Bilstein B6 HD with OEM Springs Review

Watch this!

What you just witnessed is ‘

The system that was first developed in 1955. That’s right, it’s 60 years old!

The ride quality is exemplary, no doubt you guessed as much from the video.

Such suspension is currently not available for the E46 M3, perhaps one day.

Still, it’s not like the E46 M3 has a shortage of aftermarket suspension choices is it?

We have suspension kits for all types of owners.

This includes track, weekend cruisers and the daily drivers.
​

What you just witnessed is ‘ Hydropneumatic suspension ‘ at work on a Citroën DS.The system that was first developed in 1955. That’s right, it’s 60 years old!The ride quality is exemplary, no doubt you guessed as much from the video.Such suspension is currently not available for the E46 M3, perhaps one day.Still, it’s not like the E46 M3 has a shortage of aftermarket suspension choices is it?We have suspension kits for all types of owners.This includes track, weekend cruisers and the daily drivers.

The Daily Driver

I myself fall into the cruiser/daily driver category. To me, ride quality is important. It is just as relevant on the track if you think about it. How can a driver push to the limit if he/she is not comfortable inside the car?

You can spot this in a typical Chris Harris ‘modern car’ review. With the dampers, he’ll often prefer to use the ‘comfort’ setting on canyon/country roads. This helps to soak up the bumps and undulations, allowing him to remain comfortable. If he is comfortable, the further he can push the car.

Over the years I’ve felt an increasing misconception between performance and comfort in suspensions. That is, performance and comfort cannot co-exist.

I’m not so sure that has to be the case, within reason.

I removed my Ohlins R/T coilover kit a month ago so I could fabricate a set of lower rate springs. I took this opportunity to sample the Bilstein B6 dampers with OEM springs in the interim.

B6-OEM

From this point on I will refer to the system as ‘B6-OEM’ for brevity.

The B6-OEM is in large overshadowed by the B12 kit. Recall the B12 kit is just that, a kit. It consists of the same B6 damper paired with a set of Eibach lowering springs. In other words, both items are “off the shelf”.
Unlike the B12, the B6-OEM offers no change in ride height. Actually no, it does… it raises the car a smidge over stock ride height!
This could explain why the B6-OEM is a ‘no go’ for most people, thus the lack of apparent interest.

That said, I’ve spoken to experienced individuals who have tried the B6-OEM setup. They report utter praise for how well the car performed. They implied for handling and comfort on the road nothing could match it. Intrigued by this, I purchased a set of Bilstein B6 dampers and a set of used OEM coupe springs.

Recap: B6 + H&R + GC Plates

Before delving into my findings, I’d like to recap a previous B6 setup I tried.

Indeed, this was my first encounter with the Bilstein B6 damper. At time the B12 kit received glowing reviews. My curiosity led me to experiment with the H&R lowering spring. The B6 is for use with stock springs (or a spring within reasonable range). So I knew pairing a H&R spring would need GC street plates due to a loss in usable damper travel.

You can find detailed discussion about the GC street plates in various B12 threads. In short, they restore up to 1 inch of damper travel without changing the ride height. It is a much needed component for this setup.

The ride was average. There were times on the street where it became too harsh for my liking. In contrast the fast road performance was impressive. Without a doubt the GC plates helped. In truth though, it was more a band aid for a bad situation. Without them, you’d be engaging the bumpstops way too often.

Just recently awareness of the B6’s damper travel limitations has come to fruition. We’ll discuss that later, but knowing what I know now this setup was not ideal.

Furthermore the B6 valving will not favour a spring like the H&R. I know this because the B6-OEM feels like a different setup all together.

B6-OEM Review

[Test Parameters]
Vehicle Data
Model: E46 M3 Coupe
Options: All except sunroof
Alloys: OEM 18″
Tyres: Michelin Pilot Super Sport – Stock sizes
Notes: Stock roll bars, stock bushings, RE top mounts (rear)
Duration: 30 days (city driving and country roads).

