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Discussion Starter · #1 · (Edited)
I figured out how to trick the 4C system into thinking it has the 4C shocks/struts without actually having them. This way you can run normal shocks/struts or aftermarklet coilovers without a error message and you can retain advanced mode.

Really easy actually. You have to mount the existing suspension accelerometers to your non4c or aftermarket replacements. As for the electrical side of things, each shock/strut has a 2-wire harness coming out of it... Cut the harness and in the shock's place, solder in or use butt connectors to install a simple 8 ohm 20 watt ceramic resistor. And there you go!

My front struts died and I just couldn't stomach the costs of new ones when I could get standard Monroes for like $84 per side up front. So I bought the cheap struts for now to see if I could get this to work. There was an extra bracket and bolt hole on each strut that I could mount each accelerometer to, so that was pretty easy. I bought an assortment of good ceramic resistors from radio shack (maybe $2-4 per pair) to figure out which resistance range might "trick" the 4C system into thinking a 4C strut was connected up. After testing a few different resistors out I found that an 8ohm 20 watt ceramic did the trick perfectly... I was even able to successfully run a SUM recalibration using my DICE with the resistors in place. I've been drivnig on these for about 3 months now. All 3 modes still work perfectly and without a single issue. And since the rear shocks are still 4C units, sport and advanced mode still stiffen the car up.

Note: I noticed that the standard S60 OEM Spectrum Monroes have shafts that are nearly twice the diameter of the Monroe 4C units, they're just built much better. The 4C struts look quite dinky in comparison. And honestly, with the rear shocks still functional, I can't really tell that the fronts are the cheapies, the car pretty much still handles the same. I live in the mountains and hit the twisty roads down to the valley every day, so I need my car to handle well, and it still does!

The big bonus: For those of you that want aftermarket coilovers or something better than 4C, this will allow you to run them without loosing advanced mode and without worrying about an error message/light!
 

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I've been wondering about this since I purchased the car and figured SOMEONE has had to of tried to figure out how to send the 4C a neutral signal at all times, but just figured the system was too complex. Good job! Any drawbacks you've seen to doing this so far?
 

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Discussion Starter · #3 · (Edited)
No problems so far, no bugs and it's pretty much seemless... I suppose the downside of changing out all four corners would be that you loose the pushbutton adjustability that you get with 4C. I'm running half and half right now since the rear shocks ares still ok, so I still get a noticeable difference in feel from mode to mode. Honestly, I can barely tell the difference between full 4C and the 50/50 mix. The Monroe OE spectrum struts are actually better than I thought they would be. Much bigger chunkier shaft and strut body than the 4C unit and they're a good balance between comfort and stiffness, but at like 1/4 of the price each or less (<$100 each from you local auto parts store).

I mainly wanted to post this for those folks that want turn their 4C Volvo into more agressive because it opens the doors to any aftermarket/coilover setup out there without the drawback of an annoying error message and lost advanced mode.
 

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SEVEN years, countless number of inquiries
Many good technical people this and you come up with an easy solution
Bravo my friend.

You really should change out the rears as this MUST have some goofy handling in certain circumstances!

NOW, you must know or need to know that running R springs without the 4C is very weird
They are quite soft because like Nivomats the shock does most of the work (as you probably know by now) but since you're in the dollar saving mode you probably won't change them.

AV70 AWD spring will work in the rear, any V70 spring (T5 preferably) will work in the front.
You would probably want to cut a coil out of the rear as they sit fairly tall
 

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Discussion Starter · #6 ·
Haha, indeed. Sometimes the easiest solution is right there in front of us!

I went the cheap route for now and put in some 360 degree rubber stiffeners on each spring for now (I'm amazed how well these little $8/ea things work, thought I'd just be wasting $16, but nope). This was more a proof of concept type of thing. I plan to eventually go to standard s60 or v70 springs or maybe go aftermarket springs with some bilsteins up front. The 4C struts have tiny shafts and seem susceptable to blowing the seals too easily (mine didn't last long, and I see a lot of complaints on here). So I'm not really up to spending $350-400 each only to blow them up in 25k miles on my potholed twisty mountain roads again. I'm staying with the 4C shocks in the back though, they don't seem to have the same longevity issues as the fronts and it's nice to retain at least some of the system's functionality. I'm pretty surpized that my cheapskate fixes worked so well, but I'll definitely eventually dial everything in with better-suited parts now that I've confirmed that I can trick the 4C system so easily.
 

