Computerized suspension systems

Just curious for those w/current suspension design expertise. Do any of the current manufacturers design their suspension systems so that the rear wheel suspension adjusts for what just happened to the front wheel? For example, you hit a pothole with the front wheel, get a bit of a jolt, but by the time the rear wheel hits the pothole the front wheel electronics has already communicated the pothole info to the rear, so the rear suspension is adjusted so there’s not much of a jolt from the rear?

Yes, some do. Nissan has played around with preview control since the mid 1980s with limited results. The strategy has generally been to run in the softer damping modes and add damping when needed… I’e. hit bump in soft, control the reaction by adding damping force after the bump. The faster the shock can react, the better this works. Early exampls took 120 msecs to react. In the 1990s 25-30 msecs, in the 2000s 5-15 msec reaction.

This is a reasonably accurate source that explains some of this…

Truth is, the rear will nearly always be a softer impact than the front for reasons of suspension geometry. The front will nearly always hit a bit harder.

This is a subset of active suspension:
Active suspension - Wikipedia

There’s no need for “computerized suspension systems”, nor would I want such a thing. That sounds expen$ive to buy, and really expen$ive to maintain. All that’s needed are good shocks or struts with strong springs.

The most comfortable vehicle I have ever owned was a 1995 Dodge Caravan, and I owned two of them. This vehicle had very comfortable seats–and this was the base model with hand-crank windows, not the fancier versions with power-adjustable seats. The suspension soaked up any bumps in the road.

As a side note, replacing worn-out shocks and struts can really improve the comfort and handling of your current ride. I recently had the shocks and struts replaced on my 2002 Daewoo Lanos, and I went from feeling like a bobblehead to enjoying a smooth and comfortable ride.

Monroe developed a line of shocks and struts called Sensa Trac back in the 90’s that basically when the suspension isn’t moving up and down much it’s in the comfort part of the travel and when you hit a bump or go into either extreme of the shocks travel it get’s firmer but not so still and to ruin the ride.

Came out when I was working for a parts store and I wish i still had a copy of the diagram they used to explain how it worked which was so simple but elegant. Really worked well on large SUV’s such as the Chevy Tahoe. Not as complicated as a GM Magna Ride such as on a Corvette but without the expense of the replacements.

We had a nickname for Monroe’s special shock… SensaCrap.

The principle innovation was a groove in the cylinder tube so the oil goes around the piston only in the middle of the travel. Made every application feel loosey-juicy as it rolled down the road. Awful.

Premium cars demand premium suspensions. If you have never experienced a really good controlled shock system, you don’t know how good a ride can be.

The active suspensions are another big jump in cost but, also a big jump in ride control. The results can be jaw droppingly good.

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I’ve read positive reviews about most of the ride control systems offered, You do have to pay more for replacements when the time comes but it’s the trade off for having that suspension. Coil over conversions have become somewhat popular on luxury brands but usually without the same level of ride comfort.

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The term “coil-over” is simply the spring mounted on the damper. Many, many, production cars do this straight from the factory. Nearly every strut has a spring wrapped around it. The spring is always offset to reduce the friction caused by the offset in forces from the tire to the strut. Many shocks also mount the spring but don’t need any offset. It makes assembly in the car plants easier.

The term “coil-over” has taken an almost mythical quality… the magic ride and race-car handling. The ride part is complete BS. The aftermarket coil-overs typically have very stiff springs and very stiff dampers. For racing and track days, that is fine. For road use, not so much.

Why? Because the rubber that isolated road noise is replaced by metal spherical joints making the ride loud and harsh. The struts usually have small springs mounted with no offset to clear large tires but the strut friction gets quite high (harsh ride). And the thing that bothers me the most is moving the springs from the axle to the shock in a car not designed for both those loads. They are adjustable, if you know what to adjust and why, but not for street use.

Coil-overs are much like the quick-release steering wheels some think are necessary for their riced-out Honda or Subaru. Not for street use!

