Murray, I have been having this conversation with people dating back to the FX3 suspension almost 25 years ago a hundred ways before this thread.
Will you be getting a C9 because I have a surprise coming for you!
Will you be getting a C9 because I have a surprise coming for you!
On the other hand condoms can be well worth the money.
And I have been having similar arguments with people about the value of coils over leaf springs for 60 years! It doesn't make one better than the other. It all depends on the value of the ride and the money it costs to provide it. The relative term here is ... well ... relative!Murray, I have been having this conversation with people dating back to the FX3 suspension almost 25 years ago a hundred ways before this thread.
Will you be getting a C9 because I have a surprise coming for you!
Mr.Corvette and I have been conversing privately about this, and I might be able to give a few insights.
I am a mechanical engineer with motorsport, suspension design and setup experience. If anyone wants my background feel free to PM me. I do not have experience working on semi-active MR systems, but I do have a working knowledge of the systems. I'm going to try to greatly simplify this, not because forum members are not technically knowledgeable, just that it's a big topic....
Passive suspension works on Force vs. Velocity curves for the dampers where the damper generates a certain amount of resistance to motion depending on shaft speed. I can get into linear vs digressive curves/pistons etc. Adjustable shocks change the shape of this damper curve by controlling oil bypass, allowing adjustment, but the damper will still follow a fixed curve, just a new one, allowing the suspension to be adjusted to taste/requirement. Some updated systems will let you select different damper profiles (comfort vs sport) from the cockpit, but this is just switching between 2 fixed damper profiles. For road going passenger cars, most chassis work reasonably well within a "window" of damper curves. Perceived comfort is usually at the softer end of this window with perceived control at the the other. Note my use of the word "perceived" as the actual requirements for performance can nowadays be pretty closely defined using shake rigs, data acquisition (suspension histograms etc.) etc. then it's often basically a click here or there off baseline to tune for driver taste, conditions etc. with passive systems in racing. The non MR shocks in the Corvette will have well developed damper profiles that are likely somewhere in the middle of this window making a compromise between perceived comfort and control. A happy medium that won't offend and work pretty well in most conditions.
MR is completely a different concept. As many of you know instead of oil/piston/valving systems MR uses a fluid that has variable viscosity depending on the current applied to the electromagnets in the shocks. This gives a very wide damping force range that is almost instantly variable. Some other semi active systems use servo operation of an oil bypass (Porsche PASM), but this type of system is less responsive than the MR system in the Corvette. MR also has accelerometers in the suspension and in the chassis. GM/BWI in the latest generation of MR has made some great updates in terms of using accelerometers where position sensors were used, and in changing the design of the shocks themselves to better control magnetic fields. The latest system in the C8 is much faster and more precise even than previous MR systems. If anyone wants a breakdown of these advances on the latest system I can go into details.
MR works very differently to passive suspension. It's closed loop. It has algorithms that read chassis and suspension accelerations and adjusts the shocks almost instantly to produce the desired result. What is the desired result? I believe almost all MR programs are now using a variation of an algorithm called "skyhook" which aims to minimize chassis acceleration (stabilize the platform), as opposed to "groundhook" which aims to maximize tire contact. I think it was either the C5 or C6 where the more aggressive (sport or whatever) setting was groundhook and many found it harsh (because the algorithm is working to maximize tire contact, not reduce chassis motion) and the cars were actually faster around a track using the "softer" setting because it was using skyhook and drivers found it more predictable. Randy Pobst commented on that with a previous generation MR equipped Corvette at Laguna where once he selected the softer setting, the car was way better - he didn't realize it was the MR program he was changing from one based on groundhook to skyhook. As I understand, the GM MR program updates that became available from dealers replace the groundhook algorithm with a second, "sportier" skyhook one. Jim Mero offers custom MR profiles.
