BC Racing ER series coilover comprehensive review!

[antonch]

Preface

First of all, I think there are way too many bias on the forums. I am not new to modifying cars and I can totally see a group mentality forming on each car forum. Just try to different Subaru forums and you will immediately notice that each suspension/track section will have some group recommending a similar setup. Now this is not particular to Subaru's, I've seen it happen many of times on other car forums. I believe that a self-reinforcing feedback mechanism is responsible for this behavior. Someone buys a setup that is proven to work well, the next consumer will go with the recommendation of what has worked well in the past, and this process repeats itself until everyone in the group eventually has a similar setup. I decided to try a different and less reputable product just to see how well it stacks up to manufactures claims.

This review will start out pretty informative with my commentary peppered in and out and will get more opinionated near the end.

BC-ER series CO

These coilovers are manufactured by BC Racing (not to be confused with Buddy Club). They are well known for producing their cheaper BR series coilovers. The ER series coilover is a mono-tube shock coilover with an external reservoir for independent dampening control. There are ~30 levels of adjustment for both Bump and Rebound, adjusted independently. Spring preload and ride height can be adjusted independently of each other.

Coilovers come with pillowball mounts, camber plates in the front and rear, and finally rebound adjustment knobs for the rear seat. The adjustment knobs are a very nice addition to the package and a must for any coilover in my opinion. I can adjust the dampening without the hassle of removing the rear seat.

In addition, coilovers can be ordered with any spring rate combination: 8/6 kg/mm, 10/8, or 12/10. I ordered mine in the stiffest setup available: 12/10k f/r setup (650/550#'s springs). The math works out to ~2.6/2.8Hz for techies that understand ride frequencies. My friends thought I was crazy.

Packaging
The box was promptly drop-shipped straight from Taiwan via DHL. Everything came in in one big box. Each coilover was already pre-assembled and packaged in a smaller box wrapped up with popcorn. The smaller boxes had several holes although no damage to the coilover was observed.







The package contained:
-4 fully assembled coilovers
-2 adjustment wrenches
-BC racing sticker
-A poorly translated instruction manual

Out of curiosity I immediately took them apart. It's a shame that special tools are not provided to remove the pillow-ball mounts. Tien provides a wrench to remove the top nut. I had to look for extra tools to remove it without damaging the shock.

In the picture below you can see the coilover fully disassembled.


The coilover seem to be built with quality in mind. The dust boots are very thick. The metal locking rings look like they are coated with a rust proof material. External reservoir is connected by a stainless steel braided line. The shock body itself has been dipped in a pretty thick coat of paint, it looks nice and glossy. Upon installation I found out that the paint is very easy to scratch off. If you are not careful, the coilover will not look as nice once installed. I am glad I do not live in an area where it snows, otherwise a Stainless Steel coilover would be much more appropriate.

The bump stop is about 1.5" long. It is hard as rock. It is made of some incompressible rubber that I could not compress by hand. With the bump-stop installed there is about 2.5" of shock travel available. This should be plenty for a street car. Remember that on these coilovers ride-height and spring preload are adjusted separately so the amount of shock travel does not change no matter how low you go. This is a very nice design feature.


Pillow ball mounts felt very tight, there was not a whole lot of play. It took a lot of force to move them around. My main concern at the time of install was that they are going to squeak and make a lot of weird noises. They ended up being OK.

To my disappointment the front and rear springs are different lengths. I am sure there is a good reason to do this. I’ve seen other manufacturer’s package a helper spring in the rear just to be able to interchange springs. I was not aware of this at the time of purchase. You will not be able to put the front spring in the rear.

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[antonch]

To take my curiosity level a step further, I had all four dampers shock dyno’d. Front and rear left got the full sweep at various bump and rebound combinations. Front and rear right were only checked for matching. Dyno plots are located below.






Prior to ordering the coilovers I requested a set of shock dyno sheets from the seller. He has provided me with a dyno at extreme settings. Event thought the information was incomplete, it gave me an idea of their adjustment range and roughly where I would want to run them. Kudos to the seller, there are very few companies out there these days that will provide shock dyno’s to their products.