Yes, electronic shocks, air-ride systems and active systems ARE expensive to replace. Very expensive. There is a lower cost aftermarket for these parts. Arnott is one. They don’t work as well as the factory stuff but they don’t cost $4000 a corner either!

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If someone can afford about $80,000 for a car why should they be stressed out with a $4000 suspension repair bill?

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It’s when the $80,000 vehicle is worth 20k or less that an owner would hesitate to pay that much. Can get aftermarket for less but depends on vehicle

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How can you beat air suspension with minimal unsprung mass?

Air suspension doesn’t reduce the unsprung much if at all.

Air suspension can give very non-linear springrates for a soft ride but still have decent stiffness for handling. It also maintains a consistant ride height.

I feel the same way… but the market apparently doesn’t think like we do.

@wolyrobb has it right. Buying a used 80K Bentley for 20K, 4K for a replacement strut is significant.

The original owner of this hypothetical $80k luxury vehicle could certainly afford to pay $4k for a suspension repair. And if such a repair were to be needed during their ownership of the vehicle, it would be done, at a dealer, using OEM parts.

The problem is that most people who could afford an $80k vehicle generally aren’t going to drive it for more than 5-10 years, and it is the third or fourth owner who gets stuck with the huge repair bills. By this point, the car is worth nowhere near its original purchase cost, and the current owner might be a “baller on a budget” who could barely afford to buy the car (at its now-reduced cost) but simply cannot afford the expensive repairs.

A person who buys a 20 year old luxury car for $8k almost certainly does not have the income and resources needed to buy the vehicle new for $80k, and even if they could afford a $4k suspension repair, it would likely be a waste of money. A cheaper alternative would be needed, such as replacing an active suspension with standard spring-loaded shocks and struts.

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The guys from the Youtube channel and TV Show Everyday Driver bought a VW Phaeton for $5,000 and ended up putting another $5,000 into the front air suspension. They bought the Phaeton and a $10K Maserati Quatroporte as a “how bad could they be” challenge. The Maserati wasn’t nearly as costly to maintain but could have easily been worse.
Quattroporte and Phaeton - Bad Ideas - Big Sedan Challenge #2 | Everyday Driver (youtube.com)

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I watched the video, and cars like this are on a whole other planet from anything I have ever owned or driven. My idea of “luxury” is the 1998 Toyota Camry, which my father bought, which had a 4-cylinder engine, automatic transmission, in-dash CD player, and no other options. What a great car!

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That is not unusual, I have performed $10,000 suspension repairs on Lexus LS460s. Air springs leak, dampers leak oil and mounts break. Original owners will look at new cars while waiting for the estimate and will often have the repair completed, a new LS500 is $95,000.

The guy that buys used from Bob’s used car lot never has money for the repairs.

Broken upper mount.

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Back in the 80’s, Aman Bose (the late founder of the speaker company with this name) developed an electromagnetic car suspension.

It was a technical success but also a commercial failure. Despite working exceptionally well, it was too costly and heavy to commercially produce. That makes sense given it developed well before today’s inexpensive and lightweight computerized controls were widely available.

It’s amazing to see how well it worked. Here’s a short video demonstrating it.

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I worked with a couple of people who drove that car with the Bose system. The video was impressive but it did not ride very well which is why no company picked it up until recently. The intellectual property was purchased by a ride control systems company.

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Were you involved during the early MagneRide years with the Magneto-rheological shocks? I had a coworker that bought a new vette back in the day when that was fairly novel and the ride was pretty astounding for the time.

Yes I was involved with MagneRide. I was also involved with 3 of the 4 versions that preceeded MagnaRide. I worked with Bilstein on the first Corvette SRC system offered in the 90s and then the next 2 generations of electronic damper systems on the Corvette before MagneRide. Each system got progressively better.

Corvette’s goal was making a great handling car more comfortable. Chevy wanted a switch to select various calibrations. Ferrari and Audi were similar but those programs were handled out of the European office.

The systems installed on Cadillacs were the opposite. Make a nice riding car handle like a sports car when desired with NO switches. They wanted it fully automatic.

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