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Author Topic: BC Racing BR Coilovers With Custom Spring Rates  (Read 18352 times)

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Ben L

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BC Racing BR Coilovers With Custom Spring Rates
« on: May 01, 2009, 08:42:08 AM »
My BC BR coilovers from Circuit Motorsports arrived yesterday.  It took a little while, because the stocked item comes with 7kg/mm springs front and rear.  To tame the understeer demon, I special ordered mine with 6kg/mm fronts and 8kg/mm rears.  According to the conversion factor I found through the magic of the Interweb, that should convert to 335 lbs/in. in the front, and 446 lbs/in the rear.  Comparing this to the 175/220 lbs stock GXP springs, this should be considerably stiffer. 

No, I do not care much about ride quality.  The BCs also have 30 position damping adjustability, controlled by a knob on the top.  This should be easily accessible on the fronts, where I think most of the tweaking will happen.  I am sure my setup choices will reinforce Snapon and others' opinions that I don't know what I'm doing, generally, and specifically, in maintaining the stock front/rear bias in switching to coilovers.  Probably that I am going too stiff, as well.  They may be right.  But I've never been one to take advice very well, and I have my own ideas.  Like all of us in life, I must walk the course I have charted for myself. 

Initial impression right out of the box:  the precision and quality of the machining, materials, and finish visible to eye are outstanding.



They have high pressure nitrogen charged 53mm bodies, made from nicely machined and black powdercoated aluminum.  The locking rings are very precisely machined and nicely finished gold andonized T6061 aluminum.  The piston diameter is 43 mm.  There is a nice poly bumpstop, and the shaft is protected by a rubber boot.

There is a lower locking ring, and the lower outer body rotates permitting you to set the "bottom" for corner weighting, and the body is nearly fully threaded, making for almost infinite ride height adjustability.

The fronts come with pillowball (spherical bearing) mounts, and the rears with rubber mounts.  The mounting plates are thick T6061, also andonized gold to match the locking rings.



There are a number of pleasantly surprising detailed touches, which, Chinese or not, suggest precision and quality. 

Each damper is dyno tested before it leaves the factory, and matched to within 5%.  They put a little sticker with handwritten results on the top of the body under the boot.



The lower mount bushings are high density poly, not rubber.



The price was $999, with the custom springs, and a set of pillowball mounts for the rears (I might use them, but they may be too harsh) delivered to my office. 

Chris at Circuit Motorsports was a pleasure to deal with, and indulged my desire for extras without any trouble.  Yes, I had second thoughts when I saw the HKS deal from DDM.  But these look pretty nice, and they get high praise from owners of other marques.  BC also makes a bunch of well known dampers for the tuner crowd. 

They are unabashedly, unapologetically Taiwanese made.  But they are proud of their spiffy huge factory and quality control focus, and splash both all over their packaging.  Sometimes in hilariously butchered English.

I do think, Taiwan or not, they are serious about quality and precision.  We'll see.

In conclusion, out of the box, they look pretty nice.  I am very much looking forward to mounting them, and running them hard.  I will post a second "function" review when I have them on.

« Last Edit: May 17, 2009, 09:02:00 AM by DeepBlueGXP »

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #1 on: May 01, 2009, 01:15:53 PM »
Thanks for the update.  I look forward to your review.

lil goat

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #2 on: May 01, 2009, 02:24:00 PM »
You put some thought and some of your own engineering into these, I hope they work as expected.

Ben L

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #3 on: May 15, 2009, 08:55:52 PM »
Going out to Urbana where my friend Larry has a lift and alignment tools, and mounting the BC Racing coilovers tomorrow. 

Install pics and performance review to follow . . .  :drool:

Ben L

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #4 on: May 16, 2009, 09:36:18 PM »
Not sure anyone's reading, but I'll put it out there anyway.

I just got back from successfully installing my BC Racing coilovers, and slapping a quick alignment on my GXP.

I have to say this is a very worthwhile mod, and the BC's deliver a whole lot of performance for the money.

We set the ride height as low as seemed practical for the street, and even then, I am rubbing the bottom edge of the air dam on steep driveways and speed bumps.  But dropping the car really improves the looks of the OZ wheels and Dunlop Dirrezas I am running.



I ordered my BCs with 6kg/mm front springs and 8kg/mm rears, maintaining the stock springs "softer front/stiffer rear" bias, in a continuing quest to try to conquer my car's understeering tendencies.  To start, I set the damping at 10 out of 30 clicks for the front, and 20 for the rear.  I had my friend Larry, an accomplished local Cobra driver and seriously competitive autocrosser test drive it before and after with me riding passenger.  The car corners noticeably flatter now, with zero body roll, tosses right to left under power with alomb, and plants into a set and stays put.  The pushing is nearly gone. This was tested by Larry going flat out down a twisty country road near the top of the tach in 4th and then braking hard (activiting ABS) into an off camber down hill right hander on rough pavement.  The car tracked right through the corner like it was on rails, without any of the familiar protesting noises from the front tires.  In fact, the rear even walked out a little, and then hooked up as throttle was applied.  Perfect!

