CB7 Lowering Spring, Full Coilover, and Damper compilation

[cuate01221]

I am rocking tein s tech springs on replacement shocks. Kinda sags in the rear which pisses me off and tempts me to buy f&f type 1s

before


after

[AAPOQ]

My upper balljoints are autozone adjustable ones. My old joints were definately bad, and i had the ebay camber kit that automatically added way
to much camber, and were so cheap. The upper A arms were hitting the edge of the shock tower. Still want to get an alignment check.

Once those autozone adjustables wear out you should look into Ingalls adjustable upper bj's.....
Also, you will want to get an alignment done.

[ali954]

Originally Posted by AAPOQ

Once those autozone adjustables wear out you should look into Ingalls adjustable upper bj's.....
Also, you will want to get an alignment done.

I have life time warranty on those bj's, Ingalls were out of the budget and the old ones were very bad. String alignment done to fix toe. Although I do want to get a free alignment check to make sure.

[RedFalcoln]

I'm looking into buying a cb with

Function & Form Autolife Type 1: 672F, 336R Damping adjustable: No

and I was wondering what any members experiences or knowledge on this suspension setup was? I currently drive a 1990 LX with OEM suspension, Will the improvement be great over my car? Body roll? grip? I'm also hoping for a much stiffer ride.

The cb has Falken Ziex tires.

[cb7beater]

im currently on fuction form type 1 coilovers and love them for what they are.and im pretty low.no complaints.

wondering if any one here is sporting the function form type 2.5 coilovers.interested in there input.considering getting them in the near future.

[marcusv8thunder]

Im on the case for the specs on the Bilstein coilovers i have. So far Bilstein have got back to me. Just trying to understand what they have given me!

Maybe someone can get it.

So far i THINK VA=front, HA=rear. Links=left front damper Recht=right front damper.



"Thank you for your inquiry and interest in Bilstein.

Please see below all the information we can provide!

F4-BE5-6428-M0 HONDA ACCORD VA LINKS -rating 320/170
F4-BE5-6429-M0 HONDA ACCORD VA RECHTS -rating 320/170
F4-BE5-6430-M0 HONDA ACCORD HA -rating 195/95

For the springs you must contact H&R for more information:
front
H&R 29370VA
rear
H&R 29370HA

hope to have been of assistance!

Best Regards / Mit freundlichen Grüßen,
Luís Gonçalves"


So im on the next task of speaking to H&R for the spring rates. Although im 90% sure they are H&R Race Springs F485 R305

[HappyGilmore]

So adjusting the screw at the top of the koni yellow strut will help get rid of some of that bouncyness I have going on then (in other words ridding way too soft.) correct?

[Speedz]

lowered on TruHart springs & shocks.. 2.5" front 2.25" rear. riding on 16x7 et38 Buddy Club P1 reps. 205-50-16 tires. car needs to be lower though. but not with the wheel/tire combo.. they stick out to far.. would be rubbing like crazy.. i suppose if i stretched some tires i could get away with it.. but i'm not into that.

[ol blue]

I noticed ksport lowering springs were not on the list, so I will just say I emailed them about there spring rates and they are progressive front and back. The drop you get from them are suppose to be 2.25in front and rear.

[F20A CB7]

Bringing the thread back because I was looking for information thank you.

[CyborgGT]

I've been looking into full coilovers lately, seeing if there's a better option than the popular Koni Sport + Ground Control setup. I saw an ad in the UK's Honda Tuner magazine for BC Racing coilovers (I hadn't looked at this thread probably since I first signed up here, so I've forgotten my options). Europeans tend to know more about making a car handle, and there's a friggin' McLaren race car with BC sponsorship... I think I'll do some research. Found this interesting post on an NSX forum (photos didn't appear there); the whole thread is really worth a read.

Originally Posted by BC Racing Coilovers - Comprehensive Review

source

As many of you may know from reading my other threads here on Prime, my hopes for an OEM Type-S suspension were dashed when I discovered they have been discontinued. The similar unavailability of the NA2 NSX-R suspension and very limited support for the system here in the US led me to embark on a quest for a street/track suspension option for my NA1 NSX refresh project. Of course, my budget was limited to the price of a new Type-S or used NSX-R: $1,500. After weeks of research online, talking to some motorsports friends, and discussions with suspension shops I know, I was led to a somewhat unlikely place: BC Racing. After setting forth my goals, the general advice was “if you have unlimited funds, just get Motons or Penskes and be done with it. But for your budget, BC Racing is a good option and the best bang for the buck at that price point.”

