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Koni Shocks versus Bilsteins on a lowered application?

9.7K views 62 replies 14 participants last post by  toonwarrior  
#1 ·
Pretty specific question but I didn't realize Koni had a shock specifically for lowered cars, I went with bilsteins but gotta say the ride does not feel good and I think it's due to how lowered my car is and how compressed the shock is just at ride height. I couldn't find any info on the bilstein compression/rebound ratio but the Koni Streets are 35/65.


When I did my suspension overhaul I ran Canuck 2/3 drop springs, at the time everyone said Bilsteins was fine with the lowered setup so I went with it but the ride quality has just not been that great to be honest.

As mentioned in this video it has a pogo stick sensation.

 
#2 ·
What size tire/rims are mounted presently?
 
#4 ·
Bilstein's aren't going to affect ride lowered ,or not. Springs make much more difference...
They're likely what are affecting your ride quality. Any lowing spring is going to give a firmer ride.
But ,differences do exist between brands/types. Installing Air-Lift bags inside rear coils may help.
 
#17 ·
Bilstein's aren't going to affect ride lowered ,or not. Springs make much more difference...
They're likely what are affecting your ride quality. Any lowing spring is going to give a firmer ride.
But ,differences do exist between brands/types. Installing Air-Lift bags inside rear coils may help.
I'd always heard that shocks make much more difference than springs regarding ride quality. When I put the stiff front springs and koni's in the front of my wagon, the ride was definitely firmer, but was not at all harsh. I got no complaints about ride quality from my wife, but she did notice the huge decrease in body roll.
 
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#5 ·
You are never going to know without trying.
Notes:
Your car looks pretty dumped in the front, likely riding on the stops .
Koni says their shock is specifically valved and designed for your car. Yeah right ,then listed for any car it will bolt into, including an Avanti !!

While I dont think it is the shocks position in its range causing issue , you could test that by spacing the lower mounting down 1/2 - 3/4 " with spacers and longer bolts .

My crystal ball sees thicker spring pads or taller springs in your future🙂
 
#6 ·
OP - As 95 wagon said, your car looks like it's sitting on the bumpstops up front which is why you don't like the ride. There's a **** ton of NVH being transmitted to you through your frame and it's also limiting your travel. I just pulled out some old Vogtlands (at least I think that's what they were) from the front of mine and replaced them with Eibach's for the same reason. I've never been an advocate of special shocks for lowered cars. To me, they're snake oil and a way to lighten the load in your wallet more than anything else. A GOOD shock is going to perform exactly the same throughout the travel of the plunger. I have not had good luck with Koni reds, either. I had them on my M5 and they went in the trash about a year after install and I've been running Bilstein's ever since.
 
#22 ·
OP - As 95 wagon said, your car looks like it's sitting on the bumpstops up front which is why you don't like the ride. There's a **** ton of NVH being transmitted to you through your frame and it's also limiting your travel.
Until you notch the frame or raise it up to get it off the bumpstops, the car will ride like hot garbage. I loved the way my wagon looked all the way down, but I just couldn't take the ride anymore.
Yea I actually did the zq8 bump stops which helped the banging against the old one's, ended up trimming a ton due to how the height.
When I did my suspension overhaul I ran Canuck 2/3 drop springs
I would suggest you get your ride height sorted out before ordering new shocks.
If my memory is correct I contacted Canuck Motorsports years ago as they advertised "custom" springs. I asked if they could make a set of "stock" Impala springs. They replied If I sent them springs they would duplicate them.
I asked how they could engineer lowered springs for a Impala without knowing the specifications of the "stock" springs? They quit responding. I am not seeing a web site for them are they Ebay only now?
I ran Bilstein "sport" shocks with my Hotchkis springs and I wasn't really a fan for a daily driver. They were great handling wise, but the rear was way too stiff on compression and the rear wanted to jump and skip around on every bump.
This shows how different mixes of components produce different results. I ran Bilstein shocks with my Hotchkis springs and experienced no wheel hop. I sent my car to a "hotrod" shop I knew to check out the steering. He replaced the center link instead of the idler arm that was failed in my insurance inspection. When I dropped off the car he suggested the lowered car would handle badly. When I got the car back he said he was surprised that it handled "OK" and it was "fun" to drive. It must have been as this little test drive rolled nearly 100 miles off my odometer.

