Thought I'd share lessons learned from the 2003 autox season and some of the setup plans for the 2004 season.

The goal is to have the car setup so that it will rotate predictably. Also learned that setting up a car is about compromise, i.e, if it’s perfect in the sweepers it’s too tail happy in the slalom. I need to find the balance that fits my style of driving (which is evolving)

Suspension Setup 2003
================================================== ======
Quaife Limited Slip Differential (Jan 03)
Leda Coilovers (Mar 03)
Spring rates F 250 lbs, R 350 lbs (Jun 03 – Prior - Mar 03 - was 250 F 185 R – I know, they were delivered with the wrong springs, and we didn’t catch it till June)
H-Sport 25mm hollow rear swaybar (Jul 03 – prior was 22mm Madness solid bar)
Alta Rear swaybar links (Jul 03)
H-Sport adjustable rear control arms (Jul 03)
P&D front camber/caster plates (Polyurethene Bearing) (Mar 03)
AK SSP 15x6.5 Wheels w/ 205/50/15 Falken Azenis (Apr 03)
Kosei K1 15x7 Wheels w/ 225/50/15 BF Goodrich g-Force TA-KD (Mar 03)

Adjustability 2003 – Final Settings
==============================
Front Toe 0
Rear Toe .06
Front Camber -2.2
Rear Camber –1.2
Rear swaybar (Firm/Middle/Soft) Firm
Front Shock Rebound (24 settings 1 is softest) 10
Rear Shock Rebound (24 settings) 15
Tire size/type 205/15/50 Falken Azenis
Front Tire pressure 33 psi
Rear Tire Pressure 33 to 35 psi

Suspension Setup 2004
================================================== ==
Quaife Limited Slip Differential
Leda Coilovers
Spring rates F 250 lbs, R 275 lbs
· The front springs are now barrel shaped instead of cylindrical (This is a redesign from Leda)
· The rear springs are softer, and both front & rear are only slightly stiffer than stock
H-Sport 25mm hollow rear swaybar (3 settings)
H-Sport 27mm front swaybar (2 settings)
· I’m going to test the softer springs -- stiffer swaybar theory
· The soft setting is 18% firmer than the stock bar
Alta Front and Rear swaybar links
H-Sport adjustable rear control arms (upper and lower)
Redesigned P&D front camber/caster plates (Spherical bearing)
SSR Comps 16x7 Wheels w/ 215/45/16 Falken Azenis (Slightly taller .55” but also slightly wider .40” than last years 205/50/15’s)

Adjustability 2004 – Initial Plan
==================================
Front Toe 0
Rear Toe .05
Front Camber -2.2
Rear Camber –1.2
Rear swaybar (Firm/Middle/Soft) Middle
Front swaybar (Firm/Soft) Soft
Front Shock Rebound (24 settings) 12
Rear Shock Rebound (24 settings) 18
Tire size/type 215/45/16 Falken Azenis
Front Tire pressure 33
Rear Tire Pressure 35

Variables
==================================================
Adjust Rebound settings on Leda’s for surface conditions & rotation
Take pyrometer readings on tires after runs and adjust pressures
Adjust rear swaybar to firm
Watch out for heat soaking the tires (and intercooler) on hot summer days (Ice water)

 

That has to be the most information on set up I have ever seen anywhere. Thanks for sharing what has to be thousands of dollars in set up research.

 

>>Thought I'd share lessons learned from the 2003 autox season and some of the setup plans for the 2004 season.

>>· I’m going to test the softer springs -- stiffer swaybar theory

I'm going to test the stiffer spring softer swaybar theory, I love my KW's.


>>SSR Comps 16x7 Wheels w/ 215/45/16 Falken Azenis (Slightly taller .55” but also slightly wider .40” than last years 205/50/15’s)

I've ordered some 16's as well but may just put some rain tires on them. I expect to be mostly autocrossing on 205/50/15 Azenis again in 04.

 

Well, to kick in another variation on suspension setup:
Sept '02 build 2003 MCS

SPAX coilovers - 28 adj steps - spring rates unpublished -
Front typically 24 (22-26 depending on course and surface)
Rear typically 26 (25-28 depending on course and surface)
RDR rear sway bar (3 holes, 5 settings) set on firmest
P&D poly camber plates, changed to K-Mac poly in September
H-Sport rear links - upper and lower
16x7.5 Kosei with 215 Azenis
Toe - zero front and rear
Camber - -2.2F, -1.8R
Caster 5deg currently

neutral breakaway if you don't move your right foot too quick, drop throttle rotation if you want it.

