Thats true engineering. Only an engineer can build a house that barely stays up but still stays up, usually. ..takes a marketeer to sell it at stone castle pricing though
'Good Enough' is fine until there are unintended consequences that end up in the bay of a technician to diagnose and repair. Arrogant engineers and 'Good Enough' cause more time wasted down the road in diagnosis/repairs than they do in hours billed being saved in the engineering process.
I am also a Mechanical Engineer (at least, that's what my business cards say...). I'm wondering what it would cost to have Matt follow me around for a day to narrate my life...
Stiffness in an air spring is not simply a function of the air pressure - it also depends on the air volume relative to the effective piston area. You can soften an air spring by plumbing it to an additional rigid chamber. That means that for the same vehicle weight, a higher ride position means *softer* springing (because there is more air volume and the same pressure); however, those convoluted style bags don't act as ideal air springs at all because the rubber resists both stretching for suspension extension and collapsing for suspension compression. This is why good air springs are of the rolling lobe (a.k.a. reversible sleeve) type. RideTech offers both the double convoluted air springs like these, plus reversible sleeve and a variation of reversible sleeve which is tapered to change the spring rate progression, in both versions that mount over dampers and versions that mount separately.
Spot on. Lots of people make the mistake of thinking higher ride height means more pressure, when really it means more volume. Especially when using rolling lobe springs. The pressure in the airbag is set by the weight of the vehicle. Lifting the vehicle doesn't change the weight of the vehicle, it just expands the spring. Therefore, same pressure, more volume. This is also why cars and trucks with airbags use ride height sensors and don't rely on pressure sensors.
@@Lucidbkeo Just an enthusiast... with a technical education, decades of interest in automotive technology, and enough curiosity to dig into topics of interest. Unfortunately, no one has ever paid me to work in the automotive field, but maybe that's why it's still fun. 😉
@4:06 A properly designed 5-link is not over-constrained - it is ideal. Just count degrees of freedom: there are 3 translational and 3 rotational degrees of freedom, and the suspension needs to move in one degree (controlled by the spring and damper), so the remaining 5 degrees must be controlled. All of the links of a 5-link locate in only one dimension (they are under compression or tension only, not bending) except the spring link (for designs like this that mount the spring and damper to a control arm instead of directly to the hub carrier), so if ball joints are used there is no binding. The bushing deflection occurs because they are not ball joints, and not perfectly parallel to the instantaneous axis of rotation of each link end. The bending load mentioned in the construction of the adjustable link exists only because the bushings on the ends are not ball joints.
I was going to look it up and write a very detailed analysis for you. But in the end I figured it was "Good Enough" to let someone else do it and just give them props for it.👍
I’m currently in the middle of building a HomeKit controller for my unpowered sky light blinds. Project is about a month in now, I went from DC motor, to steppers, to now using a DIY servo motor. The code is getting insane and I haven’t even gotten to the PID parts. I should have just spent $300 on an OTS assembly but at this point I’m too far down the rabbit hole to quit and I’m learning a lot in the process.
All hail the algorithm! Seriously, love your show and your humor style. It makes your videos enjoyable to watch. Seriously, thank you for not starting your videos with a scream.
If you're welding sleeves into/onto tubing you should drill holes around the perimeter for plug welds. Or if you want to keep it in the jaguar spirit you could use rosette welds.
It brings peace to my heart knowing that I'm not alone with lots of ongoing and unfinished projects... Also, good enough™ just made my day. Thank you Matt!
Pneumatic Vice is pretty good one. I recently saw one guy make it with pedals on floor to operate it. Pretty useful when You can focus with Your hands on holding and positioning, and with Your foot on clamping or releasing it
Matt; I would have bet money that you would have gone with the self-leveling Citroen Hydro Pneumatic suspension. But then there is Future Matt that will do that.
i designed my own airride, and i did it the right way. You dont use pressure EVER as rideheight setting. Its completely ret*rded. The reason you talked about in the video, the lower the car the lower the pressure. But then someone gets in, or you load up the back of the car with stuff and now all of a sudden the pressure rises because the bags have to carry more weight. Want to guess what the air suspension is going to do? Its going to lower the car even more in the back even tho it was allready getting lower because of the weight you added there. So instead of the car going level again when the air suspension activates it wil actually lean back even more. So the only way to go is to include height sensors. Height sensors and pressure sensors would be best if the system looks at both and trys to get the pressure left to right equal at all times. If you use that you should prettymuch have the same corner weight on each wheel.
I recently was designing an air ride system for a project...didn't know anything about how to do it. Spent days and day designing circuits electrical and air, and trying to source individual bits and bobs Ended up using a set of used oem bags and struts and purchasing a new aftermarket controller and valve bank. NOTHING rides like air! Love the channel SFM! 😃
@7:10 Thanks for the metric conversion, imperial units don't make any sense. I don't know how you can make anything functional with them. I mean what the hell is a volt? definitely can't be as sensible of a unit as a flarg.
@SuperfastMatt I just discovered your channel, lots of great stuff! I believe what you said about air suspension at :55 is backwards; to raise the car you need more air volume, not pressure (the weight doesn't change). A greater volume of air has lower spring rate than a smaller volume.
I was binge watching the series instead of doing my german revision, guess i have to do that now, or i could watch something else of yours, i love your content
Another great video! I like the way you narrate the story and the decision making process. Much more informative and interesting than watching other "build" channels that just bolt together free parts from sponsors and never experience a setback. A project is never a linear path and it's kind of reassuring to watch someone change directions during a projects the way the rest of us do. ("All hail the algorithm!")
Many factory air suspensions, like that on my 2001 Audi allroad, have a lower spring perch that is kind of pear shaped (as are many things on a 22 year old car), so the spring gets stiffer as the suspension gets lower. In the rear, they also have dampers that are adjusted by an air valve so the damping adjusts as the suspension adjusts.