Summary of the shock dyno sheets:
-Little to no cross talk between bump and rebound
-Rebound has a ton of adjustment range
-Bump adjustment is not as sensitive
-First 10 clicks on bump adjustment do nothing
-Bump curve looks pretty digressive
-Rebound curve starts pretty progressive then becomes linear and you stiffen it up even further it becomes slightly digressive. This is just the way the bleed and shim stacks adjust.
-Each coilover is very consistent. Data that you see is the actual raw data with no averaging. Most of the time you will see a shock dyno with only five points tested and straight lines drawn in between. We tested the shock at setting 15 then went to full stiff and back to 15 and were able to get the same plot all day long.
-There is slightly too much bump dampening, I would like to have the room to go just a tad softer.
-Front and rear dampers are valved exactly the same
-There is about 2 click offset between left and right dampers

A little side note on damper curves, I have a stack of about 10 papers on my desk right now on just dampers. It is by far one of the most misunderstood suspension components. No one really knows how the best damper curve should look like. There are few high end motorsport grade dampers that are valved linearly while some are digressive. I personally prefer linear damper curves only due to their simplicity. Controlling a linear spring is simplest with a linear damper.

The progressive rebound curve itself is not a problem but the changing shape is. You end up increasing the low speed rebound much faster than the high-speed part. This will change the coilover feeling as you increase the rebound. It also makes front and rear dampening tuning more of a headache.

The front and rear dampers appear to be the same internally. Most likely they have just different mounts fabricated. This is a big money saver for them. I would not be surprised if the dampers are also similar for other vehicles with just different mounts. Using the same damper for front and rear is not a big of a deal as the adjustment range is huge, it has enough room to cover both front and rear. The changing rebound shape is a problem. For example, say you chose a setting in the front with 70% CD(critical dampening) at low speed and 50% CD at high speed. Since the spring rate in the rear will be less than in the front, you need to run a lower rebound setting in the rear. So then you chose a setting that gives 70% CD at low speed but since the shape of the curve changes, you may end up with 80% CD at the higher speed. This was a headache for me.

Left and right dampers are mis-matched by about 2 clicks on both dampening and rebound. It’s is not a big deal for dampening because each click does not do as much. 2 clicks on rebound is a ton of change though, it’s something that one ought to feel. The mismatch appears to be fairly consistent throughout the adjustment range—it’s a consistent 2 click offset at full soft and full firm.

Install
Installation of these coilovers just as with any other coilover is very straight forward. Install went without a glitch. One word of note, at the alignment rack we were able to get only ~2* of camber up front even with the camber bolts. I do not think it was an installation issue but something to keep in mind. In the rear there is room for a ton of camber adjustment. You can go as much or as little as you want. During the install one of my concerns was the clearance between the stainless steel braided line and the CV boot. I didn’t snap any pictures but while the car was on the alignment rack I took a sneak peek. There is a little over 1” of clearance. Even if you slam your car, you should have no problems clearing the CV boot.


There are adjustment knobs on both rebound and bump. Compression is adjusted on the external canister. Rebound is adjusted at the top of the shock tower. It is nice not to have to carry tools with you and be able to adjust the damper without getting your hands dirty. As I mentioned earlier, rebound could be adjusted without pulling the seat.



Ride impressions

Dare I say that these coilovers are actually comfortable? Yes! My daily commute from work and back is about 100 miles and I still consider them to be very comfy after putting ~5000 miles on them. They are actually feel more comfortable than stock suspension. I know its not a very good comparison to stock suspension as pretty much anything out there is softer than stock. In my opinion stock suspension is fairly harsh, but the BC coilovers just absorb all the little bumps. I would not mind taking this car to a 5 hour road trip.

So far I heard nothing but positive things about the ride. My gf approves it. My friend asked me if they make these coilovers for his car. My alignment guy, who is involved in auto-x/track events, likes how responsive the ride was to inputs.

