BC Racing BR-type Coilover on OBXT

[dschultz]

Hi all:
Just thought I'd share my installation notes for anyone considering these on their OB. I was originally considering installing the Megan Racing coilovers for the OB but got talked into the BC Racing coilover with the argument that they are higher quality units. There's no direct application for the OB so I got the ones for the Legacy (part # F-04).
Application Guide

Removal of the stock system and installation of the BC Racing units was straight forward. I extended the ride height adjustment to full height before installing them as I new I would need it.

Here's a couple shots of stock vs BC.
Rear:


Front:


After installation I had lost more height in the back than the front.

Height  Before   After    Diff
RR      28.7500  26.4375  -2.3125
RF      29.1250  27.5000  -1.6250
LF      29.0000  27.3125  -1.6875
LR      29.1250  26.8125  -2.3125

I also noticed that the rear toe-in was excessive. To the point that if one wheel ran over a manhole cover the car would shift to that side and straighten out once back on the pavement. It was worst in the rain, like the "ghostwalking" problem but in the summer! So I need to fix the ride height.

A little more after the fact research revealed that the rear BC units can be purchased with a 1" longer housing for about $95 each.
ref: http://legacygt.com/forums/showpost....5&postcount=29
I suspect that if I knew that ahead of time I could have ordered them that way.

I thought I could remove the rear subframe spacers to change the geometry, but the problem there is the rear swaybar mounts are attached to the subframe and this causes the RSB to hit the body as it is moved up. The RSB mounts would need to be extended to accommodate the subframe being closer to the body. Plus shorter helper stops would be needed, like the ones from a Legacy wagon.
This is what I wanted to do:


I guess a shack of washers could provide a variable amount of space and they could be tailored so the RSB is still a reasonable distance away from the body. An option I may still investigate.

So before I go spending more on longer rear housings I had the thought of raising the rear 1" with some HDPE spacers (cutting boards) on top of the coilovers. I sourced some 1/2" thick stuff and layered them to create the 1" height I needed. I did find 1" thick stuff but in a quantity I would never need.

So I went to work to make my shims. All you need is a jig saw and optionally a hole saw. I had a 2-1/8", used for door handle mounting that did the trick.
I made a template to transfer the shape to the HDPE and then cut out my shims. I pressed out the mounting studs at the top of the coilover and replaced them with 50mm long bolts. The bolts are quite snug as I drilled a 3/8" hole for them in the HDPE spacers which is slightly smaller than the 10mm bolt I used. Here's the shim on the coilover ready for install.


Here's a shot installed:


I later discovered that you can buy the shims here:
Saggy Butt Spacers But I made mine for a quarter the price.

Anyway, I have my inch back, the car looks much better and I love the ride. Absolutely no bounce, corners like it's on rails, but may be too stiff for the casual driver.

I still need to get it in for a proper alignment. I'll hold off on that till I look into the stacked washer idea.

Dale

[OhBe1]

Did raising the rear take care of toe without further adjustment?
And where did you source the coilovers?

[dschultz]

The affect of the toe-in problem was reduced with the extra height but I still need to have an alignment done. I'm not sure if there is enough adjustment in the rear to get it back to spec. toe-in though.

I got the BC Racing coilovers from AJW Performance over at LegacyGT.com

[bobbyjimmy]

If you keep having problems with toe (and camber?), Whiteline make a replacement lateral link set (4 arms, front and rear - not the upper that the bump stop touches).

[dschultz]

Just a quick update on my experience. Since installing these I decided the spring rates were too stiff for daily driving. So I picked up two 4kg/mm Swift springs and put them on the front. The ones I removed from the front (6kg/mm) were moved to the back to replace the 8kg/mm. I then set the spring preload to 45% of the stroke in front and 40% in the rear. The car is about 1.5" lower all around now and the suspension is much better than stock and more forgiving than it was with the stiffer springs. All in all, I'd say, coilovers are probably great for the track but not so much for the pothole ridden public roads.
I also have Whiteline rear camber inserts to be able to adjust the rear's camber back into spec., forting the Ghostwalk issue.

[timmafod]

Newb from central NJ here, just registered so i can post in this thread. Hello...

