As I get more and more into understanding setting up a MINI for autocross I realize how the suspension is setup and how some aspects can be tuned to take the most advantage for Solo II races.

First, while the MINI is quite good, it is also camber challenged to a great degree so before you add $3000 for a set of outstanding super light weight rims and Hoosier tires you'd better be thinking of the weak link you might have in suspension.

The stock MINI has about -0.1 to -0.9 degrees negative camber in the front with most running about -0.5 degrees. Without camber plates to adjust this there is no way to make negative camber greater which would help in autocross handling.

While there are many options for camber plates the simplest solution for many of us is the RDR camber plate. Sold by helix13.com, Outmotoring.com and RDR for about $549+ it installs at the top of the front strut and allows addition of a front tower strut brace if you like. Once installed you can adjust front camber from stock settings to about -2.2 degrees. Different models exist for MC or MCS.
http://helix13.com/html/products/suspension.htm
http://outmotoring.com/rdr_camber_plates.html
http://www.mini-works.com/chassis.html

From Helix13.com Quote:
RDR has come up with the simplest solution for the hard-core enthusiast and weekend warriors: their CNC machined camber plates. These top-quality camber plates are hard coat annodized aircraft quality aluminum, with fully captured polyurithane bearings. They have been track tested for durability as well as driven daily in the north woods of Wisconsin. By having just camber adjustment, and not caster, they allow the MINI enthusiast to drive daily with stock camber settings, and then easily adjust the suspension to full negative camber at the track or autocross. When the event is over, the suspension can be re-adjusted to stock without getting an alignment.

So for me I have stock 15x5.5" holie rims with Kumho victoracer V700 tires in 205/50-15 and H-sport springs and lower adjustable rear control arms and BMP front tower brace. I'm adding the RDR camber plates and Mintex M1144 brake pads front and rear (street and track pads).

I'm going to set my alignment to the following and keep it for both street and autocross/track use. If I find it is not quite right for street driving I can adjust the front back to stock settings.

Front
negative camber -2.0 to -2.2 degrees
Toe- zero to toe out 1/16 to 1/8"
Rear
negative camber -1.0 to -1.2 degrees
Toe- zero to toe in 1/16

Rear madness swaybar set to firmest of two holes.

I have 17x7 wheels for street use and 15" wheels will be used to determine the alignment. But I don't think it will make much difference which wheel is used for alignment.

I'll mark the settings on the RDR plates so I can go back to them if needed or add or decrease front camber. The rear will be stuck at -1 or -1.2 degrees and I have no easy way to check that I adjusted them just right other then how many turns I do. As I change the front camber from autocross to street settings I am concerned that the front toe may change and I don't want any toe in. I might have to do two alignments, one with full negative and one with least negative settings and see what range toe is then choose a toe that works for both extremes.

I'm trying to find a good balance for SM class driving given my suspension and wheels/tires. Maybe as I get better I can graduate to Kumho ecsta V700 or V710 or even Hoosiers some day.

 

I agree that the RDR plates are probably quality pieces. I think I may be more inclined to go for the H-Sport Sport camber plates (if using stock/standard lowering springs) You may have to drill two holes for install, but they look a little beefier and they are $450 from H-Sport, so about $100 cheaper. I'd like to hear more opinions on both though. Also the P&D camber/caster plates ( Alittle more $, but you get caster adj)

Fred

 

MiniHune,

What method are you using to change the rear camber ? Do you have some adjustable camber plate back there as well ??

BB

 

various companies- Alta, H-sport- make adjustable lower control arms. That is the only way to adjust rear camber. The stock range in the rear is about -1.0 to -2.0 degrees. Once you lower the MINI it will be more most likely but it does vary. Most times if you are less than -2.0 degrees it will be fine.
When I installed H-sport springs in my MCS my rear camber was -2.4 degrees before alignment.

Camber plates are only for the front end.

RDR are nice plates because you only need to adjust for front camber by sliding the nuts and tightening from one end of the slot to the other. So one for stock and the other for max front end negative camber which ends up being about -2 to -2.4 degrees which can be measured. No other adjustments can be made such as caster but few of us adjust that anyway. Toe in or out can be adjusted a little with an alignment to your specs or stock specs.
I like not to drill holes and I think the RDR plates are solid enough.

 

OK, The RDR camber plates are in.

Here is what happened.
The plates were installed and the settings were to full stock.
alignment looked like this
Front
negative camber left -1.1 , right -1.2 degrees
caster left 4.5 degrees, right 4.2 degrees
toe left 0.12, right 0.12 degrees

Then front was set to -2.2 degrees left and right (could go even more like -3+ degrees on my MCS with H-sport springs)
Front
negative camber left -2.2 , right -2.2 degrees
caster left 4.5 degrees, right 4.2 degrees
toe left 0.49, right 0.56 degrees

Rear camber and toe not affected by front changes

That makes for a really big difference in toe for stock vs -2 camber settings.

So I decided to keep my -2.2 front camber and drive it on the street with
toe out 1/16 which was -0.03 degrees in the front with
rear negative camber -1.2 degrees and toe in 1/16 or +0.03 degrees

This setup feels good for handling but is a bit rougher than my stock setting alignment for street driving.

If I move my front camber to -1.1 degrees then I'd expect that my front toe would be about 1/2" out or +0.37 to 0.44 degrees different.

All this means is when you have camber plates you can adjust negative front camber at the expense of front toe. Depending on your setup your front toe may change drastically even with only a one degree more negative setting change. So just be careful.

