Any reason why I should not run the Whiteline 30mm front sway bar? I am running the NM engineering 25mm rear on the stiff setting and the stock front. The car is currently lifting the inside rear on hard corning.

 

Are you running a liimited slip differential?

If so, have at it.

If not, be advised the eDiff will start eating your front brakes at the rate of every 25-30k miles.

Stiffer bar, more weight transfer up front, therefore less traction on the inside front contact patch at corner exit.

Damn near all fwd cars will lift the inside rear on corner entry when driven hard, it's the front that matters most.

Cheers,

Charlie

 

yes I installed a wavetrac!

 

so the plot thickens was just given advice that putting a stiffer front bar will put the understeer back in the car. The thinking being that the heavier rear bar removes understeer and I would be "cancelling" that improvement out.

What do you think Mr. Charlie?

Thank you in advance, John

 

Camber matters. Are you all the way to camber plates and coil-overs?

Are you auto-crossing? Track days? HPDE?

A front bar would probably be the last mod I would consider, and only if I had good cause. A lift of the inner rear is not alone sufficient.

I hope others might chime in here - Eddie07 for example.

Here's Golllum, cocking a leg at the Dragon.

Cheers,

Charlie



Early in his development - just Bilsteins, the RSB, and a half-degree of front negative camber (crash parts!).

 

Yes, camber matters. And on a Mini, when the front starts to lean in a corner, front camber will go positive. A bigger front bar will help keep the roll in check, and keep the front tire contact patch in contact with the road. If you are serious about handling, a front bar can help. Additional front camber will also help. A bigger front bar will help with turn-in response.

 

Yes I have camber plates and coil overs and I use the car for auto cross not a daily drive just to events and back

I used your alignment numbers except caster (don’t have the bushings yet) and I am having tires mounted to the same wheels you run. 17 x 8 center bored by the same shop you used! I study your posts closely.

you have certainly jump started me in getting the car sorted


That’s a note on my tool box lol even noting the approximate post number you discuss ride height.

you have been a big help.

thank you!

 

In reference to Nik's observation, and at the considerable risk of a bad pun, I agree - but it is a matter of degree is it not?

All these questions were part of Gollum's refinement, and tested in competition at the NER.

How much roll does an F56 with an NM 25mm RSB have at .9 lateral G? Turns out to be 2.75 degrees in this case. A bit less now that I'm running the JCW Pro coils instead of the OEM sport springs with Bilsteins.



So my best guess, which I've now driven for 70k miles under all conditions, is a symmetrical setup as described in this alignment sheet. Since 2019 I've added a degree of caster, but left the camber alone.



An Nick points out, a FSB will quicken turn-in, but given the turn-in on Gollum has startled every guest driver I've had, the improvement may be unneeded. What the FSB definitely does is increase the rate of weight transfer during turn in, loading the outside tire more swiftly.

For Gollum, who sported 255 whp for much of his life, the ability to keep the front end stuck on corner exit was very important. After I put the Quaife in, and on a cool day, I joined a local highway from a fairly tight on-ramp - aiming for the merge lane generously provided. I accelerated too hard in 3rd and wound up immediately in the RH travel lane instead, as both front tires spun. I learned!

There may be merit in a FSB, but I've not tried it. Jon (Eddie07) may have. Nik have you tried it? What were your observations, what were the specs used, and so forth?

Cheers,

Charlie

PS: Here are current spec JCW Challenge cars (with VERY fancy coil-overs, stiffer springs, 3-way adjustable shocks) looking pretty flat (little roll) but STILL picking up the inside rear tire on trail braking.

