Adjusting/modifying the internal bump stops on B8 struts… (please lend help & wisdom)

[GoatAutomotive]

I need your help, gents. Mostly good, but some unplanned “bad” that’s got me pretty upset and disappointed.

I finally purchased and installed the last of the missing ingredients for my chassis setup on the Stormtrooper: Bilstein B8 dampers.

Their road and track manners are, for what I was after, truly awesome. The car feels like a BMW M3 with wrong-wheel drive (FWD), with a firm refinement that never lets the car or tires get out of sorts. The car has almost zero pitch, roll or squat now. Chuck it into a corner. It gives zero f***s.

Leave a light aggressively in first. It now digs and claws into the pavement, as the car no longer lifts the front end when launching. I honestly thought I would need pricey coilovers and stiff spring rates to reach this summit of suspension greatness.
So all is right in the world, right?

Unfortunately, not quite. And this is where I need the wisdom and experience of other current/former B8 owners:

The front B8s are doing what many others have reported: bottoming out and smacking on big dips and hard bumps/impacts.

This began in the first ~15-20 miles following installation. Any harsh drops in pavement surface, or sudden rises/impacts when you’re driving above ~30-35mph, and they crash like a musician on a bender.

It’s a horrible sound and sensation, not becoming on any German vehicle:

Think Holly Holmes giving someone an uppercut and hearing the skull disconnect from the vertebrae:

POP! BANG! [insert vintage Batman comics here]


For clarity, I am running the H&R OE Sport springs. These did extremely well with the stock dampers on the car, and ZERO trimming of the OE bumpstops at that time.

H&R advertises a 0.75” drop (20mm). As others have cited, final drop (after settling) is closer to 1” all around, and that is utilizing the Audi TT rear pads for leveling. Look at the pics and it’s identical to the VWR or Eibach drop, but with a progressive spring.

I’ve observed lots of folks running the VWR and ED springs, which have very soft spring rates, excessive drops, or both – and they encountered this bottoming out issue on the B8s. I thought I would be immune with the superior H&R springs and the reduced drop, hence this post.

The crash event is exclusively from the front of the car, which checks out, because I trimmed a modest ~20mm from my rear bumpstops, but the front B8s have internal travel limiters inside the strut body itself.

I did some research to see what was needed to modify the front bumpstops, and it’s wretched:

You have to take the entire strut back apart from the car, mounts, springs, etc…disassemble it on a bench/vice, and separate the entire monotube (chrome strut body) from the yellow steel casing.

Helpful, short videos here of this being done:

I went through hell to get all four corners done in time for my recent track event on 5/10 (along with redoing all the brakes, flushing the fluid, etc). Consequently, the thought of doing any more suspension work on the car this month is pretty nauseating. Just being honest.

More than anything, I just wanna drive and enjoy the fruit of my efforts & research.


Background established, my question to all you fine folks:

Has anyone here trimmed/modified the B8 internal bumpstops on their car, and with what success?


Videos above of the B8 anatomy and disassembly; pictures of Storm's ride height below. Begin discussing amongst yourselves.

I am about to email Bilstein N/A to get their input.

Thank you in advance, fellas.

 

[GoatAutomotive]

Last thing, relevant to our discussion – springs!

There is the obvious, sensible argument that a stiffer, stronger spring might help resolve/manage this issue. Unfortunately, if you really do your research, none of the standard springs for our cars (with stock style struts) have anywhere near enough rate to matter. Most are within 5-10% of the current H&R progressives in either direction (softer or firmer).

Neuspeed Sports have the highest rated springs @ 230#/260# F/R, but they drop the car so damned much that it’s a moot point (up to 1.3”, just like the EDs).

A linear Golf R Eibach Pro Kit is not out of the question, but I cannot find spring rates for them, and they all put the car at the same ride height where I currently sit. There is a set new in box currently for sale near me for $230 OBO. Evidently they have skyrocketed up to $350 new?!