I also have to say that although I nearly doubled the stock spring rates, the ride is not nearly as harsh as I was expecting.  The suspension is very firm, but even over bumps and uneven surfaces, the BCs damp well and I experienced no wheel hop or skipping around, and all my fillings stayed in my teeth!

The installation was time consuming, but really straightforward.

Remove 18 mm upper LCA ball joint nut.  We used a soft BFH (could not find the pickle fork and wanted to save the boot) to dislodge the ball joint.  No problem.  Surprised to see no castle nut or cotter pin.  We made sure to torque these and all other fasteners to spec!

Disconnect sway bars.  Please don't be stupid like us and pop off the rubber cups from the steel ball studs.  There is an Allen keyhole in the end of the machine screw.  Use an 18mm ratcheting wrench and an Allen key.  Its tight and on the rears you can only get 1/4 turn at a time.  Be patient. 

Remove bottom two 13mm shock mount bolts and nuts.  Remove 15 mm upper shock mount nuts.  Push lower control arms down, and walk out the sprung Bilsteins, intact.  Bingo, time to slap in the coilovers.

Front and rear are nearly exactly the same.









Installation was the reverse.  We loosened the locking rings so the springs would not load when installing the coilovers.





We used a hole saw to cut a little hole in the trunk so that the rear adjuster dials were accessible without removing the wheel.

Conveniently, the carpet was already cut in that location.  I will clean up the loose fibers and probably make a rubber grommet later.





Setting ride height was next.  We used a precision steel rule, measuring between the upper locking ring and lower locking ring at the base of the shock.  Got it right on the second try!





Alignment was tedious, as always.  Target was negative 2.3 deg. camber front, neg. 1.3 rear, with zero toe.  Right side was nearly spot on.  Left side took a few tries but we got it within a tenth or so.

Alignment is adjusted using eccentric cam bolts, two per control arm, per side.  Nicer than shims!





Had to take some toe out after setting camber. 

Anyway, a very worthwhile and enjoyable day.  I really believe the BCs are steal for the money.  The handling and neutrality of the car (and now adjustability) is really light years ahead of where I started.
« Last Edit: May 17, 2009, 09:05:22 AM by DeepBlueGXP »

Offline DeepBlueGXP

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #5 on: May 17, 2009, 09:08:46 AM »
Awsome.  Love the looks.    Did you put greased skid plates under the tires for doing the alignment.

Ben L

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #6 on: May 17, 2009, 12:47:29 PM »
I do have a set of metal ball bearing turnplates, but you busted us, Joe. 

Remember I said we slapped a quick alignment on there?  We measured and set camber and toe, front and rear, but did not measure or reset caster. 

You measure front caster across a 20 degree range by turning the wheels on plates, but plenty of folks just use garbage bags, or anything slippery that will allow the tires on the lift or floor to turn freely, with the car sitting on the suspension.  I like my plates because they have a little protractor and pointer, so that you can count off the degrees predictably and accurately.  You need a special digital guage to measure rear caster on our cars, I understand.

As I've been taught, and observed myself, in terms of what the driver feels, caster translates to return force in the steering wheel.  Meaning, when you jam a turn how much does the steering wheel want to return to center?  Caster also is related to bump steer, but I am still figuring that out. 

I like tons of caster in the manual racks I run on my Cobras.  I have always liked the "wheel feel" of the GXP.  Plenty of return force and power steering that is not overboosted, and linear (doesn't get progressively easier or harder as you turn).  That all makes for good road feel.

Anyway, when we test drove (the ever living snot out of) the GXP after the alignment, there was still plenty of that really good return force in the wheel.  Also, in the front we ended up at - 2.3 degrees left and -2.2 degrees right on camber, and only needed to move the left about a hash mark and a half (with plenty of adjustment remaining) and the right not at all (lowering generally speaking will increase neg. camber).  So I do not think we dramatically altered caster.

I was really happy to learn that DIY alignments are not too hard on our cars.  I have to make some fine tuning adjustments, but we got pretty darn close on the alignment, done the last hour and a half before sunset, after a long day.

I just got back from another long run.  New suspensions settle, so driving on them a lot is a good idea.  The car is as slammed as low as you'd want it, gets around OK (have to take speed bumps at an angle, but that's about it).   

