So changing out the runflat tires is a must on my 09 MCS, and I plan on doing that very shortly. Any recommendations here, let me know. Secondly, I was thinking of throwing on a strut bar (front/rear), or some other mild modification that wouldn't void warranty but improve the cornering and minimize body roll. Any brands/setups you guys recommend? Finally, other 09 MCS owners can probably attest to the fact that the car tends to oversteer when acclerating and turning at the same time. So anything that can be done to make improvements here as well? Thanks.

 

If you aren't changing anything on the suspension, then the only things you can change to improve cornering are wheels, tires, and a driver mod.

Strut bars won't do a thing.

If you change something from stock, you are voiding that parts warranty. That being said, you won't have any major issues replacing the springs or rear sway bar.

I think you are thinking of something different. Oversteer is what happens when the back end of the car comes around (wants to swap ends with the front). Understeer is what happens when the front of the car just plows forward when you really want to turn. If you are accelerating and turning, this would produce understeer. Really the only time you should be experiencing oversteer is when braking and turning or lifting off the throttle mid turn.

 

Loosen the three nuts on your front strut towers,reach up under the fender(with the MINI up on a jack)and push your strut inward while tightening the nuts back to 25 ft/lbs. You could also loosen up the two nuts on your rear lower control arms and and get a decent amount of negative camber from the stock setup. Just mark the original location of the notch and re-tighten to 75 ft/lbs.Then get yourself a set of 8" wheels with some spacers.

 

Whoops, I meant understeer. Thanks for the correction. Is there a noticeable difference with the rear sway bar?

 

You can do a little with front and back tire pressure differences.

You can pump up the front (to a point) to reduce understeer. You need to experiment to get to the point of max grip for your tire. Do this with hot psi.

A hot 4-6 psi difference between the front and back induces oversteer.

Reducing the rear camber also induces oversteer.

As mentioned already, if you add -0.5 degree negative up front, it will reduce understeer.

Otherwise, remove weight up front (such as relocate the battery or lighter battery) will reduce understeer.

 

How about the Alta PSRS?

Apart from that I would do would OXY suggested and get some additional camber at the front, and maybe a 19mm swaybar after that. Also, I got exceptional gains by playing around with the tire pressures.

Also, get yourself some sticky rubber, like Dunlop Direzza Star Spec Z1s

 

PSRS, adjusts caster, would not be one of my first choices since it is a relatively major piece of work. There are lots of things you can do before going to caster.

 

Absolute best thing you can do is lose the runflats and get some decent tires. Immediately.

 

a sway bar is not the end all be all of understeer fix... if anything that will give you snap oversteer... which is a lot harder to control than understeer... not to mention the stock suspension setup is going to give you snap oversteer under heavy turn-in... the higher rear spring rates and decent sized rear sway bar mean under heavy breaking and turn in the front and sideways weight shift combined with higher rear rates than front make the car snap oversteer... you go aftermarket swaybar without any other helping agents then you will have a car that will feel tighter but the threshold between the warning period and actual oversteer will have shortened... leaving you less time to react than stock setup allows... if you want handling best possible for the money, get tires, if you have more i suggest JCW suspension... it's a great setup and is extremely underrated in terms of suspension upgrades, wont void warrantee and will give 70% of people the increase they are looking for...

ps. i've heard the Alta PSRS tend to fall out :/ there are a lot of other ways to get better steering and handling than those. Heim joints and the such should be for a purely track car, not a street driven car cuz the PSRS would have to be cleaned on a normal basis... i suggest poly inserts for all suspension pieces to get rid of play instead of going heim :P also the idea that it will increase caster... MINIs and basically all german cars have a CRAPLOAD of caster stock... japanese cars tend not to have this and therefore run more static negative camber to make up for the lack of caster at full lock... our cars can do absolute wonders with just -0.7 degrees of negative camber because our caster is sooo high. so no need for PSRS on ur mini... i can guarantee you that.

 

PSRS are stiffer than regular poly bushes though, and I don't mind cleaning them, nor the aggressiveness of a heim joint setup. Though I do agree that it should be mainly for people who see the track a lot.

I probably won't be increasing the caster all that much, for the very reasons you suggested. Just looking for something to get rid of the chocolate we R56 owners call FLCA bushes, especially to make way for my future coilovers.

 

Dunphyj,

What is snap oversteer? as compared to regular oversteer, TBO and TTO? I am a long time track junckie and have never heard this term from any of the other track junkies, racers and skippy instructors in the NE.