I still have not been able to take the car to any auto-x/track event but the car feels very neutral on the street. With these spring rates body roll is virtually unnoticeable. I am a little surprised as I am pretty low by the forum handling guidelines. But I guess this is the case where you are so stiff that it doesn’t really matter how low you are, the suspension will not compress any more. When you jack the car up there is only about an 1” of movement before you start to lift the wheel. The extra roll resistance is most noticeable on tighter lower speed corners. I remember a corner where you would start to feel the front end start to roll and push. No more, it feels just as neutral. I noticed that on higher speed corners I am able to go faster. Again think, lower CG, less camber loss being the dominant effect here.

As far as noise goes, they are pretty quiet. No squeeks nor rattles. With the rear seats off I can hear only Psst, Psst, noises come from the shocks when I go over bumps. The overall vehicle noise did go up. This is especially noticeable on rough roads. The solid camber plates do not provide the same isolation as stock rubber mounts do and transmit the high frequency vibrations to the chassis.

Below are my recommended base settings to try and dial in from there. These settings will not apply to a different spring rate. All settings measured in clicks from full soft.
My setup: all stock otherwise for TIC fender braces, Kartboy rear endlinks, 245/40/17 RE-01’s.

Super soft (if you are in cupcake delivery business)
Bump (f/r): 15/10
Rebound (f/r): 10/7

Full soft (recommended street setup)
Bump: 15/10
Rebound: 15/10

Medium (track setup)
Bump: 25/10
Rebound: 20/18

Full stiff (auto-x setup)
Bump: 25/10
Rebound: 23/20

Super soft and full soft settings focus on ride comfort and maximize the total amount of road grip. Medium setup is a good compromise between road grip, overall vehicle control and transient response time. The comfort level is pretty comparable to stock and as I said earlier I do think stock is a tad harsh. Full stiff maximizes vehicle response and control. It is far too uncomfortable and twitchy for the street.

Overall, I am very happy with the coilovers. They are very comfortable. I would recommend these to someone who wants a solid coilover for the street. They can be easily adjusted for more dampening, perfect for someone who wants to take their car to twisties, auto-x, and open track day events on the weekends. Due to the funky rebound curve and poor left-to-right matching I would not recommend these for someone who does serious competitive racing. It’s a shame though considering how consistently these coilovers perform.

[IMPORTIMAGE]

thank you for taking the time to review these for us!

i think it will give others an idea of where to start with as well considering most have not posted yet.

[STi 33W]

excellent review. I have these at home waiting to go on my 06 STI. Same spring rates too. I will definitely make use of your bump/rebound recommendations since I will have too many other things to do to play around with that.

[boost junkie]

I applaud you for taking the time to dyno them and get into a more technical review. A few observations:

-That is...not a lot of bump travel at all. I imagine with softer spring rates that are more along the lines of what most people would use on a street car, you would be in the bump stops often.

-That's a lot of bump and very little rebound damping. I'm surprised the car isn't really bouncy with that little rebound and those spring rates.

-Using the same dampers front and rear is good for cutting costs, bad for everything else. You can band-aid it by playing with the settings but it's not the proper approach.

-From the pictures, the quality of the little parts like camber plates, upper spring perches, adjuster knobs, etc. looks pretty good.

-The mismatched dampers seem to be par for the course, but don't underestimate the effect this can have, especially if the rebound adjustment is fairly sensitive.

I can't express too strong of an opinion without driving or at least riding in a car that has them installed, but these are the things that stood out to me in your review. I also thought the preface was kind of ironic since BC's are probably the single most common suspension setup on this forum

[lemon19mmm]

when's ur next track day, antonch?

I would like to ride with you for couple laps if you let me. ^^

How about the next buttonwillow cw13 event (August 1st)? I will be there.

[Mind]

Great writeup.

On the dynos, the rebound is the upper half, correct?

Overall the shocks are a lot more consistent than I would have thought - I think the 2-click offset on the rear is quite good, and the repeatability of the fronts at 15 was impressive.

