TRD shocks and springs

[NoHachi]

As much as you can above the perch.. Or better yet, take one of my pretty pictures, take some of the formulas mentioned above and make your own. Place it in the forum along with the calcs and either me or the greek delegation will check it for you its not hard at all once you start working on it.

[jondee86]

Damn !!! Reading all those posts made my head hurt

I already have AGX with 40mm cut above the perch, but only 3kg/mm
springs, so comfortable for DD, but on the bumpstops under anything
like hard cornering.

I'm looking to go to BC Racing BR-Series (Gold) coilovers with spindles.
For DD with occasional track use on high performance road tyres, I am
thinking to go with the 6kg front / 4.5kg rear spring combination.

Anyone have any experience with this setup ?? Like to comment ??

Cheers... jondee86

[NoHachi]

There is nothing wrong with cornering on the bump stops! just invest in some bump stops that fit your suspension in length and rate. If you like how a BMW, new Mini, Miata or newer Honda's ride, then you already know how good it can be.
3kg/mm can definitely be made to work for track days on street tires!

BC-racing, K-sport and just about every brand that has suddenly popped up for the 86 are the same product. Fun to see new companies spring up that have ordered them in a new colour and start claiming that they have "developed" something new. Great work, you developed the colour black! (see club4AG for good examples lately)
Good things are the cheap price and the new spindles (then again, if your old ones are OK, why change). Bad things are:
http://www.aeu86.org/viewtopic/nohachis-...ad/t/10156
Post #4

Probably not too shabby if your last name isn't Fujiwara. Could get funky on track if you happen to get a particularly poorly matched set.

[jondee86]

Thanks for the reply. As it happens, I didn't settle on BC Racing at
random. I have been looking at various options for several years as I
work (endlessly) on engine and management issues. I first became
interested in this style of coilover with spindles when the GReddy units
came out a few years back.

At the time, the GReddy's were a bit expensive, only had an 8/6kg/mm
spring set, and did not have the bearing under the pillowball at the front.
Since then I have discovered the BC make coilovers for several other
vendors, and are very possibily the largest manufacturer of coilovers in
the world. Also, they are not in mainland China, but Taiwan.

If you visit their website, you will see that they have a whole range of
styles, and a wide range of vehicle fitments. I have examined the actual
product in store, and consider the quality and presentation to be
exceptional for the price range... and they make black coilovers

http://www.bcec.com.tw/function/Dyno.html
http://www.bcec.com.tw/function/images/dony-2.pdf

If you look at this information, I think you will see that there is little
chance that they will be as bad as the K-Sport units, which are widely
regarded as being well down the quality ladder.

My interest in using the BC units is to have a wider range of damping
adjustment, the ability to corner weight, raise and lower the car, and
of course, the bling factor If it were available, I would prefer to have
4/3kg/mm springs. However, if the shock valving is matched to the
springs, I think 6/4 may deliver an acceptable ride for a car that is not
a daily driver, nor a dedicated race car.

Cheers... jondee86

[NoHachi]

Hmz, usually the dyno curves from the manufacturers are mostly marketing. Found someone that did some independent testing:
http://www.iwsti.com/forums/gd-suspensio...eview.html

If your coilover ships with those exact damper curves then they will be suboptimal with lower spring rates. At the lowest setting they are progressive and basically suck. Too little low speed damping and body control, way to much high speed damping and unnecessarily harsh. In the middle setting they are linear and acceptable. Similar damping style to tokico HTS in those settings. In the higher settings they are progressive and start to show the type of curves that I'd like to see from a big monotube.


And I'm affraid that Bor Chuan enterprises is responsible for both the K-sport and BC racing brands. Same product line, different packaging. Same goes for Greddy, Megan, D2, Apexi, stance, etc, etc, etc. They all suddenly popped up at the same time, from the same place etc. Not that thats a problem mind you. For most drivers and DD duty they will most likely do just fine. For more serious use they would be a gamble.

[jondee86]

I think the K-Sport, and indeed the early series BC coilovers (now
superceded by the BR-Series) were nothing special from a quality point
of view. The later series appear to be much improved, and the ER-Series
which is a more race orientated version, appears to meet with some
qualified approval in the review link that you posted.

When you say "lower spring rates", are you referring to 6/4 or 4/3 ??

I have wondered what the effect is, when the shock valving is designed
for 8/6, and you change the springs to 6/4 ?? How far can you stray
before shock no longer matches the springs ??

The comment is sometimes made, that a stiffer spring combination with
well matched shocks, will ride better than softer springs with mismatched
shocks. Is this really true ??

