High Plains on near stock power and street rubber. I always felt my tires were the limiting factor at the track, not the suspension, which felt good.
 
Answered my own question. Took apart my Ohlins to find out. Looks like more than an inch needs to be in the bottom bracket as determinedby the machined mark/line.

Wow - When did you get DFV'S? Are you making the adapters or is a suspension tuner helping out? I've wanted to do this for a long time! Cool!
 
Those BC Coilovers are the same as D2 and KSport. It should be screwed into the lower cup at least 1".

Preload must be determined by installing it and measuring how much the damper is compressed by the weight of the car. There should always be preload on the spring. The damper should be compressed by more than 50% but not more than 66% (2/3) of total suspension travel. Good starting point is 2-5mm of preload on the spring.

When the preload is set correctly you can set the ride height by adjusting the lower cup without messing up the spring preload like on most other coilovers. Thats the beauty of this type of Coilovers.

Its true for everything and especially for adjustable suspension. If there is a lot to adjust it gets messed up by someone who thinks he knows what he is doing but actually has no clue :D

Bernhard
 
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Those BC Coilovers are the same as D2 and KSport. It should be screwed into the lower cup at least 1".

Preload must be determined by installing it and measuring how much the damper is compressed by the weight of the car. There should always be preload on the spring. The damper should be compressed by more than 50% but not more than 66% (2/3) of total suspension travel. Good starting point is 2-5mm of preload on the spring.

When the preload is set correctly you can set the ride height by adjusting the lower cup without messing up the spring preload like on most other coilovers. Thats the beauty of this type of Coilovers.

Its true for everything and especially for adjustable suspension. If there is a lot to adjust it gets messed up by someone who thinks he knows what he is doing but actually has no clue :D

Bernhard
Good general rule of thumb, but it depends on total travel and chosen spring rates.
 
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