Anyone have BMR perf springs/Koni setup?

[Bluemustang]

Yes, full stiff will feel like a racecar but it'll knock your teeth out. So it's the "best" and the "worst" at the same time.

I'm surprised that full soft is floaty with the mild BMR springs - seems odd since, in my experience, full soft is slightly overdamped for stock springs. That said, the BMRs are linear and shorter which both require more damping to properly control than a longer progressive spring of similar rate.

I'm very interested in where you end up as I'd like to upgrade my dampers - but only if the results I want are possible. Because you're finding 1.25 turn too stiff I'm thinking that our tolerance levels for discomfort are similar.

I'm not sure if floaty is the right term, just a little bouncy.

Kelly at BMR told me his favorite settings for the street were 1/4 turn rear, 1/2 to full turn front. Earlier today I set it at 1/4 turn rear and 1/2 turn front and here are my thoughts:

This felt really good and pretty well balanced front and rear. I have the needed compliance to where normal bumpy roads are not bad at all. Going slow and getting stuck behind slow people, it feels nicer. With the shocks set in the middle, I felt like my back was bouncing back and forth against the seat. Like not bouncy as in the car was bouncing, but I was bouncing. This is the main characteristic I'm trying to get rid of. On long trips getting stuck behind slow drivers doesn't feel good, even though the car is completely tied down.

This 1/4 turn rear, 1/2 turn front setting feels excellent. If it's not 100% there it's close. Some more driving will tell me for sure. But I took a nice spirited drive and it handles really well. With this setup, long sweeps are no problem and I can go really fast without fear of losing traction. From a stoplight I can make turn and carve right around- chirp the tires in 2nd and just a slight rear slide and I'm off.

This feels closer to what I would call a luxury sports car ride, which is sort've what I'm after. I have much needed compliance but it still feels tight. Very little bounce or float.

I'm not really sure how it is supposed to handle in some ways. Some of the back roads I have near me have load of bumps everywhere. So, in a few of really tight turns at high speeds, I got a little more bounce than the stiff settings. For instance, I'm going through a very tight turn, shift down in 2nd, carving around the corner exit and hit a bad bump- I don't lose traction but the bump kindve upsets things a little and I have to cut throttle to get through. That's the only "problem" I had. In this situation, the stiff settings handled this with more confidence because the suspension was too firm to make it move. But I'm not sure if this is problem- I think it's just bad road. I'm confident with a well paved surface, I could have peeled around that corner no problem.

I might have been going faster than I really should have for those bumpy roads. They're not meant to raced on, like on a track. As always during spirited driving, you've got to be careful and driver mod on.

I turned off the TC for most of the trip but left advancetrac on. I may have some slight tweaks to do or perhaps I'm done and I'll leave it. I'll have to drive it more this week to see how it feels over different surfaces. There will be trade off, and no one setting will be optimal for every situation. But this new setting gives me much more compliance and still good handling.

Still wondering what affect shock settings have on going over bumps mid-corner. But I'm thinking that bad roads are just bad roads. Not good for performance driving.

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[Bluemustang]

Yes, full stiff will feel like a racecar but it'll knock your teeth out. So it's the "best" and the "worst" at the same time.

I'm surprised that full soft is floaty with the mild BMR springs - seems odd since, in my experience, full soft is slightly overdamped for stock springs. That said, the BMRs are linear and shorter which both require more damping to properly control than a longer progressive spring of similar rate.

I'm very interested in where you end up as I'd like to upgrade my dampers - but only if the results I want are possible. Because you're finding 1.25 turn too stiff I'm thinking that our tolerance levels for discomfort are similar.

Yeah it does seem like our tolerance levels are similar. I'll let you know if I do further tweaks. I'm looking for that luxury sports car type of ride and I definitely think that's achievable or at least very close.

 

[EricSMG]

Great feedback - keep up the testing and reporting back. My hunch from the beginning was that you'll likely end up in the ~1/2 turn range, give or take, given how you described 1.25 turns.