Problem is, while the jag has good front and rear angle, if you hit the ramp with enough speed to make that assertion true, you'll compress the front suspension and risk driving into the ramp with the front! This is also better in theory than in practice, as a certain Tesla driver recently proved in LA...!
Can you make a quick vid where you compare aerodynamic drag at different ride heights at highway speed to determine power consumption and affect on range? Nice system
Very impressed. You have the ability to engineer solutions and the temperament, objectivity and dry wit to document the process! Oh, forgot to mention your excellent taste in both the selection of drivetrain and powertrain. Thanks for taking the time to document your hard work.
Definitely. When I converted my car to discs I made sure to use a kit for the front that uses all standard parts so I can easily get replacements. The rear has less easy to source parts but those don't wear out as fast
There are several controller options that could be used for EFI set-ups. A Micro-squirt unit is likely the most user friendly for the price, if you have more knowledge when it comes to a Adrino or raspberry set-up there is a Speedduino unit that is kind of interesting and fairly inexpensive. You can put together a EFI set up fairly easily and inexpensive. Infact if you look around at Matts projects i belive he does a Microsquirt set-up on his Grom or even his land speed rig. Whatever the case he has done it a couple times and gives pretty good info as to mak8ng the conversion. One of my first was making my KTM 525 fuel injected and for it i used a Microsquirt. I believe the controller was under $ and all the parts were sorced form the car junkyard and the motorcycle junkyard with a piece here and there being bought new.
Top tip: for comfort use a fridge kompressor - super low noise, won't last 20 years without lubricant, but it will be fine. But perhaps leave the noisy one in for speed. 🧐🤔🤓
That rear multilink has very specific bushes that bind in weird ways to provide passive steering effort depending on where the wheel is throughout it's travel. I hate modifying cars with multilinks because changing things even very minorly can throw the whole thing off.
Passive steering doesn't result from bushing binding - it results from toe changes due to the link geometry and due to busing deflection. Replace the bushing with rod ends and you would still have the geometric effects; add compliance to compression and extension of the links and you would still have the effect of bushing deflection even without any binding.
Matt, I saw your Death Valley - Road Closed video, and thought that was pretty cool. I'm not sure what convinced me to start your Jag EV swap... but I have become a HUGE fan! As a civil I get your sense of humor and have really enjoyed all the videos in the Jag series. Anyway, love your stuff and I'm really looking forward to watching more of your videos. Right now you're still under 250k subscribers, which for me is cool because you're going to hit it big and someday I'll say, "I knew Matt when he was just a quarter mill!"
You can change the characteristics of a air spring by reducing the volume with a liquid such as a silicone oil. All telescopic motorcycle forks are coil/air spring hybrids ,whether they are pressurised or operate at ambient pressure. Changing the oil level alters the air space above the oil and therefore changes the air spring characteristics.
Creating the DIY air suspenstion system was like almost every software project I've been involved with. People with way too much talent and skill excited to DIY a solution. Which is awesome if it was a stand-alone side project, but not in the middle of a big production system that noone will know how it works in 3 years.
Although I agree, I recently see it the other way. For something that is built in language and supported natively with just a little bulky interface, people will pull few dependencies that do it with easier interface. I agree that interface could be better, but I prefer to have lowest amount of dependencies
@@darekmistrz4364 It needs a balance, given the projects constraints. It's clear Matt loves the DIY solution and we love watching him do it, but he saw the resource issues and pulled in the external dependency. Of course, the analogy breaks down somewhat. He doesn't need to rebuild his car every few months because of traffic law updates, and doesn't have to worry that the company who made the air suspension solution no longer exists or was compromised.
I was at a wedding and was sat next to someone that did suspension design for a German auto manufacturer, we briefly talked about what we did, then got on the subject of modified cars. I showed him the diagram for the double triangulated 4 link (solid axle) rear suspension I made for my Explorer, talked about design goals and shortcomings etc. He was tickled that I was planning to put such a highly modified vehicle back on the road, something he described as impossible in Germany, but mostly laughed and suggested it was quaint compared to the five link designs he worked on. It took me months of revisions to get the 4 link how I wanted it on paper (to be seen in the real world), but still I didn't disagree. 5 link independent are absolutely mind boggling.
Isn't the pressure the same regardless of ride height? You have the same mass at each corner, so the force on each airbag is the same, so the pressure is the same. Unless the airbag shape or suspension geometry changes. You just have more air in the bag at higher ride height which makes it longer. Which would also make it ride softer because you need more travel to halve the volume and double the force. Or am I missing something??
You are correct. That's exactly how it works and exactly why aftermarket kits, passenger cars and commercial vehicles that use airbags all use ride height sensors instead of trying to determine ride height based off pressure.
That's all correct, for an ideal airbag. The reversible sleeve (or rolling lobe) designs are close, but Matt is using the double convoluted bellows type, and the rubber in those interferes with the ideal behaviour. Still, they're closer to the ideal that you describe than the behaviour which Matt suggested.
The internal spring pressure is the same at all ride heights. Resistance, like loading the vehicle will increase the internal spring pressure. Here is a question for you. Does your Jag get heavier at the full height of a lift on a hoist? I know it does not. Adding more cubic air to an air spring will cause it to extend until it meets resistance, only then will the internal pressure start to rise to meet or exceed the resistant load.
Unfortunately, the double convoluted bellows design of air spring, including the ones that Matt is using, have far from ideal air spring behaviour - it's almost like using a tire as an air spring, while the other type of air spring (the reversible sleeve or rolling lobe) acts more like a piston in a cylinder.
