tarzancoe

Anybody has tried this combination? The 993 folks do it with their M033 equivalent and love them.

In the US they recommend to use the fsd's with Eibach prokit springs (or stock springs) but that would lower the ride 30mm and I think it might have a negative impact in the effectiveness of the fsd's damping as it would have less travel.

feds

I was wondering this too.

tarzancoe

I have not found any references. I think I'm going to take the plunge and give it a shot. My Indy will get me the springs as I can't find them online. I only find the whole kit (springs, shocks, sway bars).

I wonder if it might be worth using the MO030 sway bars. Or, gt3 sway bars.

tarzancoe

I talked with Gert from Carneval. He was very knowledgeable about the topic. He recommended NOT to use MO30 springs with the FSDs, as they will not work well because the MO30 is a sports spring.

The 993 has the M033 available and that's what they use to pair it with the FSDs. The M033 springs are a shorter version of the stock springs so your car can be lowered, but it is not a sport spring like the MO30. There is no M033 equivalent for the 996.

He says that yes you can go with Eibach pro springs and FSDs as they recommend it in the US, but then again you will be lowering the car a lot.

So, no MO30 springs with the FSDs. If you want to lower the car just a bit, MO30 kit (springs/shocks/sway bars) is still the only option, but ride will be a tad sportier (less compliant) than the FSDs.

The only other suggestion he had is using the stock ROW springs. But all it will do is lower the car 10mm in the front, compared to the stock US suspension. The rear springs are the same.

alpine003

On a somewhat related note, I found it interesting when I was contemplating this setup for my wife's BMW that a Koni sales rep actually recommended to go with the higher spring rate of the H&R springs over the Eibach springs for a better setup. I found this a bit odd but there have been some debates on this as some think the Eibach's can be a little soft for some people's tastes, especially when paired up to the FSD's. I guess it might boil down to individual tastes and whether a ride characteristics can be "ruined" for some by using one or the other.

Now I don't know how the springs rates of the ROW compare to the Eibachs and H&R's.

tarzancoe

My understanding is that spring rates for HR's are hardest, and that do not work well with the fsd's.

Regarding the fsd's for BMW's vs porsches:

The reason why the koni websites do state that they should be only used with standard shocks, is that they were tested and engineered to those specs. Then and after doing so, koni did test different spring combinations in each different car. In the 996 case, they found out that Eibach springs work well for 996s.

The following is an post from a Saab forum around 2007:

"Maybe I can shed some light on this situation with KONI-FSDs. I work for KONI-North America and was partly responsible for putting together the FSD/Eibach kits we offer here in the US market. First, you need to understand that FSDs are not designed like other KONI shocks. They really are unique, in that they use two valve assemblies which work in parallel. One is sensitive to wheel frequencies (10-15 Hz) and the other works on the much lower body frequency (1-2 Hz).The FSD ride benefit is gained using the smaller valve for higher frequencies; it reacts much faster to road irregularities like tar strips or currugated pavement than a standard main valve. When you drive a road with low-frequency, large undulations, the damper reverts back to the main valve system. KONI technicians tune the frequency responses and crossover point from small to large valve and back again for each vehicle.You will note in the KONI product catalogs, both European and US, the FSDs are not matched to lowering springs. The reason is that, due to their frequency response characteristics, the FSDs must never ride on the jounce bumpers for an extended period of time. If they do (like with some lowering springs), the shock valving will read the jounce bumper as a high-frequency disturbance and back off the damping force. I think that is what some of you are feeling with lowering springs.We do offer FSDs and the Eibach Pro-Kit lowering springs for some vehicle applications, but only after we have studied the specific vehicle situation. We wanted to offer FSD/Eibach kits on the current MINI, for example, but could not, as that vehicle did not have sufficient wheel travel with the Eibachs to stay off the jounce bumpers.The Saab 9-3 is listed as an FSD application with the 4-cyl turbo, but not with the US-market Aero V6T, nor Eibachs with any powertrain (they have not yet been approved).A long explanation for this concern, but I thought you should know the facts."

tarzancoe

I ordered the FSDs from Paragon. Aston Martins, Gallardos, and McLaren F1 use them stock. They can't be that bad right? Will decide about springs while they arrive, but chances are that it will be either stock or eibachs. Or, I might get some ROW stock springs for a minimal 10mm drop in front.

alpine003

ah, so if I'm understanding the article correctly, the FSD's are more sensitive to the actual height and not so much the spring rates?