Yes, a shitty road is a shitty road. That said, try to pay very close attention as to what each end of the car is doing. It could be just that you need a pinch more out back, or maybe up front, or a little less, etc. With the work week approaching it'll be interesting to see how you feel after a few days' commute

Edit - yes, luxury sports car ride. I know precisely what you're after. The closest I ever got were custom valved Billies on my E46 M3 - but that took two revisions and the 'right' tuner. If Billies were out for this car I'd have the same work done by the same guy, without a doubt.

 

[Bluemustang]

Great feedback - keep up the testing and reporting back. My hunch from the beginning was that you'll likely end up in the ~1/2 turn range, give or take, given how you described 1.25 turns.

Yes, a shitty road is a shitty road. That said, try to pay very close attention as to what each end of the car is doing. It could be just that you need a pinch more out back, or maybe up front, or a little less, etc. With the work week approaching it'll be interesting to see how you feel after a few days' commute

Edit - yes, luxury sports car ride. I know precisely what you're after. The closest I ever got were custom valved Billies on my E46 M3 - but that took two revisions and the 'right' tuner. If Billies were out for this car I'd have the same work done by the same guy, without a doubt.

Thanks A LOT dude. Really appreciate your contributions to this thread. Sounds like you are more picky than I am and you know a lot more about suspensions than I do. It's so so helpful just to be able to talk this out with someone.

Thanks [MENTION=21756]Azzurro[/MENTION] for your contributions as well. Much appreciated buddy.

 

[BMR Tech]

I'm not sure if floaty is the right term, just a little bouncy.

Kelly at BMR told me his favorite settings for the street were 1/4 turn rear, 1/2 to full turn front. Earlier today I set it at 1/4 turn rear and 1/2 turn front and here are my thoughts:

This felt really good and pretty well balanced front and rear. I have the needed compliance to where normal bumpy roads are not bad at all. Going slow and getting stuck behind slow people, it feels nicer. With the shocks set in the middle, I felt like my back was bouncing back and forth against the seat. Like not bouncy as in the car was bouncing, but I was bouncing. This is the main characteristic I'm trying to get rid of. On long trips getting stuck behind slow drivers doesn't feel good, even though the car is completely tied down.

This 1/4 turn rear, 1/2 turn front setting feels excellent. If it's not 100% there it's close. Some more driving will tell me for sure. But I took a nice spirited drive and it handles really well. With this setup, long sweeps are no problem and I can go really fast without fear of losing traction. From a stoplight I can make turn and carve right around- chirp the tires in 2nd and just a slight rear slide and I'm off.

This feels closer to what I would call a luxury sports car ride, which is sort've what I'm after. I have much needed compliance but it still feels tight. Very little bounce or float.

I'm not really sure how it is supposed to handle in some ways. Some of the back roads I have near me have load of bumps everywhere. So, in a few of really tight turns at high speeds, I got a little more bounce than the stiff settings. For instance, I'm going through a very tight turn, shift down in 2nd, carving around the corner exit and hit a bad bump- I don't lose traction but the bump kindve upsets things a little and I have to cut throttle to get through. That's the only "problem" I had. In this situation, the stiff settings handled this with more confidence because the suspension was too firm to make it move. But I'm not sure if this is problem- I think it's just bad road. I'm confident with a well paved surface, I could have peeled around that corner no problem.

I might have been going faster than I really should have for those bumpy roads. They're not meant to raced on, like on a track. As always during spirited driving, you've got to be careful and driver mod on.

I turned off the TC for most of the trip but left advancetrac on. I may have some slight tweaks to do or perhaps I'm done and I'll leave it. I'll have to drive it more this week to see how it feels over different surfaces. There will be trade off, and no one setting will be optimal for every situation. But this new setting gives me much more compliance and still good handling.

Still wondering what affect shock settings have on going over bumps mid-corner. But I'm thinking that bad roads are just bad roads. Not good for performance driving.

That's why I am here. You know I have your back.

Call me sometime tomorrow in the afternoon and let's chat. I have some ideas to throw at you. :cheers:

 

[Bluemustang]

Ok, so after driving to and from work the past few days, I still wasn't satisfied with the shock settings. 1/4 rear, 1/2 front- Over a lot of bumps I could feel the rear bouncing up a little bit. I can feel it in my butt. And front to back it felt just a bit unbalanced.