There is another solution to the ride height adjustability problem, hydropneumatic suspension uses a cylinder and piston filled with hydraulic fluid at each corner to sort of act as a spring. The cylinders are attached by high pressure hoses and hardlines to a nitrogen filled sphere (which is attached to the car's chassis) which acts as a compressible springing medium. Further more, there is a hydraulic system with a pump and valves which adds or removes hydraulic fluid from each corner to change the ride height and keep the suspension level. This system, introduced by Citroen for the DS was also used by Mercedes for its hign end cars, most notably the 300SEL 6.3 and later 450SEL 6.9. It was considered miraculous at the time but the system's complexity made it something of a maintenance hog. This may not be a problem for a high end Mercedes, but was a thorn in the side of many less than wealthy Citroen owners. Over time, these systems lost favor with manufacturers. Air suspension may have its faults, but it can be good enough for most purposes. Hydropneumatic suspension is a fun system to re
I had air springs on my 36 foot dual rear axle 8 wheel motorhome. The driven rears were ride height adjusted. There was no controller, just the ride height valve. The fronts had a fixed pressure that I checked before each trip, and the tag axle had a pressure gauge and mechanical pressure release valve on the dashboard. Again, no controller. I could deal with the ride height problem (rear tow hitch) with the dashboard adjuster. By the way, the fronts make a big noise when they blew out when I hit a big bump. Also, I found you can pay someone $600 to take the front suspension apart to replace one or you can find someone who knows that if you roll them up and put soap on them you can have them installed for $30 the second time you blow one out. I also found that I could do it myself with the soap method once I watched the guy do it so third time was a charm. I don't think you will blow them out as my motorhome was 12,000 pounds so much higher loads. It was only the fronts that blew out and they were inside coil springs so not a huge deal. I often wondered what would happen if the rear bags went but never found out.
Brilliant. I will now watch it. (Update, having just watched it, around 1m00 you show a madeupgraph(tm) that ride height is proportional to pressure. I dont think it is. In fact the pressure may be (approximately*) constant as a function of ride height .. what changes with ride height is the volume of gas in the system, not its pressure, cf orthogonally if you change the weight of the car by filling it with fat people, the pressure will need to increase to give you the same nominal ride height even though the volume is unchanged. Maybe. Its just a theory, I haven't inserted pressure sensors in the air suspension of my 21 year old lexus ls to check. You could probably insert 60 seconds of humorous explanation of the gas laws in your next if you wanted. *its affected by bag and suspension geometry etc
Assuming everything is flat and nothing's changing, the ride height is proportional to the spring/bag height and that is directly related to the pressure. So yeah, right height is proportional to the pressure but it's not linear and it's not constant. The problem is it's not constant. That's why we have to use ride height sensors instead of simple pressure sensors. That said if your car was equally loaded on all four corners, with identical suspension on all four corners, you could theoretically put them all to the same pressure and the car would be level and at varying ride heights depending on the pressure.... But since we live in A world where the driver is often offset to one side and the weight on all four corners is not the same etc etc... We need ride height sensors.
no, ride height does have a relation to pressure. The bag contact patch (where the bag rests against the end pieces) gets smaller as they extend, thus reducing the effective area, and requiring more pressure for the same load. Your approximation would be correct for a pneumatic piston, though.
Correct. Ideally, changing the amount of air in the springs without changing the weight of the vehicle will just change the height without changing air pressure at all, but this style of air bag (convoluted bellow) needs more pressure to stretch so it is far from ideal; the rolling lobe (also called reversible sleeve) type would be closer. Your Lexus probably has rolling lobe springs.
@@kain0m totally agree, I was trying to keep it simple but did actually have a note (*) saying its affected by bag and suspension geometry etc. My core point is that its not the simple proportionality (ie goes through the origin) with pressure as shown in the graph seen around 1m00, on the contrary its a comple curve (eflecting bag and suspension geometries) closer to a band (depending on load etc) *parallel* to the axis
@@TravisFabel with respect I think you are wrong. You don't explain why, just state that bag height is related to pressure ... but (* for now overlooking the non linearities due to the shape of the bag) Imho that's not the case, as stated variations in the height of a bag (if we idealised it for a moment as a pistons as others have commented) is due to changing the amount of gas inside, not its pressure. Indeed think what a pump/controller is doing, it's pushing gas into/letting gas our from the bag. But I agree real world bags are not linear pistons. Using position sensors is perfect since that compensates for everything in one go . Changes in load (due to aero effects as well as fat passengers etc and non linearity due to real world bag and suspension geometries etc)
@SuperfastMatt, Lovely video *But* ... In the future, please refrain from giving me thoughts of using cheap automotive parts for costly non-automotive projects at the very time that other projects are running behind. Thanks!
I am in the process of swapping out the rear coils on my Discovery 2 and installing the factory air bags. I have all the bits, just got to install them.
Hi Matt, While your example of low ride height equals soft and hi ride height equals stiff is probably somewhat true for the double bellow airbags you are using, generally in an air suspension pressure is a function of load whereas height is actually a function of volume. If the bellows volume is sufficient (or if you were to utilize sleeve airbags such as most OEMs generally use), there would be next to no stiffness change (or pressure change) at different ride heights. Have you fallen prey to the balloon analogy (bigger balloon = higher pressure)? :-p And drop the Viair compressor and pick up a used compressor out of an OEM air suspension. You won't have to redesign the mount and you will not hear any compressor noise anymore.
Pressure in the air springs isn't really ride height, so using actual height sensors works much better. Of course, that's why manufacturers go to the expense of using those height sensors.
@@darekmistrz4364 the tilt of the vehicle on hills will shift load between axles slightly, changing ride height and potentially triggering air spring adjustments. The simplest way to fix that is just to have the controller only adjust when adjustment is manually requested (by pushing a button), but more sophisticated solutions for this (and for the similar effect of accelerating, braking, or cornering) include allowing a "deadband" allowance for slight changes, averaging height out over a reasonable time, or even measuring acceleration and compensating for it.
This is a dumb non engineer question but once the air bag lifts the car up 2 more inches, doesn't it take the same psi to hold it there as the lower setting?
