Real world demonstration of high gas force ('gas spring') - MCS 2WNR vs FCM Elite H&R Bilstein

[@z06van21]

Playing devil's advocate, if you understand the basics, why would someone want to pay an extra $3k to $5K on top of the dampers for your valving profiles, when they could just ask MCS to custom valve them, or any MFG. really? It would be a lot cheaper to do that from the beginning, rather than after the fact.

[@SuspensionTruth]

Yet those companies clearly aren't doing that, or haven't been to the making of the various videos I've produced. Can they 'do better'? Sure, and everyone would benefit! From what I see they don't "understand the basics." So that kind of shoots your whole comment in the foot from the beginning. ;) But it gets worse, because even if they wanted to create more 'Ride Harmony' and 'Race Synergy' there are limitations with their damper designs which would prevent it. Namely, for a strut-based suspension that uses larger shafts (19 or 22mm), that generates high gas force and high seal drag. An inverted design would have half or less the gas force of a non-inverted, which is a fundamental advantage for grip and ride (they're connected). MCS also seems to prefer stiff low-speed bump damping which compromises grip, tire life, and ride in exchange for 'responsiveness.' See my video here for someone who ran MCS 3-ways and could NEVER get them to work right, and got faster with better tire wear with an FCM Elite solution: kzbin.info/www/bejne/qau9p4SXhruhias I don't know enough of how they are designed but from what I've seen they don't look interested in changing. Time will tell. No one is forced to work with me, clearly. And I don't really want to work with everyone - who I have as a customer matters to me, whether a casual driver or a hardcore racer. You aren't paying simply for my 'valving' (there a lot that goes into how and why my damping designs work) but my ability to create and recommend an integrated package of components. You would be paying for my understanding and results, avoiding throwing money away on parts that won't work right. People or vendors who think in terms of 'buy this part, then buy that part, then throw this on' are missing the picture of how the suspension works as a whole, how and why to pick the RIGHT springs, sway bars, and yes, even bump stops. Throw a bunch of parts at a car and it'll be fighting itself. From what I've previously seen and heard from customers, MCS *never* uses Flat Ride - a customer has to change spring rates on their own to achieve that. That's a fundamental deficiency. Their dampers are not capable of low-jerk / low gas force if they're non-inverted 22mm shafts (vs. an inverted H&R / Bilstein with 11 or 14mm shaft). You're not gaining any useful advance with the bigger shaft because you can get plenty of displacement from a smaller shaft. This is contrary to an engine where more bore equals more useful torque (although more gas consumed, everything has trade-offs). I've seen the same damping profile on different vehicles using MCS which suggests they really aren't doing any sophisticated tuning, just throwing you a knob or two or three plus a generic damping profile and saying 'here, go play with yourself!' Having a knob is a cop out for a manufacturer - it puts the blame on YOU, instead of them. "Car doesn't work the way you want? Keep tweaking it, or upgrade to the more expensive model!" I see vendors who give you knobs as an acknowledgement that they can't come up with an excellent recipe that works extremely well (or better) and DOESN'T require added complexity and failure points, or the need to 'recharge / rebuild every 24,000 miles' or some-such. Many people I talk to get frustrated with 'playing with knobs' and don't know if it's doing anything useful. It takes careful thought, planning, and execution to provide a non-adjustable, OPTIMIZED, damper package with appropriate springs, bump stops, etc. === Here's an example - I was working with a Dodge Magnum customer which used non-inverted Bilstein (double wishbone / multi-link suspension) but those Bilsteins came with 18mm shaft. I was concerned with the gas force being high because of that. I did a good job on the damper tuning and the customer liked the setup for handling and performance, but he did notice a bit of 'bounciness' and roughness on relatively smooth roads. There was nothing in the valving that would have caused it - the problem was simply due to HIGH GAS FORCE as I'm pointing out in this video. Fast forward a year and I've got a local VW Touareg customer. Same situation - the Bilstein we were going to use came with 18mm shafts. I told him about the Magnum customer, my assessment of why the ride wasn't as great as it could have been. He did some research, found that certain models had an adjustable suspension which used a hole in the shaft to control the forces, hence the need for an 18mm shaft. But, the non electronic suspensions had dampers with 14mm shafts. So he was comfortable using a 14mm shaft instead and we went to the trouble of sourcing some long-bodied truck shocks to get shafts that my machinist could turn down to fit his Touareg length and thread patterns. End result was a setup that handled his off-road needs, along with having a good street ride. I never drove the Magnum but by the numbers, I could imagine why he had some issues. The Touareg rode really well though, and I KNOW WHY. I had to stick to my guns and convince my customer to make that change - going to a SMALLER shaft because of the technical merits. Because small details matters more than many realize. === If MCS or other vendors did improve their approach and damping then everyone would be the better for it. That's one of the reasons I do post videos publicly, with data and measurements. I don't know everything and my goal is to always learn and improve. It's why I've incorporated technologies used in F1 and Rally racing into my FCM Elite methods. It's all to make a better end result for you, if you're willing to understand some of WHY I make the choices I do. Anyone who wants a great, integrated, thoughtful result, and to have someone take the time to explain vital concepts like Flat Ride, jacking down, the impact of high damper gas force, how bump stops work, etc. will find me very willing to educate them. I want a smarter customer at the end of the process, because it keeps me from having to do a lot of advertising and back and forth. The proof is in the pudding, and perhaps - if you haven't already - you can feel what I'm talking about. As the expression goes, 'when you buy Quality, you only cry once.'