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Patent it and market it or contact ipd. Good job - i am pretty sure this is the same idea used to get around the self leveling airbag system LR uses. Just provide us some item codes to buy the exact same stuff and a diy before you sell the idea!

Be prepared for all the what coil overs should I get threads....


Sent from : my summit catalog on the Coil over page.
 

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if you hook up with the guy working on the infinitie 4C modes you guys could create some pretty cheap magic.
 

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Not to rain on your parade (since Jim hadn't), but Lucky did this a few years ago with a customer's car - basically did what I am doing - took the 4C shocks/struts out of the 4C loop and controlled them manually. He put resistors in-line with the 4C harness wiring (at each corner) which makes the car think that the shocks/struts are connected.

It won't throw a message on the dash during normal driving, and I don't think it has a crazy bad impact on the rest of the safety protocols that are tied into the 4C system. However, if you drive like a d*ck and get the car to roll/dive/jump/whatever enough, the computer will realize the shocks/struts actually aren't there doing there job. It's a simple reset though (I think it gets reset every time you restart the car, but don't quote me on that).
 

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Discussion Starter · #11 · (Edited)
Not to rain on your parade (since Jim hadn't), but Lucky did this a few years ago with a customer's car - basically did what I am doing - took the 4C shocks/struts out of the 4C loop and controlled them manually. He put resistors in-line with the 4C harness wiring (at each corner) which makes the car think that the shocks/struts are connected.

It won't throw a message on the dash during normal driving, and I don't think it has a crazy bad impact on the rest of the safety protocols that are tied into the 4C system. However, if you drive like a d*ck and get the car to roll/dive/jump/whatever enough, the computer will realize the shocks/struts actually aren't there doing there job. It's a simple reset though (I think it gets reset every time you restart the car, but don't quote me on that).
Remember, the accelerometers are still on the moving strut body, so they're still getting readings and sending info back to the SUM. If any safety equipment functionality is tied into the SUM, then it's still reading what it's supposed to be reading. Airbags and other safety systems are typically designed with their own accelerometers and redundancy, so I doubt this has any effect on those systems. I really don't think 4C is as precise as the marketing folks would like to make you believe, otherwise I'd have some sort of SUM related error by now. Also remember that engineers have to design in quite a bit of variability to these types of systems because they have to have a range available that takes into account large tolerances for manufacturing differences and regular wear over the course of 100k+ miles. It's a good system, but it's simpler than you think. A computers reads accelerometers at various points on the car and makes the decision to raise or lower the duty cycle on a hydraulic solenoid in each shock, changing the stiffness of that shock. And as for the shocks themselves... They're oil shocks, ancient technology. I've dissected my shot Monroe 4C struts, and the main notoable difference between them and old oil shocks are that solenoid. A valve surrounded by a 5 ohm coil, nothing space aged at all!

As for the traction control, most cars use the ABS sensors to sense wheelspin (some of the more advanced systems may use accelerometers as well). Ours is also not as advanced as Volvo's marketing folks would love for you to believe. It acts like a system that senses a difference in speed from wheel to wheel, and with help from a steering angle sensor, it identifies wheelspin and limits throttle accordingly. I have yet to feel any kind of pulse in the pedel while seeing the traction control light, I doubt it applies or modifies braking much if at all.

Why am I about 0% concerned that this will have a major negative effect on the safety of the car? Safety systems are almost always designed with the worst case scenario in mind. For example, I if I were desinging airbags to be somehow integrated I would design them such that all 4 shocks could have failed, half the accelerometers are toast, the car is upside down, and the system will still perform how it needs to (like what might happen in a accident). The SRS system has its own accelerometer specifically for the airbags, so other than being tied together on the CANbus for diagnostic purposes, these systems are essentially seperate.

Th R was really really good value when it came out. And cars that show really really good value always have compromises. It has some very good technology on it, especially for '04, and probably very safe as are all Volvos, but if you think for a minute it has the same kind of functionality that you would see on an $80k or higher priced car, think again. Those kinds of cars have more advanced and pricey tech like magneto-rheological $hocks and such.
 

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Discussion Starter · #12 ·
Also one more note... I drive CA highway 18 up and down a mountain every day. Google what that road looks like (nothing but every kind of turn imaginable over a 10 mile stretch).