Dude! You're building a speedboard type skateboard! This is the only time I'll say this ever, but don't finish that too fast. I'm currently building my own one and it's pretty epic and I want to make a video about it, but I kinda ran out of money and need a few weeks to get the project back up and running. Or we could combine forces and build an even more epic one, that would be absolutely awesome! I'm a 23 year old mechanical and electrical engineering student from germany working on this on and off for about a year now and it's been working great but broke again and like I said, money problems. I also already got ideas and CAD drawings for a much improved version. Let me know if you'd be interested in some kind of joint project :D Btw: you're literally doing all the projects that I ever dreamt of (minus the land-speed vehicle, I'm not that interested in that, but still plenty fun watching you develop and build it).
I have installed air suspension on my vehicles. I bought Holland Neway leveling valves, an air tank. pressure switch and a compressor. The system I installed is like the system used on public transit busses and 18 wheelers. KISS.
Assuming you Arduino the solution, make sure you add a CanBus hat. Then you can read the VSS and tell it to not adjust pressures unless VSS=0. Otherwise every single dip in the road (etc etc) will make it a non stop battle to adjust itself. That's what the back of my '01 Seville does anyhow.
Yea putting his cartoon matt profile pic was not a good choice i thought... I love the channel and want to support it but I'm way too cool to wear a cartoon matt on my back or a hat how bout that?
@SuperFastMatt when you get tired of car projects you should tackle some basic DIY home projects... like electric opening doors using the guts of a Model S door controller.
I agree with Luaa, plug welds on the modified link would make me feel much better. I have never worked on an air suspension system but it looks to me that if you control each corner separately you could have a good chance of having a different spring rate at each corner, probably not the best idea. Always great to watch your vids!
A bigger issue that different spring rates is diagonal loading bias - one front wheel and the opposite-side rear wheel with more pressure and carrying more load than the other two.
ok as a software engineer the code with the diy route is super simple and it doesnt require the ride height sensor since i know how much air is in the bag !!! in the code i wouldve made a table with all four wheels desired pressures in it and in an infinite while loop i would check every wheel pressure with the sensor and compare it to the table and do an action to lower or inflate more the buttons if i press high i would swap the values in the table and the while loop will inflate all the bags to reach the pressure if i press low i replace the values in the table and while loop would deflate the bags you can also make custom values to make the car dance if you want to
ALL HAIL GOOD ENOUGH (tm)
Thats true engineering. Only an engineer can build a house that barely stays up but still stays up, usually.
..takes a marketeer to sell it at stone castle pricing though
Basically Sloppy Mechanics.
Fixed is fixed
'Good Enough' is fine until there are unintended consequences that end up in the bay of a technician to diagnose and repair. Arrogant engineers and 'Good Enough' cause more time wasted down the road in diagnosis/repairs than they do in hours billed being saved in the engineering process.
@@86coupedeville Too serious bro, too serious...
@@86coupedeville there speaks the cranky throat-rasps of bitter dissatisfaction.
My goal as a Mechanical Engineer is to have Matt's humor!
I am also a Mechanical Engineer (at least, that's what my business cards say...). I'm wondering what it would cost to have Matt follow me around for a day to narrate my life...
If that is your goal expect to be on the receiving end. We are already loading up on your random capitalization.
@@timeastman8319 now that would be funny! 🤣
@@ShainAndrews It's really not random at all. It's the same as in German. Obviously the language of mechanical engineers all around the world
@@molunos8842 Four words have no business being capitalized. I read it again... did not see any German.. only English.
Stiffness in an air spring is not simply a function of the air pressure - it also depends on the air volume relative to the effective piston area. You can soften an air spring by plumbing it to an additional rigid chamber. That means that for the same vehicle weight, a higher ride position means *softer* springing (because there is more air volume and the same pressure); however, those convoluted style bags don't act as ideal air springs at all because the rubber resists both stretching for suspension extension and collapsing for suspension compression. This is why good air springs are of the rolling lobe (a.k.a. reversible sleeve) type.
RideTech offers both the double convoluted air springs like these, plus reversible sleeve and a variation of reversible sleeve which is tapered to change the spring rate progression, in both versions that mount over dampers and versions that mount separately.
If I could, I would leave 10 thumbs up, instead I will leave this comment as Thank You
Who are you and what do you do?? You're wayyy too knowledgeable about automotive suspension to just be some hobbyist.
Spot on. Lots of people make the mistake of thinking higher ride height means more pressure, when really it means more volume. Especially when using rolling lobe springs. The pressure in the airbag is set by the weight of the vehicle. Lifting the vehicle doesn't change the weight of the vehicle, it just expands the spring. Therefore, same pressure, more volume. This is also why cars and trucks with airbags use ride height sensors and don't rely on pressure sensors.
Thanks for the explanation, this deserves more than one like
@@Lucidbkeo Just an enthusiast... with a technical education, decades of interest in automotive technology, and enough curiosity to dig into topics of interest. Unfortunately, no one has ever paid me to work in the automotive field, but maybe that's why it's still fun. 😉
@4:06 A properly designed 5-link is not over-constrained - it is ideal. Just count degrees of freedom: there are 3 translational and 3 rotational degrees of freedom, and the suspension needs to move in one degree (controlled by the spring and damper), so the remaining 5 degrees must be controlled. All of the links of a 5-link locate in only one dimension (they are under compression or tension only, not bending) except the spring link (for designs like this that mount the spring and damper to a control arm instead of directly to the hub carrier), so if ball joints are used there is no binding. The bushing deflection occurs because they are not ball joints, and not perfectly parallel to the instantaneous axis of rotation of each link end.
The bending load mentioned in the construction of the adjustable link exists only because the bushings on the ends are not ball joints.
I was going to look it up and write a very detailed analysis for you. But in the end I figured it was "Good Enough" to let someone else do it and just give them props for it.👍
Came here to say this... luckily you already said it in a much more eloquent way lol
Only if by 'properly designed' you mean: all links are orthogonal/independent.
I’m currently in the middle of building a HomeKit controller for my unpowered sky light blinds. Project is about a month in now, I went from DC motor, to steppers, to now using a DIY servo motor. The code is getting insane and I haven’t even gotten to the PID parts. I should have just spent $300 on an OTS assembly but at this point I’m too far down the rabbit hole to quit and I’m learning a lot in the process.