 

For ref

https://www.minichallenge.co.uk/mini...r-information/

https://minichallenge.co.uk/download...%20(Clean).pdf


regulation 5.10.4

rear bar
33506853918

front bar
31306859880

these are the standard items ( as fitted to my SD with DDC) not even the sports suspension ones

rear springs are 1000lbs inch or 800lbs
fronts are much softer

 

B16 PSS10








different car but with superpro front and rear bars fitted, only the GP 2 free camber from slotted towers,
https://www.superproeurope.com/produ...vehicleid=5622
i think the front bar is worth considering seriously, I have bookmarked the H&R pair for my next F56, and some KwV3 ready to go
unfortunately I fitted mine as a matched pair to the roadster with the coilovers so cannot give you any meaningful before and after feedback on just front bar.

it’s a street biased setup I drive to the track, for proper aero I should probably put the roof up, but going topless adds to the fun element, possibly costing 5mph by the end of long straights.
been corner weighed and just shy of 1250kg, quaife diff, OS giken clutch, manic stage 2 tune, A052 Yokohama, Gp2 brakes RS29 padgid pads
car laps same times as Alpine 110S (better corners and brakes, lose a little to him on the long straights) big Gt circuit here
https://www.bedfordautodrome.co.uk/a...ircuit-layouts

 

Auto crossed last Sunday and the car is quick but I don't have it sorted correctly. I don't know for sure how high it is lifting rear wheel while cornering but i have to believe reducing that would be the best path for tuning the car. Currently running the Ohlin's MCS MU00S1 coil overs. I think this weekend I am going to lower the car slightly. I am still a bit taller than Mr. Thompsons ride height. I have Vorshlag camber plates running -2.0 camber .04 toe and the same on the rear. caster is 4.27 and i plan at some point to get the bushings to allow the caster adjustment. All advise is welcome.

regards, John

 

way too much.. more front spring ?

 

sorry double post - deleted

 

That's more roll than I expect.

I've never found a reliable source for spring rates unfortunately, leaving anecdotes as data which I do not trust.

I believe, but can't prove, that front spring rates for that car have two flavors: Stock, and "Sport Suspension". Likewise I think the JCW coils are the stiffest - but again, no data!

I also note that my RSB (NM 25mm) can generate 375 lb/in of force, which means the rear spring on the inside wheel can never reach full droop (notice in the photo that wheel is not extended).

Perhaps you've said, and I missed it, but what's your current spring/shock setup?

I'm scratching my head a little here....

Cheers,

Charlie

 

Here is the current set up
Vorshlag camber plates
Ohlins coil over MCS MU00s1
The front springs are marked 48000 15/60 L 3820 (Left spring) I didn't take the right wheel off the car last night.
The catalog states the spring is 60 N/mm and that converts to 342 pounds/inch and measures 180mm by 65mm ID
They have a 48000 - 19 that is 70 N/mm 180mm 65mm ID that coverts to 399 pounds/inch
and a 48000 - 23 that is 80 N/mm that coverts to 456 pounds/inch

I am going to call Ohlins and see about ordering the stiffer springs possibly both sets but at least the 70 N/mm set

I am running the same rear sway bar as you Mr. Thompson

 

The real answer is that it is complicated and it depends…

The simple answer is that you definitely need a larger front swaybar to balance the large rear bar.

Setting up a car’s suspension is all about controlling the tire’s contact patch on the surface the tire is on. Your picture seems to show a left front tire that is rolling onto its sidewall. A larger front bar, with that large rear bar, will improve that. it may not fix it as that will take camber and caster in addition to the front bar.

Once the rear tire is coming off the ground, there is nothing more to be gained by having it being further off the ground. Once the tire comes off the ground there is no further weight transfer to be had to improve the front end traction. Actually, additional rear wheel lift is indication of a losses due to the extent of the dip in the front end and the loss of front negative camber. That dip in the front is also an indication of weight transfer to the front, which will exacerbate the handling. Yes, in general moving weight forward is a good thing, such as trailbraking into a turn. However, if the tire contact patch is already compromised (eg: the tire is rolling over onto its sidewall), more weight on that tire is not going to help.

On my R56 I have experience with the combination of a larger front and rear sway bars and can say that the combination actually reduces understeer. There is less body roll, thus less loss of front wheel camber, which reduces understeer.