Frankly, I was surprised. BC Racing is little known in the NSX community and what information I could find lumped them in with the “cheap asian coilover” crowd of Megan, D2 and Ksport. However, as I researched the company I was pleasantly surprised. Turns out these dampers are being used and actively campaigned on tracks all over the world with good results. Moreover, they seem to be overwhelmingly well-regarded by other sports car groups like STi, Evo, M3 and GTi. Thus, the initial research looked promising and I decided to dig deeper.

The following were my initial concerns about these coilovers:

CONCERNS

1. Made in Taiwan. Let’s face it- this can be an issue. We have all seen the horror pics of failed Megans, D2’s and others. BC Racing coilovers are indeed made in Taiwan by the Bor-Chuann suspension company. The BC Racing factory is ISO9001 certified for quality control and its coilovers are German TUV certified. That’s a big deal (especially the TUV, which is a rigorous standard) and it alleviated much of my concern.

2. Inconsistent adjustment between shocks. A big problem I found with entry-level coilovers (and why I initially was not interested in them) was that people were reporting the dampening adjustment clicks were not consistent left to right. However, BC Racing shock dynos each coilover before it leaves the factory, physically records the value on the damper, and then matches pairs to ensure 5 clicks on the left side is the same as 5 clicks on the right. Again, I was both surprised and impressed. Below is a picture of my new coilovers. Under the dust boot is a marking showing the damper rates of each shock as tested on the dyno before it leaves the factory. My dampers were matched to within 2% tolerance. For reference, OEM acceptable tolerance is 13%.

3. Lack of droop travel. Like all entry-level coilovers, the BC Racing units have less droop travel than a standard twin-tube shock, meaning the damper piston has a shorter amount of travel distance before it hits the bump stop. This can be a real problem if the system is undersprung or, like many cheaper coilovers, the user lowers the ride height by compressing the spring (thus reducing travel even more). What happens is that you end up blowing through the droop, hitting the bump stops and the ride is horrible. BC Racing solves this issue by making ride height adjustment independent of the spring perch, by way of a threaded lower mount. Thus, no matter how much you lower the suspension, you have the full droop travel of the shock available. Again, I was both surprised and impressed.

4. Poor damper valving. This is really one of the biggest issues with entry level coilovers and a major driver of the vastly lower price compared to industry leaders like Penske and Bilstein. These coilovers, as well as many of the JDM name brands, follow a fairly typical damping profile. Compression (bump) damping is digressive and generally low. Rebound damping is generally very high and follows a progression of progressive, linear and digressive curves as the adjustment is increased. This presents a problem for tuning because if rebound is set too soft, the progressive curve will result in the car pogo sticking over even small bumps at low speed. If rebound is set too high, the suspension will not be able to return to neutral at high speeds because the damper is over-controlling the springs. The result can be a “jacking down” of the suspension as the car goes through the turns on a road course. The result of this valving scheme is a somewhat limited “middle window’ of adjustability and lack of overall compression damping that will cost performance on the track. Like the JDM name brands, BC Racing addresses this issue by using stiff springs to control suspension movement. The standard kit for the NSX is 10kg/10kg. Also, in a move that really impressed me, they sent me the shock dyno data for the NSX coilovers. I appreciated the candor and the attitude that they have nothing to hide. Below is the dyno plot they sent me for the NSX kit.



As you can see, the curve is what it is. There’s no way around it- these coilovers will lack some performance on the track. Indeed, Evolutionm.net tested the BR kit on its shop race car on the Sebring 12 hour course and found that while the kit performed exceptionally well, it was about 2 to 3 seconds slower than their normal race suspension (unnamed, but likely Motons or something similar). Is 3 seconds worth $5,000 to me? No. But, it is clear that the less than ideal valving profile is hurting the BR kit on the track, especially through the high speed turns. This is to be expected, as the BR kit is about 5 times less expensive than a full-up triple adjustable race suspension. I’m ok with that. In addition, during my discussions with them directly, BC Racing was clear that the BR kit is designed primarily for street driving with occasional track use. Thus, for my 80% street 20% track application, they fit the bill.

5. Ridiculous number of adjustment clicks. It seems like the less expensive the coilover, the more “clicks” you get for adjustability. The BC Racing BR kit is no different, with 30 advertised clicks. My research revealed single clicks do not make any discernable difference on the BR and the adjustment should instead be viewed as 15-way with half click increments.

6. Adjuster “cross-talk”. Many entry level coilovers use valve adjusters that affect both rebound and compression. This is not always ideal and can cause tuning nightmares. Thankfully, the shock dyno shows the BR kit has virtually no cross-talk between rebound and compression, which only slightly increases even on maximum stiffness. This means it truly is a single adjustable damper and indicates better quality internals.