Don’t let a pesky thing like monetary investment stop you from being able to say “look what I made!”
Just remember "Sunk cost fallacy" is a thing.
But you know, as long as it's fun, keep at it.
You could buy a more expensive dc servo with built in pid.
What you're using for the diy servo tho?
Learning is priceless.
Unless you can find a day course.
@@lasskinn474 It’s a geared DC motor + AS5600 mag position sensor. I was close to dropping coin on a ClearPath until I got it working this morning.
All hail the algorithm! Seriously, love your show and your humor style. It makes your videos enjoyable to watch. Seriously, thank you for not starting your videos with a scream.
If you're welding sleeves into/onto tubing you should drill holes around the perimeter for plug welds. Or if you want to keep it in the jaguar spirit you could use rosette welds.
make sure you pre-rust the rosette welds too if you are going for the jaguar feel
It brings peace to my heart knowing that I'm not alone with lots of ongoing and unfinished projects... Also, good enough™ just made my day. Thank you Matt!
"The perfect is the enemy of the good enough."
That's the essence of engineering.
Of life
I would love to see a project using the junkyard pneumatic valve. Adjustable height work tables?
Pneumatic Vice is pretty good one. I recently saw one guy make it with pedals on floor to operate it. Pretty useful when You can focus with Your hands on holding and positioning, and with Your foot on clamping or releasing it
@@darekmistrz4364 and when you are ready you can crush your hand with it. 😀 only joking with power comes responsibility as always
Matt; I would have bet money that you would have gone with the self-leveling Citroen Hydro Pneumatic suspension. But then there is Future Matt that will do that.
As a previous owner of a 67 Citroen DS21 (and a 68 parts car), I broke out in hives at your suggestion.
@@ottokiehl5413 Lol, more recent models have it all working well 🤗
For more reliable parts source, one could use the Lexus Active Height Control system.
Sunday morning + iced coffee + Superfastmatt new release video = wife, leave me alone for 10:59 minutes!
this channel is one of the best on youtube. . You deserve 1.68 milion subs, not 0.168
i designed my own airride, and i did it the right way. You dont use pressure EVER as rideheight setting. Its completely ret*rded. The reason you talked about in the video, the lower the car the lower the pressure. But then someone gets in, or you load up the back of the car with stuff and now all of a sudden the pressure rises because the bags have to carry more weight. Want to guess what the air suspension is going to do? Its going to lower the car even more in the back even tho it was allready getting lower because of the weight you added there. So instead of the car going level again when the air suspension activates it wil actually lean back even more. So the only way to go is to include height sensors. Height sensors and pressure sensors would be best if the system looks at both and trys to get the pressure left to right equal at all times. If you use that you should prettymuch have the same corner weight on each wheel.
I recently was designing an air ride system for a project...didn't know anything about how to do it.
Spent days and day designing circuits electrical and air, and trying to source individual bits and bobs
Ended up using a set of used oem bags and struts and purchasing a new aftermarket controller and valve bank.
NOTHING rides like air!
Love the channel SFM! 😃
Matt’s level of skill makes his good enough pretty darn good. Constantly impressed with the difficulty level of the projects he’s willing to tackle.
@7:10 Thanks for the metric conversion, imperial units don't make any sense. I don't know how you can make anything functional with them. I mean what the hell is a volt? definitely can't be as sensible of a unit as a flarg.
volts are metric
Ah yes, the gargaflargs. Always wondered about those.
@SuperfastMatt I just discovered your channel, lots of great stuff!
I believe what you said about air suspension at :55 is backwards; to raise the car you need more air volume, not pressure (the weight doesn't change).
A greater volume of air has lower spring rate than a smaller volume.
All true, but he's using convoluted bellows, so he's fighting the stiffness of the rubber in addition to the spring characteristics of the air.
I was binge watching the series instead of doing my german revision, guess i have to do that now, or i could watch something else of yours, i love your content
Erledige deine Arbeit!
setzte dich auf deinen hintern und lerne und trotzdem es lebe der algorithmus
Another great video! I like the way you narrate the story and the decision making process. Much more informative and interesting than watching other "build" channels that just bolt together free parts from sponsors and never experience a setback. A project is never a linear path and it's kind of reassuring to watch someone change directions during a projects the way the rest of us do. ("All hail the algorithm!")
Your narration is poetry 😍
Thank you for bringing back the old outro :)
Very cool... my head exploded at 8:25. Brillaint.
Definitely one of the best Podcast of the entire UA-cam Channels. I buy a t-shirt Good Enough... why.. Because it is ... good enough.
Many factory air suspensions, like that on my 2001 Audi allroad, have a lower spring perch that is kind of pear shaped (as are many things on a 22 year old car), so the spring gets stiffer as the suspension gets lower. In the rear, they also have dampers that are adjusted by an air valve so the damping adjusts as the suspension adjusts.
No such thing as poor break over angle with enough speed
The approach angle may have issues with that.
@@bedlamite42 the approach angle was already Good Enough™
Problem is, while the jag has good front and rear angle, if you hit the ramp with enough speed to make that assertion true, you'll compress the front suspension and risk driving into the ramp with the front!
This is also better in theory than in practice, as a certain Tesla driver recently proved in LA...!
@@edumaker-alexgibson recently? that video is way older then 4-5 months
@@Robo-xk4jm all is relative. Ironically you are replying to my post of 4 months ago, when it was 4 months more recent. Have a lovely day.
Can you make a quick vid where you compare aerodynamic drag at different ride heights at highway speed to determine power consumption and affect on range? Nice system
More lower is more better.
@@markm0000 You'd think. But I'd like to see the numbers.
@@Jeremy-fy1sz me too
Very impressed. You have the ability to engineer solutions and the temperament, objectivity and dry wit to document the process! Oh, forgot to mention your excellent taste in both the selection of drivetrain and powertrain. Thanks for taking the time to document your hard work.