I guess though the spring rates could dictate to some degree how much the shock could potentially temporarily stay in a lowered state if the spring rates were soft enough over various road conditions.

When FSD's first came out, I do remember reading that they were to be used with stock springs only until they partnered up with Eibach springs. IIRC, the part numbers for FSD/Eibach combo were different on the shocks than with regular springs.

A couple friends likes the FSD's and I see nothing wrong with them for their intended purpose. Please report back on your findings specifically with the 996. I would like to hear some good news that you were able to have your cake and eat it too.

tarzancoe

It seems that both spring length and spring rates affect the fsd's; if springs too short, there is not enough travel on the fsds. And if rates too high, fsd's get confused. Probably that's why they went car-by-car, to see the effects of the combination of different spring length/rates.

I will post results, probably in a couple of weeks.

tarzancoe

I did look into whether the kit offers the same items; the answers I got is that yes, you can buy separately the shocks and the Eibach springs as there are the same. The Koni North America site seems to indicate it as well. http://www.koni-na.com/fsd.cfm. I certainly hope so because the kit was not available and I purchased the shocks alone while I decide what springs to use.

alpine003

Koni only offers the Eibach/FSD combo's for certain cars and not all as you've noticed.

tarzancoe

Yes you are correct. They had to try in each car individually. Also, if you notice in the link to their site in the previous post, it states "Pair with Eibach springs for 1"-1.5" lowering(Excludes Mini)". To me this means that you do it on your own. I'm not 100% sure as I could not reach Koni. TireRack says that it is the same but who knows if the sales guy really knew or just assumed.

I doubt that they did custom setups for each individual car. Not cost effective, that's why adjustable coilovers are for.

tarzancoe

Finally, I installed the FSDs with EUROPEAN stock springs. The springs lower the car about 10mm on the front, and they stay the same in the rear when compared to US version. Thus, the stance of the car is improved to Euro stock. I almost went with Eibach pros, but ultimatelly I decided that a 1" drop was too much for daily driving.

The shocks: I have driven about 300 miles with them. They work so good, that I will keep my 19" wheels as I was going to 18"s to improve the ride. The car is much more compliant around the horrible LA roads. It does not "slam" onto every single bump on the roads like before. The shocks are also a bit firmer than stock, it is easily noticed. I'm glad that I did not go with the ROW030.


All in all, my hopes of a more compliant ride and a bit sportier than stock have been met. I recommend them, specially with a pair of euro springs. I got them for 100 euros including shipping from Gert, can't go wrong with that.

MiamiC70

So this is confusing the Koni site contradicts itself.

On one page it says "FSD kit must be used with stock height suspension."

http://www.koni-na.com/cat_search.cf...&submit=Search


Yet under product details is says "Pair with Eibach springs for 1"-1.5" lowering(Excludes Mini)"

http://www.koni-na.com/fsd.cfm

So which is right? I been following the story on FSD shocks and since now th Porsche X74 is seemingly no longer available I have been looking at the FSD with some lowering springs. Anyone actually install these with lowering springs?

tarzancoe

Yes they must be used with stock suspension. Howewer, on a case by case koni engineers tested individual cars. They approved the FSDs to be used with Eibach pros on Porsches. I did not do it as I did not want to lower the car that much.

But I would not compare them to x74, they are softer. I'd go with koni sports if u want lowered and sportier.