I took this picture of three springs available for the E46 M3. I did this to illustrate the differences between them.
The difference between the Eibach and OEM is quite noticeable. It’s interesting because I often see divided opinions about eibachs ride quality on forums. Close to OEM they may be, but they’re different enough to displease some.
Bilstein state the B6 is for use with OEM springs, but I don’t think it’s that black and white. It’s more realistic to assume the valving is set to a rough OEM range. Despite Eibachs being a little stiffer, they are still in scope.

The picture on the left EricSMG took when he tested how much usable travel the B6 has. You can read more about his findings

It was rather illuminating to see just how travel challenged the B6 is. You can visualise the detrimental effects of using aggressive lowering springs with the B6. It emphasises the importance of using GC street plates.

Pictured on the right is the cause of it all. The ‘long’ internal bumpstop Bilstein is infamous for. It’s common for B6 owners trim parts of the bumpstop to reduce its size. Generally, such actions could be frowned upon, much like cutting springs. Bumpstops also act as tuning devices afterall. In the case of the B6 though, trimming bumpstops is standard practice, an exception.

Ride Height

Let’s get this out of the way. It’s likely what your most interested in at this point.

Images of the E46 M3 and B6-OEM are scarce to nonexistent.

The above image illustrates the ride height difference between OEM and B6-OEM cars.

Both cars were well matched – not just in colour!

The fuel ballast was the same along with options.

A few of the differences were:

• Alloys/Tyres
• Sunroof, no rear blind on the OEM
• Rear Blind, no Sunroof on the B6-OEM

By studying the image, it’s clear the B6-OEM has a taller ride height. That’s no surprise, we know the high gas pressure in the B6 influences the ride height. The PSS 18″s with their chunky side walls helps cut some of the arch gap. Worth noting, cars with more options (heavier) may benefit too.

In all honesty I’ve become accustomed to the ride height. I did feel somewhat conscious at first but this feeling soon subsided. Generally, most cars on the road have a much higher ride height. So in relative terms the B6-OEM ride height looks “low” depending on the context.

The car currently has 12mm/10mm spacer arrangement from my last setup. This is temporary.

Trading low ride height yielded serious improvements to the ride quality…

The Positives

People often describe the B6 damper as ‘firm but not harsh’. I prefer to say it’s ‘taut’. When driving with this setup the quality valving soon becomes clear.

Bumps and imperfections iron out well. You’ll sense the suspension pushing the wheels into the holes. This results in great stability and comfort.

Interior rattles is one way to quantify this. Many irritating rattles emitting from the cabin over rough imperfections have diminished. The difference is significant, it highlights how much plusher the car rides.

In spite of that, my most profound observation with this setup is the stability. Point the B6-OEM on a poor maintained suburban road and feel the car leap like a scalded cat. The bumps and imperfections are ‘eaten’, nothing upsets the chassis. To feel an E46 M3 perform like this on the street is remarkable.

This setup feels well suited to the E46 M3 suspension geometry. The chassis feels less inhibited, more unhinged compared to my previous setups. I can say with confidence this is the most compliant suspension I’ve experienced.

You’ll only appreciate it by sampling the B6-OEM – it’s not obvious until you do.

The B6 valving is digressive. To test the high speed valving I located a road with an evil manhole cover. The manhole cover dips down to around an 1″ inch or a bit more. As the car went over the manhole cover, it softened the initial hit and made a mild “thud” sound.

On the back roads the B6-OEM is a hooligan. Yes, there is body roll but it’s well controlled. It never catches you by surprise in the way a full OEM setup would. It provides plenty of grip too.

It won’t beat lap times but it will make you smile. I found carving through the country roads lots of fun. The chassis feels much more playful. My Ohlins R/T felt like a surgical tool on country roads, sharp and precise. The B6-OEM is not as focused, you have to grab the car by the scruff of the neck. It’s quite entertaining and enjoyable to ‘feel’ the car transition into the turns.

Remember, not all country roads are ‘smooth’… no road is in truth. Thus the quick stabilization by the B6 makes it more than capable for this kind of activity.