[@sr20dett1000]

Because when you explain to them what you want and why. They will dismiss you. Contacted Fortune Auto and they will not do coilovers with flat ride. Will try to convince me not to. Same with TCkline. For the e90 plat form all coilovers will give pitch. Some coilovers are over 200-300% stiffer in front while the back is less then 100%. I get it that is what everyone thinks they want and their is money to be had. Why because stiff riding on rail is what a sport suspension suppose to be. The only other coilovers manufactured that focus on flat ride is YCW suspension. I like that they don't even recommend a springs rate. If you which to buy coilovers without springs you can.

[@ax13h]

You're measuring how much force it takes to unload the shaft from the internal stop. When it's on the car that's on its wheels this force is completely balanced by the mass. Instead of pressing on the unloaded shock, load it up with say 100lb then zero the scale. Then it will only take an additional 10lb to start moving the shaft. If you loaded it up with exactly the gas pressure then it wouldn't take any additional force to move it: just the oil flow pressure plus the incremental gas pressure.

[@WTGRacing]

The car is supported by springs when it is on the ground, so shouldn't the force on the damper be zero?

[@ax13h]

@@WTGRacing The springs that support the car are the coil springs PLUS the gas springs. If the shaft isn't moving, the net force on it is zero. In the test in the video, the net force at rest is zero because the gas force is opposed by the [very low] compliance of the internal stop. In reality when you put even 1lb of force on the shaft it does move, just not very far because the stiffness of a solid hard stop is extremely high. This is exactly analogous to preloaded coilover spring where the initial very high stiffness is only due to unloading the internal damper stop and has no functional effect so long as you never unload the wheel so far as to reach the extension limit of the damper again.

[@SuspensionTruth]

No, the force to start the damper moving ALWAYS requires overcoming the gas force - the internal stop provides no appreciable resistance. You either haven't done this or are imagining something that isn't true in reality. The gas force is always present, regardless of the shaft's position in the damper body. As you displace the shaft farther, the gas force increases since you're also collapsing the nitrogen chamber (which increases the nitrogen pressure).

[@SuspensionTruth]

@@WTGRacing 'Should'? In an ideal damper with zero gas force, yes. But a pressurized damper (which is the vast majority outside exotic dampers like thru-rod or perhaps an Ohlins TTX) has some degree of nitrogen pressure (via a separate chamber or air bladder) and that results in a non-zero rod force.

[@SuspensionTruth]

@@ax13h No, Mark, the net force on the vehicle is not zero if the shaft isn't moving - the GAS FORCE is always present, and always pushing outward which results in a gas spring. The rebound stop is not responsible for the 100+ lb of resistance you see on the MCS damper. This is also NOT analogous to a preloaded spring. They are different devices and different mechanisms of action, a spring being position-sensitive and a damper being velocity-sensitive. With the additional of a gas charge the damper now also effectively becomes displacement sensitive where sufficient force is requires to overcome the gas force prior to the damper moving, REGARDLESS of the shaft's position inside the damper. Quoting from a very sagacious comment on F1Technical.net: "The spring effect of a shock is there and is very real and as long as we run single rod dampers charged with nitrogen this will be the case. An ideal damper will exhibit a force output that varies strictly with velocity, which is what I think you desperately want to believe you have. However, the single rod charged dampers we use are actually an ideal damper and small gas spring in parallel. The spring effect is a by-product of the damper and doesn't effect the velocity dependent characteristics of that damper, it's just a necessary component of the system. If your charge is high enough you better factor it into your suspension setup and possible choice of springs. What matters in the end is the total spring rate acting at the wheel and if you add a bunch via your damper you may want to remove some via your spring to maintain your operating point. There is a real reason base valves and the like were invented. There's a real reason guys prefer to minimize damper charge pressure as much as possible. If the gas spring effect in the damper never made a difference we'd never need base valves and we'd never worry about keeping charge pressures low. We'd just charge dampers with 500 psi with no ill effects and no worry of cavitation. But this isn't the case. 500 psi is going to manifest itself as a HUGE GAS SPRING (emphasis Shaikh's) that will likely be unwanted in our setup. Therefore we spend time with base valves, anti-cavitation devices, and achieving low charge pressures. It keeps our damper as close to the ideal damper as possible." Mark, if you're interested, I recommend you watch the video 'Spring vs. Damper' (kzbin.info/www/bejne/f3q9f3WIgat8gdU) and read the comment threads there to increase your understanding of the effect being illustrated. To those who have experienced high gas force / rod force, they would never want it again. Off-road racers get this, and hopefully more on-road / track / street / autocross enthusiasts will become better-informed as to why one needs to care about and avoid high rod force whenever possible.