Because the MR damper FV profile can be adjusted almost instantly over a wide range, damping can be added or reduced as needed to both comp and rebound as needed in milliseconds. With skyhook, as the algorithm prioritizes chassis stability possibly at the expense of some tire contact, it can lead to some "wheel hop" over surface irregularities (the priority is a stable chassis), and would require an unsprung mass of 0 to work perfectly ideally (as would any car suspension!). I have a suspicion that with the Z06 they introduced the carbon wheel option because this will not only improve overall performance, but the advantages will also improve the MR performance. I think now though GM/BWI has possibly gone to a hybrid of skyhook. They keep their latest developments and programming pretty guarded. Some of what the MR system allows engineers to do on the fly during the development phase is really amazing.
Passive shocks can be tuned very well, but cannot adjust on the fly, and will be a compromise depending on the conditions/driver preferences. MR is closed loop adapting almost instantly to "read" the road and control the chassis. Remember the chassis "window" I mentioned for passenger cars? This is where the 3 settings of tour, sport, track will come in with the C8, adjusting the MR profile to optimize to either the "comfort" "middle" or "control" end of that window. The non MR system on the C8 is set to one setting that is a happy medium decided upon by GM. Remember what I mentioned about the compromises in the C8 passive damper tuning? Greatly eliminated.
Listening and reading some of Jim Mero's stuff is also great for more insights, as Jim Mero did a lot of the development work on the Corvette MR tuning I believe up to the C7. As many of you know Jim is a Nurburgring expert, and has also raced at LeMans. He says hands down he'd take MR in a Corvette at the Nurburgring. It also works better on the street/highway offering better comfort. Semi-active suspensions like the Corvette MR system are also banned in many classes of racing, and are often faster than the best tuned passive racing systems. For the $2180? option price MR offers huge advantages considering the price of some aftermarket passive systems. Replacement MR shocks also seem to be reasonably priced ($650 ea. or so?) in the event of wear/failure.
Hope it helps people understand the differences!
Some white papers for anyone wanting to go down the rabbit hole:
http://inpressco.com/wp-content/uploads/2014/04/Paper56265-269.pdf
I am a mechanical engineer with motorsport, suspension design and setup experience. If anyone wants my background feel free to PM me. I do not have experience working on semi-active MR systems, but I do have a working knowledge of the systems. I'm going to try to greatly simplify this, not because forum members are not technically knowledgeable, just that it's a big topic....
Passive suspension works on Force vs. Velocity curves for the dampers where the damper generates a certain amount of resistance to motion depending on shaft speed. I can get into linear vs digressive curves/pistons etc. Adjustable shocks change the shape of this damper curve by controlling oil bypass, allowing adjustment, but the damper will still follow a fixed curve, just a new one, allowing the suspension to be adjusted to taste/requirement. Some updated systems will let you select different damper profiles (comfort vs sport) from the cockpit, but this is just switching between 2 fixed damper profiles. For road going passenger cars, most chassis work reasonably well within a "window" of damper curves. Perceived comfort is usually at the softer end of this window with perceived control at the the other. Note my use of the word "perceived" as the actual requirements for performance can nowadays be pretty closely defined using shake rigs, data acquisition (suspension histograms etc.) etc. then it's often basically a click here or there off baseline to tune for driver taste, conditions etc. with passive systems in racing. The non MR shocks in the Corvette will have well developed damper profiles that are likely somewhere in the middle of this window making a compromise between perceived comfort and control. A happy medium that won't offend and work pretty well in most conditions.
MR is completely a different concept. As many of you know instead of oil/piston/valving systems MR uses a fluid that has variable viscosity depending on the current applied to the electromagnets in the shocks. This gives a very wide damping force range that is almost instantly variable. Some other semi active systems use servo operation of an oil bypass (Porsche PASM), but this type of system is less responsive than the MR system in the Corvette. MR also has accelerometers in the suspension and in the chassis. GM/BWI in the latest generation of MR has made some great updates in terms of using accelerometers where position sensors were used, and in changing the design of the shocks themselves to better control magnetic fields. The latest system in the C8 is much faster and more precise even than previous MR systems. If anyone wants a breakdown of these advances on the latest system I can go into details.