The only thing about helm joints is that it is noisy and a little harsh.

A 19 mm sway bar is fine generally. Going 22 MM may be a little too much for many, especially the unsuspecting. Many people do some suspension work to get to more neutral handling (whatever that means) but just don't overdo it. This is the case where the more the better is not always right. The stock suspension is balanced to a little too much understeer for my liking since I like to induce rotation using the point and mash technique.

I think the op wants to know some things he can do w/o going overboard. I still think that the most important thing before you start to change suspension is to understand what problem you want to fix and understand/feel how the car handles with each change. And do the changes slowly.

You made some interesting comments on PSRS which I am not familiar with.

 

I can tell you the additioin of the 19 mm bar on my Clubman made a world of difference. Put on the middle hole, it really flattened out the car a ton! I've autocrossed and raced Legends for years and this car is as stable as anything I've driven. Of course, I ditched the runflats early, so that helped too.

But like the otehrs have said, good tires, lighter wheels and a GOOD alignment will help make the car feel better.

 

hey Slinger,

First off agreed fully, 19 is all most need, 22 is WAY too intense for even a very enthusiastic driver outside the track.

As for snap oversteer... it's something typically found and coined in mid-engine cars, it's also known as throttle lift oversteer, not power oversteer though... but it's caused by the front springs having lower rates than rear, and decent sized rear sway bars, what happens is under heavy weight transfer aka a heavy braking session or in a corner when the weight is shifted forward because your off throttle, the weight in the back is pulled vertically, making the springs and way bar do their job not QUITE as well and this causes the rear to brake away resulting in oversteer... the mini has a tendency to do this in stock form but because of the wheel base and setup of the car it's easier to make it controllable. so in extremely simple terms lifting throttle in turn can bring the back end around. my preferred way of doing that is in an E36 M3 :P but that's with the throttle on which is power oversteer (oversteer caused by more power sent to the rear in a way that the tires can't grip... ) these two are a couple ways to drift although technically you can't drift a FWD layout.

but back on topic... a larger stiff rear swaybar will compound the snap oversteer effect that MINIs naturally have... so a rear sway will definitely help, but all i'm saying is keep in mind that if you go that road, the car will corner better but if you get to the point of snap oversteer it will happen more suddenly than with the stock swaybar... reason being, you've increased the tension (resistance to roll) but haven't yet increased the tire's grip or the suspension's way to react, most people fix this by just increasing everything, grippier tires, higher spring rates, better shocks, and swaybar.... another easier way to do that is JCW kit :P BUT... IMHO if you're reaching the snap oversteer point on the street, you're probably doing a no no on the street, then again that's a typical thing when you have a gokart car that just had this shinny new part put on and you want to try it out... i suggest a track day to figure out the limits in a safe way.

Would agree with your statement that you need to know what you're trying to fix before fixing it... i got coilovers because i track my car, did the research and found that my driving style suggested near neutral understeer at the limit to get the most out of my driving... so i got custom coilovers to get exactly that, to get better cornering i got camber plates and rear control arms paired with 19mm swaybar and tires to get better sideways grip, for speed you do basic bolt ons, for comfort you get your shocks valved in a way to work with the springs but be livable on the street. but with all things tuning, for every step you go in one direction you leave the opposite direction behind. it's near impossible to find a track car that's comfortable, just like its hard to get a luxury car that will take a track like a lotus elise... tuning outside of MINIs own in house tuners are going to be more compromise. if you want a car that's more agile and can handle better but still isn't over the top then JCW is the way to go and throw on some better tires when you have the money, otherwise, outside of Koni FSDs and a good lowering spring, maybe the eibach pro-kit and FSD combo, but outside of that you most likely will get harsher as you go...

Neutral handling btw is what BMW is all about... typically it's a car setup to have 50/50 or close to that weight distribution, from that point the car is made to not understeer or oversteer naturally... it will basically do exactly what you want it to... which is why BMW is one of the ultimate driving machines ever made (personal opinion at least). now i have my car setup for near neutral understeer at the limit... what that means is because the car is front heavy, i did calculations and looked at race setups to get spring rates that will cater to the higher weight up front versus the less weight in back, the swaybars are simply a finer tuning element for the setup which is what any race team will concur on... technically a well designed coilover system can be put on the car with stock swaybars and you could be happy as a kid in a candy store.

as for the PSRS... i just honestly have never come across anyone who daily drives with that kind of setup... also just regular poly-u bushings/inserts will do it for most.

hope that covered all your questions in a decent manner.