It is amazing how sometimes the OTS is just what you needed. I have come to that conclusion when considering EFI for my MGB.
can you give some details or links? I have a MGB and never heard of someone installing an EFI
Definitely. When I converted my car to discs I made sure to use a kit for the front that uses all standard parts so I can easily get replacements. The rear has less easy to source parts but those don't wear out as fast
There are several controller options that could be used for EFI set-ups. A Micro-squirt unit is likely the most user friendly for the price, if you have more knowledge when it comes to a Adrino or raspberry set-up there is a Speedduino unit that is kind of interesting and fairly inexpensive. You can put together a EFI set up fairly easily and inexpensive. Infact if you look around at Matts projects i belive he does a Microsquirt set-up on his Grom or even his land speed rig. Whatever the case he has done it a couple times and gives pretty good info as to mak8ng the conversion. One of my first was making my KTM 525 fuel injected and for it i used a Microsquirt. I believe the controller was under $ and all the parts were sorced form the car junkyard and the motorcycle junkyard with a piece here and there being bought new.
I made a very similar 2 wheeled skateboard!! I love it! With my steering system design I needed a steering dampener to get rid of random speed wobbles
Needs more caster?
@@simonsnaplick895
Needs more caster (sugar)....is it not sweet enough?
Top tip: for comfort use a fridge kompressor - super low noise, won't last 20 years without lubricant, but it will be fine. But perhaps leave the noisy one in for speed. 🧐🤔🤓
3:14 I missed the appearance from future Matt but I guess I'll take the Good Enough™
Goodenough is one of the greatest engineers of the modern era :-D
Thanks for always putting a smile on my face. All hail the algorithm. 😁🍻👌
Hail, hale, Skipper.
That rear multilink has very specific bushes that bind in weird ways to provide passive steering effort depending on where the wheel is throughout it's travel. I hate modifying cars with multilinks because changing things even very minorly can throw the whole thing off.
Passive steering doesn't result from bushing binding - it results from toe changes due to the link geometry and due to busing deflection. Replace the bushing with rod ends and you would still have the geometric effects; add compliance to compression and extension of the links and you would still have the effect of bushing deflection even without any binding.
AHTA. That's what I love about your videos Matt, they're always Good Enough.
Your honesty on projects does me good
Matt, I saw your Death Valley - Road Closed video, and thought that was pretty cool. I'm not sure what convinced me to start your Jag EV swap... but I have become a HUGE fan! As a civil I get your sense of humor and have really enjoyed all the videos in the Jag series. Anyway, love your stuff and I'm really looking forward to watching more of your videos. Right now you're still under 250k subscribers, which for me is cool because you're going to hit it big and someday I'll say, "I knew Matt when he was just a quarter mill!"
I liked this video. but didn't share since most of my friends won't understand Matt's humor. Good Enough™.
Best automotive UA-cam channel out there. Easy to understand and Matt is easy on the eyes too. So it's a win win.
You can change the characteristics of a air spring by reducing the volume with a liquid such as a silicone oil.
All telescopic motorcycle forks are coil/air spring hybrids ,whether they are pressurised or operate at ambient pressure.
Changing the oil level alters the air space above the oil and therefore changes the air spring characteristics.
Creating the DIY air suspenstion system was like almost every software project I've been involved with. People with way too much talent and skill excited to DIY a solution. Which is awesome if it was a stand-alone side project, but not in the middle of a big production system that noone will know how it works in 3 years.
Although I agree, I recently see it the other way. For something that is built in language and supported natively with just a little bulky interface, people will pull few dependencies that do it with easier interface. I agree that interface could be better, but I prefer to have lowest amount of dependencies
@@darekmistrz4364 It needs a balance, given the projects constraints. It's clear Matt loves the DIY solution and we love watching him do it, but he saw the resource issues and pulled in the external dependency. Of course, the analogy breaks down somewhat. He doesn't need to rebuild his car every few months because of traffic law updates, and doesn't have to worry that the company who made the air suspension solution no longer exists or was compromised.
It's the maintenance of DIY systems over time that kills their viability ... there normally is no manual ... just vague recollections ...
I was at a wedding and was sat next to someone that did suspension design for a German auto manufacturer, we briefly talked about what we did, then got on the subject of modified cars.
I showed him the diagram for the double triangulated 4 link (solid axle) rear suspension I made for my Explorer, talked about design goals and shortcomings etc.
He was tickled that I was planning to put such a highly modified vehicle back on the road, something he described as impossible in Germany, but mostly laughed and suggested it was quaint compared to the five link designs he worked on.
It took me months of revisions to get the 4 link how I wanted it on paper (to be seen in the real world), but still I didn't disagree. 5 link independent are absolutely mind boggling.
10:50 ohh... Gold...
This channel keeps me from staying anymore projects. Thank you for your service
Good Enough is the best kind of good
Matt, I’ve been watching you since the beginning… of the dry sump video, and I gotta say, you’re must watch UA-cam.
Isn't the pressure the same regardless of ride height? You have the same mass at each corner, so the force on each airbag is the same, so the pressure is the same. Unless the airbag shape or suspension geometry changes. You just have more air in the bag at higher ride height which makes it longer. Which would also make it ride softer because you need more travel to halve the volume and double the force. Or am I missing something??
You are correct. That's exactly how it works and exactly why aftermarket kits, passenger cars and commercial vehicles that use airbags all use ride height sensors instead of trying to determine ride height based off pressure.
That's all correct, for an ideal airbag. The reversible sleeve (or rolling lobe) designs are close, but Matt is using the double convoluted bellows type, and the rubber in those interferes with the ideal behaviour. Still, they're closer to the ideal that you describe than the behaviour which Matt suggested.
Another excellent video, this channel is so underrated. Tall your friends about this fun corner of the Internet!
The internal spring pressure is the same at all ride heights. Resistance, like loading the vehicle will increase the internal spring pressure. Here is a question for you. Does your Jag get heavier at the full height of a lift on a hoist? I know it does not.
