Koni Yellow vs. Bilstein B6 vs. Bilstein B8
 

Hi Guys,

I am thinking about upgrading my suspension to lowering springs with quality shocks. I have already decided on Hotchkis Lowering Springs because it fits the handling characteristics that I want in my brz. The 185lb/265lb spring rates seems like it won't increase harshness too much. I am looking for a set up that is comfortable on the street, but can perform well on the track with similar balance as the BRZ. The purpose of my car is 99% street with 1% track days.

My questions is in regards to shocks. I am interested in the koni yellows, B6 or B8's. However, I am conflicted with which shock to go for. I understand that the B6 is ideal for stock springs, but can be used with a lowering spring that lowers 25mm or less (according to the bilstein website). I also understand that the B8 is a shortened shock designed for lowering springs, which allows for more bump travel, but sacrifices droop travel because of its overall length. I am also interested in Koni Yellows, which for the most part have read a lot of comments of premature blow outs. I have noticed that Koni has released the full front shock/strut instead of the inserts, so that may make them more reliable.

Overall, I just want to know your guys opinion on what the ideal shock would be with the chosen lowering springs and why? Input is greatly appreciated:) I am also including a pic of my car with my new STI wheels and bf goodrich g-force sport tires in 215/45/17 for your viewing pleasure:)

http://i1320.photobucket.com/albums/...psa60a406d.jpg

I just recently put on a set of B6s with RCE Yellow springs. Daily, around town, spirited stints are fantastic. I have yet to track this setup - might have a track day 1-10-15. If you are still on the hunt by then, I will update (if I make the TD).

It was explained to me that the B6 is a better fit because the B8s on our car reduce travel too much. I have no other experience with aftermarket suspension upgrades. All I can tell you is I would do this again.

E-

I can't comment on the B6 or Yelow, but I just did a writeup on the B8:

I initially didn't want to rush a review on these struts. That ended up turning into a bit of a delay as they have been on for about 6 months now. I'll consider this a long-term test review...yeah, that's it.

Parts:
Bilstein $838 shipped, Tire Rack- http://www.bilstein.de/gr/products/h...s/bilstein-b8/
Whiteline $197 FT86 SpeedFactory - http://www.whiteline.com.au/whitelin...and-86-models/
Perrin $148 FT86 SpeedFactory- http://perrinperformance.com/i-14754...-fr-s-brz.html

I'll start by noting that I had some Koni yellows (which I've had on many other cars) but would have really liked a direct swap option. Shortly after the Koni's arrived the B8's were announced. Ugh. So I sold the Koni's to a local 86er and put the B8's on order. Since I was going to be down there I also ordered the Whiteline roll-center kit and the Perrin solid end links. I installed everything at once so this review can't be a direct review of the B8's, but I feel they were the largest part of the upgrade and also made the most difference.

They are matched to the Eibach Pro Kit, and compliment them well. Install was easy, with the Whiteline parts needing a press for the lower ball joint, and the Perrin parts needing some strong loving to get into place as the poly bushings make for a tighter fit than the OEM end links.

I'd say that the slow speed dampening is equal too or improved over the OEM setup (springs and struts) although the rear seems under dampened for slow speed bumps. You still get a pretty hard bump if you roll over a pothole with the rear. At medium or high speed they are nearly flawless. If the OEM dampers are a stick of butter that's been sitting out on the table all day the B8's are the same stick only on the counter for 10 minutes. Firm in the center but slightly soft around the edges, absorbing bumps and dips with a sport-tuned OEM feel. At medium to high speeds I'd compare them to a stock STI suspension as far as stiffness goes.

Up to this point I'm talking about straight line characteristics. Once you turn in...that's when the magic happens. I'll bring us back to the roll-center kit and end links and suggest these as upgrades even if going with a different suspension. They tighten up the the steering input and it becomes more direct than it already is. So, back to the magic. These dampers are some of the best I've had on a car. Through the years I've had tried almost every model from the name brand suppliers and find these at the top of the pile. The shortened height of the strut really shows in how quickly the corners of the car respond to quick input. Even moving back and forth between quick esses is smooth and stable. Paired with a quality progressive spring in front I go back to the 10 minute butter sensation from earlier. The inital turn in is quick and easy, then firm...not frozen butter firm, but 10 minute butter firm. I've put this suspension through it's paces on back roads and a few auto-x events, both with my 245/40 Dunlop ZIIs and the grip is seemingly endless. I have yet to push the suspension to it's limits on a full track, but this point is moot as this setup is designed for a car which will see most of it's days on the road.