But the real payoff is the performance, which is awesome.  And performance, after all, is why we are all here!

Offline GXPinKC

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #7 on: May 17, 2009, 01:45:36 PM »
Ben L, masterful job of documentation and the pictures told the whole story as they should.  Thanks for the great post.  Take pride in the end result.  Your Deep GXP should drive and handle like a Swan on ice skates.   :brnout:   Can't wait to see it at a Meet some day.

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Offline Critterman

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #8 on: May 17, 2009, 06:42:23 PM »
Great write up Ben.
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lil goat

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #9 on: May 17, 2009, 07:11:08 PM »
Very nice write up Ben, my HKS go on next weekend. I will take some pictures, I have not even seen mine yet as the DDM guys are taking them to Joe's. I hope I come out as well as you did.

Ben L

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #10 on: May 17, 2009, 07:41:09 PM »
You are going to love them!

lil goat

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #11 on: May 18, 2009, 06:23:44 AM »
I know I was able to push the car to pretty close to it's limits running the other weekend, I was leaning so much on some of the switch backs I was uncomfortable. I look forward to that going away.

Ben L

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #12 on: May 18, 2009, 06:26:25 AM »
That is the first, most noticeable change.  NO body roll.  The car just hunkers down into the set it takes in a turn and stays there.

lil goat

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #13 on: May 18, 2009, 08:03:22 AM »
I get the Pro Beam at the same time, should be SWEEEEEEET! Finally the package is complete, sticky tires lightweight wheels and the DDM goodies and now the coilovers.

Offline LatinVenom

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #14 on: May 18, 2009, 06:37:36 PM »
The ProBeam is a most to complete the handling package.
Are FE3 suspension is pretty darn good, and it will closely match the ZOk once you add the ProBeam and BackBone.
Take it one step further and add coilovers, whether your wallet can buy the BC,  B&G, HKS or higher and you will have a superb handling machine.   
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lil goat

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #15 on: May 19, 2009, 06:21:35 AM »
The ProBeam is a most to complete the handling package.
Are FE3 suspension is pretty darn good, and it will closely match the ZOk once you add the ProBeam and BackBone.
Take it one step further and add coilovers, whether your wallet can buy the BC,  B&G, HKS or higher and you will have a superb handling machine.  

LV your not paying attention, the HKS coilovers go on with the Pro Beam, and DDM is doing the corner weighting at the same time. My suspension will be DONE!

Offline wspohn

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #16 on: September 03, 2009, 08:08:11 PM »
So how did the difference in spring rates work out for you long term?

Do you feel that softer in the front is the way to go?
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Ben L

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #17 on: September 03, 2009, 09:01:33 PM »
Great and absolutely I do. Love the much stiffer rates, and tendency to push is minimized by the front/rear bias and running the front damping soft.  Finishing touch will be a Z0K bar  in the rear.  I will then likely back the damping off a bit in the rear. 

BCs are holding up great to harsh city driving, but also made my car a low slung super grippy speedster.  They helped a lot autocrossing.  I wish I could get soem track time. 

If I was going to continue to ax the GXP, I would mark the stock location on the tie rod, dial in a tad of toe out on site, to make it turn in better, and reset it before going home.  Other than that, the suspension and chassis are set as far as I am concerned.  Except for maybe those rod end billet control arms . . . .

Offline kennysabarese

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #18 on: September 03, 2009, 09:30:53 PM »
I'm debating between these and the KWv3's  1,000 bucks difference in price :)
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Offline Uranium-238

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #19 on: September 03, 2009, 09:33:12 PM »
How much are the BC's?
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Offline kennysabarese

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #20 on: September 03, 2009, 09:34:20 PM »
solstice sport has them listed at 975 and then 10% off if you sign up for the newsletter
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Offline Uranium-238

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #21 on: September 03, 2009, 09:58:34 PM »
That's odd. I was looking at the Saturn-sport page this morning, and noted they were out of stock. However, on solstice-sport they're in stock.
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Ben L

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #22 on: September 04, 2009, 06:36:17 AM »
Solstice Sport's is a great deal.  BC makes coilovers for lots of "private label" makers.  Given their quality of workmanship and solid performance, I really would have a hard time justifying spending double for anything except maybe double adjustable Konis

Offline kennysabarese

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #23 on: September 04, 2009, 06:58:47 AM »
KW's are double adjustable and German. So they MUST be good ;)
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Offline Uranium-238

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Re: BC Racing BR Coilovers With Custom Spring Rates
« Reply #24 on: September 04, 2009, 07:02:08 AM »
My experience with German products is that they're often the best in the business, but also terribly expensive.

That being said I tend to pony up and pay the extra price...some of their products are that good. hk, anyone?
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