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E46 M3 (2001-2006) Engine: S54 - Max Hp: 333 hp at 7,900 rpm / 262 lb/ft at 4,900 rpm
Total Produced: 45,000+ - Years Produced: 2001 to 2006.


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Old Wed, Nov-09-2016, 04:03:53 AM   #181
ShaikhA
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Default Re: Shock dynos, Fat Cat Motorsports and custom valved Bilstiens

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Originally Posted by Imola46 View Post
Any updates on this? Drove my B6/OEM spring coupe today for the first time in ages and the ride is horrible on lumpy UK roads!
We haven't made any more changes to Eric's setup since his last update, but I've made further improvements to the Ripple Reducer option (smaller holes and more of them, already felt the improvement on the BMW's front struts - rears already had a lot of holes!). I'm now testing all dampers out to 15 in/sec and KBO setups out to 22 in/sec. I make sure there's no jacking down as far out as I can test and the results are stellar.

I'm also developing a new version of KBO that I called Velocity Dependent KBO (VDKBO) which creates a 'rally-style' suspension response. We can design whatever low speed damping profile we want (including regressive damping!), including a good blow-off region, and create a progressive damping increase at very high velocities (>20-30 in/sec) to help keep the chassis from bottoming out. I'll be testing this on my E46 330i sedan in the next couple weeks. Also designing and planning to patent a new piston to allow us to do this more easily. This isn't available yet, but would be the 'ultimate KBO' that can handle track, street, and backroads. Could be used with OE/lowering springs or firmer springs especially if you keep Flat Ride in the spring rate choice.

I gotta say you guys endlessly waiting are missing out! I know what I'm doing, and I know what the E46M needs. I'm not promising perfection, but with his feedback and what I'm continually learning you'll get as close as anyone will bring you.

Here's a blog post for those who want more to chew on and to read some recent customer feedback:

https://the-perfect-ride.com/2016/11...e-suspensions/

===
http://www.fatcatmotorsports.com/FCM...anS_C5_Z06.htm

'02 C5 Corvette customer, only changes from factory dampers to FCM Bilstein with Ripple Reducer (no KBO yet):

"Now onto handling: it only took about 2 corners driving out of my neighborhood to know the car was completely different. The best way I could describe it is the car has got more tires now. The biggest difference was in the rear end. The stock shocks had a feeling of the rear end might slip out under me without notice. That was how it felt at the first track day: the rear did not have enough grip, and it would easily give out if I applied throttle just a bit early. I used to drive with traction control on, because I wasn't sure when the rear end would slip out or if I could easily recover. After just a few corners on the street, the car gave me a lot of confidence. The track day further confirmed the confidence: it allowed me to corner faster, and get onto throttle as soon as I hit apex. It is almost like my AWD Subaru coming out of corners. I felt like a superman driving out of high speed sweeper turns (until the oil really heated up after a few laps... well, another issue to address...). The tires sticked to the ground very well and would only gradually give away if I do something wrong. In the tighter turns, the car had much better composure and body roll control. In the braking zone and corner entry, stability was much improved. The added low speed compression really helped."

===
http://fatcatmotorsports.com/FCM_Eli...t_99_Miata.htm

Street class (stock springs) autocross Miata customer from last year (mid-pack finish at his first Nationals):

"I am so much faster. One section I am considerably faster is the slaloms. Car is just planted. Took me a few runs to find its new limit. Once the OTS konis were near the limit, they were just unpredictable; the Fat Cats are so so "smooth." Adams fastest run in my car was a 48.7 and mine was a 48.8 so I'm right there."
===

What are you waiting for?
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Old Wed, Nov-09-2016, 01:58:35 PM   #182
Obioban
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Default Re: Shock dynos, Fat Cat Motorsports and custom valved Bilstiens

I'm waiting for you to reply to my PM
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Old Wed, Nov-09-2016, 10:33:09 PM   #183
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Default Re: Shock dynos, Fat Cat Motorsports and custom valved Bilstiens

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Originally Posted by ShaikhA View Post

What are you waiting for?
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Originally Posted by Obioban View Post
I'm waiting for you to reply to my PM



ShaikhA, how much would it be to have a set of dampeners dynoed?
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Old Fri, Nov-11-2016, 11:51:07 AM   #184
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Default Re: Shock dynos, Fat Cat Motorsports and custom valved Bilstiens