Scott
90STX
90SM for 2004 due to pulley, fun but trophy fodder for a real SM car. I've got a local EM and CM that need to be beaten on raw time.

 

>>SPAX coilovers - 28 adj steps - spring rates unpublished -
>> Front typically 24 (22-26 depending on course and surface)
>> Rear typically 26 (25-28 depending on course and surface)

Scott,

Are your Spax settings on the firm side or the soft side?

Also, what kind of pulley did you get? If you have the kind that Helix does with the hub and six allen headed screws, you can get a regular sized carrier and switch back and forth between stock and 15% reduction. If you're running locally, I bet no one would care and I don't even think that would be "protestable" at a National level event.

David

 

David,

1 is soft, 28 is full hard on the SPAX. There is noticably less body roll that stock MCS when I compare event pictures. The approach I have tried to take is to balance transient response with traction. I started out with everything set as stiff as they would go and then adjusted down until the back tires could follow the pavement over ripples and bumps and in the front I had as little wheelspin as possible. After a few events I had a pretty good feel for what would work for various pavement conditions and course layouts.

Since I did not have an LSD last season all the suspension mods and settings were done with the goal of minimizing wheelspin. They made a significant difference (and had other benefits), but you might also note that I now have the Quaife installed. I'll be re-evaluating the shock settings this season to see if they need to be tweaked since I'll have more traction now, but I doubt that they will change much.

My pulley is from Helix. Thanks for the tip about going back to stock diameter. Eric mentioned it too. For the regional events I don't care since the local STX class needs a break and SM has had it easy for a while. I might consider the change for any CENDIV events I make (at least one, maybe more at Peru) but I'm going to have the chance to head to Topeka any time soon so I'm more worried about making sure that I'm driving as well as possible.

Two more weeks until our first event.

Scott
90SM

 

90STX Australian Pursuit

A shot at 1.18g sustained according to my G-Cube. The corner radius impacts the g potential (meaning that is not directly comparable to magazine skidpad numbers), but that is full out for that corner and pavement. Note the outboard wheels are nicely perpendicular to the pavement. That is all the body roll my car has now, but when I hit a little whoop-de-do mid-course the chassis doesn't get upset and the backend doesn't snap out if the shocks are set right. The car breaks away into a 4 wheel drift in steady state cornering, but the backend can be easily rotated with the throttle, even in 1st gear.

Works for me.

Scott
90SM

 

After reading your setup I noticed your tire size is 15". You are running a Cooper and not an "S" Right?? AS I'm sure you know that in STX you must run stock wheel size which is 16" or 17". Nothing else is legal. But I'sm sure you already know this. I just wanted to add my .02. Good Luck this season.

 

Actually in STX you can run any wheel diameter that fits as long as it is not more than 8" in width (Not diameter), so 15x7, 15x7.5, 16x7, 16x7.5 etc.

_________________
Moderator: SCCA STX Forum
dpayne@northamericanmotoring.com

 

I have always thought and I may be wrong but you might want to read that section again and make sure. I think it states that the tire size must be the same as stock. heigth-width etc. I'm pretty sure thats the way it reads.

 

>>1 is soft, 28 is full hard on the SPAX. There is noticably less body roll that stock MCS when I compare event pictures. The approach I have tried to take is to balance transient response with traction. I started out with everything set as stiff as they would go and then adjusted down until the back tires could follow the pavement over ripples and bumps and in the front I had as little wheelspin as possible. After a few events I had a pretty good feel for what would work for various pavement conditions and course layouts.
>>
Garfield and I started stiff with the rebound adjustment on the Ledas and then gradually softened up the settings as the season progressed. I think we could go much stiffer on smooth pavement, but most autox courses we ran on were choppy. We always tried to keep the rear stiffer than the front to aid rotation. Brian is such a smooth driver that he can handle a less forgiving setup than I could, as I still tend to overdrive the car. At the end of the season the car was almost rotating too well as we both spun out on one of our runs at nationals.

Your car looks absolutely flat in that picture.

Here's one of mine at the Petersburg Pro last year (That's Chris Bolings H STock MINI in the background) Pic 1

And at the DC National tour Pic 2

_________________
Moderator: SCCA STX Forum
dpayne@northamericanmotoring.com

 

>>I have always thought and I may be wrong but you might want to read that section again and make sure. I think it states that the tire size must be the same as stock. heigth-width etc. I'm pretty sure thats the way it reads.

