BC Suspension

RoadskiN · Post by **RoadskiN** » Sun Mar 31, 2013 10:18 am

Hey guys,

I was just wondering if anybody here has some knowledge on BC?

I've had a ton of work done to my MZ20 Soarer by a garage (primarily an auto-R154 conversion) and I bought some BC Gold coilovers (BC-C-13-BR) that are labelled for the MA70, but assumed they would just bolt in.

I got a phone call from the garage saying they've put the BCs in there and "tried to raise it as much as they could" but the front guard is pretty much sacked on the wheel (you cant even fit your fingers between the guard and wheel). The rears however have a good 25mm of clearance between the guard and tyre. Basically as it is, although it looks really sweet with my new BBS 18" rims, is very unsafe to drive and will mangle my guards and tyres with every bump and turn lol

Anybody know what's going on here?? The info states that it can be set to OEM height if desired (I was hoping for about a good 10-25mm between the tyre and guard)

I've been reading around and supposedly they need to be raised by adjusting the lower collar on the body, and by not touching the springs as this will fiddle with the spring rates.

Is this something the garage could've overseen?

Grrrrrrr! · Post by **Grrrrrrr!** » Sun Mar 31, 2013 11:10 am

Any chance the garage put the fronts in the rear and vice versa?

RoadskiN · Post by **RoadskiN** » Sun Mar 31, 2013 11:18 am

Is that even possible? I thought the fronts and rears were quite different?

d1 mule · Post by **d1 mule** » Sun Mar 31, 2013 2:54 pm

70 series supra and 20 series soarer are the same. they are muppets.

Bling · Post by **Bling** » Sun Mar 31, 2013 3:13 pm

RoadskiN wrote:Is that even possible? I thought the fronts and rears were quite different?

They do look quite different if google is correct, so I don't see them being installed at the wrong end. Perhaps wrong parts supplied?

RoadskiN · Post by **RoadskiN** » Sun Mar 31, 2013 4:17 pm

BZG|Bling wrote:
RoadskiN wrote:Is that even possible? I thought the fronts and rears were quite different?

They do look quite different if google is correct, so I don't see them being installed at the wrong end. Perhaps wrong parts supplied?

The box said MA70 and I've been told they share the same chassis

Kiwi-Corolla · Post by **Kiwi-Corolla** » Sun Mar 31, 2013 4:57 pm

They're probably trying to adjust the spring load rather than the ride height. The ride height is adjusted by loosening the bottom collar and then turning the top collar either up or down to go lower or higher. Turning the very top collar will adjust the spring rate only, which is definitely not what you want to happen.

Here's a photo borrowed from the internet. In order to adjust the ride height you need to loosen 'C' (usually sits on the bottom of the thread but has already been loosened in the photo) and then twist 'A' either up or down. Twisting 'A' clockwise will go lower and counter clockwise will go higher. NEVER touch 'B' unless you have a reason to. The preload should only be enough so that the spring doesn't move up and down. You don't want the spring to be compressed at all when the car's weight isn't on it:

RoadskiN · Post by **RoadskiN** » Sun Mar 31, 2013 6:19 pm

Omg thank you, I will show them this!

Grrrrrrr! · Post by **Grrrrrrr!** » Sun Mar 31, 2013 6:37 pm

Kiwi-Corolla wrote:They're probably trying to adjust the spring load rather than the ride height. The ride height is adjusted by loosening the bottom collar and then turning the top collar either up or down to go lower or higher. Turning the very top collar will adjust the spring rate only, which is definitely not what you want to happen.

Spring rate is not adjustable, its inherent in the spring design.
Its adjusting preload, which is pretty much what it says, how much you have preloaded the spring at the maximum strut extension. Cranking the preload up will raise the static rideheight, but will limit the suspension travel in droop.