I have FLOGGED the car with the setup. Gotten it out of shape, gone from heavy understeer to getting the tail quite loose. Taking turns with yellow signs that suggest I should go 30, looking down and realizing I entered at 60. The SUM hasn't even given a hiccup. I usually drive it in advanced mode where the system really should notice it, but it just doesn't.

The SUM reads accelration of the strut body and changes a duty cycle within a given range (that range changes depending on mode), that is all it does. It is a purely reactive system. Takes an input gives an output, doesn't care if the output is working or not, as long as there is a proper ohm load at the output. For the SUM to take a reading, generate an output, and confirm the output would require a more powerful computer. And while reading an accelerometer 300 times a second may sound really spiffy in a marketing brochure, keep in mind that an old Atari or Commodore could do a lot more than 300 instructions per second. It's not all that impressive in the right context.
 

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Now, have no real idea how everything really works, but is it possible that since the 4C is still getting some values/data from the rear shocks that whats causing it not to go on the fritz? Certainly not questioning your theory or results, just want to make sure before everyone goes cutting wires. LOL!
 

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It's impressive, and it's unimpressive, depending on what you're looking at. The safety protocol I was mostly referring to was the DSTC. It shouldn't have a severe impact, but it will react differently than designed.

I commend you for doing what you did, and am surprised more folks haven't. I'm interested to hear the long-term ramifications (or more so, the lack thereof). It's just truly a shame that Volvo dropped proper funding to make the R what it should have been, instead of an afterthought.

That being said, 4C is the reason I didn't buy another R :D
 

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Discussion Starter · #15 · (Edited)
Now, have no real idea how everything really works, but is it possible that since the 4C is still getting some values/data from the rear shocks that whats causing it not to go on the fritz? Certainly not questioning your theory or results, just want to make sure before everyone goes cutting wires. LOL!
I thought about that, but I feel it's unlikely. The OE spectrum struts are a good bit softer than the 4C's in advanced, so I'd think it would have thrown a code in the past few months. Or at least something would be acting strange by now. But so far, not a single issue.

It's impressive, and it's unimpressive, depending on what you're looking at. The safety protocol I was mostly referring to was the DSTC. It shouldn't have a severe impact, but it will react differently than designed.

I commend you for doing what you did, and am surprised more folks haven't. I'm interested to hear the long-term ramifications (or more so, the lack thereof). It's just truly a shame that Volvo dropped proper funding to make the R what it should have been, instead of an afterthought.

That being said, 4C is the reason I didn't buy another R :D
Traction control seems to function exactly the same throughout my daily drive on CA-18 as it did when the car was fully 4C equipped. The electronic nanny still kicks in when she's on, and without any noticeable difference in operation. Still turns off too, which is the best part!

The R was a technological marvel for the price. When new, it was similar in price to a much less advanced Impreza WRX STi, but marketed alongside the S4 and M3. But it's tech is limited by that price. It's just not as advanced as we would all love to think, that's all. The price was why I bought the car. Really nice interior with all the goodies and safety features, really truly one of the best engines ever put in a car, 6 speed, and AWD to tackle to local winters, but for half the price of a used M3.
 

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good work...only thing I don't like are the power resistors. If those things get anywhere close to dissipating 20watts via heat and you got 4 (potentially) mounted somewhere near flammable stuff, well ya know what happens. But this is just me being picky :) And yes I do have experience with these in the R by replacing brake light bulbs (LED project) with them. I know that with just sitting at a stop light waiting for the green light, those resistors got WAY to hot to touch (I burned myself, yup)

another thing about this idea is the difference in shock rebound between oem and aftermarket? this would def cause different readings to be sent to SUM (as you said I think) and in turn to other critical systems which although you might not get an CEL/error, might be an issue in critical situations (which I agree with Athruc on). For example, lets say a hard braking is in order, you get nose dive, SUM wants to stiffen up front struts, well its not stiffening anything up anymore and who knows, does this play into the criticality of other systems, ABS, SRS etc. Maybe one may never know I guess but we do all know that this car's modules all communicate to one another basically through the CEM/ECU sooo....as they say all roads lead to Rome?
 