MR works very differently to passive suspension. It's closed loop. It has algorithms that read chassis and suspension accelerations and adjusts the shocks almost instantly to produce the desired result. What is the desired result? I believe almost all MR programs are now using a variation of an algorithm called "skyhook" which aims to minimize chassis acceleration (stabilize the platform), as opposed to "groundhook" which aims to maximize tire contact. I think it was either the C5 or C6 where the more aggressive (sport or whatever) setting was groundhook and many found it harsh (because the algorithm is working to maximize tire contact, not reduce chassis motion) and the cars were actually faster around a track using the "softer" setting because it was using skyhook and drivers found it more predictable. Randy Pobst commented on that with a previous generation MR equipped Corvette at Laguna where once he selected the softer setting, the car was way better - he didn't realize it was the MR program he was changing from one based on groundhook to skyhook. As I understand, the GM MR program updates that became available from dealers replace the groundhook algorithm with a second, "sportier" skyhook one. Jim Mero offers custom MR profiles.
Because the MR damper FV profile can be adjusted almost instantly over a wide range, damping can be added or reduced as needed to both comp and rebound as needed in milliseconds. With skyhook, as the algorithm prioritizes chassis stability possibly at the expense of some tire contact, it can lead to some "wheel hop" over surface irregularities (the priority is a stable chassis), and would require an unsprung mass of 0 to work perfectly ideally (as would any car suspension!). I have a suspicion that with the Z06 they introduced the carbon wheel option because this will not only improve overall performance, but the advantages will also improve the MR performance. I think now though GM/BWI has possibly gone to a hybrid of skyhook. They keep their latest developments and programming pretty guarded. Some of what the MR system allows engineers to do on the fly during the development phase is really amazing.
Passive shocks can be tuned very well, but cannot adjust on the fly, and will be a compromise depending on the conditions/driver preferences. MR is closed loop adapting almost instantly to "read" the road and control the chassis. Remember the chassis "window" I mentioned for passenger cars? This is where the 3 settings of tour, sport, track will come in with the C8, adjusting the MR profile to optimize to either the "comfort" "middle" or "control" end of that window. The non MR system on the C8 is set to one setting that is a happy medium decided upon by GM. Remember what I mentioned about the compromises in the C8 passive damper tuning? Greatly eliminated.
Listening and reading some of Jim Mero's stuff is also great for more insights, as Jim Mero did a lot of the development work on the Corvette MR tuning I believe up to the C7. As many of you know Jim is a Nurburgring expert, and has also raced at LeMans. He says hands down he'd take MR in a Corvette at the Nurburgring. It also works better on the street/highway offering better comfort. Semi-active suspensions like the Corvette MR system are also banned in many classes of racing, and are often faster than the best tuned passive racing systems. For the $2180? option price MR offers huge advantages considering the price of some aftermarket passive systems. Replacement MR shocks also seem to be reasonably priced ($650 ea. or so?) in the event of wear/failure.
Hope it helps people understand the differences!
Some white papers for anyone wanting to go down the rabbit hole:
http://inpressco.com/wp-content/uploads/2014/04/Paper56265-269.pdf
Last edited:
Nobody "needs" Magride. The base and Z51 suspension in the C8 is simply fantastic and the ride is more than comfortable enough to daily the car.
As a person that has owned both my opinion is that Magride gives the car that much more adjustability to tailor the ride and handling to suit the way you feel at that moment. The car becomes that much more Dynamic and in my opinion much more fun. Throw in the relatively low price and to me its simply a no brainer.
Like others have said, if you never had it you wont miss it but I did have it and I miss it dearly!
As a person that has owned both my opinion is that Magride gives the car that much more adjustability to tailor the ride and handling to suit the way you feel at that moment. The car becomes that much more Dynamic and in my opinion much more fun. Throw in the relatively low price and to me its simply a no brainer.
Like others have said, if you never had it you wont miss it but I did have it and I miss it dearly!
We haven't heard from Murray. I suspect he is in the barn fitting leaf springs onto his C8 to prove a point...