Adding more cubic air to an air spring will cause it to extend until it meets resistance, only then will the internal pressure start to rise to meet or exceed the resistant load.
Unfortunately, the double convoluted bellows design of air spring, including the ones that Matt is using, have far from ideal air spring behaviour - it's almost like using a tire as an air spring, while the other type of air spring (the reversible sleeve or rolling lobe) acts more like a piston in a cylinder.
All hail algo! Need more 4runner!
How about making a barrel nut for the one bolt that you have to cut off every time?
There is another solution to the ride height adjustability problem, hydropneumatic suspension uses a cylinder and piston filled with hydraulic fluid at each corner to sort of act as a spring. The cylinders are attached by high pressure hoses and hardlines to a nitrogen filled sphere (which is attached to the car's chassis) which acts as a compressible springing medium. Further more, there is a hydraulic system with a pump and valves which adds or removes hydraulic fluid from each corner to change the ride height and keep the suspension level.
This system, introduced by Citroen for the DS was also used by Mercedes for its hign end cars, most notably the 300SEL 6.3 and later 450SEL 6.9. It was considered miraculous at the time but the system's complexity made it something of a maintenance hog. This may not be a problem for a high end Mercedes, but was a thorn in the side of many less than wealthy Citroen owners. Over time, these systems lost favor with manufacturers. Air suspension may have its faults, but it can be good enough for most purposes.
Hydropneumatic suspension is a fun system to re
Systems like that still exist, including Lexus Active Height Control.
You don't make Videos, you make art
I had air springs on my 36 foot dual rear axle 8 wheel motorhome. The driven rears were ride height adjusted. There was no controller, just the ride height valve. The fronts had a fixed pressure that I checked before each trip, and the tag axle had a pressure gauge and mechanical pressure release valve on the dashboard. Again, no controller. I could deal with the ride height problem (rear tow hitch) with the dashboard adjuster. By the way, the fronts make a big noise when they blew out when I hit a big bump. Also, I found you can pay someone $600 to take the front suspension apart to replace one or you can find someone who knows that if you roll them up and put soap on them you can have them installed for $30 the second time you blow one out. I also found that I could do it myself with the soap method once I watched the guy do it so third time was a charm. I don't think you will blow them out as my motorhome was 12,000 pounds so much higher loads. It was only the fronts that blew out and they were inside coil springs so not a huge deal. I often wondered what would happen if the rear bags went but never found out.
I love your channel, the humor and nerd level is supherb. Love from Germany
Love the Jag videos. All hail the algorithm !!!
One of my favorite builds!!!
Brilliant. I will now watch it.
(Update, having just watched it, around 1m00 you show a madeupgraph(tm) that ride height is proportional to pressure. I dont think it is. In fact the pressure may be (approximately*) constant as a function of ride height .. what changes with ride height is the volume of gas in the system, not its pressure, cf orthogonally if you change the weight of the car by filling it with fat people, the pressure will need to increase to give you the same nominal ride height even though the volume is unchanged. Maybe. Its just a theory, I haven't inserted pressure sensors in the air suspension of my 21 year old lexus ls to check. You could probably insert 60 seconds of humorous explanation of the gas laws in your next if you wanted.
*its affected by bag and suspension geometry etc
Assuming everything is flat and nothing's changing, the ride height is proportional to the spring/bag height and that is directly related to the pressure.
So yeah, right height is proportional to the pressure but it's not linear and it's not constant.
The problem is it's not constant. That's why we have to use ride height sensors instead of simple pressure sensors.
That said if your car was equally loaded on all four corners, with identical suspension on all four corners, you could theoretically put them all to the same pressure and the car would be level and at varying ride heights depending on the pressure.... But since we live in A world where the driver is often offset to one side and the weight on all four corners is not the same etc etc... We need ride height sensors.
no, ride height does have a relation to pressure. The bag contact patch (where the bag rests against the end pieces) gets smaller as they extend, thus reducing the effective area, and requiring more pressure for the same load.
Your approximation would be correct for a pneumatic piston, though.
Correct. Ideally, changing the amount of air in the springs without changing the weight of the vehicle will just change the height without changing air pressure at all, but this style of air bag (convoluted bellow) needs more pressure to stretch so it is far from ideal; the rolling lobe (also called reversible sleeve) type would be closer. Your Lexus probably has rolling lobe springs.
@@kain0m totally agree, I was trying to keep it simple but did actually have a note (*) saying its affected by bag and suspension geometry etc. My core point is that its not the simple proportionality (ie goes through the origin) with pressure as shown in the graph seen around 1m00, on the contrary its a comple curve (eflecting bag and suspension geometries) closer to a band (depending on load etc) *parallel* to the axis
@@TravisFabel with respect I think you are wrong. You don't explain why, just state that bag height is related to pressure ... but (* for now overlooking the non linearities due to the shape of the bag) Imho that's not the case, as stated variations in the height of a bag (if we idealised it for a moment as a pistons as others have commented) is due to changing the amount of gas inside, not its pressure. Indeed think what a pump/controller is doing, it's pushing gas into/letting gas our from the bag.
But I agree real world bags are not linear pistons. Using position sensors is perfect since that compensates for everything in one go . Changes in load (due to aero effects as well as fat passengers etc and non linearity due to real world bag and suspension geometries etc)
I love this Jaaag project so much
@SuperfastMatt, Lovely video *But* ...
In the future, please refrain from giving me thoughts of using cheap automotive parts for costly non-automotive projects at the very time that other projects are running behind.
Thanks!
You speak so well. It's so satisfying.
Nice work and explanation. Look up plug welds for your contrl arm tubing. Add a lot of strength
“SuperSmartMatt” should be your channel’s name.
It often comes down to the standard formula: Money vs Time (+ skill).
I am in the process of swapping out the rear coils on my Discovery 2 and installing the factory air bags. I have all the bits, just got to install them.