[antonch]

Originally Posted by STi 33W

excellent review. I have these at home waiting to go on my 06 STI. Same spring rates too. I will definitely make use of your bump/rebound recommendations since I will have too many other things to do to play around with that.

Great choice on the spring rates. I am really starting to think that this may be the most appropriate spring rate combo for the GD chassis.
Don't delay and install them. Post up your findings once you do!

Originally Posted by boost junkie

I applaud you for taking the time to dyno them and get into a more technical review. A few observations:

-That is...not a lot of bump travel at all. I imagine with softer spring rates that are more along the lines of what most people would use on a street car, you would be in the bump stops often.

-That's a lot of bump and very little rebound damping. I'm surprised the car isn't really bouncy with that little rebound and those spring rates.

-Using the same dampers front and rear is good for cutting costs, bad for everything else. You can band-aid it by playing with the settings but it's not the proper approach.

-From the pictures, the quality of the little parts like camber plates, upper spring perches, adjuster knobs, etc. looks pretty good.

-The mismatched dampers seem to be par for the course, but don't underestimate the effect this can have, especially if the rebound adjustment is fairly sensitive.

I can't express too strong of an opinion without driving or at least riding in a car that has them installed, but these are the things that stood out to me in your review. I also thought the preface was kind of ironic since BC's are probably the single most common suspension setup on this forum

1. I really do not want to turn this into a coilover comparison but so far the travel range has not been a problem. With the spring rates that I used, I have yet to hit the bump stops.
A little back of the envelope math: with bump stop installed there is ~2.5" of travel. At ride height suspension will compress by ~1". You still have about 1.5" of travel left.
2. You are looking at the dyno all wrong. Rebound dampening is above the x-axis. 1000lbf at 10"/sec is more than enough rebound dampening even for 650# spring.
3. I had my shocks dyno matched, that was definitely worth getting done.
4. BC is the most popular coilover installed because of the low price, I don't think its that widely adopted by the enthusiasts though. I suspect they can make afford to sell them so cheap by sharing shocks across different chassis and having a manufacturing facility in Taiwan. What really sold on these coilovers was that for well under 2,000 shipped I got a coilover with whatever spring rates that I wanted, camber plates all around, and the warranty.

Originally Posted by lemon19mmm

when's ur next track day, antonch?

I would like to ride with you for couple laps if you let me. ^^

How about the next buttonwillow cw13 event (August 1st)? I will be there.

Buttonwillow is too far from me. Infenion is much closer but I heard Thunderhill is a good first day track. I missed the i-club track event a few weeks ago. I am definitely interested in taking my car to the track though.

Let me know if you go to a closer track.

Originally Posted by Mind

Great writeup.

On the dynos, the rebound is the upper half, correct?

Overall the shocks are a lot more consistent than I would have thought - I think the 2-click offset on the rear is quite good, and the repeatability of the fronts at 15 was impressive.

Thanks, yup yup rebound is uppper half.

I was a little surprised by the consistency myself. The guy that did the testing also made a comment on that.

[boost junkie]

Originally Posted by antonch

1. I really do not want to turn this into a coilover comparison but so far the travel range has not been a problem. With the spring rates that I used, I have yet to hit the bump stops.
A little back of the envelope math: with bump stop installed there is ~2.5" of travel. At ride height suspension will compress by ~1". You still have about 1.5" of travel left.
2. You are looking at the dyno all wrong. Rebound dampening is above the x-axis. 1000lbf at 10"/sec is more than enough rebound dampening even for 650# spring.
3. I had my shocks dyno matched, that was definitely worth getting done.
4. BC is the most popular coilover installed because of the low price, I don't think its that widely adopted by the enthusiasts though. I suspect they can make afford to sell them so cheap by sharing shocks across different chassis and having a manufacturing facility in Taiwan. What really sold on these coilovers was that for well under 2,000 shipped I got a coilover with whatever spring rates that I wanted, camber plates all around, and the warranty.

