BC Coilovers question for those with them

[Moss236]

I received my BC Coilovers yesterday and noticed that there is a dampening adjustment knob for the rears, but there does not appear to be one for the fronts? Is this correct?

[Solid Red 98]

There should be an adjustment on the front pair as well. The rear shocks on mine have a knurled adjustment knob, while the fronts have an allen socket style adjuster for some reason. (looks like what you have there) I had to fabricate a tool to adjust them easily. At first, I just glued a cut allen into a cheap knob from Home depot. Later, I glued a cut allen into a piece of flexible rod to accommodate the awkward angle for easy field adjustment.
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[Moss236]

Thanks guys!

[Fatboy 18]

How come they are so short compared to the OEM Koni

[river rat]

How come they are so short compared to the OEM Koni

I believe they are setup with a 1" drop from the factory.

[Boosted Motorsports]

I love my BC Racing coilovers. Had them for 3 years now and still working great!

[Viper98912]

I'll be putting mine on here in a few weeks. The stock suspension is a little bouncy (worn out) after 22 years...

[ACRSNK]

Where is the best place to buy BC Coilovers? Considering a set.

[Viper98912]

Got mine from whiteout

[river rat]

Anyone running these with the swift springs?

[DustyD]

I believe they are setup with a 1" drop from the factory.

thats kinda crazy that the spring itself is only about half the size of the oem spring!

[dave6666]

I believe they are setup with a 1" drop from the factory.

I would suspect they screw the bottom all the way on at the factory and to get the basic shock length correct the bottom will need to be unscrewed to match the factory shock length. Or whatever your length goals are.



Is it okay to talk about length goals on a forum that's mostly dudes? Asking for a friend.

[Fatboy 18]

So If i understand you dave, it would need a 1" extension? :lol2:

[GTS Dean]

I would assume then, that they have a range of top eye lengths to screw onto the shaft, keeping the body and shaft lengths constant. That's fine as long as the motion ratio of the suspension doesn't bottom- or top-out the shock piston.

Or, is the shock body screwed into an adjustable internal threaded cup-type lower, secured with a lock nut?

[dave6666]

The entire shock body is threaded as shown in the pic. You can therefore infinitely adjust the lower shock perch and the bottom eye until it un-threads and falls off.

[ky13]

I would assume then, that they have a range of top eye lengths to screw onto the shaft, keeping the body and shaft lengths constant. That's fine as long as the motion ratio of the suspension doesn't bottom- or top-out the shock piston.

Or, is the shock body screwed into an adjustable internal threaded cup-type lower, secured with a lock nut?

The bottom collar is to adjust height (and lock it in place), the upper collars are to lock in preload.

[dave6666]

I pulled out a new BC and used OEM to look at the length difference and it's about 1-1/4". Another interesting discovery is the 1-3/8" long snubber under the boot on the BC albeit they both have 4" of shaft travel sans the snubber on the BC

So has anyone every studied the geometry on these? Or does everyone just throw them on the car? That's a lot of lost suspension droop.

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[GTS Dean]

The G2 Viper does not have a bump stop on the wishbone like the G1 rears do, so the shock has it installed to keep from bottoming out the piston in the shock body at full bump and making your spring rate go to infinity as you lose control of the car. If you look up under the top eye cap on the OEM shock, you will see a bump rubber tucked up there. Racing shocks are typically fitted with a variety of shapes of bump rubbers to control the spring rate increase as it approaches full bump.

I have exchanged emails with several people who asked about the BC product. I have never held or seen one in real life, but looking at pics similar to those above, I've noted that they all tend to be delivered MUCH shorter than the OEM shock. If the shock goes to full droop as you unload over a hump in the road, without enough rebound damping, your shock piston will crash into the threaded cap at the top of the shock body. This doesn't happen very often in most cases, but could regularly occur on the inside tire if you corner hard enough at the track. I would be interested in how close to the OEM length the BC lower eye cup can be adjusted.

Is there any mention of this critical adjustment in the installation instructions?

[river rat]

Hilarious that Dave chose to take a pic sitting right on top of a Roe supercharger.

[dave6666]

It was the only clean spot in my garage right now. I'm in extreme clutter mode.

[dave6666]

The G2 Viper does not have a bump stop on the wishbone like the G1 rears do, so the shock has it installed to keep from bottoming out the piston in the shock body at full bump and making your spring rate go to infinity as you lose control of the car. If you look up under the top eye cap on the OEM shock, you will see a bump rubber tucked up there. Racing shocks are typically fitted with a variety of shapes of bump rubbers to control the spring rate increase as it approaches full bump.