The Negatives

No suspension is perfect, the B6-OEM has its drawbacks too.

Over severe rigid bumps I can hear noise from the rear suspension. I would describe the noise as a mild ‘clunk’. It tricks you into thinking there is something detached in the boot. I’ve heard this kind of noise before, it’s suspension related for sure.

Some owners of the B12 kit also cited similar experiences. According to some of the reports the ‘clunk’ fades as the miles rack up. I too have noticed it fading but it is still there sometimes.

In contrast the Ohlins R/T were silent, no abnormal sounds whatsoever.

At times when driving on a city road in mild traffic the B6 becomes a little overzealous at handling the road imperfections. This is of course during it’s low speed valving region. It’s so eager to iron out the bumps it may feel edgy, most often in the rear. EricSMG uses the term ‘rowdy’ to describe it, I couldn’t agree more!

Attack the same piece of tarmac at higher speed and all is bliss.

During the early days of testing I found the damping to be inconsistent day to day. Some days it would ride great, others not so good. In contrast the Ohlins R/T is much more consistent. My feeling is that it has to be down to environmental factors such as temperature. There is good news though, adjusting the tyre pressures adds greater consistency.

The B6 is non adjustable. It is what it is. That said, you will need to experiment with tyres pressures to get the best comfort. I’ll go into more detail shortly. I’ve listed it as a demerit as it involves manipulating the tyres, rather than the damper itself.

Advisories

If you want to try out the system, I have composed some extra notes to help you.

Run-in time
You may dislike the B6-OEM at first. The ride could be stiffer than you imagined. I experienced this too. The system just needs miles. After two weeks of daily driving or 300+ miles you should feel the B6 softening. They’ll continue to soften with more miles. It’s similar to trying on new shoes for the first time, they don’t feel great at first.

Tyre Pressures
The B6-OEM is sensitive to tyre pressures. You will need to adjust them to cater for your needs. During the first few weeks of testing, I found the B6 too ‘busy’ for my liking. I reduced my tyres pressures by 2 psi all round. I noticed an improvement in comfort but something about the ride just didn’t feel right. Convinced I was heading down the wrong path I went back to stock pressures, and the ‘busy’ behaviour returned.

Turns out, I was on the right track. I owe special thanks to ‘nrubenstein’. A few weeks ago he posted his results with regards to the B12 and lower tyre pressures. He found that by lowering the tyre pressure by 5-6psi resulted in a more compliant ride. Once again I tried decreasing my tyre pressures, this time by 5 psi.

The difference was remarkable, the car has never felt soo good over urban roads!

It is a compromise though, the car feels less perky at these pressures, not by much but noticeable. I may try bumping the pressure up a tad.