Thanks for your concern, but last year we (me & Garfield - my co-driver) ran my MCS in STX and competed in numerous national events. All but one of the Cooper S's competing at Topeka (4 out of the 5) were running 15" wheels. Trust me, you can run these on an S in STX. You cannot run them on an S in Stock class however.

 

David is correct. STX allows wheels up to 8" in width. I personally ran 15x7 or 7.5 at Nationals last year. Stock categories are the only ones where you can't deviate but a few millimeters from stock sizes. Here is the link on the Mouton site relative to STX allowances. Also, be sure to check out the latest Solo 2 rulebook and Fast track publications for rule updates.

Mark

 

David,

Choppy, rough pavement is going to require a softer rebound setting. Most of the surfaces we run on aren't too bad from that standpoint, though several sites do tend to be dirty so the first heats get to finish cleaning them off and the potential grip is lower until that's done.

If the tires can't follow the contours of the surface they're running on then they aren't going to be able to do much to help you get through a course quickly. That is why I indicated a typical range of settings in my first post. I run as firm as I can without letting the tires skip over bumps, which sometimes means you have to soften the shocks up quite a bit more than is needed at other sites.

At Peru (Indy region event, not CENDIV) last year I could run pretty much full hard and get away with it. The fact that I designed the course meant that I avoided the few rough spots.

Scott
90SM

 

David,

Thanks for the post on your Autox setup. I recently purchased 15x7 wheels with Falken Azenis 205/50 15 tires... can't believe the grip I have now. Anyway, I will be going to my first autox with this setup and noticed you are only running 33psi in the front and 33-35psi in the rear. Is that sufficent enought to prevent sidewall wear on these tires? Are they that stiff? Thanks also for the posts awhile back on 15" wheel setups, I'm so glad I went that route now. Acceleration is tremendous with this setup compared to the 17" S-lites and Runflats.

 

>>David,
>>
>>Thanks for the post on your Autox setup. I recently purchased 15x7 wheels with Falken Azenis 205/50 15 tires... can't believe the grip I have now. Anyway, I will be going to my first autox with this setup and noticed you are only running 33psi in the front and 33-35psi in the rear. Is that sufficent enought to prevent sidewall wear on these tires? Are they that stiff? Thanks also for the posts awhile back on 15" wheel setups, I'm so glad I went that route now. Acceleration is tremendous with this setup compared to the 17" S-lites and Runflats.
>>
Check out the thread in the GStock forum on Falken Azenis vs Kumho MX.
As Brian states, you can run the Falkens between 30 and 40 psi without much change in temperature, they are that stiff. Last season we religiously stuck them with the pyrometer after runs - we just settled on 33 F to 35 R. Experiment with Tire pressures yourself and see.

BTW I put the H-Sport front bar on last weekend - I'll get to try it out in a couple of weeks.

David

 

One thing I think we determined was that the Falkens could be run at the lower 30's pressures if you wanted them to heat up faster (kinda rare to need that during the regular season), but could be run at the higher 30's and low 40's to prevent overheating.
The tipoff was Courtney Cormier running much higher pressures than us but claiming to ALSO have even temps on the pyrometer, and the cars were very similar, especially in camber. After that discussion, we went slightly higher and noticed that the even temperatures across the tires did not change, just got a little cooler.
This is what led me to have a discussion with another STS competitor and "we" determined that the carcass was so stiff that instead of the tire "rolling" over, it shifted from side to side, giving even temperatures.

So remember, in the rain, drop them REAL low (mid to high 20's) to get heat and flexibility in them, I guarantee you'll get good stick. We did this on the North Course at Nationals last year, and aside from my spin, the car handled incredible in the deep rain, incredible enough to beat the WRX's.