1) 1.5" of bump travel is nothing. It's enough to get you by on a perfectly smooth road or track, but think about what happens when you hit a mid-corner bump and the loaded side of the suspension wants to compress. Even with those spring rates, you will be in the bump stops. With normal street spring rates it'll be even worse. I don't know how my comment was turning this into a comparison, I didn't mention any other coilovers.
2) I don't know what kind of shock dyno you're using, but I have never seen a dyno that displays rebound on top and compression on bottom. I believe you are the one who is reading it all wrong.
3) What do you mean by dyno matched? Are you saying you asked BC to choose dampers with matching dyno plots for your set? Because you said that when you independently dyno tested them they were mismatched. My point is, you shouldn't have to make an educated guess as to how different the settings need to be from one side to the other in order for the damping rates to be the same.
4) I understand why they are popular, and why they are so inexpensive. Some may disagree with me, but I would say that the things that make them affordable are also the things that make "enthusiasts" shy away from them. You do get a lot of features for the money, but the most important part of any suspension is damper valving and construction quality. No matter what I say, BC will continue to sell coilovers and life will go on, I'm just offering my opinion based on the information that's in front of me.

[Mind]

Originally Posted by boost junkie

2) I don't know what kind of shock dyno you're using, but I have never seen a dyno that displays rebound on top and compression on bottom. I believe you are the one who is reading it all wrong.

I've seen some Koni dynos around here that had rebound on top, so I think it's just an axis thing.

1.5" bump travel before the bumpstop - is that more than a stock STI?

[boost junkie]

Originally Posted by Mind

I've seen some Koni dynos around here that had rebound on top, so I think it's just an axis thing.

1.5" bump travel before the bumpstop - is that more than a stock STI?

Interesting...seems ass backwards to me but if that is in fact the case, I retract my statement. Or I should say I reverse my statement, that would make them look pretty underdamped in the compression department.

Comparing bump travel between these and a stock STi isn't exactly apples to apples. Unloaded, these have about 2.5" of bump travel before the bump stop, which appears to be linear and quite hard. The stock STi has about 3.5" before the bump stop unloaded. The difference is, the stock setup obviously has much softer springs, so at static ride height they will compress quite a bit more. However, the stock struts use progressive bump stops that are designed to work almost as a secondary spring. Why they did it this way, I don't know. But that is a big contributor to the bouncy ride and poor turn-in response of the stock car. Trimming one progression off the stock bump stop seems to help, but there's no doubt that the stock struts are very limited in bump travel. Overall stroke isn't bad though, they just have a lot of droop.

[Mind]

Just for ref here's the Koni dyno that had the rebound on top.
http://forums.nasioc.com/forums/show...5&postcount=12

[boost junkie]

Yeah I did a google search and discovered that there actually is at least one dyno that puts rebound on top, my mistake. But there is still a very large gap between the two. I would say they have too much rebound and not enough bump, but I need to find time to take a closer look to see exactly how they look with these spring rates.

[Turn in Concepts]

Originally Posted by Mind

I've seen some Koni dynos around here that had rebound on top, so I think it's just an axis thing.

1.5" bump travel before the bumpstop - is that more than a stock STI?

We work with Koni NA closely on development of shocks for new cars and all dyno plots from them always have rebound on the bottom.

edit: just saw your post. Doesn't look like an actually Koni performed dyno which is why it's different. I guess the machine can be setup however.

The tricky part about bump stops and stock suspensions are the intents of the manufacturer in using them. Many newer car suspension use bump stops as additional spring rate. BMW started this back in the 90's and others have caught on. From a street perspective only it can work fine, but from a performance perspective it is not a good thing. Bump stops should also be progressive with a soft beginning quickly upping the rate for shock protection. An almost solid bump stop essentially removes that portion of shock travel fromt he equation as the dynamic transition in handling will be so severe when hitting the stop that the car will immediately begin to skip across the ground. A soft progressive bump stop can be felt in cornering with input adjustments made before the car suddenly starts to slide.

Tony

[sigurd]

Originally Posted by boost junkie

No matter what I say, BC will continue to sell coilovers and life will go on, I'm just offering my opinion based on the information that's in front of me.