At the beginning of the week I gave Kelly a call at BMR and - Man he is just a wealth of knowledge and I can tell he really loves talking suspension and loves what he does. I talked with him for about 40 minutes and easily could've talked to him for another hour and pick his brain. So props to Kelly for his dedication and just being a good dude, I appreciate it.

So anyway he gave me a lot of good information. Based on my springs he said they've had on the dyno and right about 1/4 turn rear 1/2 front is where it should be, but as he's found from experience on the road that the best setting may actually be 1/2 turn rear full turn front, which is what suggested to me to try.

So in taking [MENTION=26094]EricSMG[/MENTION]'s advice, I decided to bring the rear up only, so I could see the difference. So this evening I set front and back to 1/2 turn. Went a for a drive and it feels almost perfect. The car stays flat and even over bumps, and the front/rear feel more connected. No more bounce up from the rear and it feels balanced and comfortable. Still feels stiff but I have needed compliance for less than average roads. And my steering feels good.

I'll have to drive it around the rest of the week and see how it feels but I might have it now. If I do anything I think it will be to bring up the front damping force a little more. I'm gonna see how it feels this week and then bring it up in small increments until I've got it. But the fronts are the easy part, no more jacking up the car.

My goal is adjust the damping force to match my springs so I don't have too much or too little. I'm not dealing with track springs with 300 and 900 spring rates, respectively. So after talking with Kelly, I think anything more than a full turn is too much. I'm starting to learn what the car is doing like EricSMG said. I've been trying to focus on what end of the car is doing at all times which is not always easy at all, especially on varying surfaces, speeds.

 

[Ryubb]

keep us updated on your findings bluemustang. I have the same issue with that bouncy feeling on mine, the sp080 helped, but still present. Also have the CB005 lockout kit, no other suspension mods. I am wanting to replace my rear PP shocks only, front seems tight and right, just that damn bounce in the rear.

Your findings will help determine if I want to buy the rear koni shocks or just deal with the bounce.

 

[Doctor Fishtail]

Ok, so after driving to and from work the past few days, I still wasn't satisfied with the shock settings. 1/4 rear, 1/2 front- Over a lot of bumps I could feel the rear bouncing up a little bit. I can feel it in my butt. And front to back it felt just a bit unbalanced.

At the beginning of the week I gave Kelly a call at BMR and - Man he is just a wealth of knowledge and I can tell he really loves talking suspension and loves what he does. I talked with him for about 40 minutes and easily could've talked to him for another hour and pick his brain. So props to Kelly for his dedication and just being a good dude, I appreciate it.

So anyway he gave me a lot of good information. Based on my springs he said they've had on the dyno and right about 1/4 turn rear 1/2 front is where it should be, but as he's found from experience on the road that the best setting may actually be 1/2 turn rear full turn front, which is what suggested to me to try.

So in taking [MENTION=26094]EricSMG[/MENTION]'s advice, I decided to bring the rear up only, so I could see the difference. So this evening I set front and back to 1/2 turn. Went a for a drive and it feels almost perfect. The car stays flat and even over bumps, and the front/rear feel more connected. No more bounce up from the rear and it feels balanced and comfortable. Still feels stiff but I have needed compliance for less than average roads. And my steering feels good.

I'll have to drive it around the rest of the week and see how it feels but I might have it now. If I do anything I think it will be to bring up the front damping force a little more. I'm gonna see how it feels this week and then bring it up in small increments until I've got it. But the fronts are the easy part, no more jacking up the car.

My goal is adjust the damping force to match my springs so I don't have too much or too little. I'm not dealing with track springs with 300 and 900 spring rates, respectively. So after talking with Kelly, I think anything more than a full turn is too much. I'm starting to learn what the car is doing like EricSMG said. I've been trying to focus on what end of the car is doing at all times which is not always easy at all, especially on varying surfaces, speeds.

Thanks for this thread. I am going to try your adjustment advice and see what happens. I am on the Konis. But on the Swift Spec-Rs. Thanks guys.

