suspension help

[justintime]

ok, so It seems that when you tinker with the suspension (expecially alignment) one thing you change for the better, or worse doesn't affect the entire pattern of the cars handling. These are what I want to learn.. the good and bads of each thing you change and how to change them.

I have figured there are 6 basic things id like to mess with.

corner entry speed- I know its affected with toe, but what else. keep in mind stabability is key for me

corner exit speed- with my current set up there is an almost invisible forcefield that is slightly noticable when accelerating through an apex. How do I fix that?

highspeed stabability (long sweepers 85+mph) I realize this is alot to do with drivers ability..along with the rest of this but for an example.. my car currently.. if you are traveling down the highwway at 70-80mph there is extreme response from the steering wheel. enough so that if you did a slalom type mostion across the lane the back wants to kick out tremendously.

low speed maneuverability (autocross, certain sections of canyons.) haha, well this is mostly driving in my opinion and not a huge concern on focusing on. but input would still be nice

understeer- no understeer to me wouldn't be very well balanced. I eliminated as much as possible, and though its a blast rotating the car into on ramps and autocross sections just by trailbraking, lifting off the throttle, or left foot braking..it doesn't seem like it would be the fastest suspension set up. with the low hp of a MC I dont have any powerunder steer issues.

Oversteer- as above stated I would like there to be slightly more oversteer than understeer but over all a well balanced set up.

No alignment as of yet


My current set up-
m7 uss, h&R coilovers, madness 22mm rear sway, alta front and rear sway endlinks. and I have the helix adjustables on their way.

I get the idea of negative and positive camber very well..

what I would like to know more about and how it affects things is caster, negative and positive toe (if such a thing) spring rates, rebound rates, chassi flex, weight balance (for instance removing my rear seats roates the car more but I get more flex pita) and of course the sidewalls of tires

thanksss


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[k-huevo]

To get the most out of your suspension seek professional help from a driving instructor on a closed course. There are many events around the state; here is an option not too far away http://texasworldspeedway.com/msc.htm . High performance driver training is the single most powerful tool, even better than sway bars & springs. To be prepared, read every high performance driving instruction and suspension design book you can locate.

Lowering the vehicle may look good in your eyes but it is counterproductive to performance handling without major modifications to the chassis and sophisticated dampers. There is nothing “wrong” with wanting the look :cool:, but it is not appropriate in the area of performance. Too many crucial aspects of the MINI’s engineered suspension geometry are unfavorably altered; body roll can be increased, even though that sounds counter intuitive, because roll center is affected. If you are not willing to give up the H&Rs, at least use greater block height springs like the stockers.

Get front camber plates, whether fixed or adjustable, caster enabled plates are not critical and I wouldn’t be concerned about increasing caster via the control arm bushing; get adjustable lower rear control arms (camber links), and then, an alignment. For an aggressive setting but still street friendly and autocross biased, -2 degrees camber (per side) up front and -1.2 degrees in the rear, .1 degree toe in (positive) front and .15 degree rear toe. Since your car is not track dedicated there are too many trade-offs going neutral or negative toe out. Without having balanced alignment you will not be able to differentiate between driver and mechanical error. You must also experiment with tire pressures.

For moderately powered vehicles, exit speed is determined by entrance speed, but in your case the first thing to try is re-fitment of the stock header.

I would have liked to start with this recommendation, but I know you would have turned me off completely ;), and that is return entirely to stock and spend lots of weekends in driver training. In the end you may discover the only non-stock things you need are sticky tires and a harness.

[justintime]

I would have liked to start with this recommendation, but I know you would have turned me off completely ;), and that is return entirely to stock and spend lots of weekends in driver training. In the end you may discover the only non-stock things you need are sticky tires and a harness.


I a-hundred percent agree, the mini is a blast and handles amazing stock if you drive it right. I love driving Josh's stock mini in autocross. However, I just have a bug to figure out how to make things go faster. The new header is loud and did not increase performance noticably at all. I really need an alignment. I have been reading around alot and I realize that the modifications I have made suspension wise are pointless without the alignment(kind of like the header is without the exhaust side ported.) The camber plates you have are set at -1.7? or what was it at? I like the price of them and even though everyone recommends -2.0.. -1.7 actually seems reasonable for street (and tire wear) I was told on another forum the h&r springs could not be replaced, I dont understand why since they are split rate, which I believe are basically the same thing as the stock progressive spring. also, I figured the stock spring might be to big? but mabye the konis would work, but not veil much of a difference? after lowering I did notice expecially with the rt-615 tire being so sticky, that the front toe is horribly out of wack to the point when I accelerate I can actually feel it.

[k-huevo]

I am entirely street focused and running -1 degree front camber on my custom fixed camber plates. Ireland Engineering Fixed Camber Plates will give an extra -1.25 degrees over stock settings; if you have .5 to begin with, then you could expect near -1.75 degrees after fitment. After changing my control arm bushings and struts, the measurement changed from -1.3 to -1 degree, so there are variables involved in the final outcome for each vehicle.
There are many brands of linear rate springs with varying heights and diameters that will work with the H&Rs, Hypercoil are the best, but you will need appropriate spring hats for these kinds of springs. Linear rate springs will provide greater predictability and allow for more negative camber adjustment up front.

[justintime]

I am entirely street focused and running -1 degree front camber on my custom fixed camber plates. Ireland Engineering Fixed Camber Plates will give an extra -1.25 degrees over stock settings; if you have .5 to begin with, then you could expect near -1.75 degrees after fitment. After changing my control arm bushings and struts, the measurement changed from -1.3 to -1 degree, so there are variables involved in the final outcome for each vehicle.
There are many brands of linear rate springs with varying heights and diameters that will work with the H&Rs, Hypercoil are the best, but you will need appropriate spring hats for these kinds of springs. Linear rate springs will provide greater predictability and allow for more negative camber adjustment up front.

linear rate springs.. are those ground flat? where the coils are all the same size and thickness? if so are we also talking about springs made FOR the mini or just a spring I could purchase that would work? Im sending you a pm :thumbsup

thanksss as always keith!

[k-huevo]

BTW, the stock springs are linear rate even though they are not flat on the ends. Look here for spring information http://www.afcoracing.com/tech_pages/spring.shtml
For the many options available from Hypercoil http://redlinerennsport.homestead.com/Hypercoil.html
Top spring perches (hats) run about $45 each.

I know H&R is aware of the suspension travel problems arising from their red springs used on your kit and that Don of DMH was working with them on a solution; I'll make an inquiry.

[justintime]

BTW, the stock springs are linear rate even though they are not flat on the ends. Look here for spring information http://www.afcoracing.com/tech_pages/spring.shtml
For the many options available from Hypercoil http://redlinerennsport.homestead.com/Hypercoil.html
Top spring perches (hats) run about $45 each.

I know H&R is aware of the suspension travel problems arising from their red springs used on your kit and that Don of DMH was working with them on a solution; I'll make an inquiry.

oh ya, I have an entire kit of polyuerathane bushings from energy bushings that I bought for the crx, however Im selling it so I dont need them anymore. But do you think any of them are the same? mabye if I took them and let you look at them. I mean naturally I know alot arnt (like the shifter linkage, front and rear sway and motormounts.