Coilover Adjustments (BC Racing)

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Old Sep 14, 2011 | 02:57 AM
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Question Coilover Adjustments (BC Racing)

I got my coilovers installed and I'm looking to adjust them and I want to make sure I'm doing it the right way.

My rear is pretty slammed with the fender tucking over the tire while there's about a 1/2" gap in the front. I'm looking to raise the rear.

Adjusting the Front:
Rather easy and straight forward.



http://www.bcracing-na.com/HEIGHTADJUSTMENT.htm

Loosen the lower lock ring. Using the spanner wrenches that comes with the kit, turn the upper spring seat (2a) counter clock-wise (right to left) to lower or the lower lock ring (2b) clock-wise (left to right) to raise the vehicle. Tighten lower lock ring.


Adjusting the Rear:
More complicated than the front.



Strut
Loosen collar on strut. Turn strut by hand. Turn cartridge right to raise, left to lower. Tighten Strut Collar.

Spring Perch[/B]
Loosen top collar, bring it to the top. Then, with the lower collar you turn it down (clockwise?) to raise your car and up to lower (counter-clockwise?) your car.


Is this correct?
At what point will I need to pre-load the rear spring again?
Is there any way of knowing how much my car will drop by turning the threads in the lower strut/spring perch?
Say I want to raise my rear 1/2" how many turns should I turn the strut and spring perch?
Do I turn the strut and spring perch the same exact amount of turns? (I will put a piece of tape or post-it to record how many turns I've done.

Thanks!
 
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Old Sep 18, 2011 | 04:24 PM
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Update: Lowered the rears today but it still needs to be a little higher...

What I mean about to the pre-load of the rear spring is:

Say I raised the car about 1" in the rear through turning the spring perch and strut. Doesn't this tighten the rear spring causing a greater pre-load than what is needed? Hence, squeezing the spring more than need be? Can this cause more bounce and a harsher ride?

Here are pictures and my current set-up with measurements in the rear:

As you can see here: there is a little gap near the hole where you can see threading of the strut. Right underneath the BR logo on the strut.
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Here are the measurements of the rear:

Top of threading taken from the top of the metal piece right above the threading all the way down to the top of the lock ring of the strut. 9 inches:

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Spring perch measurements: taken from the top of the inside of the spring perch (black plastic piece) down to the lowest part of the lower adjustment ring. - 2 1/8" inches

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Does this look right? I'm still not sure if I have to redo the pre-loading aspect of the rear spring?

I'm going to be raising the rear once more because it's not 100% even with the front.

Thanks! and hopefully everyone will know how to adjust the coilovers on their cars. It's a little time consuming but it's rather easy and simple.
 
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Old Sep 18, 2011 | 05:43 PM
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From: Inside my G
Here's what i understand and can recall about the rears, based on what Pete from BC told me before.

You use the spring perch to adjust the height, then follow-up with the strut by either:
a) With minimal load on the spring bucket (i.e. jack it up just enough to keep the spring taut), match the holes up between the bucket and the bottom strut mount holes - this is zero pre-load
b) If you want to pre-load the springs, jack the bucket further (mine is by 5mm, or roughly half the hole is now covered up by nature of the bucket being higher than the strut). Then, shorten the strut assembly by the same amount until you match the holes up again.

It's been a while, but i think that's the gist of it.
 
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Old Sep 18, 2011 | 05:59 PM
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that sounds about right! Thanks!

I'm trying to think this through. The pre-load was done at the time of the coilover install. If I'm just adjusting the height and giving equal rotations on both the spring perch and strut I wouldn't have to pre-load the spring again right? or should I because I changed the height, thus increasing pressure on the springs?...
 
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Old Jun 1, 2013 | 01:34 AM
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how low can these coilovers go in the rear since they aint true coilovers
 
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Old Jun 3, 2013 | 12:11 PM
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From: New Mexico
Originally Posted by ven377
how low can these coilovers go in the rear since they aint true coilovers
They're the same setup as my Megan Coils, you can go as low as the tires rubbing the fenderwells, the main problem w/ the BC/Megan setup is raising the rear, going slammed low is NO problem. You need to keep about 1/2" of thread beneath the rear threaded collar so your springs can safely seat, and even at this height the rear is still quite low. I'm at the highest safe setting and I'm still at zero gap (26.25" to the fender edge). Luckily this is exactly the height I want, but for those just wanting a 1.5" or less drop it's going to be an issue. Here's a "fix" from the 370z forum.
http://www.the370z.com/brakes-suspen...coilovers.html
As far as preload, Soundmike is dead-on (as always), just get to zero preload and further jack up the bucket another 5mm, do this every time you raise or lower the collar, then adjust your rear shock length accordingly so it's snug in the mount.
 
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