Brian

 

Thanks guy's for the info on the Falkens. I've only been to one Autox so I don't know what the @#$% I'm doing. At my first autox it was 45deg and very windy. I had my Pirelli Run flats at 44psi and they were crowned so bad that I didn't get any grip at all on the track. I was concerned of rolling them over and going by what others were telling me. Also dropped the rears 10psi to get it to rotate more... per others. I've learned since that I should have done the opposite... I think people are messing with me. Anyway, the falkens I have now are unbelieveable compared to my Prielli run flats as far as grip. Even had them in a rain a few day's ago and they were great. Love these tires. And the H-sport springs/bars are wonderful. Driving school next weekend and 2nd autox in a couple of weeks. WhoHoo

 

Glad you had fun... people were not messing with you just kinda missinformed.... Street tires normaly require alot of pressure to keep from rolling over too much... but runflat tires have very very stiff sidewalls... allowing a runflat tire to survive the autocross enviroment with "street" pressures.... A local Atlanta driver found runflats gave much better grip in the mid to high 30 pound range compared to pressures in the 40s... anyhow you will love the Falkens!!!! soo much better than the run craps...

 

Suspension Setup Update
Halfway through the 2004 season and the setup looks like this:
==================================
Front Toe .25
Rear Toe 0
Front Camber -2.2
Rear Camber –1.2
Rear swaybar (Firm/Middle/Soft) Firm
Front swaybar (Firm/Soft) Firm
Front Shock Rebound (9 settings) 6 (9 is softest)
Rear Shock Rebound (9 settings) 4
Tire size/type 215/45/16 Falken Azenis
Front Tire pressure 35
Rear Tire Pressure 36
==================================
Major change is going from the Leda's to the PSS9 Bilsteins and setting the H-Sport front sway bar to Firm (+27% stiffer than stock).
I still want to try the Bilsteins on firmer settings but stiffening the front sway bar actually helped improve turn in and did not reduce rotation. I found it was easier to drive with this setting and was suprised because the book says that a stiffer front bar means more understeer.

 

Thanks for the update. I'm interested in why you switched from Leda to Bilstein? After shelling out that much money for Ledas, most would do anything to make them work. I've always been impressed with Bilstein on other euro makes and it's good to see that they're finally making them for Mini. They're site says they're in development. Where did you get yours? Are they any less expensive then the Ledas? Are they less expensive than the H&R Cups?

 

I got the Bilsteins from www.stranoparts.com for $1699. Great place and a great price.

I've had the Leda's since Mar 2003 (I have the oil ones) and they are too harsh for my taste on the street - even when they are set to soft. I have tried different spring rates with them and had settled on the 250F, 275R which are only slightly stiffer than stock rates. As far as for autocross, at the DC National tour event (May 04), I had the right rear shock lose it's seal and dump oil into the wheel well. I had to get the front right one rebuilt a year ago, but that was my fault, I dinged the shaft with vise grips while changing them

My point is I paid a lot of money for these shocks and I would expect them to last - I'm not keen on wondering when the next one is going to let go. Yes they can be rebuilt but why should they have to be?

The very best thing about the Leda's is the 24 position, easily accessable, rebound adjustment. You can go from street to autocross trim in a couple of minutes, you can adjust them between autox runs.

The Bilsteins have the 9 position adjustment and while nice the Leda adjustment is easier to use.

 

David,

You have front toe set at 0.25 ???

I have just converted my MCS from GS to STX. Quaife, RDR rear sway bar(stiff), RDR camber plates (-ve 2.0deg) I will swap the Leda's off the STS MC as soon as I can get them from Elliot . Flaken Hanabie 15 x 7 wheels !! with Hosiers. The SCCA is quiet at this time of year in the NE so I am running in BMW CR class with no penalty .

First time out last weekend we found the Quaife was dynamite but we could not handle the speed. Good turn in but way too loose in the rear. I was running with 1/16 (total) toe out front and rear. I am thinking of going to 0 toe front and back. Any thoughts?

I am going to Mt Tremblant for a couple of track days with BMW CCA in a couple of weeks. Does anyone have sugestions for suspension settings? I will be running with Kumho MX's 205/50/16.

Malcolm

 

You need to run street tires in STX, tread wear rating of 180 or higher.

 

yes .25 total toe out in the front. .12 on the left and .13 on the right. The car turns in real well. But notice I have 0 toe in the rear. Adding Toe out in the rear should be done gradually and carefully as the result is somewhat unpredictable oversteer.

If you are doing track events as well as autox you need to be more conservative on your setups -- what works great on the autox course may have you into the barrier on the track.

I'd say you want to dial out most of the understeer but leave some predictable lift throttle oversteer. So maybe zero toe front and back is ok. When you get the Leda's, you can adjust to conditions and dial in some rotation with the rebound settings.

And yes if you want to autox on hoosiers you are in DSP not STX - as I'm sure you know - but your Kumho MX's are an approved STX tire.

David