Technical advice for getting Bilsteins revalved

[JGood]

I was finally able to reach Koni.

325iX Koni Sport, part # 8641-1144Sport
500/650 comp/reb, Newtons @ 75mm/sec

325i Koni Sport, part # 8641-1021Sport
500/850 comp/reb, Newtons @ 75mm/sec

So identical compression, softer rebound. Rebound is adjustable on these though, so I'm not sure if that would even matter. I'm sure you can get all the rebound you need if you max it out.

I didn't bother asking about the Corrado Koni valving, because I can't think of any reason to use them instead of the iX Koni's.

[einstein57]

After talking to one of the bilstein techs for about a half hour we came up with a street/auto-x valving for my ix inserts. Unfortunately they have been sitting in the box for about a year now. I will be installing them this summer finally. When i spoke to the Koni reps about re-valving a set of ix inserts they said it would be $120 each plus parts. I would recommend purchasing the Konis from GC over re valving a set.

[JGood]

Got the Koni 325iX shocks installed. What a difference! The car feels so much better. Way smoother ride, I'm guessing the softer Bilstein iX's were bottoming out on every bump, and the lack of rebound means it was bouncing around a lot too, which is now gone. With the Koni's, the car feels like it did before I shortened the struts, when I was just running 450 lb springs and stock-length Bilstein Sports. Very streetable and planted in corners over bumps.

Here's some pics. In addition to the more appropriate valving, I also gained about 2-3" of suspension travel, and lost about 2" of unneeded droop. These are really the way to go with shortened struts, IMO.


Koni 325iX on top, Bilstein 325iX on bottom







Fully compressed. Probably 2-3" difference.

[nando]

sweet, glad that worked out for you!

the more people that buy ix parts the better - it means the supply won't disappear because of lack of interest. :p

[dsm2002]

Got the Koni 325iX shocks installed. What a difference! The car feels so much better. Way smoother ride, I'm guessing the softer Bilstein iX's were bottoming out on every bump, and the lack of rebound means it was bouncing around a lot too, which is now gone. With the Koni's, the car feels like it did before I shortened the struts, when I was just running 450 lb springs and stock-length Bilstein Sports. Very streetable and planted in corners over bumps.

Here's some pics. In addition to the more appropriate valving, I also gained about 2-3" of suspension travel, and lost about 2" of unneeded droop. These are really the way to go with shortened struts, IMO.

I like how you are chasing hard figures. Excellent! One issue is that figures at 52mm or 70mm is just a small part of the picture. The figures are just a couple of points on a plot and the shape of the plot lines is the critical issue.

I'm wondering if the suspension simply hits the bump stops often. A few using the iXs have cut their bumps stops down. Did you cut yours?

I had a similar occurrence, i.e. crashing on the bump stops, with an E30 with softer front springs and Bilstein HDs. I found that raising the suspension 15mm almost eliminated completely the harshness on the bump stops on hard bumps. The extra travel made the difference, something you have gained with the Konis.

As a matter of interest, do you have ride height figures (preferably centre of wheel to fender lip vertically above) for the current setup?

Fully compressed. Probably 2-3" difference.

This is the telling shot. As you say, extra suspension travel.

[nrubenstein]

You can, of course, cut down the bump stop in the iX Bilsteins. The difference is night and day in terms of ride quality.

Edit: The thing to remember about that photo comparison is that the Bilstein has the bump stop installed (which is 3-4" long), while the Koni is bottoming out. The Koni has much less travel available in real life usage, while the Bilstein has significantly more potential. Cut an inch off the internal bump stop of the Bilstein and add a bump stop on to the Koni and you are even.

[dsm2002]

'xactly. in my example a mere 15mm was the difference between horrible and mostly comfortable.

[JGood]

Nope, didn't cut the bump stops down. My car is different, so measuremenys won't help. I have ~1" spacers between the front subframe and the body, effectively raising the body in relation to the suspension.

When I had the car about 3/4" higher, it felt about the same. I understand a full plot would tell the story better then a single reference point, but I'm guessing since that single point on the iX Bilsteins is about 1/2 the comp/reb as a normal Bilstein Sport, they are probably much softer overall.

[JGood]

Also, I've had shocks bottom out before. When I was running Bilstein sports with H&R Sports and 15mm drop hats, it would bottom out. Switching to H&R Races actually made for a smoother ride.

But what I was experiencing was bouncing, the car felt like it would just jump off the road if I hit a bump while cornering hard. It could be the bump stops, but it felt more like the coils just bouncing. I guess it's a little late to know for sure, I sold the Bilsteins already.

[ngampleh]

what IX koni part number that you bought?
is it 325iX Koni Sport, part # 8641-1144Sport
where you bought + how much?

thanks

[hopeful]

I was finally able to reach Koni.

325iX Koni Sport, part # 8641-1144Sport
500/650 comp/reb, Newtons @ 75mm/sec

325i Koni Sport, part # 8641-1021Sport
500/850 comp/reb, Newtons @ 75mm/sec

So identical compression, softer rebound. Rebound is adjustable on these though, so I'm not sure if that would even matter. I'm sure you can get all the rebound you need if you max it out.

I didn't bother asking about the Corrado Koni valving, because I can't think of any reason to use them instead of the iX Koni's.

a BIG THANK YOU coming to you from 2024. I cannot beleive how difficult it is to find the information for shorter shocks for a platform as whored out as the e30.