Overall, my concerns about these kits were largely alleviated by a little detective work. Turns out most people who have them like them. They are great on the street and decent, but not ideal, on the track. Of course, as I drive them I will report back with any problems. They will be tracked and I will be honest. Now however, let’s talk about some positives about the BC Racing BR kit that led me to my decision:

1. High pressure monotube design. Monotubes offer advantages over twin tubes in that they allow for more fluid volume, which better controls shock temperature. Also, they allow use of larger pistons, which can provide smoother ride quality through fluid displacement.

2. 46mm piston. One of the tricks that makes the Bilstein and other race monotubes so comfortable is the use of a large piston. A large piston can displace more fluid with less movement, resulting in a more refined ride quality.

3. Concave lower locking ring. I don’t know much about coilover tuning, but I know that the perch often can work itself loose. This mechanism prevents that.

4. Japan-made pillowball mounts with spherical bearing. This was a big deal to me. Through feedback from actual customers, BC Racing has refined this design several times and the mounts now used are very robust.

5. 1 year warranty and afterwards only $95 to replace the entire damper unit.

6. Rebuildable at BC’s Florida facility and custom valving offered for FREE.

7. Swift spring upgrade offered directly from BC Racing. This is awesome. For a ridiculously low price, BC hooked me up with Swift springs in a 10kg/8kg setup, re-valved the rears for 8kg, installed them on the dampers and shipped to my door. Incredible service and the feedback I got regarding the Swifts was an enthusiastic “go for it” and “they will transform the shock.” Swift racing springs are simply the best in the world.

8 kg Rear Springs



10 kg Front Springs



8. OEM Fit. Unlike other units, the BC Racing coilovers do not make you use zip ties to mount your brake lines. They spend the extra money to give you proper mounts, seen below on my front coilovers:



9. Positive actual user reviews. I did a ton of research on these coilovers and I would say at least 90% of purchasers were happy. These reviews in particular were very helpful to me:
The S2000 is a close performance analog to the NSX. Moreover, this owner evaluated the system from the track to the ever-important “wife/gf ride test.”
S2000 Review
This is a review of the top-line ER double-adjustable damper, but indicative of the quality of construction and a good discussion of the valving limitations
Sti ER Kit Review

Moreover, NASIOC has a 90-page thread on these coilovers with nearly a unanimous positive review.

The coilovers arrived in a very well-packed box. Pics are below.

Originally Posted by Review Update - Driving Impressions

I finally finished the car and was able to take it out for a shakedown run around the block. The point was mostly to make sure I didn't screw up anything in putting the car/engine back together , but I was also able to get an initial impression of the BCR dampers. Note the ride height still is not set and the car has not yet been aligned. I set the dampers to 10 clicks from full soft all around.

In a word: WOW . The best comparison I can make to the street ride is an NSX that I rode in with JRZ's. The ride is fantastic. All of the small undulations and bumps are just soaked up by that big monotube piston, resulting in a glass smooth ride. I aimed for some big bumps and manhole covers to get an idea of the hard bump characteristics and was impressed. Most coilovers give you a jolt that will knock the fillings out of your teeth, but these BCR's are different. I would describe the hit as firm but smooth. There was ever so slight pogo sticking after the bump, meaning that I am still slightly underdamped at setting 10. 12 would probably be about perfect.

While not at track speeds, I did try to hit some hard corners just to get an idea. All I have to say is Swift springs are amazing. They really are linear. Really. I strongly suspect cranking the dampers up to 20 or 25 is going to create a very competent track suspension. I should be heading to the track later in July, so I will report back.

The verdict? Two enthusiastic thumbs up. At this price, I do not think you can buy a better suspension for the NSX. Value index = HIGH.

[...]

This setting passed the pregnant wife comfort test btw.

[...]

Quick update. I just had the car aligned and the ride height set to NSX-R spec. I have to say it is AMAZING.

[...]

Track Report Update

Well I spent 4 hours today at High Plains Raceway with NSXCA's own Bruce McPherson and I can report the BC Racing suspension is a great track system. Bruce liked it at 15 F 20 R (0= soft), but it was too loose for me and I preferred 20 F 20 R. The suspension was predictable, smooth and transitioned sharply. I did not experience any reduction in performance due to heat and never did it feel like the car was wandering or unstable (other than the compliance bushing stuff, which is normal for these cars). Strangely, my right front suspension now appears to be sitting about 1/2" lower than the other side. Not sure what that is, but I will have the guys at Acura take a look.

[...]

Just another track update from two days at the NSXPO HPDE. This setup is amazing, especially for the money. I have an incredibly stable, neutral car that sticks like glue in all types of corners. My first instructor thought I had Motons. Just for future members searches, I was running 20 clicks (from full soft) front and rear. The car is sharp and responsive with this setting. Going stiffer did not seem to have any effect. And, funny enough, I ran the first session on my "street" rebound settings (11 F / 10 R) and still was within about 2 seconds of my best time. The car definitely transitioned slower though. 20/20 is a good track setup for a NA1 NSX on the BC's with the NSX-R rates. I set the car back to "street" for the ride home and it was like a cadillac.