Those of you running the Golf R Eibachs with the B8s – what is your incidence of crashing/bottoming on rough roads, dips, etc?

Out of desperation and creativity, I have even looked into running some 034 Motorsports S3/RS3 springs, since they have much higher spring rates, and their non-MR versions are direct fitment to the MQB GTI & Golf R.

But admittedly, I'm afraid they will make the rear of my car sit way too high (like a dragster), and perhaps ride too harshly compared to what’s on the car now.

You can just look at close-up pics of them, they are SUPER girthy compared to OE/H&R springs:

S3 non-MR - https://www.034motorsport.com/dynamic-lowering-springs-for-8v-audi-a3-s3-non-magride.html
RS3 non-MR - https://www.bmptuning.com/products/034-motorsport-dynamic-lowering-springs-8v-a3-rs3

NOTE - About 100lbs of the additional weight on the AWD/Quattro models is all near/over the rear axle, and ~50lbs is the Haldex unit up front, but I’ve found some folks running these springs on their 4-Motion GSWs (3250lbs) and tracking their car with great success at tracks like VIR.

I’ve included a pic below for GSW-owner & track hound Terrence Singh (found in one of the FB group communities). He is one of the first folks I came across who runs the 034 RS3 springs on his ride.

 

[GoatAutomotive]

This was something I did every time I installed a set of Bilstein or H&R dampers years back.

Pull them out and remove the bottom nut and the cartridge will slide out but some dampers the piston rod stem is threaded into the housing so you would use a hex bit to un-screw it out.

PSS9/10 are disassembled a little differently due to the adjustment knob, Bilstein used 55mm avg bump stops solely to keep your wheel from engaging contact into your chassis if you were on the lower side, I personally and Sachs run a 25mm bump stop and max I use is 35mm.

This is where part of my confusion and frustration enters:

With how time and labor intensive it is to adjust these bumpstops, I truly have no idea how much to begin trimming initially to assuage the issue.

 

[GoatAutomotive]

Official contact form/message to Bilstein N/A:

Dear Bilstein,

I need help from your tech support dept. I recently purchased a set of your B8 dampers (front & rear) for my 2017 VW GTI SE shop car. The goal was to obtain a better ride with improved suspension management.

The car is equipped with a set of H&R OE Sport springs, advertising a 20mm drop, and coming in at an honest 25mm drop. They are progressive springs with a solid reputation on this platform.

The issue I am having is, right out of the gate (first 20 miles of driving), these B8s are bottoming out on dips and bumps above 35mph.

I trimmed the rear bumpstops by 20mm, as I did not feel comfortable with the compression travel when measured off the car. But the fronts, due to their internal design on the B8 inverted monotube, I did not touch.

I am concerned at the prospect of having to completely disassembly the front struts (time and labor intensive), completely disassemble the strut assembly, and modify or replace the included bump stops/travel limiters.

Please let me know what your protocol is for customers who experience this.

I know am not the first. In the months preceding my purchase, I read about 10-12 people experiencing it over the years, on the same platform with the same (nearly) ride height on various spring setups.

Right now it seems my only options are to remove and modify the B8 bumpstops, or move to a different spring, such as the linear rate Eibach Golf R springs.

Here is a link to the full write-up on my issue:

https://www.golfmk7.com/forums/inde...on-b8-struts…-please-lend-help-wisdom.422926/

Please reach out to me as soon as possible so we can resolve this issue.

The overall handling and ride quality improvements of the B8s has been sublime thus far. I just need this bottoming out/crashing issue resolved.

Thank you in advance.

-Michael

 

[GoatAutomotive]

My goal for this thread is 2-fold:

1) To obtain speedy resolution for this bottoming out, so I can continue using the B8 dampers.

I like their design and technology, and I love the way they feel outside of the bumpstop contact moments.

2) To help others in the community considering this damper, or experiencing the same issue, since I am now just one of a dozen or more who have experienced this problem.