Hi Matt,
While your example of low ride height equals soft and hi ride height equals stiff is probably somewhat true for the double bellow airbags you are using, generally in an air suspension pressure is a function of load whereas height is actually a function of volume. If the bellows volume is sufficient (or if you were to utilize sleeve airbags such as most OEMs generally use), there would be next to no stiffness change (or pressure change) at different ride heights. Have you fallen prey to the balloon analogy (bigger balloon = higher pressure)? :-p
And drop the Viair compressor and pick up a used compressor out of an OEM air suspension. You won't have to redesign the mount and you will not hear any compressor noise anymore.
Pressure in the air springs isn't really ride height, so using actual height sensors works much better. Of course, that's why manufacturers go to the expense of using those height sensors.
Wouldn't those sensors freak out in hilly areas like San Francisco?
@@darekmistrz4364 the tilt of the vehicle on hills will shift load between axles slightly, changing ride height and potentially triggering air spring adjustments. The simplest way to fix that is just to have the controller only adjust when adjustment is manually requested (by pushing a button), but more sophisticated solutions for this (and for the similar effect of accelerating, braking, or cornering) include allowing a "deadband" allowance for slight changes, averaging height out over a reasonable time, or even measuring acceleration and compensating for it.
@@brianb-p6586 Thanks for explaination, makes sense
This is a dumb non engineer question but once the air bag lifts the car up 2 more inches, doesn't it take the same psi to hold it there as the lower setting?
Wow. All hail the Matt.
i’d def. toss a couple inches of polystyrene foam on the inside of the air compressor box, wild how loud those things are.
Screw compressors are quieter but I never see small versions of them, only industrial ones.
@@darekmistrz4364 - i’m sure roots makes a tiny supercharger…
The best kind of good. Good enough.
I believe the technical term you're looking for is "shock condom."
I'm building some active aerodynamics and I was thinking of using some air shocks, this is going to help me out alot. Thank you!
Dude! You're building a speedboard type skateboard! This is the only time I'll say this ever, but don't finish that too fast. I'm currently building my own one and it's pretty epic and I want to make a video about it, but I kinda ran out of money and need a few weeks to get the project back up and running. Or we could combine forces and build an even more epic one, that would be absolutely awesome! I'm a 23 year old mechanical and electrical engineering student from germany working on this on and off for about a year now and it's been working great but broke again and like I said, money problems. I also already got ideas and CAD drawings for a much improved version. Let me know if you'd be interested in some kind of joint project :D
Btw: you're literally doing all the projects that I ever dreamt of (minus the land-speed vehicle, I'm not that interested in that, but still plenty fun watching you develop and build it).
I'm curious why you didn't use mechanical leveling valves with electric dump valves?
Mechanical valves are extremely common on bigrigs
That's only a straightforward solution if you don't want ride height to be adjustable.
The dry sarcasm and resignation in the intro feels like a particularly endearing personal attack. 😅
I love watching a DIY video about buying stuff. All hail the good enough! 🥰👍🏻
I watch all of your vids and i’m not even a car guy, they are just interesting and entertaining 👍
Cars are just the canvas, this is a garage engineering channel
I have installed air suspension on my vehicles. I bought Holland Neway leveling valves, an air tank. pressure switch and a compressor. The system I installed is like the system used on public transit busses and 18 wheelers. KISS.
Assuming you Arduino the solution, make sure you add a CanBus hat. Then you can read the VSS and tell it to not adjust pressures unless VSS=0. Otherwise every single dip in the road (etc etc) will make it a non stop battle to adjust itself. That's what the back of my '01 Seville does anyhow.
This video is definitely Good Enough
For the same reasons (hard in high, soft in low) I have opted to use a lift kit from Stanceparts. Wonderful stuff, really cool!
am I the only person that wants an "All hail the Algorithm" T-shirt? (with UK shipping)
as well as one that says "good enough"
Yea putting his cartoon matt profile pic was not a good choice i thought... I love the channel and want to support it but I'm way too cool to wear a cartoon matt on my back or a hat how bout that?
Good Enough Matt, good enough. 👏🏻
That heatshrink labeling really is the bomb. Algorithmic comments FTW too.
@SuperFastMatt when you get tired of car projects you should tackle some basic DIY home projects... like electric opening doors using the guts of a Model S door controller.
Neat, thanks.
I agree with Luaa, plug welds on the modified link would make me feel much better. I have never worked on an air suspension system but it looks to me that if you control each corner separately you could have a good chance of having a different spring rate at each corner, probably not the best idea. Always great to watch your vids!
A bigger issue that different spring rates is diagonal loading bias - one front wheel and the opposite-side rear wheel with more pressure and carrying more load than the other two.
ok as a software engineer the code with the diy route is super simple and it doesnt require the ride height sensor since i know how much air is in the bag !!! in the code i wouldve made a table with all four wheels desired pressures in it
and in an infinite while loop i would check every wheel pressure with the sensor and compare it to the table and do an action to lower or inflate more
the buttons if i press high i would swap the values in the table and the while loop will inflate all the bags to reach the pressure
if i press low i replace the values in the table and while loop would deflate the bags
you can also make custom values to make the car dance if you want to
"It's not just good, it's good enough!"
-Krusty the Clown
Great video Matt! Your Jag is awesome. All of your projects are super interesting. It is amazing to see all that you do.
Does manual air suspension exist? Instead of a tank and pump, could each strut just have a schrader valve?
That's what Matt said he was doing at the front, until he upgraded to this system.
Love the videos, now we just need the "Good Enough tm" t-shirts!
You should make a "good enough tm" t shirt
Thanks Matt, usually enjoy your videos but this one was Good Enough.
The name Goodenough was good enough for John Goodenough, more-or-less the inventor of lithium-ion batteries. So, Good Enough is excellent in my book.
I just had to look that up... and it's actually true! 😄
@@brianb-p6586 Answers with Joe has a pretty good bit on John
That will do, hopefully