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MINI Adjustable Camber Plates DIY

I had been using Bavarian Autosport lowering springs for about a year.  I like the drop in ride height resulting in a lower center of gravity and less body roll, but the struts were overpowering the springs resulting in a harsh ride.  I had also been using Ireland Engineering fixed camber plates which gave 2.7 degrees of negative camber up front.  The problem with this combo was that the front air-dam was was only about 2 1/2 inches off the ground, and the driver’s side spring would bind at lock.

spring binding

So I figured it was time to rethink my entire suspension set-up.  I needed to dial back the negative camber slightly to prevent binding and improve tire wear; I wanted to increase ride height by about 10 mm to better clear speed-bumps and road debris; I wanted to better match my struts to the spring rate of the BavAuto springs to improve the ride quality; and I’m slowly adding Powerflex bushings to reduce deflection in the suspension.

rear shock

Starting in the rear, I added new Bilstein Sport Struts which have a lower spring perch resulting in a similar ride height as before, but longer suspension travel.  I topped them off with Powerflex rear strut top bushings.

front strut

The Bilstein Sport Struts in the front raise my ride height by about 10 mm when combined with the Eibach (SPC) camber plates.  This set-up is still about an inch lower than stock.

camber plates

Using the instructions that come with the Camber plates and your Bentley manual, the installation is pretty straight forward.  You can actually install them without removing the axle shafts from the transmission or separating the tie-rods.  Just lower the entire strut by removing the 3 nuts to the upper shock mount (it won’t pull out completely); compress the spring by using a spring compressor; put the upper shock mount back into the cavity; remove the upper shock mount; then the strut will pull out the side.  Finish removal as per the Bentley manual.

top plate

Installation is similar.  Attach the strut to the hub; place the spring on the strut while it is still compressed; and attach the lower plate.  At this point you can remove the spring compressors.  Slide the strut and top plate into the cavity and attach the top plate through the circular opening. Use a lever to stop the top plate from spinning on the shaft so you can tighten to torque spec.  Finish by attaching to the adjustable plate.

finished camber plate

When the whole thing is installed, you can adjust camber to maximize negative camber while avoiding spring binding.

Getting the MINI Low-down

New Wheels

We’ve been busy here at GeorgeCo during the last few weeks of Autumn, taking advantage of the warmer than expected weather to get some projects done before the cold and snow of Winter sets in. Even as we prepare to sell the GeorgeCo Blue MINI, work continues on the Red MINI. In addition to getting the FES-Auto shift light to work in the new car, we finally made some suspension modifications. Here’s a brief recap:

We picked up a set of 17 inch R90 wheels couple of months ago and they were a little worse for wear under the previous owner. Nothing structural, but better to be straightened than to worry. A quick trip to the Rim Doctor and they look great, but they also really highlighted the fact that the car rides too high in stock configuration. (You can thank taller springs from the factory due to our crappy roads in the US for that.) Keeping in mind the performance goals of this car — faster, quieter, and smoother than the Blue MINI — we set to work on the suspension.

The stock Cooper S suspension is very competent from the factory. Optimized for occasional spirited driving, it starts to show its weaknesses when you get it on the track and really push it. The front wheels have little to no camber. The 16mm rear swaybar is undersized. The result is a serious tendency to understeer and excessive tire wear on the outer edges. The taller springs increase body roll and exaggerate the understeer.

We solved the camber problem in the Blue MINI with adjustable camber plates, but they proved too harsh for daily driving and were a major source of the uncomfortable ride. We liked the performance of the Bavarian Autosport lowering springs on the Blue MINI, but the Koni shocks just added to the harshness. To build on what we learned from the Blue MINI, we started with the parts we liked (BavAuto springs, stock shocks) and built from there.

New vs stock spring

BavAuto springs lowered the car and eliminated the raked stance that comes from the factory. We installed them over stock MINI shocks. Since the rear end picks up camber with the lowering springs, we added Hotchkis adjustable control arms to reset camber to negative 1.5 degrees. (Toe is set to 1/8 inch Toe-In for the rear to provide high speed stability.) We added a 22mm adjustable Alta rear swaybar to dial-out the inherent understeer. By sitting lower on the springs we also needed to reset the swaybar back to a right angle relative to the droplink, so we added adjustable drop links, also from Alta. (While we had the wheels off, we also added brass bushings to the rear brake calipers.)

rear spring

Having finished the rear end, we switched our attention to the front where we installed Ireland Engineering fixed camber plates over the BavAuto springs on stock MINI struts. If you remove the wheel liners, you can actually install the springs and camber plates without removing the strut from the hub. Just disconnect the strut from the front sway bar, compress the springs, disconnect the strut tower plate from the car and you can remove the springs and reinstall the new camber plates. The IE fixed plates are supposed to provide 1.25 degrees of negative camber on stock springs. Unlike the adjustable camber plates where the bearing is set in a thin setting of urethane, the fixed plates are set in a rubber bushing. You end up trading adjust-ability for ride comfort. When we got the car back from the alignment, we were happy to see they provide 2.5 degrees of negative camber on the BavAuto springs. (Toe is set to zero in the front.)