[@JohnFaire]

Thank you for showing us this truth.

[@SuspensionTruth]

You're welcome, John. I appreciate you commenting. It's seemingly-small details like this which really affect the car's ride and handling in ways that are irritating, annoying, and even dangerous. When high gas pressure / high rod force is marketed as a 'good thing' I really take exception. Off-road racers get this and I hope more on-road drivers/enthusiasts/racers will pay attention to safely minimizing rod force and all the benefits that come along with it.

[@SuspensionTruth]

In case you've yet to watch this, Maksezzy talks about how he narrowed down the problems with his MCS 2-ways on his BMW E46 M3 to the dampers, and the high gas force in particular: kzbin.info/www/bejne/nJ7PkqZurZilhpI

[@SuspensionTruth]

#1 - Click 'SHOW MORE' to READ THE COMMENT in the video description! It touches on many points of why high nitrogen force is a Bad Thing. Also, see comments in this video: "Spring vs. Damper - How the Gas Pressure in a Shock Absorber affects ride and grip" for detailed Q&A: kzbin.info/www/bejne/f3q9f3WIgat8gQ. #2 - I've removed (and will continue to remove) inflammatory and disingenuous comments by people who like to argue without understanding facts or being willing to learn.

[@0foxgiven]

Can you explain why this matters? 0-80lbs, you get no movement, ok but the corner weight is a lot more than 80lbs. Between 1000 and 1080lbs you'll get movement (minus seal drag), the pressure will be higher, the preload will be higher, you'll need to account for it for spring rate, but it will move, so why does this pressure preload matter?

[@SuspensionTruth]

Think in terms of the suspension cycling, especially at small amplitudes and higher frequencies, like over general road surface irregularities a few tenths of an inch high. Visualize a vertical ramp at zero velocity in the damper force as it moves into compression. That vertical ramp creates 'jerk' - a sharp rate of change in acceleration. Very undesirable for ride and grip. If the suspension moving over a small feature doesn't generate enough forced overcome the gas damper won't open and instead you have the tire acting as your spring! You're literally bouncing on the sidewall. A big problem is people usually see 'idealized' dyno graphs with gas force subtracted when the damper doesn't behaves so smoothly in the real world. There's a sharp step-up that has negative effects on tire contact patch and comfort. Many vehicles you'd expect to ride well don't because of high gas force. Did you read the comment I put in the description? Zero gas force is ideal but impossible for most monotubes. Many OE dampers are twin-tube partly because you can run lower nitrogen pressure and get better ride (and grip to a degree). High gas force creates jitter, a similar effect to using 55 psi (max pressure) in your tires instead of ~34 psi (something more optimal). Do you gain grip with max tire pressure? No, you lose grip! Same with high gas force which becomes a high frequency impedance to sis pension motion.

[@0foxgiven]

@@SuspensionTruth I think you didn't understand my question. The way I'm understanding it, this gas pressure acts 100% like an air spring, or say a regular progressive spring with an 80lb preload. Once you get past the preload, it's not there anymore. Same as a regular spring. It's not like if you preload a 320lb/in spring 1/4" of an inch, you'll have a worse ride. You wouldn't even know it's preloaded except when you encounter droop travel.

[@SuspensionTruth]

I think you're missing the point that the suspension is always cycling and every time you go into rebound them back into compression you have to overcome that gas force ('preload') before the damper will move. That's all I have to contribute - to further refine your understanding you'll need to research or feel it on your own.

[@0foxgiven]

@@SuspensionTruth I hope you actually understand that you're incorrect and are using this as a selling point. Best of luck.

[@SuspensionTruth]

It's a very effective selling point, because everyone who knows what they're doing would rather have lower gas force than higher. We have science and logic on my side, no need for luck.

[@ClaytonYatescarenthusiast]

Hello, great video. I'm getting custom valved mcs 2 way remotes and curious if the behavior of all mcs shocks stays the same even with custom valving?