 

[BmacIL]

Thanks for this thread. I am going to try your adjustment advice and see what happens. I am on the Konis. But on the Swift Spec-Rs. Thanks guys.

Possibly 3/4 to 1 turn on the front for the Swift (they have a decently higher front rate) than SP080s.

 

[Doctor Fishtail]

Possibly 3/4 to 1 turn on the front for the Swift (they have a decently higher front rate) than SP080s.

OP is turning 1/2 a turn up front with a lower spring rate. I am gonna try the 1/2 turn. I have it a complete full and 1/4 turn up front. I do have the extra weight of the blower but it is bit to stiff.

 

[CrazedAntelope]

I thought I'd chime in with my settings even though I am not running BMR springs. Through this whole process of upgrading suspension, I found I am quite NVH intolerant.

Allow me to open up with a video. You need only to watch the first 5 seconds:
[ame]
(p.s. If you watch the whole video, you'll see a pretty shitty line. This was my first trackday and I was getting nervous a Focus RS was breathing down my neck.)

If you look closely at 0:02, you can see my car (red mustang) get pretty upset and continue undulating at the bump of turn 1 at Sonoma Raceway.

The settings for my car was as follows:

Steeda Ultralite Linear (198F/874R)
Koni Shocks at 1/2turn front and 3/8ths turn rear
Eibach swaybars at medium front and rear​

I ran the same combo of parts on the street and found the ride quality was quite poor, no matter what settings the damping was. In terms of comfort, my main gripe was not with small imperfections or rough asphalt, but with dips and troughs where bridges/overpasses meet freeway. I could very clearly feel the front and rear were not acting in unison on my commute to work. Going over these dips at highway speed, I could feel a very small and forgiving "bump" from the front, followed by a huge "bump" from the rear a few miliseconds later. The "bump" coming from the rear would regularly make me jump out of my seat.

It was clear to me that the 874 lb/in springs in the rear were way too stiff for street use. Either I would get spinebreaking stiffness with a high damping setting, or an uncomfortable underdamped mess if I turned down the damping. I knew I needed a softer rear spring, and but I have an ecoboost mustang so the BMR/Vogtland/aFe/Swift springs weren't really an option for me. Cue the BC racing springs from the BR coilover kit.

I made a special order just to get the BC springs with spring perch, locking rings and spanner wrenches. No front coils or rear shocks as I was quite happy with the front Steeda's and Koni's. Going with the adjustable perch also gave me the option of fine tuning my "stance" in terms of rake. The BC racing rear springs are rated at 14kg/mm or 784lb/in.

So now I am running 198F/784R along with my Konis at 5/8ths turn front and 1/2 turn rear. The ride is now perfectly comfortable for me and quite OEM like. The car now glides over dips on the freeway in one motion instead of having two distinct "bumps" coming from the front followed by the rear. Please note I was able to turn up the damping as opposed to before. The ride feels critically damped and only a hair or two more uncomfortable than my stock setup.

I'd describe the whole package as "Performance Pack Plus". I'm in the camp that bouncing and shaking all over is not fast on the street, and that softer is often better. Even though my car will be seeing a handful of track days and HPDEs a year, I'm not trying to break any records on track. I expect my car to be quiet and comfortable on the street. That being said I am headed to the skidpad and slalom on October 1st and I will be keeping the damping settings as is. I'll report back if anything groundbreaking happens.

DISCLAIMER: I have an ecoboost so YMWV

 

[Bluemustang]

Thank you [MENTION=17119]CrazedAntelope[/MENTION]. Very good analysis/input here. I think your BC springs are similar in rates to my BMR springs, yours are a little stiffer. If I recall, the SP080s are something like 170/760. Maybe [MENTION=9985]BMR Tech[/MENTION] can confirm the rates. With your settings similar to mine, seems like I'm on the right track.

I think a lot people recently have been writing off the Konis because they're "uncomfortable". Yet they set rebound damping too hard. There is a lot of adjustment here and small increments make a noticeable difference. Also, the Konis are rebound adjustable but not the compression. So being that you are unable to adjust the compression and rebound independently, I think there is a likely a smaller window of adjustability based on what springs you are using.

