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dmsfun 05-25-2013 09:37 AM

Koni FSD's installed
Ordered the FSD's from Koni US, and was surprised that they had a set in stock, so got them delivered in 2 days and just installed them along with new OEM springs, mounts and isolators. These replaced the Bilstein HD's which I had for about 10k. The price will scare off most, as they are 3x the cost of the HD's at $980 a set.

The FSD's do not give a luxury car ride, they give a firm, more controlled ride than the Bilsteins, with better handling under all conditions, plus they are smoother over bumps. I drove the same route I'm used to and through corners with bumps, the FSD's soak them up and the car remains level, where the Bilstiens had impact harshness and would bounce around, upsetting the handling. At higher speeds, the FSD's seem to get that much better, with a very confident feel with quick lane change manuevers, and harder cornering. Just did some mild off roading and they soak up the bumps better too.
One note, ride height is 1/4 " higher than the Bilstiens, which could be either the FSD's or the new OEM springs need to settle a bit. Either way, to me this is an added bonus for Jeeping, as it handles great without having to put on stiffer, lower springs and SRT Bilsteins, which improve handling, but make it harsh riding, and next to useless off road.
The Bilstein HD's represent a solid value for the price, but you get what you pay for, and to me the FSD's are 3X as good, for 3X the price.

ALPINEST4RS 05-25-2013 09:42 AM

Re: Koni FSD's installed
Finally somebody did it!! Don't they sell coilovers also??

dmsfun 05-25-2013 09:49 AM

Re: Koni FSD's installed
The only other WK Koni's are the heavy tracks, which are adjustable monotubes similar to the Koni Sports, where the FSD is twin tube with automatic adjusting. The Heavy tracks are rougher riding, as are all monotubes.

ALPINEST4RS 05-25-2013 10:14 AM

Re: Koni FSD's installed
Oh alright. Well thanks for the review!

dmsfun 06-24-2013 07:37 AM

Re: Koni FSD's installed
update... 4 weeks and 1000 miles with some off roading since installing the shocks/coils/isolators and the ride has smoothed out a lot. The new OEM coils were definitely worth it over using the 86k originals, and just needed to settle in.
Am very happy as it rides and handles so much better than the Bilsteins and is great for off road too. I highly recommend new OEM coils if you are replacing shocks and have high mileage.

bobharly 07-15-2013 11:29 AM

Re: Koni FSD's installed
After thinking about your posts, both here and else where in other threads, this is probably a good option for someone who desires both good handling on the street and off road ability. Traditionally, you have to sacrifice one for the other. I would also like to add that I was surprised that the coils had worn out in my jeep too. When I converted to an SRT suspension I only dropped 1/4" in the front. It took me a while to realize that the old coils had compressed with mileage. That was was at 60k miles I believe.

Post your ride height, front and rear, measured from the center of the hub to the edge of the fender. I am curious now.

dmsfun 07-20-2013 08:23 AM

Re: Koni FSD's installed
With the FSD's, new OEM coils, mounts and isolators, the fronts measure 19 1/4 in. from hub center to lower fender lip. The rears measure 19 1/2. This is raised from what is was with the 86k coils and Bilstein HD's.
The FSD front struts have a longer body than the Bilstien HD's, so had to remove the front lower control arms to install them, a bit of a PITA, but well worth the extra time. The Jeep is now level instead of raked, as it was previously. While some prefer a raked look, where the front is lower, this really worsens handling, braking, and ride quality, i.e., the WK (especially the Hemi) is already very front weight biased, and raking increases the front weight distribution even more.
IMO, Bilstein did little if any real world testing with the WK HD's, i.e., the valving is way off, resulting in rough bouncy ride with poor control and handling. Koni engineers know what they are doing, and the results tell the story. The handling is superb, and much more controlled, balanced, and level compared to Bilsteins, and the ride is sooooo much smoother. With the Bilsteins, I had to deflate my AT3 tires to 29 psi, or else it would crash badly over bumps and manhole covers. With the FSD's I run 35 psi, and the ride is 10x smoother. On was on a back road yesterday with a railroad crossing where the road was raised up around 6 ft, and the track surface very rough. Cars ahead were all slowing to a crawl... I gunned it and went right over at with total control; even got a little air. My passenger lives nearby and drives this road often, and also has a GC and a pickup, and was amazed how easily, tight, and in control it felt.

bobharly 07-20-2013 10:15 AM

Re: Koni FSD's installed
I'm curious about how the raked look affects handling. I was pondering getting a set of SRT Eibachs and installing the fronts only to lower the front. I need the stock srt coils in the rear because I actually use the jeep and can't afford to lose anymore travel in the rear. Can you expand on the physics of why the raked stance is worse for handling or provide a web link with a good explanation?

And thanks for the measurements. Your jeep sits roughly one inch higher than mine with the SRT bilsteins and coils.

dmsfun 07-20-2013 09:50 PM

Re: Koni FSD's installed
The ideal weight distribution is 50%/50% front /rear for neutral handling, (no understeer or oversteer) and best braking. Road race cars are corner balanced using 4 scales, one under each wheel. To distribute the weight as evenly as possible, the corner with more weight is raised accordingly, typically done using adjustable spring heights with coil overs. The WK is already front biased, and by lowering the front, you increase the front weight bias more, and you will get understeer (push) and worsened braking distances.

bobharly 07-20-2013 10:34 PM

Re: Koni FSD's installed
Fascinating.... Thanks, just saved me from making a mistake.

Billyb.cpt 07-25-2013 03:24 PM

Dmsfun do you think with 127,000 miles on my WK that new springs/isolators would help out the ride alot? How's the noise inside the cabin? Is there less transference of sound, is it quieter? Only thing is that I have the Bilsteins, so I know they'll still be harsh but do you think with replacement of just springs/isolators that it will help control them a little better? I do have 127k on the originals, just curious. Thanks in advance!

dmsfun 07-27-2013 09:06 AM

Re: Koni FSD's installed
New springs and isolators at 127k would help. I put in new isolators about 5k after putting in Bilsteins and it bounced around less, cornered better. The WK is just not a very solid build quality like the WK II, and is noisy inside in comparison. To make it quieter, I put in additional weatherstripping on all the door surrounds, which helps a lot. Before, there were loud air leaks and road noise at highway speeds. IIRC, cost $4 at Menards.

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