What he said ^^^
Jack: Leaf springs were cheap and they worked. Coils work better, but are more expensive. I won many drag races with leaf springs beating cars with coils. It doesn't make me better or my car. It didn't decrease my enjoyment of the car. I simply knew no better and I simply loved my car.
I wanted a Camaro, but could only afford the Duster with it's leaf springs. Camaros were $200.00 more!
I wanted a C8, but could only afford a 2LT, the wheels, exhaust and the front lift. I love our C8 as does my wife. Mag ride would not make me like it any better or worse. However, the point is moot. I have my sports car and won't be buying another, unless of course I meet black ice.
Also, in 2020 mag ride was not a $2000 no brainer option, but rather something like a $7500-8500 option (can’t remember exactly)as you had to get Z51. With the car itself at around $80K with 2LT, it’s a 10% increase in the price. Not small change as some seem to make it out to be.What he said ^^^
Jack: Leaf springs were cheap and they worked. Coils work better, but are more expensive. I won many drag races with leaf springs beating cars with coils. It doesn't make me better or my car. It didn't decrease my enjoyment of the car. I simply knew no better and I simply loved my car.
I wanted a Camaro, but could only afford the Duster with it's leaf springs. Camaros were $200.00 more!
I wanted a C8, but could only afford a 2LT, the wheels, exhaust and the front lift. I love our C8 as does my wife. Mag ride would not make me like it any better or worse. However, the point is moot. I have my sports car and won't be buying another, unless of course I meet black ice.
Running 30.5 PSI 20/21” wheel set up and the ride is fantastic without magnetic ride. Is it nice to have? Sure but perfectly doable without.
Thanks for the links @slegros, very interesting.
I quickly glanced at the papers and the simulation equations use a single dimension x representing the vertical axis. I am curious if you have any links to the actual algorithms used by the magride control unit, how it uses other sensor inputs, etc, and whether it is more sophisticated than the models in the papers.
I quickly glanced at the papers and the simulation equations use a single dimension x representing the vertical axis. I am curious if you have any links to the actual algorithms used by the magride control unit, how it uses other sensor inputs, etc, and whether it is more sophisticated than the models in the papers.
Not stuff I keep on file.. LOL! Those links were from a quick google search.
Chassis acceleration and wheel acceleration in the vertical axis are basically what you are looking to control with suspension. This is the basic concept of shake rigs, to subject each wheel to oscillating vertical loads of varying frequencies to fine tune damper force velocity curves. In the development process the sensors in MR system basically give the engineers/MR controller this data in real time on the road, and I have a suspicion the damper curves selected for the non MR shocks were probably arrived at in part based on data taken from the MR systems in testing. With MR its closed loop. In theory you could also have infinite fixed damper profiles with MR to select from, but that would only be using a fraction of the power of the system when you can close the loop and have the suspension continuously adjusting on the fly to produce the desired result.
The algorithms/programs are proprietary, you'll find stuff on the basic concepts but very few specifics of the implementation. Jim Mero did a lot of the development for GM and specifically the Corvette MR systems up to and including the C7. Have a look for some of his interviews/articles where he talks about "rebuilding" the MR programming I think around the time of the C7 to base it on something new (All based on skyhook? a hybrid? He doesn't say), and how he made that available through his upgrades for older Corvettes. The programming while likely based on skyhook also has many other variables that can be tuned. Jim doesn't go into specifics about his/GM/BWIs secret sauce. As with any suspension system to an extent it only as good as its tuning (though MR has many technical advantages not present with passive systems), but in the case of the Corvette Jim Mero in my opinion is a VERY smart guy and the GM/BWI vehicle dynamics engineers really know what they are doing with MR at this point to where it has progressed beyond what can be achieved with passive dampers. It seems MR is definitely the point of focus as far as Corvette suspension at this point.
This is a good interview with Jim Mero. He discusses MR, but there may be other interviews out there with more on MR programming theory:
Similar threads
-
Ron Fellows Performance Driving School-Would you consider going?- Started by Mr.Corvette
- Replies: 99