I've been reading the active suspension threads here, but thought I'd offer up another question to see if I get different answers.

I live in Vermont, and my Cooper is my daily / year round driver. That means a lot of rough roads. I try like hell to avoid the dirt roads which are usually washboarded - and when I do find myself on a dirt road I'm driving very slowly, so I guess we can ignore that as a criteria. Even so, the paved roads are nowhere near flat. Pretty much every other corner is going to have a bump of some sort in the middle of it.

I'm assuming that soon I will have to replace the struts / dampers that I currently have becuase of mileage / wear. Since it will cost some unknown amount to replace them even with stock parts, it seems like a good time to see how much more it would cost to go with something better.

Here's what I've got so far... started with the stock suspension (the SS, not SS+) and the goodyear performance runflats. When I'd hit those mid corner bumps, the whole car would shift to the outside of the turn a bit (guessing 6" or so) and there would be a slight increase in understeer. So, I put in an RDR (now Helix) rear sway bar. The car would still shift to the outside, but there was no longer an increase in understeer. When the stock tires need to be replaced, I went with Bridgestone S03 Pole Positions. Now, when I hit the mid corner bumps, there's just a slight outward movement of the car (as long as the tires are warmed up) - guessing around 3" as opposed to 6" with the stock tires - just guesses though. I've gotten used to it and it's very predictable.

I wouldn't be upset with a firmer ride as long as I also got improved grip out of it. If the ride was firmer and the car also got more unsettled when it hit a bump, that would be pointless - and I should just stick with stock.

From the marketing speak, the JCW suspension kit sounds like a winner. I like that it mentions real world driving, rough roads, and just a small ride height drop. As long as the JCW kit really can be put on pre 05 cars.

The last variable is that I drive in the snow... so I'm nervous about losing ground clearance. Perhaps it's not much of a problem, I'm not sure.

Whoops, left out that I'm just starting to get into autocross / light track use. I'm not too concerned with mods changing what class I'd be in, as I'm not doing it to be super-competitive. And the local sports car club has their own rulebook about what mods move you to what class.

 

There are many aspects to great handling, but, from the perspective of your driving environment as you point out.

Compliance is very important to a real world car, as you point out. This can be as much subjective, as objective.

My suggestions:

.Buy a spring and damper designed to work together - PSS9/Spax etc

.Too much roll stiffness isn't going to help with mid corner bumps

. Do not lower too far - a very big deal! Aside from the scraping you note,
camber curves come into question as does the relationship between roll
centers and CG (Center of Gravity). I am working on the the latter as we
speak; lowering a car 1" for example will lower the center of gravity along
an axis (front and rear CG are not the same) by 1". However, the roll
centers may drop by 2" or 3" effectively increasing the vertical distance
between CG and RC. What this means is that a lowered car in this
scenaerio will actually roll more - the CG is higher relative to the RC.

You can play games with roll centers front to rear if you know what they are doing and how they are affected by CG. You might be able to lower the front - rake - a bit more than the back to get the front end to tuck in a bit more midway thru a corner allowing you to use a slightly smaller rear bar, for example.

There are lots of tricks and this is definately one. jlm defined camber changes at the front for three height adjustments ( I think three???) and determined almost no bump steer issues - great! But, armed with roll center and CG info you will know when you've exceeded the point, with this car, where too low is too low. After a point, low affects ride comfort, and much much more...

Michael

 

Thanks for the reply, Michael. Of course, I only understood about half of it.

I've decided to go with the JCW upgrade package. Not too much of an increase in price over just replacing the dampers with stock (which seems way too expensive compared to Bilstein shocks), and I'm pretty sure the whole kit will work well together.

I don't need adjustable things (ride height / dampening) as I'd probably never adjust them. Just give me something that's adjusted well right out of the box.

There's a bit of a gap right now, as I see it, in what's available for suspension parts. The stock dampers are way too expensive. Anything aftermarket (I only saw Bilstein SP and Koni Yellow) will not be matched to the stock springs, so you'd want to replace the springs too. And the only options I saw for new springs were too low for me. Perhaps there is a "like stock, but cheaper" route for replacing that I didn't find it. So, I'm going with a mild upgrade.

Going in for the work on Thursday... I made sure to mention the "03" part of "03 Cooper" a few times, and the dealership never balked at that.

 

From what I've read and heard, you won't be dissappointed with the JCW kit as an all-round performance package. And, the concerns about dropping too much are side stepped completely with this kit, as I would expect.

Good luck. PM me if you don't mind after you've had a chance to drive the kit for a few days. I'm also considering this kit.

Thanks

Michael

 

I didnt see from your post as to whether you changed your wheels or not. Going with a lighter weight wheel helps quite a bit in reducing 'step-out' from a bumpy turn. The springs and dampers are more able to control a lighter tire/wheel assembly during sudden jounce and keep the tire on the road.

I went from S-Lites with runflats to SSR Comps with Goodyear F1 GS-D3s and the difference is considerable. The more compliant sidewall of the non-runflats absorb smaller impacts without a lot of wheel movement, and the lighter overall assembly stays planted to the road during bigger hits.

 

I've changed tires, but not wheels (yet). My Bridgestone Pole-Position S03's will be toast after the weekend at the track I have coming up. I'm planning on trying the Goodyear GS-D3's next. Not that I didn't love the Bridgestones, but why not try something else, especially if they're a tad cheaper.

I'm trying to stick to the "upgrade when the part is worn out" philosophy. So it might be a while before I get to the wheels.

 

457

 

right...