With that in mind I'd rate this setup as one of the best daily setups I've ever put together. It's sporty when you need it, a little stiffer than you might want at slow speeds, but performs flawlessly once you're on the move. For me this is the perfect daily driver setup for the driver who might see a track or auto-x a couple times a year. Out the door the setup is about $1600 (Bilstein B8's ($838 Tire Rack) + Eibach sport line ($217 Tire Rack) + Whiteline roll correction ($179 FT86 Speedfactory) + Perrin front end links ($146 FT86 Speedfactory) + Strano front sway bar ($189 Strano) = $1569.) and in my opinion it will perform far better than any coilover for around that same price point.

Yeah i've read the posts from racecomp and see that the B8's do have less travel. I may just go for the B6's instead of the B8's.

Awesome review thanks! I'm guessings that the rears feel more harsh because of the stiffer rear spring and the shorter rear shock.

I think so, and the rears just aren't that beefy like the fronts are, maybe they could stiffen the valving in the rear, but then over the normal stuff it might get too bumpy? Overall very happy. :)

Very interested in this thread. I don't want adjustable coilover suspension when it's time to replace the factory dampers - looking for simplicity and less things that can go out of adjustment/alignment (which spring perches can do...) Koni's would be nice for their damping adjustability, but I'd be just as happy with the non adjustable Bilsteins. Will most likely come down to cost. Have had good experience with both Koni Yellow and Bilstein HD dampers in the past, though on completely different vehicles. Koni Yellow versus Bilstein B6 on springs that keep the same F/R ratio as stock for the FR-S but lower maybe 20mm max is what it comes down to for me (have to double check lift clearance though... may not even be able to drop the ride height or bring the lifting frames in from the outside versus out from the center of the car.)

Edit: Bilstein does make an adjustable version of the B6 as well...hummm, is it available for FRS/BRZ applications?

http://www.bilstein.de/en/products/h...adjustible-10/

Thanks for the link. I am a bilstein guy myself, but upon further digging it looks like the standard B6 and B8 are all that is available right now: :(

http://web1.carparts-cat.com/default...9018004&12=130


As for the OP's question, my understanding is that B8s do have less travel because they are designed to work with a lowered suspension. If you run a stock length damper in a lowered car the shaft can bottom out under heavy compression. With the B8 on a lowered car the damper shaft will have a better range for both compression and droop.

I have B8s on another car of mine with coilover sleeves and when I purchased them the dealer explained that the valving wasn't any different between the B6 and B8 for that model, but that the range of shaft movement is different to work with the ride height change.
It would probably be best to contact a knowledgeable dealer and ask for a recommendation based on the ride height you want and find out if the valving will be different.

These would be sick though:

http://www.stangtv.com/news/pri-2010...e-shock-shaft/

Actually I think the B8's don't have any extra bump travel, they just have less droop travel, so cut springs or shorter coilover springs on sleeves stay captive easier.

I think more bump travel and less droop go hand in hand...Its all relative to the ride height of the car.

I have B8s with RCE Yellows and Raceseng CasCam plates, good ride quality and control, not problems bottoming out over large or long high speed bumps, car is lots of fun.

Hi Superhatch,

I had B8s on order, then read your review and picked up the Perrin front endlinks and Whiteline Roll Correction.

I had them installed for me. I'm getting a rubbery creaking noise now when turning the wheel and the same sort of noise when the suspension is compressed.

Did you experience the same? Do you have any ideas on how to minimize the noise? I've had the installer look at it and he thought everything was fine. One mechanic said he thought that was just the sound the polyurethane bushings made.

The handling and ride are excellent. It is just the noise I'm concerned with and making sure there aren't any adjustments needed.

Thanks for any thoughts.

Lee

It could could be the bushings of the front end links that was causing that noise. Just make sure the mechanic greased those bushings with the supplied grease. I did the install myself and no noise when turning the wheel.