I just installed my BC BR coilovers on my '05 OBXT today after work. I also did not know they offered a 1" longer body, it's needed. I want OEM Legacy GT ride height (or slightly higher) and can barely get it. I feel the rear shock bodies are screwed out of the lower mount a little too far for my taste. The BC instructions state 25mm of shock body insertion into lower mount minimum, I went to 22 and had to lower the front to match the rears. I priced out 1/2 HDPE sheet from mcmaster and will build some spacers; I didn't think of stacking them up to get an inch increase and replacing the BC studs with bolts, that's a good idea.

I only have about 50 miles on my setup so far and no "after" pictures yet, I will take some tomorrow and post here. The ride is definitely firm but I am ok with that, for now. There is "bounce" however. Slight. Seems like perhaps too stiff a spring for my setup; my current oem sized allseason tires are pretty squishy. I am still waiting on my "summer" wheels to arrive and I'm sure the Bridgestone RE01R's I'll be running will affect this bounce as well. I still have to play around with the rebound adjustment to see if this affects the bounce; I set all 4 corners to "20", I figured on the soft side of the middle would be a good spot to start. i will price out 4kg springs but I am a suspension "newb", not sure what you mean about preload percent (as opposed to the 5mm preload BC specs).

I'm glad I found this post tonight, searching for DIY "saggy butt" shims. Take care!

EDIT: Mcmaster has 1/2x12x12 sheets for ~$10, or 1"x4x12 for ~$9. I don't know if 4" width is good enough, but even if it is it may be difficult to hole saw or jig saw through 1" material; even though I'd have to cut out 4 spacers when using 1/2 material it still may take less time to do than hack through 1" material twice. Hmmm...

[dschultz]

Hi:
Welcome to the forums.
I used some double sided tape (carpet tape) between the cutting boards and then cut the 1" stack all at once. With a good blade it shouldn't be a problem. Don't force it as heat will start to melt the plastic.
One 12"x12" board cut in half and stacked was enough for both rear spacers of 1" high. The 4" piece should be fine, it just needs to be as wide as the top of the shock mount.

If you are bouncy, two things could be happening:
1) the dampener is set to soft, 20 (from hard) should be okay... 8 clicks from hard is the default setting (my current setup is front 32 from hard (full soft) and the rear is at about 27 from hard)
2) you don't have enough preload in the rear an you are resting/hitting the rubber helpers. I removed mine in the beginning and eventually got the helpers for the Legacy Waggon and installed those.

As for ride height, you can max them out in the rear to 25mm, that's when the dampener is even with the top of the slots in the bottom mounting cup. Also setting the preload will increase the height.

To set the preload, measure the dampener rod length with the spring fully extended. Then multiply that by 40% (0.40) and that is the amount the rod should shorten once the car's weight is back on the spring. I used 40% for the rear and 45% for the front. It works out to about 34mm shorter than full length.
My last measurements for wheel arch height measured from the wheel centre cap is:
Front R = 15-11/16"
Front L = 15-11/16"
Rear R = 15-7/8"
Rear L = 15-7/8"
I need to come down in the rear a bit. With my preload set this way I can actually remove the HDPE spacers and use the min. 25mm height adjustment on the shock body.
Good Luck!

[timmafod]

Thanks the the reply. I follow what you mean about preload percent, thanks. I will pay around with the dampener settings shortly, yes I'm 20 from full hard. 3 of the 4 dampers were set to 8 in the box, the fourth was like 15.

I also installed legacy rear bump stops ("helpers") during the install as well, I forgot to mention that.

My rear bottom mounting cups are different than the ones in your picture. There's no longer large slots but rather 3 holes @ 120°, ~3/8" diameter. The top of the holes are 28mm from the top of the cup. I estimate with my calibrated eyeballs that the bottom of the shock body is ~5mm past/above the top of the holes. Is your lower retaining ring the newer "patented" tapered design? Perhaps this is why our rear bottom mounting cups are different.

Next up is researching those whiteline camber inserts. As-is, before any realignment, the car does wander quite a bit in the back.

[dschultz]

Is your lower retaining ring the newer "patented" tapered design?

I think so as these are only a year old.

[dschultz]

Alignment results are here.