Where are our national champ drivers at? Any of them willing to share secrets on their suspension tuning?


On my HS Mini, I've got JCW suspension, + Fat Cat Bilsteins + Fat Cat bumpstops + 25.5mm hollow rear bar on 16x7 wheels, 205/50-16 RE71Rs. My camber is maxed in front (-0.6) and 0 toe all around. I've laid out all my secrets now!!


The car handles pretty decently: loose and nearly ideal in the cold or wet, and neutral-ish to understeer in the grippy, hot and dry. I'm trying to optimize my setup, but I don't know how. I've got an opportunity to revalve the shocks to my liking but I don't know what I want or what I should even want.


Is there a standard to what our cars behave ideally with? i.e., high compression, low compression, short bumpstops, stock-length bumpstops, etc.? Right now the car is very, very stiff and I don't know if it's compression or bumpstops, but I do know our cars ride on their bumpstops - even in stock form, JCW springs (0.5" shorter) notwithstanding.


Appreciate any feedback!

 

This board is pretty slow.
Your set up sounds pretty aggressive. I would be scared to drive it. I am so bad at it right now I am happy as long as it does not plow.
How is the tire wear? Do you drive the car daily?

 

Set up is aggressive, I may be able to add speed by getting the shocks a little less aggressive. Tire wear is fine, outer wear on front tires as usual for mcstruts with no camber. I "theoretically" daily drive it, in that it would be my daily if I didn't have other cars that I'm dailying lol.

lol seriously - the car feels perfect when cold. Rear sway bar is on stiffest - shocks aren't adjustable, but I'm getting them reworked soon and can "ask" for anything. Thinking about asking for lower compression or maybe just cutting my bumpstops. Stock brake pads. Here are a few recent vids:

 

Kyoo-
You are asking some of the same questions that I have asked and I have gotten the answer that "it depends". No help at all.

You would thing that the car would behave the same "cold" or "warmed up" but with a different level of total grip. Interesting that it will spin cold but not warm...Hmmmm ???

Other than the shocks, your setup sounds really good for autocross. The only reason for excluding the shocks from this comment is that I don't know anything about them.

However, there is one other question I should have asked...that is, what is your rear camber set at? For the S the factory setting is -1 deg 10 min or -1 deg 21 min depend on the side. The idea of this is to create as much stability as possible in conjunction with the ~ -0 deg 30 min front camber the factory gives you. In a word - understeer

You might want to drop this down to -1 deg 0 min or something a little less and see how that works for you. There is a fare amount of adjustment in the back for this.

As for shocks, I will start by saying I have not done much with shocks and have not tried to adjust them. But it is something that I have given some thought to. So, here is my little bit of a thought about them - if you go with the idea of weight transfer, it would seem that a little softer overall in the front might be good. This will allow the front to settle when braking which will give you more camber up front and will lighten the back which should help with rotation. A bit softer jounce will allow the car front to settle creating camber and a bit stiffer rebound will hold it down there. This seems to be the way the Bilstien B8 Sport shocks are that I just put in to replace the "beyond usable" sports suspension shocks that I bought the car with. The Bilstiens supposedly came out of a "killer" autocross MINI that had won things in Texas. None the less, I like what they do. I will be taking the car to the track this weekend for a "test" run of them. This is all just something to think about. It may give you some thoughts for talking to the people who will be re-valving your shocks. Sorry for not having anything better for you.

BTW - I plan to watch your videos when I have a chance - been busy prepping for this weekend.

 

thanks for the input - re: rear camber - I didn't think camber was adjustable back there? how is it done?


for shocks, I definitely agree I want to go softer, especially in the front.. just not sure if it's bumpstops or compression.


I thought the same way about balance staying the same with tire heat or even different tires, but I guess the rear gains grip faster than the fronts do when the tires heat up, idk

 

In the rear the lower lateral (?) arm has an adjustment cam at the wheel hub end. It looks like a really big star nut. I know that it will adjust between -1 and -2 deg (I have mine at -2 for the track). I would guess it goes less than -1.