What had me change out the Hotchkis was that my "rear frame stiffener"(hitch) was scraping the ground all the time.
As to SSandman's wheel hop I have had it happen when I changed tires but no other parts.

I think these pictures are my Hotchkis spring pictures and they may help prove the Canuck springs are lower than advertised. Canucks being lower than advertised seems to be easy to find in a web search .

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Bilstein Shock Information
By Scott Mueller.



There are two different sets of Bilstein shocks available for the B-cars, including the Impala. Bilstein lists the shocks as different versions for the '77-'90 cars and the '91-96 cars, although these are completely interchangeable under most circumstances.
Here are the intended applications and Bilstein part numbers:


Application
Front
Rear
Notes
'77-'90 B-car
#1104
#0929
Bilstein only
91-'96 B-car
#1516
#1517
Same as Chevy SEO 8X3

The shocks they specify for the '91-'96 models were specifically developed to Chevy SEO 9C1 (police) platform engineering parameters, and are actually the same (except for cosmetics) as those sold through GM under the SEO 8X3 option on the 9C1 Caprice. They are all painted yellow, but the factory 8X3 versions have black boots and Delco-Bilstein stickers and a broadcast code sticker while the OEM Bilstein ones have blue boots and regular OEM Bilstein stickers. The OEM versions are much cheaper than the 8X3 versions purchased through GM!

The 1516/1517 shocks feature slightly firmer compression but also much looser rebound settings than the 1104/0929 shocks, which Chevy believes to help control the car better when it is going over large bumps, uneven roads, or when it is coming down from being airborne. The 1516/1517 shocks are also progressively damped, which means they have a variable rate that offers less resistance to light inputs, and much greater resistance to large inputs. This gives a more comfortable ride, especially over rough
roads, and still offers greater control than the original factory shocks when the situation demands. Unfortunately the variable rate also makes them feel floaty during normal driving, especially when compared to the DeCarbon shocks that are standard on the Impala. The 1104/0929 shocks are a linear damped shock, and do indeed "feel" much firmer and offer more control, especially with lighter inputs.

Another issue is the 1517 rear shock was designed for 1" longer travel compared to the 0929 shock. This was also specifically at GM's request, primarily to facilitate tire changing on the '91-'92 Caprice 9C1 with the skirted rear wheel openings. Obviously on the '93 and up Caprice or the Impala which have radiused rear wheel openings, this is NOT an issue.



Here are the specifications on the Bilstein B-car shocks:

Bilstein B-car Front shocks:


P/N
Rebound / Compression
Notes
77-'90 #1104
4275 / 1200 N/mm
Linear rate
'91-'96 #1516
1100 / 1495 N/mm
Progressive rate


Bilstein B-car Rear shocks:


P/N
Rebound / Compression
Notes
'77-'90 #0929
2135 / 1035 N/mm
Linear rate
''91-'96 #1517
780 / 1040 N/mm
Progressive rate, 1" longer travel

Bilstein commented that the 1516/1517 shocks are one of the only ones they have done where the compression rate is higher than the rebound. These were done specifically for Chevy at the SEO 9C1 platform engineer's request. This does give them more of a "built-in float" than the 1104/0929 shocks. It helps cushion an impact (high compression), but the light rebound makes the car feel somewhat floaty. These specs are in Newtons per mm.