Setting the rebound too hard makes the car feel "jacked down". It feels like a racecar but you're not allowing the spring to properly to do its work. Some of the people are dissatisfied with their Konis may just be setting the damping way too firm. OR - they are not spending enough time adjusting them to proper damping. The Konis have 100% adjustability so that's twice as firm as full firm vs. full soft. With a wide range of spring rates, it'd be very easy IMO to set it wrong.

Also- this from Koni - they suggest for all vehicles, set it at full soft. If you have aftermarket parts (springs, tire packages etcetera) OR the driver wants more aggressive settings- a half turn to full turn from full soft is recommended. They say rarely if ever should they be set full firm. And I think even 1.25 is probably too much unless you've got really high rate springs. 1.5 turns is probably the absolute max.

 

[BmacIL]

I thought I'd chime in with my settings even though I am not running BMR springs. Through this whole process of upgrading suspension, I found I am quite NVH intolerant.

Allow me to open up with a video. You need only to watch the first 5 seconds:

(p.s. If you watch the whole video, you'll see a pretty shitty line. This was my first trackday and I was getting nervous a Focus RS was breathing down my neck.)

If you look closely at 0:02, you can see my car (red mustang) get pretty upset and continue undulating at the bump of turn 1 at Sonoma Raceway.

The settings for my car was as follows:

Steeda Ultralite Linear (198F/874R)
Koni Shocks at 1/2turn front and 3/8ths turn rear
Eibach swaybars at medium front and rear​

I ran the same combo of parts on the street and found the ride quality was quite poor, no matter what settings the damping was. In terms of comfort, my main gripe was not with small imperfections or rough asphalt, but with dips and troughs where bridges/overpasses meet freeway. I could very clearly feel the front and rear were not acting in unison on my commute to work. Going over these dips at highway speed, I could feel a very small and forgiving "bump" from the front, followed by a huge "bump" from the rear a few miliseconds later. The "bump" coming from the rear would regularly make me jump out of my seat.

It was clear to me that the 874 lb/in springs in the rear were way too stiff for street use. Either I would get spinebreaking stiffness with a high damping setting, or an uncomfortable underdamped mess if I turned down the damping. I knew I needed a softer rear spring, and but I have an ecoboost mustang so the BMR/Vogtland/aFe/Swift springs weren't really an option for me. Cue the BC racing springs from the BR coilover kit.

I made a special order just to get the BC springs with spring perch, locking rings and spanner wrenches. No front coils or rear shocks as I was quite happy with the front Steeda's and Koni's. Going with the adjustable perch also gave me the option of fine tuning my "stance" in terms of rake. The BC racing rear springs are rated at 14kg/mm or 784lb/in.

So now I am running 198F/784R along with my Konis at 5/8ths turn front and 1/2 turn rear. The ride is now perfectly comfortable for me and quite OEM like. The car now glides over dips on the freeway in one motion instead of having two distinct "bumps" coming from the front followed by the rear. Please note I was able to turn up the damping as opposed to before. The ride feels critically damped and only a hair or two more uncomfortable than my stock setup.

I'd describe the whole package as "Performance Pack Plus". I'm in the camp that bouncing and shaking all over is not fast on the street, and that softer is often better. Even though my car will be seeing a handful of track days and HPDEs a year, I'm not trying to break any records on track. I expect my car to be quiet and comfortable on the street. That being said I am headed to the skidpad and slalom on October 1st and I will be keeping the damping settings as is. I'll report back if anything groundbreaking happens.

DISCLAIMER: I have an ecoboost so YMWV

Nice write-up. Did you happen to set your rear height a little differently with the BC rears? The reason I ask is that you only changed the wheel rate by 20 lb/in (about 10%), which seems like not enough to have the type of dramatic change you're describe by itself. I wonder if you were using the bump stops too much before, or so low that undulations were causing significant shifts in your roll couple?