As for the tires, a thought came to mine. You drive to the autocross and the front tires get a bit warmed up but the backs stay cool. It isn't until you put some side load on the rears that they warm up. Maybe?

 

yea but the car usually sits for at least 3 hours before I actually start my runs anyway.


that's interesting, I did not know about the adjustment - any way you could take a picture of that? -1.0 vs -1.5 would make a decent enough difference.

 

I'll see what I can do. Will be busy into Sunday, though.

 

So I watched most of your videos. Bottom line, you drive better in the Evo. Your lines are a lot better when you drive the Evo. You actually base the apex cones. On the mini, you are at least 2 feet away from them. The one time you actually based a cone on the mini, you actually tagged it. Try tagging more. I think you're not used to your set up or you're afraid of FWD. You seem less aggressive with the throttle. I think you should try an Evo school and have them comment on your set up.

From my research on HS Mini setups, all the fast drivers are using custom built double adjustable Koni yellows valved for JCW springs. What you want to do is valve the rears for higher compression and dampening. It looks like you're driving on concrete a lot and that has a lot of grip. You want to redo your alignment to get more rotation too. The key to driving Mini's is to get back on throttle as early as possible while having enough rotation. If I were you, I would start adding more dampening and compression in the rear.

 

hey!! thanks a lot for the input! I think part of what is happening in the mini is I am way trying to overcompensate for the lack of power by carrying in as much speed as possible, which usually ends up putting me off my line.


I think the other part of it is when it gets hot out, the car gets very pushy. cold (50, 60 degrees and cooler) and wet, the car rotates really well, nearly ideal. in the hot & dry, the car feels like it pushes so much more. the result is often times, when it's hot, my first run is my fastest raw, though usually not clean, including this weekend:


1st run: mind the dnf at the end


5th run, fastest clean:


obviously, as you said I am way, way off cones on my 5th run. the car just doesn't turn like it does when the tires are cold. maybe I just need to slow down and focus on the line.


again, 90% is the driving, but I do want the car to rotate better in the hot. I'm almost certain the car rides on it's bumpstops, so maybe I need to cut a good bit off of the fronts and maybe trim the rears in relation. I should be getting the shocks revalved so I can ask him to crank up the rears a little as well.

 

I didn't watch the videos yet, but first runs for me are to warm up the bridge stones. When they are cold, they rotate very well, too well. I started with 45psi in the rear and it rotates too much. I ended with 40 psi and it gives enough rotation to be fast. When your car pushes too much, that means many things. 1 you entered the corner too fast 2. You didn't brake early enough 3. Rear tire pressures were not high enough 4 front tire pressures were too high. Play with those variables first before sending out your bilsteins. Fast drivers are able to adapt to their setup.

 

1 and 2 are definitely true too, but for me I do like the balance of when they are cold - doesn't rotate too well for me. maybe we are on different spectrums of car balance as well. I run about 39-40 psi in the fronts, any more and the tires roll over pretty badly (-0.6 degrees of camber). In the last few events I've been running 42-43psi in the rear, I can try 45psi.


Next event is on Lincoln concrete so I can't really use that as a gauge (all local sites are sealed asphalt)

 

You better up those rear pressures for concrete. That stuff is sticky as hell. What rear bar are you using?

 

the hotchkis 25.5 hollow on full stiff

 

Ok you have a pretty competitive set up, have you tried toe out in the fronts? The other thing I would suggest is doing phase 2 and challenge school of the evolution performance driving classes.

 

I haven't messed with any toe yet, frankly would rather cut the front bumpstops before doing that. got a few nats regulars in my region that all say the car rides stiffer than most ST* cars they've been in.