I have exchanged emails with several people who asked about the BC product. I have never held or seen one in real life, but looking at pics similar to those above, I've noted that they all tend to be delivered MUCH shorter than the OEM shock. If the shock goes to full droop as you unload over a hump in the road, without enough rebound damping, your shock piston will crash into the threaded cap at the top of the shock body. This doesn't happen very often in most cases, but could regularly occur on the inside tire if you corner hard enough at the track. I would be interested in how close to the OEM length the BC lower eye cup can be adjusted.

Is there any mention of this critical adjustment in the installation instructions?

The installation instructions that I received are basically "Guud ruck fo U!" The bottom cap can be extended out about 1/8" additionally while still retaining all the threads available in the bottom cap. So the 1-1/4" difference in length could become 1-1/8". It could be unscrewed out to get you to 3/4" delta by not using all the threads but I'm not going to do that without taking a look at the geometry first.

The risk is of course the wheel lifts off the ground on extreme extension of the shock as it can't extend as far downward.

The factory shock does have the snubber up in the top of the eye but that's after the 4" of shaft travel. The BC is 4" of shaft travel minus the snubber. Big difference there.

I don't doubt these can be set up to work well on the Gen 2 but the geometry does concern me. I'm going to play around with them to see just exactly what the difference is in full suspension articulation between the BC and the OEM shock. I least I'll have it written in my notes what my cause of death is.

[ViperTim]

Subbing for further investigations!

[GTS Dean]

The bottom cap can be extended out about 1/8" additionally while still retaining all the threads available in the bottom cap. It could be unscrewed out to get you to 3/4" delta by not using all the threads but I'm not going to do that without taking a look at the geometry first.

I would feel comfortable uscrewing the cup to around 50-60% of available travel since the loading is axial thru rod end bearings.


I don't doubt these can be set up to work well on the Gen 2 but the geometry does concern me. I'm going to play around with them to see just exactly what the difference is in full suspension articulation between the BC and the OEM shock. I least I'll have it written in my notes what my cause of death is.

The sticktion in the wishbone bushings will limit the full articulation of the suspension if you're still on stockers. You could loosen the pivot bolts for full range of motion, but I would recommend following the ballast/torque procedure less the height checking step. I put blocks under the lower wishbones and set them on slip plates before torquing the pivot bolts so they wouldn't be bound up. With the spherical bearings in the shock eyes, you don't need to worry about torquing them at ballasted height.

[river rat]

It was the only clean spot in my garage right now. I'm in extreme clutter mode.

When you get ready to de-clutter some more, let me know what it might take to pry that Roe from ya.

[dave6666]

When you get ready to de-clutter some more, let me know what it might take to pry that Roe from ya.

I have a growing audience for that item. It's one of 4 that have had the lower plenum volume modified. Has ID1000 injectors and a JMB long airbox. Startup tune available i.e. my old tune by Dan Lesser. Injector harness by Dan Lesser. Fuel lines by myself and Dan Lesser. MAP located directly on intake top plate and relocation included in injector harness, not remote mount MAP like comes originally so the wires reach. A well featured kit. Currently sealed up in a large industrial poly bag to keep it clean and sparkly until it is more in my way than I can stand. We never dyno'd it but I had 3rd gear traction issues at 100 mph. [x] hauled the mail [ ] did not haul the mail.

[Moss236]

37499
Got them installed, they improved the handling quite a bit and much better ride! Left them set to the drop set from the factory until I get new wheels installed next week then I will dial the height in.

[GTS Dean]

^^^^^^
Love that stance and the satin CCW's!

[ViperTim]

I've never lifted a wheel with BC, same roads as my girlfriend's stock GT3, which lifts the wheels. I've also never hit the bump stops, but I am LOW, so the car hits the road before the bump stops see any use. :lol2:

https://farm5.staticflickr.com/4817/39937974343_47884c7aa5_c.jpg

Most coilovers are significantly shorter than factory springs & shocks/struts.



Out of the box they are about the same drop as Eibach springs.



I've been running standard springs front shocks 15 clicks from soft and rear's 12 clicks from soft on my GTS for the past 30k miles and the ride is very similar to GEN2 ACR. Swift will give more of a linear compression/rebound and if you track the car will get better feedback.

Overall, if you're going between lowering caps or lowering springs on stock shocks, then the standard springs are worlds better.

What size rims and tires are those?
That sits low and mean!