Your ride frequencies went from 1.47 and 1.57 Hz, front and rear, respectively, to 1.47 and 1.49 Hz. Typically you want ~10-20% higher rear ride frequency to control the sprung mass oscillation properly, assuming something like 70% critical damping. It suggests to me that you might be very close to critically damped, as you typically do this exercise with the RF stagger to allow the rear to catch-up to the front faster. Since you found that at the lower rear rate it rides better, it's already catching up via the dampers.

 

[CrazedAntelope]

Thank you [MENTION=17119]CrazedAntelope[/MENTION]. Very good analysis/input here. I think your BC springs are similar in rates to my BMR springs, yours are a little stiffer. If I recall, the SP080s are something like 170/760. Maybe [MENTION=9985]BMR Tech[/MENTION] can confirm the rates. With your settings similar to mine, seems like I'm on the right track.

I think a lot people recently have been writing off the Konis because they're "uncomfortable". Yet they set rebound damping too hard. There is a lot of adjustment here and small increments make a noticeable difference. Also, the Konis are rebound adjustable but not the compression. So being that you are unable to adjust the compression and rebound independently, I think there is a likely a smaller window of adjustability based on what springs you are using.

Setting the rebound too hard makes the car feel "jacked down". It feels like a racecar but you're not allowing the spring to properly to do its work. Some of the people are dissatisfied with their Konis may just be setting the damping way too firm. OR - they are not spending enough time adjusting them to proper damping. The Konis have 100% adjustability so that's twice as firm as full firm vs. full soft. With a wide range of spring rates, it'd be very easy IMO to set it wrong.

Also- this from Koni - they suggest for all vehicles, set it at full soft. If you have aftermarket parts (springs, tire packages etcetera) OR the driver wants more aggressive settings- a half turn to full turn from full soft is recommended. They say rarely if ever should they be set full firm. And I think even 1.25 is probably too much unless you've got really high rate springs. 1.5 turns is probably the absolute max.

According to the spreadsheet floating around here, the BMR performance springs are 170/740 lb/in. https://docs.google.com/spreadsheets/d/1owkmhivxxWQk62GYzd-W1tL2arQSOM9Bd-TagA8py64/edit#gid=188571511

I completely agree with you. The range of adjustment is very small based on the springs. I had to do a lot of fine tuning on both sets of springs, and I found even adjusting the shocks by 1/8 turn increments yielded huge differences in ride quality and comfort. One can't just blindly turn up damping because you do really need to allow the spring to do its work.

Good thing I'm a mechanical engineer and I aced "Dynamic Systems Vibration and Control" less than a year ago, or else I would have given up and returned my car to stock. :lol:

 

[CrazedAntelope]

Nice write-up. Did you happen to set your rear height a little differently with the BC rears? The reason I ask is that you only changed the wheel rate by 20 lb/in (about 10%), which seems like not enough to have the type of dramatic change you're describe by itself. I wonder if you were using the bump stops too much before, or so low that undulations were causing significant shifts in your roll couple?

Your ride frequencies went from 1.47 and 1.57 Hz, front and rear, respectively, to 1.47 and 1.49 Hz. Typically you want ~10-20% higher rear ride frequency to control the sprung mass oscillation properly, assuming something like 70% critical damping. It suggests to me that you might be very close to critically damped, as you typically do this exercise with the RF stagger to allow the rear to catch-up to the front faster. Since you found that at the lower rear rate it rides better, it's already catching up via the dampers.

I suppose the bumpstop on the old setup could be an important factor as I did increase the rear height about 1/4" to 3/8". One way to find out would be to adjust the BC's down to the old ride height and see what happens. That way we would truly know if the problem was spring rate based or bumpstop based.

I'm not sure how you're arriving at your frequencies but if it is some form of sqrt(k/m), make sure you have adjusted for a smaller mass on the front to account for the ecoboost motor. If you have not adjusted, then the front frequency would be even higher than the original 1.47 and the front might even be higher than the rear?? I'm not sure what the implications are here.

Suspension theory is fascinating but to be honest I'm pretty happy with where I'm at now. Maybe in a few months, I'll get bored and hunker the rear down to see how the ride quality differs. You seem to know your stuff - do you know of any books or online resources regarding suspension? (you can PM me as to no highjack the thread)

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