Pics! What kind of shocks?

 

I will post them up shortly.

The shocks are made from scratch and valved completely custom.

 

We'll also need a shock dyno plot.

 

Great thread!

I'll be taking delivery of my Mini in a couple of weeks. Can't wait to start messing with it. I was wondering about the suggested adjustments. Does the mini have a motion ratio of 1:1 both front and rear?

Hi Andy! (Arnie from Nasioc here.)

 

subscribed......for pics!

 

Subscribed as well. Great info!

 

Hey!

It's approx 1:1 with the strut up front and approx 0.875 in the rear.

Extremely little travel. :(

For your 2nd gen, you have camber adjustment in the rear and there is a "free camber mod" for the front that gets you an extra 0.5 negative. Basically just a pin to remove so you can push the top mount in a little.

- Andrew

 

Good read. Thanks.

 

Welp, I'm just about done making my coilovers. Got a spring manufacturer set up to do different rates for me. I'm excited :D

 

Big subscribed thumbs up here. Thanks for the great info!

 

Wow, great thread -
Any advice for this setup:

I have Megan racing coilovers and on the track I use Nitto NT01 or Toyo R888 215/45/17.
I have a 22mm Alta solid rear sway bar on the stiffest setting (3 holes) The car height is currently at 5" front, 5.75" rear measured from the ground to the jack points (any lower and it rubs when the car is full of my track gear).
The springs are at the Megan factory adjusted height.
I adjusted ride height from just the height adjustment rings. Hard to measure, but the compressed length of the front and rear seem to be around 5.5".

I like how the car feels but would be great if it's a little more tail-happy so the car rotates better going into the corners. On the track I have been setting it at about 20 out of 32 notches rear, 15 out of 32 front.

Camber is about 2 degrees front and rear, front is totally adjustable so I can push them more negative on track days. But that gives me more toe-in correct? At the 2 degree front camber setting there is a slight toe-in, rear is closer to zero toe-in.

 

The car seems to be already setup for oversteer with the rsb on full stiff and the back higher than the fronts. You countered it pretty well with the front camber of -2. This would not be my preferred setting as it is dialed a little too much toward oversteer but if you like to drive this way, it is your choice.

What tire pressures are you running? Have you figured out which is your max grip tire pressure yet?

When you are driving on the track, do you make use of TTO, TBO at all?

 

Hi, thanks for the verification. I do like it this way - I also have a Quaife LSD, this combination seems to put the car through the corner well. With the tail just starting to hang out, it reduces the amount of front end turn in/steering input that is needed (Seems to, anyway) and the other seasoned R53 drivers I know say that they like it this way - and I suppose it helps to avoid throttle lift steering.

I am running tire pressures at about 40lbs when hot off the track, a bit more on the outside of the corners. I set the pressure by measuring how much the tire rolls over, trying to make the edge of the contact line up with the little triangle indicators on the sidewalls.

What is TTO, TBO?

 

There are three areas in a corner you can tune a car to handle. One is turn in, the other is heading toward the apex and the last is going toward trackout. I assume the oversteer you seek is the second one. This is where TT) and TBO work.

TTO = trailing throttle oversteer
TBO = trailing brake oversteer

This will help with to induce controlled oversteer. Too much and snap oversteer can occur. Both can be used to induce some controlled oversteer to point the car in the direction you would like.

Generally, I would consider 40 psi hot on r-comps is a little high, I try to run about 38 psi hot for the fronts which is where I estimate max grip for the NT01 for my previous track Mini. There is a psi range you can go with that will be fine on the tire roll method as it is not that precise. To increase oversteer, find the sweet spot with your max grip, then either increase or decrease the rear tire pressure somewhat to move it past the point of max grip or it will loose grip and oversteer. Generally I like to increase the psi, so I start with +3 psi from that point.

 

Got it and you are correct, I would like more of the apex or steady state oversteer. But not if it makes the car unwieldy at corner entry/exit. It sounds like the car is already at fairly optimum settings. I might play around with the spring pretension, if anything.
The car is a little touchy during entry, especially if there is any trail braking, nice and balanced at apex and very balanced at trackout.
I have not spun the car with this setup, so far I have always been able to get timely feedback that oversteer is about to occur and make adjustments to prevent it. (less steering input, less brake or adding throttle)

Thanks for the tire pressure advice.

Very complex stuff, I have a lot to learn.

 

I would be running a little more front camber for sure. You may have to counter that with a softer setting on the rear sway, but the overall result will probably be more grip and better balance. Would be good to know what spring rates you're running too.

- Andy

 

I will maybe play around with the sway bar setting at the track next time. I usually push the camber plates as far in as they can go when on track so I have as much front negative camber as is possible...

They are just the standard Megan racing springs, I think someone said 6Kg/mm front, 4kg/mm rear?

If I push down on the corners with my palms, the rears feel a little soft compared to the fronts but probably 50-100% stiffer than a stock R53. Maybe I should pretension the rears a bit more.

 

I found the spring rates for these Megan coilovers:

F: 62mm ID; 160mm length; 7 kg/mm
R: 62mm ID; 170mm length; 6 kg/mm

Any thoughts? Should I pretension more one or the other?

 

Corners,

I would drive the car a lot more on the track before adding too much more to it. This way you can figure out what you want to address.

Andy's suggestions are good and should be considered as a next step in your suspension tuning. It is something I have done on my car and it adds to turn in. I am still not a believer in full stiff on a 22 mm rsb on the track. Most track addicts try to strive for neutral handling which seems different from your requirements, perhaps.

Also, just be aware that Megan coils might not be long term full track capable, as you get into 30-60 days, you might consider a more track duty coil set.

 

Corner weight the car, put some extra pre-load on the rears. If you firm it up in the back, you get it tail happy at throttle-lift!

 

Adding spring preload doesn't add spring rate.

 

Very good thread, especially since i'm going to my first event this sunday. Im going to order my coilovers very soon but i have already installed a 22mm alta rear sway bar and kept the stock front (to get a little more over steer).

I must say, drag racing is so much easier lol.

 

Suscribed. Thanks for the info!

 

Of course, I didn't say that, but I gather the one asking is at 0 preload. Corner weighting is a good way to shift balance and properly set up the car.

Also adding a away bar is a band-aid IMHO. I've run stock bars with proper spring preload forever. I've never needed to upgrade the bar. I would only upgrade the sway bars on an otherwise stock suspension to add stiffness in the back.