Continued…

I myself fall into the cruiser/daily driver category. To me, ride quality is important. It is just as relevant on the track if you think about it. How can a driver push to the limit if he/she is not comfortable inside the car?You can spot this in a typical Chris Harris ‘modern car’ review. With the dampers, he’ll often prefer to use the ‘comfort’ setting on canyon/country roads. This helps to soak up the bumps and undulations, allowing him to remain comfortable. If he is comfortable, the further he can push the car.Over the years I’ve felt an increasing misconception between performance and comfort in suspensions. That is, performance and comfort cannot co-exist.I’m not so sure that has to be the case, within reason.I removed my Ohlins R/T coilover kit a month ago so I could fabricate a set of lower rate springs. I took this opportunity to sample the Bilstein B6 dampers with OEM springs in the interim.From this point on I will refer to the system as ‘B6-OEM’ for brevity.The B6-OEM is in large overshadowed by the B12 kit. Recall the B12 kit is just that, a kit. It consists of the same B6 damper paired with a set of Eibach lowering springs. In other words, both items are “off the shelf”.Unlike the B12, the B6-OEM offers no change in ride height. Actually no, it does… it raises the car a smidge over stock ride height!This could explain why the B6-OEM is a ‘no go’ for most people, thus the lack of apparent interest.That said, I’ve spoken to experienced individuals who have tried the B6-OEM setup. They report utter praise for how well the car performed. They implied for handling and comfort on the road nothing could match it. Intrigued by this, I purchased a set of Bilstein B6 dampers and a set of used OEM coupe springs.Before delving into my findings, I’d like to recap a previous B6 setup I tried.Indeed, this was my first encounter with the Bilstein B6 damper. At time the B12 kit received glowing reviews. My curiosity led me to experiment with the H&R lowering spring. The B6 is for use with stock springs (or a spring within reasonable range). So I knew pairing a H&R spring would need GC street plates due to a loss in usable damper travel.You can find detailed discussion about the GC street plates in various B12 threads. In short, they restore up to 1 inch of damper travel without changing the ride height. It is a much needed component for this setup.The ride was average. There were times on the street where it became too harsh for my liking. In contrast the fast road performance was impressive. Without a doubt the GC plates helped. In truth though, it was more a band aid for a bad situation. Without them, you’d be engaging the bumpstops way too often.Just recently awareness of the B6’s damper travel limitations has come to fruition. We’ll discuss that later, but knowing what I know now this setup was not ideal.Furthermore the B6 valving will not favour a spring like the H&R. I know this because the B6-OEM feels like a different setup all together.Model: E46 M3 CoupeOptions: All except sunroofAlloys: OEM 18″Tyres: Michelin Pilot Super Sport – Stock sizesNotes: Stock roll bars, stock bushings, RE top mounts (rear)Duration: 30 days (city driving and country roads).I took this picture of three springs available for the E46 M3. I did this to illustrate the differences between them.The difference between the Eibach and OEM is quite noticeable. It’s interesting because I often see divided opinions about eibachs ride quality on forums. Close to OEM they may be, but they’re different enough to displease some.Bilstein state the B6 is for use with OEM springs, but I don’t think it’s that black and white. It’s more realistic to assume the valving is set to a rough OEM range. Despite Eibachs being a little stiffer, they are still in scope.The picture on the left EricSMG took when he tested how much usable travel the B6 has. You can read more about his findings here . In the picture, the B6 is at full compression.It was rather illuminating to see just how travel challenged the B6 is. You can visualise the detrimental effects of using aggressive lowering springs with the B6. It emphasises the importance of using GC street plates.Pictured on the right is the cause of it all. The ‘long’ internal bumpstop Bilstein is infamous for. It’s common for B6 owners trim parts of the bumpstop to reduce its size. Generally, such actions could be frowned upon, much like cutting springs. Bumpstops also act as tuning devices afterall. In the case of the B6 though, trimming bumpstops is standard practice, an exception.Let’s get this out of the way. It’s likely what your most interested in at this point.Images of the E46 M3 and B6-OEM are scarce to nonexistent.The above image illustrates the ride height difference between OEM and B6-OEM cars.Both cars were well matched – not just in colour!The fuel ballast was the same along with options.A few of the differences were:By studying the image, it’s clear the B6-OEM has a taller ride height. That’s no surprise, we know the high gas pressure in the B6 influences the ride height. The PSS 18″s with their chunky side walls helps cut some of the arch gap. Worth noting, cars with more options (heavier) may benefit too.In all honesty I’ve become accustomed to the ride height. I did feel somewhat conscious at first but this feeling soon subsided. Generally, most cars on the