I have previously installed the SEO 8X3 (1516/1517 shocks) in my Impala, also with stiffer rear springs and the Herb Adams swaybars. I also had the 1104/0929 shocks on my '88 9C1 and am installing them on my '95 9C1 as well. From my direct experience the 1104/0929 shocks definitely feel much stiffer overall and a much less floaty than the 1516/1517s. Based on how much I liked the 1104/0929s, I will be upgrading the 8X3 shocks on my Impala to custom valved units that are much stiffer overall. I like the
stiffer 1104/0929 shocks much more than the softer 1516/1517s, but I must say that drinking a cup of coffee without chipping my teeth in my 9C1 has been a bit more difficult than in the Impala! <g>

The bottom line is if you want a more comfortable ride with less jounce, then go for the '91-'96 (1516/1517, also SEO 8X3) shocks. I would call these the "Grandpa" versions of the Bilsteins, they will far outlast the stock DeCarbon shocks on the Impala, but are a little too soft feeling for my taste. If you like a shock a little firmer than the OEM DeCarbons, then go for the '77-'90 (1104/0929) Bilsteins. These are firmer without being too firm, and they work extremely well with upgraded swaybars and springs.

Bilstein has also indicated to me that they could do any custom valving you want for $55 per shock. That way one could have any rate of compression or rebound damping they wanted. That is what I am considering for my Impala, I plan on selecting something about 25% stiffer than the 1104/0929 shocks in that case.


I understand that the correct fix is a different spring set, but man that drop looks badass so trying the wrong ways to deal with it.
Would not drop spindles be a way to go lower and keep suspension travel?
 
#8 ·
Yea I actually did the zq8 bump stops which helped the banging against the old one's, ended up trimming a ton due to how the height. Did the body bushings which definitely tightened up the ride also.

I just added a coil spring spacer at the back and airlift kit so we will see how that rides out come better weather.

As for the front I may try what 95wagon suggested and see if I can add a spacer to the front lower mounting spots but if I recall correctly they had those little clips with threads in it so not sure how that'll go.

I understand that the correct fix is a different spring set, but man that drop looks badass so trying the wrong ways to deal with it.

Would be nice if I could try those Koni's out but not spending the money to do that when I'm on a pretty new set of bilsteins.
 
#11 ·
man that drop looks badass so trying the wrong ways to deal with it.
Until you notch the frame or raise it up to get it off the bumpstops, the car will ride like hot garbage. I loved the way my wagon looked all the way down, but I just couldn't take the ride anymore. I looked at the Ridetech Shockwaves and corresponding control arms since that would give me both the look I was after and the option of a good ride, but ended up going with Eibach springs instead simply due to cost.

You could try a set of spring rubbers as a stop-gap. Longacre Coil-Over Spring Rubbers (longacreracing.com)
 
#9 ·
While Iam not saying it will do ANYTHING for you it is a matter of longer bolts and spacers between the shock ear and control arm.
The limiting factor would be how far down you can go, if at all, without the shock body touching the control arm.
Caveat , while I have done this on other cars , never a 91-96 B body.
You will have to get under the car and remove the bolts and see if you even have clearance.
That and as I said before , I question if it will even do anything for you.
 
#13 · (Edited)
I ran Bilstein "sport" shocks with my Hotchkis springs and I wasn't really a fan for a daily driver. They were great handling wise, but the rear was way too stiff on compression and the rear wanted to jump and skip around on every bump. When you live in a place with roads as bad as where I do, your car can only handles well if your tires stay planted. Solid rear ends don't articulate very well, and an overly stiff rear end just means your tires are going to leave the ground over bumps and uneven surfaces. What might perform well on a perfectly smooth track is going to be terrible on the street.

I ended up replacing my rear Bilstein sports with a cheap Monroe shock that was much softer and the car had a much better feel over all on the street. I daily drove it like that for 4 years and it felt great.


I ended up going with Koni shocks because of the adjustability aspect and I have always heard they provided a more neutral feel. Unfortunately I never had the opportunity to run them and ended up going to a speed tech coil over setup with viking double adjustable shocks and couldn't be happier.

Another thing to be careful of on a solid axle car is your trailing arm bushing design and also rear sway bar mounting position. Many trailing arm setups guys run on these cars potentially introduce a lot of bind. For example, poly on both ends is a bad idea and to make it even worse, I have seen extended arms using poly that didn't offset the upper clevis which means you are already loading the bushing awkwardly as the clevis will meet the bushing at an angle. I built my own uppers with an offset clevis that utilize a Johnny Joint (spherical joint) at one end and the factory rubber bushings in the axle end for bind free operation. if you want to go one step beyond that, which I probably wouldn't suggest for a daily driver, but spherical joints at both ends will articulate without bind, but tend to wear out quickly on a daily driver especially when they are being used at both ends with nothing to dampen impacts and vibrations.