 

toe out is not recommended for street driving, right?
Can't you re-set front toe to what you want after setting your camber, or are you saying people might not be aware that it is changing?

from my inspection of the linkages, setting the camber more negative would make the toe more negative (toed in). I'll look into this next time i have the chance. The obvious risk being that if you set the toe while at 2 deg negative camber, the toe will go positive when you re-set just the camber back to stock negative 1 degree.

 

I'm assuming from previous statements that when you lower the MINI front camber does not decrease as the rear does. Haven't checked it but just eyeballing seems to agree with this as the rear is visually obvious.

Solotime sells inexpensive toe and caster/camber guages that I think would probably be OK. Anyone have experience with these?
http://www.solotime.com/default.asp?page=1694

With caster at 4.5-4.2 this seems to make the additional expense of plates that allow caster and camber adjustment unnecessary. True?

While we're at it, how beneficial is it to install both upper and lower adjustable rear arms as opposed to just the lower?

I'll think of more stuff in a minute.............................

 

A little toe out 1/16 or 1/8" is fine for street driving. Zero is also OK.

Yes, after setting camber in front or rear you can set toe front and rear next if you have the measuring tools to check how much toe you have. The rear upper control arms help to adjust toe in the rear while the lower control arms adjust rear camber.

Yes, the point is once you set camber plates in the front to one setting which is more negative and you adjust only camber back to less negative stock settings the toe may not be in the range that is optimal. The vendors often talk about how easy it is to adjust but it is not only camber but toe that need to be adjusted.

The front camber changes do not seem to affect the rear camber or settings when it was measured. The caster was not adjustable in the front with the RDR plates and remained at stock settings the entire time.

The RDR plates weighed about 6 pounds for the pair and the stock plates were 4 pounds. On my MCS once the RDR plates were in the driver's side in full stock setting was -1.1 degrees negative camber while the right was -0.8 degrees so don't assume the to sides are equal when set to the end of their adjustable range. Stock range is -0.1 to -0.9 degrees for the front. So for me the most positive I can adjust to in the front would be -1.1 degrees for right and left front. I'd leave my rear at -1.2 degrees and see how it would drive.

 

I have been using the H- Sport for street and track days for a couple of months now with great results . Just another option for you to think about. Have a great 4th !
Randy
Team M7
www.m7tuning.com

 

my feeling in designing the P&D plates with camber and caster was that rather than not only could you set camber/caster to a different degree setting, you could equalize it LS/RS


by the way, I did extensive measurement a year or so ago and found that throughout the full compression range in the front, toe changed almost not at all (no bump steer) toe did change very slightly at full compression in the rear, but not enough to worry about. somewhere on mini2 is that post; might be the racing forum.

I should have checked toe vs camber in the front as well.

 

Does this mean that toe remains constant when camber is adjusted?
Sorry, I'm far from a mechanic or engineer, just a guy having fun with a MINI and trying to set it up to suit me.

 

to clarify:

"bump steer" is the condition when toe changes with suspension movement; not a good thing and not easy to correct. With no springs on the car and the weight supported by jacks on the frame, I ran the struts through their complete range of movement, measuring toe for every 1/4" of travel and found it to be constant.
I also found that front camber stayed almost constant for the full suspension movement.

Hune discovered that camber and toe are dependent; meaning that if you adjust one, you will have to adjust the other to retain it's setting. Typically, the use of a camber plate is not only to achieve a more desirable track setting by allowing adjustment (stock is fixed), but also to easily re-set it to the street setting. Toe is a bit harder to do as the measurement is trickier; you change it by loosening locknuts on the tie rods and adjusting a threaded segment.

for example: street camber is set to 1 degree negative, toe at 1/8" in. you get to the track and set the camber to 2.5 negative, using the sliding plate; but now the toe is 3/8" in...way too much...so you turn the tie rods about three turns each side to get a toe out of 1/8" for autox. When you go home, reset the camber, but he toe will now be 1/4" out, so you re-do the tie rods 3 turns to get toe-in at 1/8"

from the archives:
http://www.mini2.com/forum/showthread.php?t=23240

 

jlm, thanks for the link, lots of useful stuff there.

 

For those pondering drilling holes for mounting camber plates......from the SM rules at the top of this forum......

C. Suspension components are unrestricted as long as they use the original attachment points.*

Nothing like getting called on something at an event......and your competitors will......

 

While this rule does apply in SM class as stated there is more.

From the 2004 SCCA National Solo Rules book

16.1 Allowed modifications
A. All stock,Street touring, and Street Prepared modifications are authorized.
B. Competitors may pick and choose between all stock,Street touring, Street Prepared, and Street modified allowances when preparing an SM car.

This means you must look at the rules for suspension for ST and SP classes for more details.

Rule 15.8 Street Prepared Suspension
D. The following allowances apply to strut type suspensions: Adjustable camber plates may be installed at the top of the strut, and the original mounting holes may be slotted. The drilling of holes in order to perform the installation is permitted, but the center clearance hole may not be modified.
-------------------

Therefore I would interpret rule 15.8 to mean that it is legal to install an adjustable camber plate that requires drilling new holes to mount the plate.
Furthermore the original mounting holes may be slotted but the center clearance hole may not be modified.

So in Street Prepared classes, DSP for the MCS and FSP for the MC it is legal to add adjustable camber plates even if drilled holes are needed to do the install and it is also legal for SM class as well.