And people will go on doing well in motorsports with them. Whether you belive their driving is making up for poor coilovers or not.

The information I see pretty much tells me what people that have them already know. they perform well and do the job with the main (and I admit it is a problem) being a lack in travel.

but hey what the hell do I know.

[Mind]

So how much bump travel does a stock STI have before it hits the ~infinite portion of the progressive jounce bumper?

[Turn in Concepts]

Originally Posted by Mind

So how much bump travel does a stock STI have before it hits the ~infinite portion of the progressive jounce bumper?

I don't rememnber off the top of my head, but it's somewhere around 3.5"-4" of bump travel.

Tony

[boost junkie]

I took a bit of a closer look at the dyno plots (I'm bored at work). A few things I noticed:

-Rebound is pretty significantly progressive. In order to dial in the desired low speed rebound, it will be pretty overdamped in the high speed range.

-Compression is pretty linear, and underdamped across the range. Even at the stiffest setting, there isn't really enough compression damping for these spring rates. Obviously the rear isn't as bad with the lower spring rates but underdamped nonetheless.

Overall, I would say that the damper plots aren't as bad as i thought initially, but still have significant issues. It's the price you pay when you use the same damper for all different cars, the valving isn't really where it should be. I don't want to get too far into this debate because it always gets people angry and the thread inevitably goes to crap, but I'm trying to entertain myself at work and hopefully help people make an informed decision about their suspensions.

[antonch]

Originally Posted by boost junkie

1) 1.5" of bump travel is nothing. It's enough to get you by on a perfectly smooth road or track, but think about what happens when you hit a mid-corner bump and the loaded side of the suspension wants to compress. Even with those spring rates, you will be in the bump stops. With normal street spring rates it'll be even worse. I don't know how my comment was turning this into a comparison, I didn't mention any other coilovers.
2) I don't know what kind of shock dyno you're using, but I have never seen a dyno that displays rebound on top and compression on bottom. I believe you are the one who is reading it all wrong.
3) What do you mean by dyno matched? Are you saying you asked BC to choose dampers with matching dyno plots for your set? Because you said that when you independently dyno tested them they were mismatched. My point is, you shouldn't have to make an educated guess as to how different the settings need to be from one side to the other in order for the damping rates to be the same.
4) I understand why they are popular, and why they are so inexpensive. Some may disagree with me, but I would say that the things that make them affordable are also the things that make "enthusiasts" shy away from them. You do get a lot of features for the money, but the most important part of any suspension is damper valving and construction quality. No matter what I say, BC will continue to sell coilovers and life will go on, I'm just offering my opinion based on the information that's in front of me.

Do not get hung up on the details. Rebound is upper half bump is bottom, period. If you can't get past that then well you should not be looking at shock dyno's. It's rude to come in here tell me that I am the one looking at them all wrong when you don't even bother to take the time to analyze them more carefully. If you looked at the individual knobs that were adjusted and the change that occurred on the sheet, you would realize it within 5 seconds.
These are dyno matched as in I placed them on a dyno and had left to right shock settings matched. There are no educated guesses whatsoever.

Originally Posted by boost junkie

I took a bit of a closer look at the dyno plots (I'm bored at work). A few things I noticed:

-Rebound is pretty significantly progressive. In order to dial in the desired low speed rebound, it will be pretty overdamped in the high speed range.

-Compression is pretty linear, and underdamped across the range. Even at the stiffest setting, there isn't really enough compression damping for these spring rates. Obviously the rear isn't as bad with the lower spring rates but underdamped nonetheless.

Overall, I would say that the damper plots aren't as bad as i thought initially, but still have significant issues. It's the price you pay when you use the same damper for all different cars, the valving isn't really where it should be. I don't want to get too far into this debate because it always gets people angry and the thread inevitably goes to crap, but I'm trying to entertain myself at work and hopefully help people make an informed decision about their suspensions.

