Well, it took a while but the STS Cooper has finally taken a step towards being able to compete ... new Koni's, H-Sport springs and H-Sport rear camber links. These complement the H-Sport comp swaybars and RDR camber plates that were already on the car.

The first test will be in one week but only after a Group 2 alignment as reccommended by Motoring. Look for a follow-up in this thread on the 20th.

 

And now a follow-up...
Had the Mini aligned today. Putting new suspension components in the car always screws things up. On the advice of Motoring, I took the Gold MC to Group 2 Inc. I was very impressed by G2. Their front office is lined with all the parts you'd love to be using. They're people that you'd like to know because they're focus is having fun while going fast. Joe (the owner) and Chris (the mechanic) came across as honest, up front people. They're located in Seattle, WA. Not convenient to a lot of you but you never know.

On the rack, I could see that I wasn't very good at replacing the components into the same spots. But still, the car was drivable. From the start, Chris asked me what I'd like done. I said I wanted the car set-up for the street but that I'd like to know the range of adjustments from the RDR camber plates and the H-Sport rear links. Chris was enthusiastic at the prospect of exploring the components and playin' with the car. Over the course of 2+ hours, he never lost his enthusiasm.

There were a few key decisions that needed to be made and we discovered some interesting tidbits. The simplest part was the rear and the first interesting tidbit is that the factory rear alignment specs allow upto 2 degrees of negative camber. It can't be achieved without bending the factory lower links but should that happen, you could still be within spec. The H-Sport documentation say the one revolution of the adjusting barrel is about 1 degree. Unfortunately, we didn't confirm that because we decided that an agressive street camber setting would still be agressive for the autox. And since I have the adjustable rear antisway bar, I could use that and tire pressures to control rear-end rotation. So, camber has been set to 1.86/1.91 degrees negative. Another tidbit is that the rear toe is adjustable, contrary to some reports I've seen elsewhere. This was set to a not so conservative 0.15" of total toe (in). Any negative toe (out) would have been disastorous on the street. This setting is noticable but more on that later. So, there are the street/autox rear settings. Not having to mess with it will keeps things simpiler for me for the frist few outings.

The front isn't so simple. The next tidbit is that because of the rear-steer position of the tie-rods, the toe increase as camber decreases. That means going from 1.25 to 2.8 degrees negative, the toe will go from 0 to 0.6 toe in, per side. Total toe of 1.2" is less than optimal for anything. This means a toe adjustment will be required at the event when the camber is changed. With the tie-rods loose, Chris gave the rod one full revolution. This resulted in a 0.75" of toe, per side. Some calculations will have to be done but approximately one revolution per side should be in order. So, for the street, we picked 1 degree negative, just outside the factory recommended range with a zero toe. For the autox, marks were made at 2.5 for each side. This seemed to be the best setting that both sides could attain without the spring contacting the strut tower. The toe value will be unknown but could be easily toe out. This is a little intimidating but I just have to pay close attention and don't lose track of the tie rod position.

My driving impression is that the Cooper should have come from the factory set-up like this. The car is still very stable at high highway speeds but can track unbelievably well thru sweeping turns. The rear feels like it's actually turning inside of the front track but that just encourages a little more throttle to kick it out. On the same tires as before, the car gave me more confidence to drive a little deeper into the turns and car more speed thru them. The stock suspension is great but I never felt that I knew where the rear end was other than just along for the ride. The rear links removed a lot of that feeling and replaced it with the knowledge of when the inside tire was about to leave the ground and whether the outside rear was in the same track or just inside of the front. If I wasn't autoxing, I'd put the rears at a little less negative so they would follow the fronts a little more at moderate speeds. But I'm very happy with the increase feel and communication I've getting from the components and the alignment.

Look for the race feedback after Sunday.

 

I am considering getting some aftermarket parts to help with the lack of camber. I have a bone stock MC with SS+ running Azenis on 15x5.5 holeys.

I was thinking of getting RDR camber plates and rear end links and keeping everything stock. What do you think my alignment should be for 50% street and 50% autox settings? Am i going to see the same increased feel/precision of the rear end?

Thanks.

 

There are multiple answers to your questions. As I stated earlier, with all camber plates the tow-in will increase (bad) as negative camber is increased. I've been very happy with my street settings (more so than the auto-x settings) of -1 degree front and -1.75 degrees rear. With my other components, in particular the H-Sport rear Comp anti-sway bar set on middle, the ride is outstanding. The rear stays nicely "tucked" behind the front. I've done some things on the street that I shouldn't have, yet at no time has the car felt like it was going to break loose.

My last auto-x, as I had alluded to, I didn't touch the rear and made a bunch of "competition" changes to the front. Camber to max negative, readjusted the toe, and upped the firmness on the Koni's. The result was a very lively rear end! In fact, the rear felt like it was on ice while the front was very planted. I would have preferred my street settings (although next time I may simply add more camber in the rear).

My rear tires are beginning to wear on the inside edges and I'm thinking I'll decrease the camber one turn of the camber links (believed to be about a degree.) The front wear is minimal. I would suggest that you go with a -1/-1 with an eighth inch of toe-in on both ends. This should give you a similar benefit of precision plus as camber links are so easy to change, you could increase it in the driveway to see the changes of more negative camber.

 

Hi,

Where can I get more information on rear-toe adjustment? Where do you go for aligning to your prefered spec?

Thanks!
Arnel

 

Rear toe is adjustable through an access panel in the underside of the rocker panel, in front of the rear wheels. But rather than take my specs, which aren't very tested, use the specs from the April 06 issue of GRM (note that these may be counter intuitive but they are very well tested.)

Front camber: As negative as possible.
Front Toe: Total toe OUT 1/16-inch to 1/4-inch.
Rear Camber: As little negative as possible (this is the odd one.)
Rear Toe: Total toe OUT 1/32-inch and adjust to driver.

Now, these were developed on a car that's running in the Stock classes and thus doesn't have the adjustment components allowable in STS. I have not tried these myself (yet) but I suspect them to be a good starting point regardless of ride height. I can attest to the lack of benefit from negative camber in the rear. It made the car stable on the street and twitchy on the course (ie. when pushed.) Becareful with rear toe, too much and the car will turn independent of steering inputs, if you get my meaning. 1/32-inch is very small, and if you're inexperienced, you may want to start at zero.

When I had my car aligned, the act of setting the camber changed the toe. So, set the rear camber first and then adjust the toe as the sensitivity is much finer with toe than camber.

Sorry about the delay in replying. I've been preoccupied with a new motorcycle.