KONI 87-2661 Adjustable Front Strut/Shock NCV3 4x4

Just picked up a set of KONI 87-2661 adjustable front strut/shocks for my 2016 144 4x4 High Roof Crew. Ive got about 40k on the stock suspension and will be upgrading.

Upgrades to be installed over the next few weeks:

Van Compass Stage 5
KONI 87-2661 Front Strut/Shock
Van Compass Skid
Van Compass Front 2" Receiver Hitch (we are a family of 6 and have 6 mountain bikes to haul around)

Van is riding on 255/85/16 Coopers.

QUESTIONS/COMMENTS on the KONI 87-2661:

1) Strut/Shock assembly did not come with boots/dust covers - are they intending that I use the stock cover?? I'll call the vendor and ask them about this this morning.

2) Strut/Shock did not come with any directions as to how to adjust it. Looking at the assembly I cannot see how to adjust it? Possibly the plate at the base of the shaft/top of the shock body that has two holes in it? Does it require some sort of specialty tool? I'll also call the vendor on this as well.

3) I will be using this to replace the stock strut/shock tower when I install the Van Compass Phase 5 kit, which includes a secondary Fox shock. Assuming I can figure out how to adjust the KONI 87-2661, what setting should I use? I think this might require a conversation with Van Compass so I can get the secondary fox shocks set to the right setting to cooperate with the KONI shocks.

For all the naysayers out there (someone will surely have a dissenting or negative opinion), I am replacing the stock strut/shock with a new one as it will all be taken apart, the stock MB setup is feeling a bit like a box truck (!!), and I might as well replace the wearable part while it is taken apart.


Cheers!!

Nice to see an aftermarket 4x4 strut finally available in the US, I'm excited to see how these ride in comparison to the stock units.

On the 2wd Sprinter Koni struts, you have to push them in all the way and turn them either clockwise or counter clockwise to adjust them. It's not very intuitive or easy to tell what "setting" they are at. I'm sure you can dig up some instructions to the 2wd units online.

If you're looking for a new boot for the strut, rock auto sells a complete strut "wear item" kit that is a good idea to go through while you have the struts out. It's cheap insurance to change the upper strut bushing depending on how many miles you have on your van. The upper strut bushing is a wear item and does soften up over time. $27.79 per side.

https://www.rockauto.com/en/moreinfo.php?pk=6570440&cc=3310060

How heavy is your van? I'd honestly just suggest setting them to the max rebound setting and we will tune your stage 5 kit accordingly.

Thanks,

-Rob @ VC

On the Koni website it explains how to adjust these, I believe there are 3 settings... I'd see how these feel on their own before dropping the big $$ for an aux front shock kit, you may not need it (spend the $ on the VC tranny skid or rear step, etc)
I'm looking forward to hearing your impression of them after you've had a chance to drive on them, I'm ordering a set too.. $115 in shipping for me sucks... I have LSC Foxs on the back, will set my Konis to their firmest setting, I do know they can only be adjusted while uninstalled...

No naysaying here!!! The stock struts are f-ing garbage. I have the VC aux shocks up front and still have blown a stock strut since the install. Next time one goes I will be grabbing these. Cant wait to hear your impressions of the two together.

Rob - for us that already are rocking your shocks- do you also suggest max rebound? My van is 8300-8600lbs and you gave me a set of your "heavy van" shocks (fronts and remote reservoir rear).

The struts come at the minimum setting. Completely collapse the strut and turn shaft. It doesn't take much force. You should be able to feel the adjustment turn internally. I would go with max setting. I installed them in my Sprinter MH back in '07. They're still doing well with over 100 k miles.

Once at max setting, the struts are very difficult to expand. I put one end in vice and with all my weight they will slowly expand (rebound).

Save your receipt. They are guaranteed for life with proof of purchase.

Edit, I used the old stock boot again.

OffroadHamster said:

No naysaying here!!! The stock struts are f-ing garbage. I have the VC aux shocks up front and still have blown a stock strut since the install. Next time one goes I will be grabbing these. Cant wait to hear your impressions of the two together.

Rob - for us that already are rocking your shocks- do you also suggest max rebound? My van is 8300-8600lbs and you gave me a set of your "heavy van" shocks (fronts and remote reservoir rear).

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Hard to say until we try a set out for ourselves but judging from the 2wd units we've dealt with in the past, they still don't have enough rebound damping on max setting for most built vans. Maybe these are different. We'll try a set out soon and report back.

-Rob @ VC

Desertbound said:

Hard to say until we try a set out for ourselves but judging from the 2wd units we've dealt with in the past, they still don't have enough rebound damping on max setting for most built vans. Maybe these are different. We'll try a set out soon and report back.

-Rob @ VC

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but how do the ones you’ve installed in 2wds compare to the factory struts in that application ?
no real difference, moderate or a lot but not the level of a Fox ?
I sure hope they make a difference....
for the price, would you rather replace with factory struts, a different aftermarket strut or these ?

Desertbound said:

Hard to say until we try a set out for ourselves but judging from the 2wd units we've dealt with in the past, they still don't have enough rebound damping on max setting for most built vans. Maybe these are different. We'll try a set out soon and report back.

-Rob @ VC

Click to expand...