2 evo school instructors in my region and have been to evo school yes - never works out that they have phase 2 or challenge schools here, which I'd be most interested in. will probably codrive with one of the evo school instructors at the next local event though

 

Hmm. Have you tried using the factory bump stops?

Also have you taken off that front strut bar? That doesn't help you at all. It might be a source of your pushiness.

 

factory bumpstops - no, when fatcat initially revalved the shocks he put the FCM "soft/red" bumpstops in, at regular height. they're not easy to swap - the shock is inverted and the bumpstop is inside the housing, or I would have tried long ago. I do think the bumpstop is the issue here though.


I haven't tried running without it, my understanding was that it does nothing at all. I installed it to prevent any semblance of what could be mushrooming in the strut tower, but the r56s don't have this issue so much, though my suspension is very stiff.

 

I was told by another person that I am driving on 3 wheels going through the slalom. I always wanted to do it and I am finally doing it!! I wish someone would have a photo of me doing it to share with me...
I have nm 22mm rear bar.

 

Kyoo -

A couple of observations on your video in post 10.

The DNF was caused by apexing at the cone before that. That cone caused a late apex which caused you to be late for the cone you missed. You seemed to have corrected that in the later post. But you seem to be doing that even in you 5th run. Cones are the worst thing on an autocross course. They pull your eyes to them and you will then drive towards them, hence they wind up being the apex of a turn. This is done purposely by the course designers to make course difficult. Eyes up and look ahead. Look past where you are to read the next turn. I always take my first run really slow to #1 get through the course cleanly, #2 to read the course in a way you can't on a course walk and #3 establish a line that seems to be reasonably good. This helps with the memory. If you get it "wrong" the first time, you will likely get it wrong the rest of the runs. It is hard to make a lot of corrections to your first run. "Slow is faster".

In your 5th run video, at about the 22 sec mark you are too early for the next turn and this messes up the turn after that. Following that you leave space on the cone to your left and that pinches the next turn which scrubs speed.

As for suspension, you can tighten up the rear or you can loosen up the front. I vote for loosening up the front so you can achieve a bit of weight transfer to enhance throttle steer. It sounds like you have plenty of stiffness in the rear already.

Say, I have the pictures of the rear suspension adjuster. I will need to email them to you.

See this thread.
https://www.northamericanmotoring.co...ml#post4210666

The 4th picture down in post 31 shows what the rear suspension looks like when this is taken apart. It is the oblong hole that you see. I know this is a Gen I steel trailing arm, but it is the same in your aluminum one.

 

thanks for your input!! you're definitely right, my line needs work. I think I need to do more slow-in fast-out in certain spots, especially when I'm so unwilling to give up any speed that I end up scrubbing it off later in the corner


looked at the pic - I don't understand it lol, but hopefully my alignment guy will

 

Kyoo,

In ski racing they talk about hitting the back side of the gate. You can't do that if you are turning in early.

Another thing (a general thought), if you slow a bit or even trail brake going into a turn it will help to set the front end and help with rotation. If you are on the gas before the apex, the the car is going to push. You can use this, with the later turn-in, to cut some of the scrub.

Softening the front a bit will help it to settle and you will gain some camber as the springs compress. This will also help with turn-in and rotation.

 

i definitely agree and there are certainly spots that i am early apexing. gotta work on that line...

hopefully i or my codriver do decently at spring nats next weekend! wish me luck guys!

 

good luck. yeah you need to figure out where the apex it and aim for it.

 

seems like a LOT of pressure for re71's, I start mine at 32 and they get up near 40 after 2 runs both front and back heat up about the same psi on mine. If I do not air them out I start pushing wide and sliding too much in the slaloms but I never go below about 35 or they start to slide again from too little air. I've only got about 40 runs experience but there seems to be a sweet spot for my r53/re71r PSI. I run the big hotchkis on stiffest and stock S springs/shocks (shocks pretty weak now).

I made the mistake of leaving the rear go up to 40 and aired down the front to 33 and I spun out on the first slalom !