Anyway, the BC/Swift setup is a great track option and performed flawlessly over two days of hard road course driving.

[...]

I had the Koni/Comptech (similar to Koni/GC) kit on my car before the BC, and while it was a great suspension (with perfect drop IMO), it was too stiff for me. Those Konis ride hard. Just using Zanardi springs will blow out your OEM shocks, so you need to get the Zanardi shocks as well. For your needs the BC will be great, especially at that price point.

I have been daily driving my NSX since NSXPO and have no issues with the suspension. I changed my street settings to be a little softer 10F / 8R and love it. I have noticed when the temps go below 20 F, the shocks ride harder.

[ol blue]

Why not go with the fortune 500s? I heard nothing but good from them. I also believe it is af 1132 that has a set.

[CyborgGT]

... because these sound great too, and are $200 cheaper. And I just realized I can get them for my RSX, for the same price as the Progress coilovers I was planning on but with the added damper adjustment, and camber adjustment built right in (no paying extra for a "camber kit"!). Perfect way to test! Not to mention, if no one here has tried them yet, it'd be good for the community to get first-hand impressions.

[almostJDM]

I second the fortune auto 500's yes they may be $200 more but its more then worth it, they ride a lot softer then BC coilovers and you can have custom spring rates, I'm not sure if you can on BC or even have them rebuilt like you can with fortune autos, I love mine on my sti, and plan to purchase a set of 500's for my new CB when I get it in a few weeks, fortune autos are easily a step above BC racing

[CyborgGT]

You've had BCs on your STi, then? I've been finding a lot of good reviews on the BCs, and it sounds like the dampers have a nice range of stiffness to adjust through. Supposedly BC makes suspension components for some of the big Japanese companies, like Greddy. I'm just not seeing any real difference between the two. Not that $200 is much when you're already ready to fork out $1000 for something... but I'm still looking into things. The Fortunes being rebuild-able in the US is definitely a convenience.

When you adjust ride height on the Fortune 500's, does shock travel change with it?

This is a very good discussion on Fortune Auto. Interesting that they keep bringing up Koni Yellows as a sort of standard to measure up to.

[Tishock]

Originally Posted by mndude07

DAMPERS
------------------------------------------------------------------------

KYB GR2: Damping adjustable: NO

KYB AGX: Damping adjustable: YES, 8-way on car

I don't remember who it was, but I recently spoke to someone who paid more for these shocks assuming they were better than KYB's stock replacement Excel-G. Not knowing that they're the same shock. I really thought this was common knowledge. But I just noticed they were listed in this thread. Don't you think they should be removed from the list?

What is the difference between the KYB GR-2 and the Excel-G products?

http://www.kyb.com/knowledge-center/...el-g-products/

We apologize that this is a bit confusing. Both products are identical, except for the product name and paint color. KYB sells products throughout the world. Some part numbers fit vehicles from various countries that share the same chassis platform but, have different nameplates. At one time there were several KYB brand names, but we are now moving toward one name and color. So in the future all new part numbers will be branded as Excel-G and have black paint.

[ukemike]

Originally Posted by mndude07

No, that is very useful, thanks. I would like to know the forces at full stiff for the yellows also though. The units are the same as a spring rate, so lbs/in. The damping force opposes the spring force, so they must be the same units.

Those two sentences are incorrect. Damping characteristics are actually very non-linear and complex. Many scholarly papers have been written on the subject of just measuring damping forces. Traditionally and what you learn as an undergrad mechanical engineering student is that damping is measured as force per speed, so lbs per in/sec or N per m/s these could also be written at lbs*sec/in or N*sec/m. Dampers resist in proportion to speed, not in proportion to total displacement like springs.

Of course the truth is that the damping rate we used in engineering school is not a constant but is a very non-linear function of various things like speed, displacement, temperature. Damper characteristics are multi-dimensional. Imagine if you tried to boil a fuel map down to a single number or just two numbers. It would have almost no meaning. You can have a damping rate for compression but it changes based on the speed and the position. Rebound values are usually different from compression.

This is why it is hard to get numbers from damper companies and when you do get them they are hard to compare. Since the numbers on page 1 of this thread vary so widely I suspect that some might even be in metric and others in imperial units. I don't know what to make of them.

This paper summarizes the complexity of measuring damping forces on real shock absorbers. I like it because it has lots of graphs that give you an idea of the complexity.

https://www.hindawi.com/journals/sv/2016/6182847/