road have a much higher ride height. So in relative terms the B6-OEM ride height looks “low” depending on the context.The car currently has 12mm/10mm spacer arrangement from my last setup. This is temporary.Trading low ride height yielded serious improvements to the ride quality…People often describe the B6 damper as ‘firm but not harsh’. I prefer to say it’s ‘taut’. When driving with this setup the quality valving soon becomes clear.Bumps and imperfections iron out well. You’ll sense the suspension pushing the wheels into the holes. This results in great stability and comfort.Interior rattles is one way to quantify this. Many irritating rattles emitting from the cabin over rough imperfections have diminished. The difference is significant, it highlights how much plusher the car rides.In spite of that, my most profound observation with this setup is the stability. Point the B6-OEM on a poor maintained suburban road and feel the car leap like a scalded cat. The bumps and imperfections are ‘eaten’, nothing upsets the chassis. To feel an E46 M3 perform like this on the street is remarkable.This setup feels well suited to the E46 M3 suspension geometry. The chassis feels less inhibited, more unhinged compared to my previous setups. I can say with confidence this is the most compliant suspension I’ve experienced.You’ll only appreciate it by sampling the B6-OEM – it’s not obvious until you do.The B6 valving is digressive. To test the high speed valving I located a road with an evil manhole cover. The manhole cover dips down to around an 1″ inch or a bit more. As the car went over the manhole cover, it softened the initial hit and made a mild “thud” sound.On the back roads the B6-OEM is a hooligan. Yes, there is body roll but it’s well controlled. It never catches you by surprise in the way a full OEM setup would. It provides plenty of grip too.It won’t beat lap times but it will make you smile. I found carving through the country roads lots of fun. The chassis feels much more playful. My Ohlins R/T felt like a surgical tool on country roads, sharp and precise. The B6-OEM is not as focused, you have to grab the car by the scruff of the neck. It’s quite entertaining and enjoyable to ‘feel’ the car transition into the turns.Remember, not all country roads are ‘smooth’… no road is in truth. Thus the quick stabilization by the B6 makes it more than capable for this kind of activity.No suspension is perfect, the B6-OEM has its drawbacks too.Over severe rigid bumps I can hear noise from the rear suspension. I would describe the noise as a mild ‘clunk’. It tricks you into thinking there is something detached in the boot. I’ve heard this kind of noise before, it’s suspension related for sure.Some owners of the B12 kit also cited similar experiences. According to some of the reports the ‘clunk’ fades as the miles rack up. I too have noticed it fading but it is still there sometimes.In contrast the Ohlins R/T were silent, no abnormal sounds whatsoever.At times when driving on a city road in mild traffic the B6 becomes a little overzealous at handling the road imperfections. This is of course during it’s low speed valving region. It’s so eager to iron out the bumps it may feel edgy, most often in the rear. EricSMG uses the term ‘rowdy’ to describe it, I couldn’t agree more!Attack the same piece of tarmac at higher speed and all is bliss.During the early days of testing I found the damping to be inconsistent day to day. Some days it would ride great, others not so good. In contrast the Ohlins R/T is much more consistent. My feeling is that it has to be down to environmental factors such as temperature. There is good news though, adjusting the tyre pressures adds greater consistency.The B6 is non adjustable. It is what it is. That said, you will need to experiment with tyres pressures to get the best comfort. I’ll go into more detail shortly. I’ve listed it as a demerit as it involves manipulating the tyres, rather than the damper itself.If you want to try out the system, I have composed some extra notes to help you.You may dislike the B6-OEM at first. The ride could be stiffer than you imagined. I experienced this too. The system just needs miles. After two weeks of daily driving or 300+ miles you should feel the B6 softening. They’ll continue to soften with more miles. It’s similar to trying on new shoes for the first time, they don’t feel great at first.The B6-OEM is sensitive to tyre pressures. You will need to adjust them to cater for your needs. During the first few weeks of testing, I found the B6 too ‘busy’ for my liking. I reduced my tyres pressures by 2 psi all round. I noticed an improvement in comfort but something about the ride just didn’t feel right. Convinced I was heading down the wrong path I went back to stock pressures, and the ‘busy’ behaviour returned.Turns out, I was on the right track. I owe special thanks to ‘nrubenstein’. A few weeks ago he posted his results with regards to the B12 and lower tyre pressures. He found that by lowering the tyre pressure by 5-6psi resulted in a more compliant ride. Once again I tried decreasing my tyre pressures, this time by 5 psi.The difference was remarkable, the car has never felt soo good over urban roads!It is a compromise though, the car feels less perky at these pressures, not by much but noticeable. I may try bumping the pressure up a tad.