So far you have not added anything interesting to this thread. I've already said that rebound is progressive, what is your point?
Show me the math that says that these are underdamped. I know I have done it and it is not underdamped at all. FYI, the red line is 75%CD which is right smack in the middle of the rebound curve in the front. But you would have noticed that if you actually spent the time to look at the dyno sheets.
Show me a single SAE paper that says how a damper curve should look like. Is it going to be digressive, progressive, linear, where should the knee be? No one knows what is the best.
As I said earlier, a lot of including motosport coilovers have linear rebound curves while some are not. There is no single "best" curve for a chassis.

What gets people mad is not when you disagree but when you make statements like "they are underdamped, the valving is all wrong" without having anything to back that up. Blatant statements like that do not help anyone.

[boost junkie]

Originally Posted by antonch

Do not get hung up on the details. Rebound is upper half bump is bottom, period. If you can't get past that then well you should not be looking at shock dyno's. It's rude to come in here tell me that I am the one looking at them all wrong when you don't even bother to take the time to analyze them more carefully. If you looked at the individual knobs that were adjusted and the change that occurred on the sheet, you would realize it within 5 seconds.
These are dyno matched as in I placed them on a dyno and had left to right shock settings matched. There are no educated guesses whatsoever.



So far you have not added anything interesting to this thread. I've already said that rebound is progressive, what is your point?
Show me the math that says that these are underdamped. I know I have done it and it is not underdamped at all. FYI, the red line is 75%CD which is right smack in the middle of the rebound curve in the front. But you would have noticed that if you actually spent the time to look at the dyno sheets.
Show me a single SAE paper that says how a damper curve should look like. Is it going to be digressive, progressive, linear, where should the knee be? No one knows what is the best.
As I said earlier, a lot of including motosport coilovers have linear rebound curves while some are not. There is no single "best" curve for a chassis.

What gets people mad is not when you disagree but when you make statements like "they are underdamped, the valving is all wrong" without having anything to back that up. Blatant statements like that do not help anyone.

You're right, I just made this all up because it's fun to me. I have no idea what I'm talking about

You mention the rebound damping force at one piston speed and use that to illustrate the fact that these are good dampers. What about what they are doing at other piston speeds? Or the fact that the rear dampers are exactly the same but use different spring rates? Or the fact that I wasn't even talking about rebound, I was talking about compression? You posted dyno plots, I examined them, I gave my opinion based on the data I have. I don't have to defend myself, the data is right there for anyone to see.

You clearly have a lot to learn about suspension tuning and reading dyno plots. I don't claim to be the best in the world at this, but I have learned from some of the best people in the suspension industry, and that goes well beyond just subarus. The rebound/compression thing, I admitted was my mistake. The Roehrig dyno that I am familiar with, as well as most others, use positive values for compression and negative values for rebound. I think it's funny that you post all of this data and then get so pissed off when somebody actually analyzes it and says something negative about the results. You bought cheap coilovers, you got less than perfect results. If you wanted everyone to just come in here and praise your decision instead of giving substantive feedback, you should have posted in members car gallery.

[antonch]

Originally Posted by boost junkie

You're right, I just made this all up because it's fun to me. I have no idea what I'm talking about

You mention the rebound damping force at one piston speed and use that to illustrate the fact that these are good dampers. What about what they are doing at other piston speeds? Or the fact that the rear dampers are exactly the same but use different spring rates? Or the fact that I wasn't even talking about rebound, I was talking about compression? You posted dyno plots, I examined them, I gave my opinion based on the data I have. I don't have to defend myself, the data is right there for anyone to see.

You clearly have a lot to learn about suspension tuning and reading dyno plots. I don't claim to be the best in the world at this, but I have learned from some of the best people in the suspension industry, and that goes well beyond just subarus. The rebound/compression thing, I admitted was my mistake. The Roehrig dyno that I am familiar with, as well as most others, use positive values for compression and negative values for rebound. I think it's funny that you post all of this data and then get so pissed off when somebody actually analyzes it and says something negative about the results. You bought cheap coilovers, you got less than perfect results. If you wanted everyone to just come in here and praise your decision instead of giving substantive feedback, you should have posted in members car gallery.