Fixed Plate

The net result of all of these changes is pretty dramatic. The car has a nice stance; is tall enough to get out of the driveway and over speed bumps; and is firm but not harsh. We’re heading out to the skidpad on Saturday to dial-in the swaybar. For now, it’s set in the middle setting which proved the best setting on the Blue MINI in the past. The photo below shows the previous ride height superimposed on the new stance.

Comparison

More Control

I’ve been taking advantage of the unusually mild November weather to catch up on some maintenance issues on my cars. It started when I noticed a nasty screech sound from the MINI clutch on the way home from work one day. It had been a while since the MINI (now with over 135K miles/over 5K on the track) had been thoroughly checked out. Sure enough the clutch is slipping.

spec clutch

Once you know you have to drop the engine to replace the clutch, you start to think of all of the other things you might as well do while it’s all apart. I noticed steering wasn’t as precise as before (2nd set of control arm bushing shot); and I haven’t yet replaced the belt tensioner (3rd belt due to be replaced.) I started to source parts, and then realized I’d have to drive the Stealth to work while the MINI is in the shop. I ended up getting a Spec Stage II clutch and lightened aluminum flywheel along with some Powerflex bushings.

control arm

The Stealth E30 burned through a front wheel bearing on my last track day and also showed signs of control arm ball joint failure (I hate when that happens.) New bearings, new wheel studs, new control arms, new control arm bushings, and an alignment later, the Stealth is back on the road. I was able to do the control arm replacement and bushings, but the rest I had to take to York Auto.

I’m trying something a bit different with this set of control arm bushings. I used offset bushings from an E36 M3. The offset location ads a bit more track, camber and caster to the geometry. With the current setup of Bavauto springs and Bilstein shocks, I’m getting 2.5 degrees negative camber in the front (without adjustable camber plates) and 2.6 negative degrees in the back.

Stealth Not Ready for Prime Time

I was hoping I’d be able to make it to the May NCC HPDE at Summit Point at the end of the month without having to replace my steering rack, but no luck. The boots are full of fluid. There’s also a vibration in the drive-line which probably indicates the U-joints are shot.

Of course, this model doesn’t have replaceable U-joints so you have to replace the whole drive-shaft. The good news (as such) is that a replacement isn’t that expensive, and a good, re-manufactured and balanced shaft is only about $400. Of course, you have to drop the entire exhaust from the header back to get to it…

Since there’s no way it will be repaired before next weekend, I thought I catch up on some of the details I skipped when I rushed on to the track in March.

Caliper Before

I’ve always really hated how the stock rotors and calipers just rust away. If you’re running the old bottle-cap wheels, you never see it, but with the open track wheels it really looks poor. Hopefully the extra coating won’t add to the heat build-up.

Caliper after

And no, I didn’t forget the retention spring. I’m just letting the paint dry before putting it back on.

H&R Sport Springs for the MINI

H&R Springs

I’ve been having some problems with the MINI’s suspension lately. First was a thumping sound in the right rear, and the left front seemed to bottom out on even the slightest bump in the road. That and the fact that my family won’t ride in the car anymore because of the harshness of the ride, finally got me to thinking of changing the suspension again.

front

The photos above show the old TSW springs compared to the new green H&R springs. The new springs look to be quite a bit taller, but that’s somewhat deceptive. The H&R springs are progressive and have extra coils at a lower rate so they do not slip when the strut is fully extended such as when the car is on jack stands. Shorter springs will slip when not in compression and then you have to reseat them before lowering the car.

rear installed

One of the added benefits of having shorter springs and shorter struts is that you can remove the entire strut assembly without having to separate the ball joint at the hub. With the standard strut height, there isn’t enough movement in the lower control arm and axle to get the strut out of the housing. With the shorter strut, you can just drop it out.

front mounted

The front H&R springs appear to be a bit wider than the TSW springs they replaced. That means I’m going to loose a bit of negative camber once I get it realigned. We took a quick trip once I had it all back together and the harshness is gone. Seams in the road no longer bottom out the suspension.

front

Once installed, the rear has the same ride height as before. I cut down the bump stop by a half inch so I’ll have a bit more suspension travel now. It turns out the retaining nut on the right rear strut was almost completely loose. That may have accounted for the noise I was hearing. I reassembled the strut and tightened everything. If there’s still a sound there, then it’s either in the swaybar or in the subframe.

new ride height

I measured the ride height before and after the change. The rear ride height is the same, but the front is about an inch taller. That splits the difference given the two inches it was lowered previously from stock. I also found the source of the “whump” in the front. There was no bump stop installed on the front left strut. The strut was bottoming out against the camber plate.