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It's pretty wild how high the gas pressure can be on certain applications. I think the E46 M3 Bilstein HD is fairly reasonable (about 20 lb - the twin-tube Koni front strut he sent us had 25 lb). But the Bilstein rebound damping is really stiff and that's the major reason the ride quality suffers. Some Bilstein fitments can have 40-60 lb gas force and with a higher motion ratio like a BMW, Mercedes, Mitsubishi, Subaru, etc. that becomes a very stiff initial spring rate to have to overcome - each and every time the damper tries to move in compression. The suspension does NOT want to follow the road! Not to mention the Moton, AST, etc. setups that often have very high gas force and ride worse than necessary plus have reduced grip because of it.
Does the Bilstein stiff rebound damping apply to the PSS10 kit dampers too?
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Old Fri, Nov-11-2016, 06:32:58 PM   #185
ShaikhA
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Default Re: Shock dynos, Fat Cat Motorsports and custom valved Bilstiens

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Originally Posted by Namniek View Post



ShaikhA, how much would it be to have a set of dampeners dynoed?
Mr. Namniek, we only work on 'dampers', and then only Bilstein monotubes, but you can buy 'dampeners' from a number of disreputable manufacturers just wear an apron

and even re: Bilsteins we don't dyno anything not part of a rebuild. Too busy to screw around with dynoing just because. Send 'em to PSI, koni, etc.
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Old Fri, Nov-11-2016, 07:15:14 PM   #186
ShaikhA
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Default Re: Shock dynos, Fat Cat Motorsports and custom valved Bilstiens

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I'm waiting for you to reply to my PM
You guys and your PMs... I've turned PM off and updated my profile on best contact method.

Ian, I just *emailed* you a reply re: your very interesting build!
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Old Fri, Nov-11-2016, 07:18:47 PM   #187
ShaikhA
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Default Re: Shock dynos, Fat Cat Motorsports and custom valved Bilstiens

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Does the Bilstein stiff rebound damping apply to the PSS10 kit dampers too?
I wouldn't know for all applications, but generally Bilstein always overdamps the rebound of any PSSx application I've seen. If you're feeling a 'packing down' or harsher downward acceleration where you're falling into the ground *after* you've crested a bump, that's a good sign there's too much rebound.
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Take our short Ride Harmony survey and earn a credit on FCM Elite Bilstein damper services
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Old Sat, Nov-12-2016, 04:08:53 AM   #188
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Default Re: Shock dynos, Fat Cat Motorsports and custom valved Bilstiens

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Originally Posted by ShaikhA View Post
Mr. Namniek, we only work on 'dampers', and then only Bilstein monotubes, but you can buy 'dampeners' from a number of disreputable manufacturers just wear an apron

and even re: Bilsteins we don't dyno anything not part of a rebuild. Too busy to screw around with dynoing just because. Send 'em to PSI, koni, etc.
Whoops, missed that after a long day.


Gotcha. I'll find another shop then. Just trying to go with a company interested in the community without dealing with shipping. And don't want to commit to a full rebuild unless I know it's required.
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Old Thu, Dec-15-2016, 09:32:50 PM   #189
Imola46
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Default Re: Shock dynos, Fat Cat Motorsports and custom valved Bilstiens

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Originally Posted by ShaikhA View Post
I'm also developing a new version of KBO that I called Velocity Dependent KBO (VDKBO) which creates a 'rally-style' suspension response. We can design whatever low speed damping profile we want (including regressive damping!), including a good blow-off region, and create a progressive damping increase at very high velocities (>20-30 in/sec) to help keep the chassis from bottoming out. I'll be testing this on my E46 330i sedan in the next couple weeks. Also designing and planning to patent a new piston to allow us to do this more easily. This isn't available yet, but would be the 'ultimate KBO' that can handle track, street, and backroads. Could be used with OE/lowering springs or firmer springs especially if you keep Flat Ride in the spring rate choice.

What are you waiting for?
Waiting for your video on how amazing the VDKBO is and some dyno curves to back it up

My car is having the rear axle carrier panel welded and plated at the moment, no point putting new springs and dampers on a cracked M3! What sort of lead times do you have on a set of dampers?
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Old Fri, Feb-10-2017, 04:33:15 AM   #190
ShaikhA
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Default Re: Shock dynos, Fat Cat Motorsports and custom valved Bilstiens

We've been busy enough with builds that VDKBO has yet to go on Christina for road testing but I've got some dynos to tease you. Keep in mind that in terms of effectiveness, FCM Elite revalve, Ripple Reducer v1.1, and KBO v1.9 with well-chosen bump stops, Flat Ride spring rate tuning, etc. all combine to make a fantastic recipe for street and track. VDKBO is my 'what if?' answer to creating the ultimate damper and piston design that can be adapted to street / track or rally / hillclimb.