Kiwi-Corolla · Post by **Kiwi-Corolla** » Sun Mar 31, 2013 7:01 pm

Grrrrrrr! wrote:Spring rate is not adjustable, its inherent in the spring design.
Its adjusting preload, which is pretty much what it says, how much you have preloaded the spring at the maximum strut extension. Cranking the preload up will raise the static rideheight, but will limit the suspension travel in droop.

Oops bit of a typo there :oops:

. Was meaning the spring pre-load. Had just spent the last 6-hours busting my balls doing a rear disc conversion so my brain was a bit vacant :lol:

Bling · Post by **Bling** » Sun Mar 31, 2013 7:05 pm

RoadskiN wrote:Omg thank you, I will show them this!

If that is the problem.... then i'm not sure i'd trust them to do the job TBH.

RoadskiN · Post by **RoadskiN** » Sun Mar 31, 2013 7:25 pm

They've done an amazing job with everything else up until this, they're probably a bit old school and don't know exactly how this adjustable suspension works. They've probably only been playing with the spring preload to adjust the height, I had a set of Teins in my old JZA70 that only had this option.

Stott69 · Post by **Stott69** » Sun Mar 31, 2013 7:30 pm

Out of curiosity, who are you using?

h8wrxs · Post by **h8wrxs** » Wed Apr 03, 2013 7:37 pm

bc golds have HEAPS of height adjustment in them, either they are the wrong shock, been installed wrong eg fornt to back, or the dont know how to adjust them

look up on youtube for a tutorial on how to adjust them yourself is my best advice and then do it yourself?

Looonie · Post by **Looonie** » Fri Apr 05, 2013 7:45 pm

Kiwi-Corolla wrote:They're probably trying to adjust the spring load rather than the ride height. The ride height is adjusted by loosening the bottom collar and then turning the top collar either up or down to go lower or higher. Turning the very top collar will adjust the spring rate only, which is definitely not what you want to happen.

Here's a photo borrowed from the internet. In order to adjust the ride height you need to loosen 'C' (usually sits on the bottom of the thread but has already been loosened in the photo) and then twist 'A' either up or down. Twisting 'A' clockwise will go lower and counter clockwise will go higher. NEVER touch 'B' unless you have a reason to. The preload should only be enough so that the spring doesn't move up and down. You don't want the spring to be compressed at all when the car's weight isn't on it:

Err... I haven't seen BC's for A70/Z20 chassis, but I'm 99% sure that you loosen "C", then rotate the lower body inclusive of mounting point to adjust the ride height/length of the strut. Rotating "A" will adjust the pre-load of the spring and _CAN_ further lower the car, but generally it will be stupidly low anyway before you need to play with that.

My rule of thumb, adjust top collar so that spring is just firmly captive, wind middle collar up to lock firmly against top collar, then wind bottom collar up to touch middle collar and wind lower shock body up to meet this. Install and raise if dangly bits between legs are found to be absent

stoffa · Post by **stoffa** » Fri Apr 05, 2013 7:51 pm

Having just adjusted my BC's last weekend i can tell you that if C is loose and you turn A while its locked onto B the entire shock spins having the same result without having to undo the clevis mount from the hub

Looonie · Post by **Looonie** » Fri Apr 05, 2013 8:04 pm

Cheers, I'll have to try that because I'm too lazy to undo the lower mount in my Z20 to raise the rear suspension

loudstealthGT-Four · Post by **loudstealthGT-Four** » Fri Apr 05, 2013 9:40 pm

Just loosen C and wind the whole shock with your hands to desired height, thats how I do mine in car.

jacobrjett · Post by **jacobrjett** » Fri Apr 05, 2013 10:29 pm

yeah dont you wind the entire shock to adjust the height without effecting any spring preload etc. ?

not from experience, its how they did it with one of the mighty car mods episodes, ill have a dig

jacobrjett · Post by **jacobrjett** » Fri Apr 05, 2013 10:31 pm

https://www.youtube.com/watch?v=l7aXjnQkVOA

go to about 4.30