I don't claim to know it all, but no one out there really knows it either. Suspension tuning is still considered a black art.

I don't expect praise just as I never claimed that these coilovers are perfect. But they ought to be fine for the street. I don't understand why anyone would want a motorsport coilover for street use.

As long as there is enough adjustment range, using the same shock in rear with a different spring by itself should not be a problem. That is one of the reason why I like linear shocks so much--they are very simple to tune.

Most of the action (sprung weight transitions) occurs at lower speeds. It's not that interesting to me look at the faster speed stuff.

You are not looking at the data, looking at the data would be: at 3"/sec you have __%CD, I like __%CD there. Making statements that it's crap without having anything to back it up is just plain irresponsible.

If you would like to continue a technical discussion I am all for it but please keep it technical.

[sniper1rfa]

To be fair guys, BC's consistently get the best reviews of the cheap coilovers. I'm willing to accept that they are made to good standards with good shocks.


It's that 2.5" travel which is bothersome. Stock front struts have 6.5", rears 9" (total). Also, the shocks, while good quality, are not matched to individual cars.

[Bryan @ JRZ]

First off, I'm not going to compare myself with BC Racing. We're satisfying two different parts of the market.

A few notes on damping as it relates to this thread:

Using % critical damping is one way to skin the cat and can be used as a good starting point. The rub is that many people use different damping ratios as starting points with varying compression to rebound ratios.

Suspension and damping is not - in any way - a black art.

Necessary bump travel is a function of spring rate

Bump stops are a poor tuning tool and used in situations of necessity. Generally in stock cars and high downforce cars, but not always.

Technology made for motorsports dampers has a direct application in the street/club dampers. A harsh riding car isn't indicative of a responsive chassis that makes fantastic traction.

Cars that ride nice can be very fast on the track

Progressive rebound isn't bad, however the way the curve comes in is critical

The damping force above 3 ips is not trivial

Dyno plots typically run with compression as positive force.

Calculating critical damping after the knee is far more complex than a linear calculation added to the knee point.

Linear compression (at low levels of damping) is more of a comfort design, not a performance design



I'd be happy to answer any tech questions and post some data.

[boost junkie]

Originally Posted by antonch

I don't claim to know it all, but no one out there really knows it either. Suspension tuning is still considered a black art.

I don't expect praise just as I never claimed that these coilovers are perfect. But they ought to be fine for the street. I don't understand why anyone would want a motorsport coilover for street use.

As long as there is enough adjustment range, using the same shock in rear with a different spring by itself should not be a problem. That is one of the reason why I like linear shocks so much--they are very simple to tune.

Most of the action (sprung weight transitions) occurs at lower speeds. It's not that interesting to me look at the faster speed stuff.

You are not looking at the data, looking at the data would be: at 3"/sec you have __%CD, I like __%CD there. Making statements that it's crap without having anything to back it up is just plain irresponsible.

If you would like to continue a technical discussion I am all for it but please keep it technical.

Suspension tuning is not a black art, there are many people out there who understand it very well.

I don't know where anyone mentioned using a motorsport coilover on the street. Not that the technologies are so different, but I would say that the ones you bought are marketed toward a motorsports crowd. Monotube design, external canisters...these are things that are not necessary for a street damper.

If you aren't interested in high speed as well as low speed, you aren't seeing the big picture. High speed is very important, on the street and the track. Yes, on a perfect surface low speed is where you are going to gain control. But what happens when you hit a bump mid-corner? Without being properly damped in the high speed range, the car is going to become unsettled and lose grip. High speed is also where most of the comfort comes from, particularly important on a street car.

I'm all for a technical discussion, and I have taken a technical approach from the beginning. You have decided to go on the offensive because you don't seem to fully understand what I'm talking about.

Now that Bryan is here I'll stop talking, he's going to make me look dumb

[Turn in Concepts]

My understanding on low vs. high speed is this -

We feel low speed.
The car feels high speed.