The other thing that causes the rear to be overly stiff and lose articulation is the fact that the factory sway bar mounting location is pretty inefficient. It lacks the leverage of a chassis mounted sway bar so guys tend to run giant stiff bars to make up for it, which hinders articulation.

With my current setup I sit pretty low (the chassis is actually lower than the ride height would indicate but I'm on ES poly bushings that sit the body up higher than what most stock SS's would sit like with 10+ years on their body bushings). The ride quality is incredible. I've run many different suspension setups; B body performance sway bars, eibach springs, hotchkis springs, bilstein shocks, edelbrock IAS shocks and i've never been happier with a suspension setup in regards to both handling and ride quality than I am with my current setup.

I actually had the car lower than in the pics, but it was underivable as I'd bottom out the chassis on everything. In the pics there is a bit more rake than usual because I have my drag radials on it which are taller than the front tires and I adjusted the coil overs just a little higher while testing them out to make sure they didn't rub. The setup consists of the speedtech/viking coil overs, speed tech rear chassis mounted sway bar, speed tech front sway bar, speed tech upper and lower A arms, Currie lower trailing arms and my own upper trailing arms.

I wouldn't recommend the coil overs on a daily because there are spherical bushings in the design and I could see them becoming an issue over time with daily abuse combine with salt/brine winter driving etc.. but the adjustability of a setup like this is amazing. It's nice being able to adjust your compression and rebound with the turn of a dial.


A3C4EA93-1CE3-4389-AED9-DBF71A5F5166 by Kris A, on Flickr


735C1428-0545-410E-A5EF-DC4C252F95C7 by Kris A, on Flickr

CC2AAD86-F13E-4F63-9CFD-31D2E8CA9B6F by Kris A, on Flickr
 
#14 ·
Would love to see the upper control arm setup, I just installed the whole BMR catalogue on my car lol, I think it was 3cfab that created the uppers with the spherical joint but don't seem to be made anymore, could the BMR uppers be modified with that setup? Need to also relocate the spring perches and get some DMR braces, tons to do...



I guess my cause of concern comes from every online literature saying that shocks meant for a stock ride height shouldn't be paired with lowering springs to which the symptoms they layout are the same ones I feel my car exhibits.

I do wonder if you had two setups, both with the same spring rates but one taller than the other if the ride quality would be affected in relation to how the shock performs. Because based on what I've been told in the impala groups the performance of the bilstein isn't impacted by spring height to which I just don't how true that is because everything else I read says otherwise. I guess I could contact bilstein directly and ask.
 
#15 ·
Why would you think shocks function would somehow be different at various points along their travel?
 
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#16 ·
Good point, I guess it would matter if the shock was bottoming out.

My last thought is:

If the bilstein b6 is made for a stock height, wouldn't the compression and rebound dampening be setup for that (i.e a lower spring rate).

With the lowering spring that has more rebound and less compression wouldn't the bilstein not be the ideal choice? I can't find much info on the bilstein b6 series in terms of compression/rebound but if it is built with stock spring rates in mind then it's essentially doing the opposite of what we want on a lowered setup.
 
#18 · (Edited)
Apologies for the multiple edits but guess I found an older thread that addresses my points atleast in terms of the bilsteins, but still would love to see how the Koni Str.t performs.

 
#19 ·
Few (if any) of us use/or recommend the Bilstein 15/16 ,15/17 versions to improve handling.
They are not intended to compensate for poor spring choice(s),etc....
 
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#20 · (Edited)
Well I got the right shocks so halfway there, as 95wagons crystal ball says it best "taller springs in your future".

Though looking at some of these setups on the fb group the drop on the hotchkis almost looks the same as mines, keep having to remind myself spring rate is what matters.
 