I've been pondering the Koni vs. VC Fox setup for a while now. I do like Koni but I'm going to go for a known entity on the Sprinter, the VC/Fox setup, even though Brexit has washed out the GBP making it relatively expensive. I'd still be interested in your thoughts on the Koni's though
After our last trip to Africa I really don't fancy the rockin and rolling and the horrible ride on corrugated tracks on our next big trip to Western Sahara and further!!

the VC/Fox front shocks, in addition to the struts, will give you the best traction. that is the whole reason you have a 4x4 in the first place. i’d consider the Koni struts when its time to replace the factory struts. but i only have 15k miles. maybe Fox will make a strut, also. the front Fox shocks are next level though. a Koni replacement strut on its own is not a fair comparison to the add-a-shock kit.

When set to max damping, the Koni strut is far superior to any other struts. I would try that setup first before adding more damping up front.

I've done a lot of suspension testing. The majority of chassis rocking is initiated from the rear.

A seat of the pants feeling for rebound setting for driving preformance ; would be ..while driving /.. after a G-out-compression of the suspension, the spring rebound should be dampened enough that your butt doesn't hover rise much from the seats foam.

Now - the rebound setting for slow-G-0uts; such as controlling rocking from enter a driveway would require a much higher slow speed dampening setting. A compromise, In that at road speed the suspension reaction is too slow and causes the ride to be deeper into the spring rate. Making a hard ride so that your butt rises and pounds the seat foam.

A springs reaction to an impulse is an oscillation at the springs natural frequency. This is the same frequency as when the chassis is rocking. It doesn't matter if the spring deflection is caused by a G-out or just entering a driveway, the spring reaction is the same. The spring deflection amplitude may be different, but the oscillating frequency is the same.

The function of the shock absorber is to dampen the oscillation so that it doesn't go on indefinitely. The key unit of measure in a spring/damper system is the damping factor. It determines how many oscillations occur before they are not noticed anymore. The damping ratio also determines the springs reaction to the initial impulse. The goal is to achieve a damping factor of 0.2. My T1N with stock shocks had damping less than 0.1. That makes the suspension very volatile.



The initial bump gets amplified by more than 80 percent. In other words, if there's a 2" bump, the spring reacts by deflecting 3.6" and there's more than 6 oscillations that are noticeable. After installing Koni struts and Fox 2.0 shocks (damped to the max), the damping factor is now close to 0.2.

The damping ratios I mentioned are calculated from logged accelerometer measurements.

I didn't know there was going to be any math involved ��..... I just want to know how they "feel" when installed and if they are any better than the factory struts in a direct comparison....
already have remote reservoir Foxs in the back and Sumos in the front... may add the VC spring pack in back...

I spared you the math.

The damping factor IS what you'll feel.

calbiker said:

A springs reaction to an impulse is an oscillation at the springs natural frequency. This is the same frequency as when the chassis is rocking. It doesn't matter if the spring deflection is caused by a G-out or just entering a driveway, the spring reaction is the same. The spring deflection amplitude may be different, but the oscillating frequency is the same.

The function of the shock absorber is to dampen the oscillation so that it doesn't go on indefinitely. The key unit of measure in a spring/damper system is the damping factor. It determines how many oscillations occur before they are not noticed anymore. The damping ratio also determines the springs reaction to the initial impulse. The goal is to achieve a damping factor of 0.2. My T1N with stock shocks had damping less than 0.1. That makes the suspension very volatile.

The initial bump gets amplified by more than 80 percent. In other words, if there's a 2" bump, the spring reacts by deflecting 3.6" and there's more than 6 oscillations that are noticeable. After installing Koni struts and Fox 2.0 shocks (damped to the max), the damping factor is now close to 0.2.

The damping ratios I mentioned are calculated from logged accelerometer measurements.

Click to expand...

You are giving me flashbacks of mechanical vibes and control systems exams

OffroadHamster said:

You are giving me flashbacks of mechanical vibes and control systems exams

Click to expand...

Me too! Square root of k over m... ugh... Need a beer...

Montucky said:

Me too! Square root of k over m... ugh... Need a beer...

Click to expand...

There you go...

Square root (k over m) is proportional to the oscillating frequency. Frequency should be around 1 Hz. If the mass increases then spring constant should increase (more springs). And of course damping has to increase as there's more mass to control.

In the case of my heavy Sprinter 3500 motor home, it came with the same shocks that come with the lightest Sprinter van. What a disaster. The front end would bottom out when there's a dip in the freeway.

Just bit the bullet, my new Koni Struts should arrive Weds and I plan to be feeling the difference in ride by Sat !!! Bought them from the Sprinter Store and they are setting them to the max dampening for me, Jared there said they normally set them to 75%, 7 pairs left in stock....

Be sure to test them before they get installed. Put one end in vice and pull them apart. It should be difficult to get extension. It may take a minute and a lot of exertion to get full extension.

Some 11 years ago I purchased Koni shocks & struts from the Sprinter Store. They were supposed to be adjusted to 80%, but they were not. I wasn't that happy with the performance. Still, it was a lot better than before. After 4 years I removed them and sure enough they were set to min. Not so bad changing shocks, but struts are a bigger deal.

Tested out the new knoi 4x4 struts on recent trip. Took about 3 hours to install both of them (forgot to put the boot on one so had to do one twice). You need a 21mm crescent wrench as there is not enough space between the lower bolt and the caliper to get a socket wrench in. I did not adjust the struts and used the factory setting. I was surprised on how much better the ride was as I was having buyer remorse on spending $500 on replacing what I thought where perfectly good struts. No longer feel like I was hit by a photon torpedo at every bump. Have the fox shocks on the back and feel the new struts improved the ride more then then the fox shocks. Sorry I don't have any graphs or equations to quantify the improvement but would recommend them.