[@SuspensionTruth]

'Custom valving' may seem like a universal cheat code but I suggest being careful thinking you're getting magical fairy dust because someone says 'custom' anything. I like the phrase OPTIMIZED for that reason, and in my various videos (Ride Harmony and Race Synergy) I explain how I achieve more optimal results. 'Custom valving' may not change some inherent behaviors such as rod force or seal drag, or a sharp low-speed compression ramp which (IMO/IME) can cause problems with ultimate grip and vehicle stability. I would ask them to send you dyno charts including the gas force and seal drag. Then you can see for yourself. There's also the question of whether you're getting Flat Ride in your spring rate choice, which you didn't mention...

[@kelbaez]

lets say you have a set of coilovers that work fine for the first 20-30 minutes of regular driving at ambient temperatures of 85-90F, but then after that the dampening starts to degrade exponentially, gets bumpy with constant oscillation. what would be your guess on where the issue is?

[@SuspensionTruth]

Twin tube, or monotube? What brand? If adjustable, where are they set?

[@kelbaez]

@@SuspensionTruth Cygnus X1 (fortune auto), Digressive monotube, I've set them from full soft to full stiff and everything in-between.

[@SuspensionTruth]

Hmm sounds like once they get some heat, the dampers fall into a massive distortion of the space-time continuum. The astrophysicists who made it ought to be able to shed more light.

[@kelbaez]

@@SuspensionTruthlol thats pretty much how they feel.. I wish the solution would be as easy as your conclusion!

[@SuspensionTruth]

More seriously, it sounds like the dampers could be cavitating; losing effectiveness as the suspension works harder, builds heat, and causes the fluid to boil if not properly pressurized. Have you asked FA for help?

[@kelbaez]

would adding Tender / Assist springs help on eliminating the jerk feeling on small but constant bumps on the road?

[@SuspensionTruth]

No, because the problem is with the dampers, not the spring rates. If you have high spring rates as well then an assist/tender spring would soften the initial transmissibility of the spring but the problem of excessive damper rod force would still remain. The comment from F1Technical.net I linked in the description explains this well - you can't make high damper gas force disappear.

[@kelbaez]

Thanks for the reply, Im still going through your videos, there is so much good information!

[@SuspensionTruth]

Glad you have food for thought!

[@86Tony]

Man after watching your videos i dont know if i made the right choice for swaping my bilstein clubsport 2 way for mcs 2wr

[@SuspensionTruth]

I don't know the specs on the Bilstein Clubsport but presuming it's an inverted design, then with a non-inverted MCS as you see in this video, you likely now have more gas force and almost certainly more low-speed compression than your tires need for maximum grip and/or comfort (they are very connected). I'm not a big fan of the Clubsport but I get how knobs are very popular when people aren't designing or spec'ing their own dampers. When you know how to design something properly (think F1), you don't need knobs and my race customers have proven that. Anyway, sometimes it's better to NOT know something! If you're happy with the MCS, then that's great.

[@AX-Driver]

Rest easy, you did. Don't believe this supposed expert who is 100% wrong.

[@p71nero]

I've got some of the MCS 1WNR and I was truly shocked to find out upon using them that they are absolute garbage. Easily the worst shocks I've ever used, on road or on track, even compared to 300$ maxpeedingrods that my friend had. Even a stock valved BC Racing does a better job, these MCS bent my camber plates on track and broke my radio and almost made me lose control on a freeway expansion joint because they transfer basically all bump forces directly to the car. Doesn't even matter what setting the knob is on. And this is despite setting the car up with flatride, running around the same ~2.5Hz i run on all my other cars with no issues. Besides that, on track after a few laps they lose more and more control over the spring, getting bouncier and bouncier over time. I have never been more disgusted with a product in my entire life

[@SuspensionTruth]

Wow what a terrible experience. It echoes what some other former MCS owners have told me. I appreciate you finding the video and commenting. If you're willing, I can dyno test them and post the result, then we can do an interview and I can talk about your experience. The more useful information people have - especially about products that are highly-touted but often fall short in application - the better everyone is. Let me know - you can reach me via the fatcatmotorsports dot com website or suspensiontruth at gmail dot com.

[@p71nero]

@@SuspensionTruth a couple days ago I sent them to MCS so they could check if there was something wrong with them. If they say nothing is wrong/won't fix it then I will probably take you up on that. I appreciate it

[@SuspensionTruth]

I am happy to test and share data regardless of what they tell you. I have heard similar from several MCS users and I none of the dampers were broken - just, non-optimized to my standards. Ironically one person was encouraging to 'upgrade' from 2W to 3W and the only difference was a stiffer less forgiving car. None of my setups come with knobs, including those for race-winning customers. When I perform a detailed consultation and interact with my customer, you can focus on simple adjustments without going nuts 'playing with knobs.' It's truly sublime!

[@TrackDayVideo]

Completley disagree.

[@SuspensionTruth]

Who is Completley and why they disagree?