Pay particular attention to the shape of the compression curve at the very high end of the velocity range. We can test up to 22 in/sec with our Roehrig 2VS and are basically maxing out the dyno speed-wise. I'm looking carefully at the slope in various regions - low, mid, early-high', middle-high, and very-high speed. This applies to both bump and rebound, as I've been customizing the rebound port profiles as well as the bump port profiles to achieve sufficient force but also to ensure enough digression on rebound and progression on compression to provide support without causing jacking down or launching up.

(You can click on the images to see full-size versions)







VDKBO is an awesome engineering project and will work great in the real world but is rather time intensive given it involves custom pistons. I have no idea on cost right now, but for someone who has a 'money is no object' attitude we can certainly work together (I still have to test on my E46).

Trust me - KBO v1.9 is awesome especially with the extra attention I'm spending to make sure the corrected rebound high speed force (rebound - gas force) is matched to the correct compression high speed force (bump force+gas force). Our most recent C7 Z51 Corvette customer (running A Street SCCA autocross, only changed the dampers nothing else). He gave me some great feedback which I'm including here:

Quote:
Hello Shaik,

Apologies for the long silence.

I did install the shocks, and have some feedback for you.

I’m already spoiled and used to the better ride, but I enjoyed it the first few days. I really like that it still feels firm, yet soaks up the big, hard-edged stuff. More lasting in my consciousness is the extra control and stability. As an example, there’s a section of road near my house where the concrete is fresh, but droughts and flooding have caused severe angles from one slab to the next. With the OEM shocks, 80mph was enough to cause discomfort, and the car would go airborne, then hit bumpstops coming down. With your shocks, the car still goes airborne but comes down with better control. It’s still obviously hitting bumpstops but much less harshly, and without the resulting uncontrolled rebound it had before. In fact, I ended up going 90mph through there, and still felt confident in the car. That is about the most amazing difference I found. It strikes me that your shocks would likely benefit track use significantly more than autocross, based on that experience. In those conditions, the difference was night and day.

My only autocross with your shocks was under extreme circumstances. It was freezing, so difficult to get heat into the tires. Additionally, I had missed other recent events due to family obligations, so I was out of practice about 2 months. It took to my fourth run to both get enough tire heat and to remember how to drive. That run was near magic, however. I ended up 4th in PAX, but only a few tenths out of first.

That facility has a section that has upset every car I’ve driven, there. It’s a section of concrete with a “Whoop” in it, where the front end temporarily unglues while cornering hard, then eventually recovers. I didn’t realize until after the event that my car went through there completely unaffected. That is impressive.

The other good part I remember is stability through high-speed offsets. The car had a pretty nice set even though I was violent with the wheel. It would set into a drift that was decently neutral, maybe a touch tail happy, so good for speed. The tail happiness scared me a little at first, since I didn’t know what to expect or how far it would go, but by the 4th run I felt confident about how soon the car would set and stick.

On the flip side, with smooth corner entry (not a transition), the car had more push than before. This could have mostly been the temps, we’ll see. Also, it doesn’t seem to be any better at putting down power. Again, this could just be the temps.

There was half-skidpad corner, average speed probably around 55mph, with a bank. The car felt like it moved around more than I remember, but I think this is because I was pushing harder (due to confidence). I did note the tail seemed better behaved as I modulated.

It’s hard to tell how big or real these differences were, but so far it seems good, overall. Given my 2-month hiatus, I think I did really well, and I do feel like the shocks contributed. I’m hoping for better results as I continue to probe the new limits. I will try to send more feedback as the events pile up, and hope to get your feedback to help me understand what I could do differently in driving, or tuning/alignment. Right now I’m considering raising the car up maybe 1/4”, since I think it’s spending more time on the bumpstops than it should for smooth autocross events.

Thanks,

Michael
===

We've got about 4 BMW KBO builds in progress right now, an E90 sedan, an E92 M3, a Z4M, and an E36 M3. I haven't run a track day since last April I think and I'm getting serious withdrawals. But happy to be busy in the shop just the same. Our lead time is between 6-8 weeks best estimate (always subject to change).
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FCM Elite Ride Harmony suspension spreadsheet for: E46 M3, Shock dyno testing / driving feedback: E46 M3 (with Eric_SMG)

Take our short Ride Harmony survey and earn a credit on FCM Elite Bilstein damper services

Last edited by ShaikhA; Fri, Feb-10-2017 at 04:39:35 AM.
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Discussing Shock dynos, Fat Cat Motorsports and custom valved Bilstiens in the E46 M3 (2001-2006) Forum - Engine: S54 - Max Hp: 333 hp at 7,900 rpm / 262 lb/ft at 4,900 rpm
Total Produced: 45,000+ - Years Produced: 2001 to 2006. at BMW M3 Forum.com (E30 M3 | E36 M3 | E46 M3 | E92 M3 | F80/X)