#21 ·
From personal experience those Koni STR.T Shocks suck.
I had them on my lowered '96and they were so rough and mushy, didn't feel planted at all.

Swapped them out for Bilstein Sport within a year and the ride was much better and way more planted and stiff.
Looked at the Koni after I took them off and two of them were blown. and they're about half the diameter of the Bilstein.


Not sure if that helps, but I do have real experience with both brands you're asking about
 
#23 ·
I think the issue with the canucks is the spring rate because I've looked at multiple setups of the hotchkis setups and they show a very similar drop to it but the difference in height of the springs looks big.

The canuck spring is really short but provides the same ride height as the hotchkis which is a much taller spring so you can imagine how much stiffer it is. Problem with that is the compression of the bilsteins makes it even stiffer and ends up being a pretty crappy ride.

So I will have to address it with taller springs with a lower spring rate like the hotchkis springs and that should smoothen it out.

Rear coil spring, both of them together barely outsize the bilstein shock box. Wish I took a side by side of the moog coil spring I took out but I can say it is tiny, will fall out fairly easily with the car lifted.

Image


Canuck coil spring versus stock fronts.
Image


It's not bottoming out as others suggested, well it was actually but then I got the zq8 trimmed bump stops in and the ride was better but still didn't address the root issue.

Here's how the drop is, looks pretty reasonable to me, and I've seen many hotchkis setups with the same drop.

Image
 

Attachments

#24 ·
.......When I did my suspension overhaul I ran Canuck 2/3 drop springs.......
Don't feel like reading the whole thread; but if by "2/3 drop springs" you're talking about a 2" and 3" drop, then your issues stem from the springs dropping the car too far.

KW
 
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#25 ·
If the springs aren't causing the car to ride on bump stops and bottom out the shocks, are you saying I would see a difference if it were say a 1.5 inch drop with the exact same spring rate?
Based on this thread it would be no because the dampening of the shock would still be the same regardless of how compressed it is (aslong as it doesn't bottom out).

I can post many picture of hotchkis setups with the same or lower drop as my car, the hotchkis spring is much taller though as it doesn't fall out if it's spring perches like the canucks. So yes it is a 2/3 inch drop but the issue here seems to be spring rate, it would be an issue of size if it were causing me to bottom out which I don't think is the case after swapping out to zQ8 bump stops.
 
#27 ·
Main issue is even at the same heights. Different spring rates will ride very differently.
Eibach's ,and Hotchkis don't seem to generate these type complaints. My Eibach springs
have frame barely touching the ZQ8 bumpstops. Does it ride firm? Yes ,but is it harsh? No...
 
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#28 ·
Exactly what I'm saying.

And Z09 you are right. Unfortunately Canuck springs aren't made any more with little info on their specs but I will go so some digging

I will go get the measurements later today since the car is on its wheels. Only caveat now is that I added a coil spring spacer in the rear which I haven't been able to drive on just yet
 
#29 ·
A set of Air-Lift 1000 bags inside the rear coils should help a lot.
 
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#31 ·
I forgot, this is what it looks like under full compression:
Image


 
#32 ·
You maybe right actually now that I look at the picture you posted of my setup, that being said that was with the front wheels on a ramp but I'll go test it again.

Trans goes in this weekend hopefully.

Great thread thanks for that one.
 
#34 ·
I ran Koni’s with stock springs for well over 20 years and they just gave out so they are very durable from my experience. Just installed Belltech lowering springs and Bilstiens ( thank God for the unbolt mod) . It feels like a dream and holds a tighter line than ever.
 
#36 ·
In refence to a previous post about the Bilstein shocks, are the #1516 and #1517 even still available? I've searched for them for my B4U, but they don't seem to exist anymore.
 
#37 ·

Yea I can't find those either, but 91ss had a post on an alternative part number that was less stiffer than the available one's but stiffer than the 1516/1517s, I
 
#38 ·
1516/1517's were never recommended ,or well reviewed for our cars.
Why would Bilstein keep making them?