Cheers... jondee86

[NoHachi]

Hi jon,

I'm not making any judgement on the "quality" of these shocks. They look fine. The problem is that you can have very high quality shocks valved completely wrong for the application. Despite being high quality these would then return low ride quality and performance.

What springs can you match with a set of dampers..wel that depends on the types of damping curves that you dial in. Normally you want a digressive curve. Steep initial rise at lower speeds tapering of at higher speeds. The low and highspeed bits need to be set exactly right for your car. If succesfull you have a car that is controlled at speed and comfy during cruise (or at least as comfy as your springs allow). For an idea of how a digressive curve looks, take a look at the red line in the dyno's from my link.

Linear dampers like HTS are a compromise. They do not taper of at high speeds, so you are given a choice (if enough adjustment is available).
*Do I set the low speed portion right for the fast stuff (steep curve)? If so then the high speed part will overshoot and make the car lose traction over bumps and become more uncomfortable.
*Do I set the high speed damping correct and accept that the low speed section is suboptimal for body control? The car will be comfier during my commute, but I give up some body control.
Both these compromises are decent:
* Set high speed ok for track duty: optimal control and smooth tracks don't need much in the way of control over bumps or comfort.
* Set low speed ok and comfort is ok, but control less so. Not a problem since we are not introducing big forces into the chassis during DD anyway.

Digressive dampers can change exactly in tune with your suspension. This is a very delicate proces and takes some nifty adjustment hardware. Hence the huge prices of quality stuff like öhlins, Moton or Penske (notice that there are no AE86 manufacturers in that list..nobody loves us yet )

Then you have progressive dampers.. I'm sure that there is a situation in which progressive stuff is nice to have. I guess I just haven't heard of it. You have too little damping at low speeds to control chassis movement, but too much of it at high speed to be able to provide traction and control.

Now take a look at the dyno curves. At the lowest settings the BC's start of progressive.. This makes those setting essentially suboptimal, you'll always have underdamped body control or pay the price with a very stiff ride and poor grip (dorifto!).
In the middle setting they are linear.. So probably ok for track with 8kg springs, but could be better. If look at the red line for 8kg/mm (the rears of a subie) and forget about weight (ballpark ok) then you'll see that the mid-settings come out relatively ok for the low speed bit.
At high speed they are progressive...so slap these babies on a car that has stiff springs and they'll work a lot better. This includes cars with high motion ratio's like MX5's, Honda's en other non-McPherson strut cars..

Whew..lots of text..and still no idea what the 86 stuff really looks like. So you can probably ignore most of what I said. The 86 hardware is probably very different from the double adjustable stuff.

[jondee86]

Soooo, a long thread that generates more heat than light

I will put another question for the benefit of all people like myself, who
have only a slight knowledge of suspension design.

With a simple cutting of the front strut housing, and use of some shorter
springs (my case 3 kg/mm and 40 mm down), what shocks would you
recommend for a DD that sees occasional track use on road tyres ???

I see these brands being prefered by various people around forums:
1. HTS (perhaps a bit too track oriented?)
2. TRD (said to be very good with stiff springs)
3. AGX (Camaro/SW20 combination often used but scorned?)
4. Bilstein (non-adjustable but highly regarded for grip)
5. Koni (yellows, non-adjustable on-car, but highly regarded for grip)

I have the AGX and find them acceptable for DD. Have also had Koni
yellows (standard length with lowering springs), and found them very
good for DD. Should I look for some of the newer on-car adjustable
Koni's in a short stroke version ?? Maybe Camaro/SW20 combo :wink:

Cheers... jondee86

[SekiguchiUeno]

Not sure if bilstein still made ae92 fronts, 40mm shortened strut is here the problem so you cannot use B6 for ae86 or dual tube oil konis. But you can use monotube Ae92 konis with top adjustment. My friend use them on his coupe with some slightly stiffer lowering springs.

[jondee86]

SekiguchiUeno Wrote:But you can use monotube Ae92 konis with top adjustment. My friend
use them on his coupe with some slightly stiffer lowering springs.

I looked long and hard at the top adjustable Koni's before going with the
AGX. It was simply a money thing, as the Koni's were quite a bit more
than AGX to buy. Before spending that much money I wanted to know
that the damping was going to be good for my setup.

If someone can confirm the best "swap-over" Koni shocks to use for the
AE86 40mm cut struts (AE92, SW20 etc) I would probably use those. Just
need to know that they would be a decent improvement over the AGX.

Cheers... jondee86