 

No no, sorry. I replied with a very very long post about roll couple - roll center and center of gravity. I read it and decided to delete it. I get tired of listening to myself after a while. I simply had to inlcude a few characters to continue so I just hit three numbers.

Sorry!

Michael

 

velVet,

You will not be disappointed by the JCW suspension!! The JCW marketing speak is not mere hype.

I had the JCW added to my new 05 MCS before delivery a couple of weeks ago, along with a 19mm rear sway bar. I then added light weight wheels and some Proxes 4's. In comparison to my my wife's 04 MCS with runflats and a 22 mm sway, the new combination is a GIANT step up in pretty much all regards. The ride is more comfortable, it stays much flatter in the curves, and simply put, has a beautiful well-matched refined feel for road driving (we don't have any streets where I live, just lots of curvy country roads ). The new car grips, even becomes part of, the road in a way that the 04 never has, despite the fact that it too is a blast to drive.

Sorry I can't speak much to your concerns about rough roads - most of the roads around here are pretty good. The only time I have gotten into any rough conditions was a two country highway that had been driven on by way too many log trucks, resulting in really washboardy asphalt. It was pretty rugged, so I just slowed down - didn't want to tear up the new baby. All I can tell you is that the JCW takes mild to moderate bumps comfortably, in my case better than stock. However, over a good sized pothole it will rattle your fillings more than stock.

I'm too lazy to take the time to understand all the intricacies of suspensions (I take my socks off to guys like meb), and I don't do any track or auto-x, I just wanted to have as much fun as I possibly could on my local roads. The JCW gave me exactly what I was looking for at what seemed to me like a pretty reasonable price, and I didn't have to risk anything either in terms of warrantee or trying to noodle out a matched set of components on my own. Again, you're going to love it!

 

Everything I've seen indicates the JCW suspension can't be fit to a car built before 07/04. (Not that it's physically impossible, but rather that MINI won't do it and requires a VIN to order the parts.) If you do manage to get this done, please let the rest of us know how you accomplished it.

 

I can't point to the exact reference but I seem to remember reading someplace while researching my suspension that the JCW can now be installed on pre-05 MCS's (not sure about the cooper) - at the very least it can be grafted in. I think the rubber bottoming stop was the only issue, not the springs and struts. That was a lot of "I thinks", but I think that's right.

 

If you can think of where you saw it, I'd love to see the information. I was very disappointed when the JCW suspension came out and they said it was not for the older cars. Availability for my 11/03 car might change my suspension plans...

 

I don't really know anything about the JCW suspension at this time. But I wonder if the slightly adjustable rear camber with the newer cars is one of the reasons the kit will not fit older cars... If so, perhaps the added cost of replacing the lower control arms will help. Dunno.

 

From what I know, which isn't much, there's a clearance issue with some part that gets installed. To install it on early cars, they have to grind off some amount of car under there somewhere. The newer builds do not have this clearance issue.

I'll report back with more, at least a yes or no on the wether it can be done or not, late tomorrow.

From the PDF of the install instructions here:
http://motoringfile.com/howto/JCW_Su...structions.pdf

"The following work is not necessary if the recess is already provided in the area. Use a suitable tool to make two recesses in the area of the body flange above the bump stop. Use a hammer to bend over the area. If necessary cut off the wheel arch panel in area (1)." etc.

 

Could be that I spoke in haste. Tried to retrace my steps but came up empty. My car is an 05, so my focus was really somewhere else. Between advancing age and participation in the 70's, my memory should not trusted.

 

I'm right there with you... Although to be honest, I did way more damage in the 80's!

 

You guys are too funny! I used vinegar and dandlions - horrible addiction...thirty years later I'm still coughing up that fuzzy stuff. Well, technically, dandelion is (a) weed, right?

 

I think lightweight wheels with normal (not-runflat) tires would probably yield the best difference as far as your MINI being able to react to bumpy conditions fast. Also, stiffer springs (and heavy dampening) are not always the best route to go if you have to battle bumpiness. You can go as stiff as possible if we had glass smooth roads all the time, but come a bump, that suspensions not going to react well. So a soft suspension might work better, I think rally cars come with soft-suspensions for this reason, like the WRX, but I am not sure. It is all relative too of course, the JCW aftermarket kit may still be on the soft side for these issues. Just things to think about..

 

Okay, a little more time today, but not much.

If you lower the car too much, this will increase the distance from the centers of gravity to the roll centers (front to rear roll centers and centers of gravity are not the same). Think of the center of gravity as a pendulum sitting at some distance above the roll center. The greater this distance, the greater the the torque acting on the roll center.

So, you will actually need firmer springs and dampers to offset more roll! This is overlooked by lots of folks as they tend to think about the center of gravity only. Get familiar with Roll Couple and how it will affect ride and handling. Roll Couple is the relationship between CG and RC.

In the bigger picture, it may be necessary to lower the car to a point where the roll couple is affected in a negative way. If all the other things done prove out a net gain in handling, then it was a good move. But one ought to know what one is actually giving up before playing, yes?

 

Well, the dealership / service / parts is researching the possibility of the JCW suspension on an early build car. First report was "oops, we goofed. It cannot be done." A few minutes later it became "there's conflicting information". We shall see.

 

The final answer, after calling whoever knows these things, was that the JCW suspension kit cannot be installed on a pre 05 car right now. But, they're working on making it possible.

My struts got a clean bill of health, so I'll wait and see what develops.

 

FWIW, I emailed the following to MINI USA:
and got the following reply:

 

Sounds like a 'no' for now???