Hey guys, I have a 2003 MINI Cooper with mods. I have been messing with tire pressure and suspension settings since these mods were put on my car. My problem is that I can't leave it alone! It is really hard for me to find a good setting for the street and some track.

Suspension mods:
H-sport springs
Koni Yellows
18mm HandR rear sway
H-sport rear control arms
Powerflex front control arm bushings
fresh ball joints!!

Wheels and tires:
Black with red lip (Rota Group N's) (12lbs) (15x6.5)
205/50/15 Bfgoodrich G-Force Sports

For now I have the front Konis 1/2 turn from soft and the rear Konis 1 turn from soft. I also have my HandR 18mm rear sway on stiff.

For tire pressure I have the front 32psi cold and the rear 35 psi cold.

I have tried higher shock settings and higher tire pressure front to rear. But of all things I find it strange that the car handles and feels better with the lower shock setting and tire pressue! WHY IS THIS?
I want the car to be very netural with a hint of over steer. HOW CAN I DO THIS?

 

help me!

 

OK, some questions first-

Where do you go for test drives once you make the changes above?

Test on a closed track or on the street?

You cannot test much on the street limited to driving speed limits and the road surface is very different and variable compared to a track.

Tuning for street use is different than tuning for track or even autocross.

What are your alignment settings? Toe and camber front and rear?

Your tires are smaller than stock sized: 205/50-15 are about 22.8" tall and stock is 24.3". Try air pressures same on front and rear or with slightly more pressure in the fronts. Higher rear pressures help understeer.

If you have more than one setting for the rear swaybar try softest setting first.

Front shock should be set softer than the rear, you have the opposite. You can try 1/2 turn or even one full turn difference. You can search for Koni Yellow shock settings in the old treads- there is quite a bit already written.

Front camber on the stock MC is limited to -0.5 degrees which doesn't help much especially if your rear camber is -1.5 or more negative- that would help understeer.

Try things out with small changes and be patient. You'll need to get used to the changes before deciding where to adjust.

 

Thanks, when I do my test drives I do them on the street. I hardly ever track the car.

Alignment:
Front camber (-0.5 on driver) (-0.3 on passenger)
Front toe(1/16 toe out)
Rear camber (-1.4)
Rear toe (1/16 toe in)

Tire pressure right now:
Front: 32 cold
Rear: 35 cold

Koni shocks:
Front: all the way soft
Rear: 1 turn from soft

18mm HandR Rear sway:
Set soft

I find it strange that this softer setting makes the car handle and ride better. The car is less twitchy in a straight line and it seems like the car wants to turn in better. I noticed that when I put the rear sway on softest setting the steering was quicker and the car was less twitchy in a straight line. When I had the suspension and tire pressure set higher the car was not as reasponsive. WHY IS THIS? Is it all in my head? LOL!!

 

Testing for handling cannot really be assessed well on the street. Find a track to do real testing at higher speeds safely and legally.

Maybe change front and rear tire pressures to 33 each. When tire pressures are set lower you can use more of the tire tread. Some drivers like this while others don't and prefer slightly higher pressures like 37 to 39 psi. Check your tire gauge and make sure you are getting an accurate reading- compare with other gauges known to be good/accurate.

Alignment is OK.

Toe settings are fine

Rear camber could be less negative from -1.0 to -1.2 degrees and be OK, maybe even smoother ride.

Have you been to driving school? This would also help. Maybe consider an Evolution Autocross driving school, those are good. Phil Wicks also has driving school for MINIs from time to time across the country.

 

No driving school for me, but I have done about 10 autocrosses. I have a question about my rear sway. Since I only have a 18mm with soft and stiff setting, you think its really going to make the car handle different when I try soft or try stiff? I notice and difference in body roll, but when on the stiffer setting sometimes the car feels like it does not want to turn in as sharply.
So I should try 33 psi all around and adjust my rear sway and shocks or just leave the darn car alone! LOL!!!

 

As long as your rear sway bar is stiffer than stock then you will reduce some understeer up to a point. If you go too stiff you may reach the limits of any benefit from that one upgrade.

The point of going to driving school is to learn techniques to help you smooth out your driving style-

Many times we drive with bad habits like moving our hands too fast or too much on the steering wheel or jerking the wheel in turns. The slower your hands move and work with deliberation the smoother the inputs the less you upset the balance of your car no matter which car you drive. An instuctor in your car or any stock base Cooper could outdrive a modded MCS at autocross given the same wheels/tires.

Driving well and fast has less to do with your mods and more to do with your skill level. Adding suspension upgrades is fine up to a point. Once you have things set up enough then you must drive and learn how to do well with what you have. Making changes constantly will only delay your ability to adjust. What if I gave you a different weight bowling ball with different designs and you went out to practice twice a week for half an hour. You'd get frustrated over the changes in the ***** because they are all a bit different.

In autocross you want to keep things the same as much as you can and only make subtle changes when needed. Tire pressures are good to change in small amounts. Yes you can try 33 psi front and back and see how it works then try 36 psi in the front and 33 in the rear. Notice any difference.

Again for street driving, honestly this isn't the place to do testing since you can't really fully appreciate what you are trying to test. Testing is done on a closed course or track. If you push too hard to hit a slick spot and loose control where are you going to crash into? It only takes a split second to loose control.

 

Thanks for all of your help man! I will try those settings and keep you updated!