If we learn that you have to run a linear-rate Eibach Pro Kit spring (or better) to maximize the B8 performance and avoid "crashing" hits, then so be it.

@Hammersticks @tigeo @SugarMouth (just to name a few)

 

[tigeo]

Lowering a car with springs just eats into the bump travel of the damper and as such, you'll get some crashing if the spring is too soft and you blow through the v. limited travel. I had this issue as well. I spent the time a while ago to look at this issue, collect measurements from both my car and talking to Bilstein and here are my data:

So as you can see in my case, if I trim the bump stop I actually will lower my spring rate and potentially make it sag even more/cause more of an issue! I've seen some posts by BMW owners that have done it, I think it's fine if you have enough travel that you aren't already "on/in" the stop but best I can measure/tell, I'm sitting on/in it so trimming it won't do a thing for this issue....have to bolster the spring so that's what I did and it worked! I figure Bilstein knew what they were doing here w/r to the stop lengths...keep in mind it's really a small v. progressive spring vs. a hard rubber stop so it helps increase the rate to prevent the crashing issue. You just don't have much travel (4.3" max! and most of that is sagged under the weight of the car when you are at rest) and the springs are a bit soft allowing that travel to be used v. quickly.

I ended up using a spring rubber to help add a touch more progressive rate up front and wha-la...no more CRASH! on big hits for my fronts. There are nicer versions of these that wind in the coils but these were $13 at Advance Auto (Amazon has them as well) so figured worth a try/proof of concept. I don't think most folks know that they are likely nearly sitting on these at static ride height once lowered so the common "I hit my stops bro." is really not accurate...you were already hitting them bro! (takes drag of vape pen, adjusts flat-brimmed hat, engages pops/bangs, puts some Anime stickers on dash, says bro a few more times). I actually have a before video where you can hear the crash over a certain road imperfection and I can make one here today/tomorrow with the rubber and you will absolutely hear/see the differnece in the video showing how effective this is. It's just too bad H&R etc. can't make a more progressive spring that would give a bit more rate here as that's really the crux of it but folks want "lowered with stock-like ride" and here we are.

 

[GoatAutomotive]

^

That all makes sense about the suspension travel. If not for the pain of having to take these out, I’m curious if a linear Eibach would be more resilient at keeping the car off the bump stops up front…

Thank you for sharing your experiences, Adam.

I’ll post back up if Bilstein has anything helpful to contribute.

 

[MonkeyMD]

Sell it all. Get some coilovers with custom springs

 

[tigeo]

^ View attachment 281141

That all makes sense about the suspension travel. If not for the pain of having to take these out, I’m curious if a linear Eibach would be more resilient at keeping the car off the bump stops up front…

Thank you for sharing your experiences, Adam.

I’ll post back up if Bilstein has anything helpful to contribute.

I don't think it will matter at all. If anything, you should keep the same length bump stop and get a higher-durometer one.

 

[tigeo]

Sell it all. Get some coilovers with custom springs

Another option. I like my $13 rubbers.

 

[manu97]

Another option. I like my $13 rubbers.

Cheaper than kids.

 

[tigeo]

Ok @GoatAutomotive....take a watch. Please....anyone reading/watching this....subscribe to my channel!

First video you can just start at 1:20 for the spring discussion with the harsh hit around 4:10:

Today's hit with the spring rubbers in, same place/speed...quite different!:

https://youtube.com/shorts/r8qqlb0MRqA?feature=share

 

[walrussss]

@tigeo

I’m probably going to try this as I have the prokits on b8 and the bottoming out is very annoying. I just wanted to clarify. Did you only put rubbers up front? And did you only use one rubber per strut.

 

[tigeo]

@tigeo

I’m probably going to try this as I have the prokits on b8 and the bottoming out is very annoying. I just wanted to clarify. Did you only put rubbers up front? And did you only use one rubber per strut.

Yes only on fronts. 1x side.

 

[AzteCypher]

I appreciate all the info here as I just picked up some B8s.