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Discussion Starter · #17 · (Edited)
There are various computers linked together... These Volvos use a variant of CANbus. Think of it as a network, primarily used for diagnostics, so you can read codes codes from any of the various computers on the car through the single OBD port. But each computer pretty much does it's own thing in this type of system... Think about it, if SRS and the SUM were so closely tied together, it would make a lot more sense to have one computer control both functions, not 2 seperate computers. There are a BUNCH of seperate computers on our Volvos, each sorta "doin' their thing."

As far as how the car reacts to shock bound/rebound, I don't think it changes from mode to mode. The 4C cars can go anywhere from rattling your teeth out to 50s cadillac style ride quality. SRS, Traction control, and ABS all have to work under all conditions in roughly the same manner. SRS only cares about deploying airbags if it reads a negative acceleration great enough to signify an accident. Traction control cares about wheelspin, basically when one of more wheels is going faster than it should be, it tells the ECU to limit throttle when it sees such a condition. Similarly, ABS only cares if one or more wheels is locked while the car is still moving, and it releases brake pressure dependant on lack of wheelspeed. None of these systems really have anything to do with shock bound/rebound. ABS is still going to release pressure throughout the braking system if a wheel stops when it's not supposed to under braking. Airbags are still going to deploy even if all 4 wheels have been torn off of the car give the needed amount of deceleration.

I know a car packed with tech can be somewhat intimidating to modify. While it is a lot more advanced than grandpa's 57 chevy, I'm not worried about my Volvo acheiving self-awareness and taking control. It's just not as advanced as many of you seem to believe.
 

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I think the car would drive like crap because all the systems work together. so if the haldex things you have stiff left rear and right front it would adjust power accordingly .... the ride will be ****ed up if you take corners fast. You should see an intro movie where they show how suspension and powerdelivery is working together.
 

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The R was a technological marvel for the price. When new, it was similar in price to a much less advanced Impreza WRX STi, but marketed alongside the S4 and M3. But it's tech is limited by that price. It's just not as advanced as we would all love to think, that's all. The price was why I bought the car. Really nice interior with all the goodies and safety features, really truly one of the best engines ever put in a car, 6 speed, and AWD to tackle to local winters, but for half the price of a used M3.
I'm not trying to flame you, but the R was quite a bit more than the WRX STi, I don't know where you got that information. Also, the STi's AWD system is a lot more advanced than the Volvo's and a lot more robust.

My R was about $44k in 2004. My old STi was about $32k in 2004- $10k is a significant difference in price. They were both 2004s, just to make that clear.

My STi had a computer controlled adjustable center diff that allowed me to run 35/65 F/R bias to make the car feel a lot like a RWD car (allowing for tail-out power oversteer, for example) and tone it down to 50/50 locked for winter stability much like my Audi quattros. I wish the Volvo had that system- the Haldex setup is far from ideal- I hate the fact that it drives like a FWD until the wheels slip, then it activates AWD. Causes some weird handling characteristics, especially tied in with the overly intrusive DSTC that has to be completely turned off if you want to be able to drive the car in fairly deep snow or lots of fresh snowfall.

Give me the STi drivetrain in a mid-sized wagon (if they made a Legacy STi wagon like they do in Japan) and I'd never own a Volvo V70R. I know all about the weaknesses of the 2.5L turbo four and the big fuel economy hit, but it's no worse than the V70R which gets 15 city/20 highway most of the time unless I set the cruise to 65, then maybe I can get 22mpg on a several hundred mile trip.
 

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I think that what Jan may be trying to describe is the Level of Sophistication of the SUM.

It appears that as long as it:
-sees oscillations from the Accellerometers on the Inputs - it's happy
-sees a load (Solenoid Coil or equal) on the Outputs - it's happy

It probably, for the most part, responds to fixed programming - If I see too big of oscillations, send the signal to stiffen the shocks.
Apparently, it lacks the "feedback loop", to look for the anticipated response
(If I stiffen the shocks, I should see a reduction in oscillations at the Inputs by X amount)

If it worked this way, faking it out with resistors would freak it out:
Because it would never see the change in Input behavior that it was expecting
If the new shocks do not change stiffness - then sending output signals to them would not change the Input oscillations sensed by the Accellerometers
If it "had the smarts to put 2 and 2 together" it would deduce that the CCCC was not functioning properly.

In other words (at least, for the SUM)
-It responds to Input data by blindly / semi-blindly sending signals to Outputs (according to some table / algorithm)
-However, it does not check for the proper response to Output signals
 
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