Charlie and I both opted for the JCW Pro suspension for our JCWs. I went with it on belief the engineers at BMW/MINI, who get paid a lot to understand the dynamics of suspension design, know how to improve the handling of their cars. Unfortunately, without knowing spring and shock rates there is no real way to tell what one set of coilovers is going to do to a car’s handling vs a different set. So, going with the MINI design seemed like the best choice without knowing anything else. My observation from the comparison of your car picture to Charlie’s is that the spring rates of your coilovers is much lower than that of MINI’s JCW Pro suspension. A less desire match to the rear sway bar you both have.

Spring rates are another factor effecting body roll, thus effecting handling and changes the balance (understeer vs oversteer) of the car. While stiffer springs may give the same roll stiffness as a larger sway bar, it will do it without connecting the left side of the suspension with the right side, allowing more independence between the sides which can be good if jumping curbs on a race track. But this comes with a loss in compliance, which may be important for keeping tires on the ground on rougher surfaces. Stiffer springs will also affect the amount of camber that is gained when trailbraking, especially with a MINI. A MINI gains negative camber when the suspension is compressed. This helps with cornering. Stiffer springs, less camber.

Ugh - like I said, complicated. How about moderately stiff springs and moderately stiff sway bars? But one needs to know spring rates in order to know what the springs are doing for the car’s handling.

As for shock…. Unless they are specifically designed for and tested on a particular car, such as the MINI stuff, there is no guarantee they are right for your purposes and there is no guarantee that some aftermarket supplier has actually do that amount of work to figure it out. This is where a good set of adjustable shocks (Bilstein, Koni, AST come to mind) come in. Stiffer front, softer rear moves handling to more understeer and vice versa. With the front and rear sway bars in place a good set of adjustable shocks can then be used to fine tune the handle. I have seen the shock adjustment be used to take a car that was “trying to kill me” (too much oversteer) to a car that was extremely quick on the track.

About lowering the car… Don’t go too far. I know you have been following Charlie’s thread. Pay close attention to the roll center discussion. Going too low (about an inch) will cause handling issues. Also, be aware that on most coilovers the “height adjustment” only changes the location in the shock’s travel the car will rest. Lowering the car will reduce the upward travel of the suspension, which may cause it to bottom out.

The down side of all of this is that it may make the car harder to rotate. However, this can be mitigated by how the car is driven. This is where the throttle and brake come in.

Hope this helps.

 

Ah, the wise Eddie07s -- that's what I wanted to know. I thought you were running a front bar on the R56!

I just spent more time searching for spring rates, to no avail. Arggh. As you've mentioned the MU00S1 is listed as 342 lb/in front and 456 lb/in rear.

With 880 pounds load on the front corners (and 500 out back) I suspect that Ohlins front rate might be a bit too gentle, but suspicion ain't worth much.

But that photo looks like some one just put a round through an elephant using an express gun - the car is kow-towing!

I'm interested to see where this trail takes you - more spring, or more front bar, or both. Do please keep posting.

Two more thoughts...

For Heaven's sake I'm Charlie - Mr. Thompson is defunct.

At the risk of being thrown bodily out of this thread, have you experimented with "slow in - fast out"? [ducks, and runs]. Having said that, I'm NOT suggesting that this is primarily a driving issue. That picture is damn dramatic, and your Mini should do better.

Cheers,

Charlie

 

Thanks all for the comments and advice

I ordered the 400 pound springs about a 60 pound increase. I have a few weeks until the next event so I will go over everything and install the heavier springs. The guy at the Ohlins service center was going to check on a couple things and get back to me. Was lucky a car friend told me about the picture because I had no idea how much of a lift I was getting. I also plan to order a camber/caster gauge. I also have to get new bushings if I want to mess with caster.

Best regards to all, john C

 

I called Yegor - currently a Service Advisor, formerly a Tech - at Mini of Peabody, and promised him unspecified but glowing rewards if he could find out....

What are the front and rear spring rates for the JCW Pro Coils.

He took the bait, but I'm not optimistic.

You see the Ohlins springs are linear (constant coil spacing and diameter). From appearance however, the JCW Coil springs are progressive!





We shall see.

Cheers,

Charlie

 

One crazy thing about this sport is that I have never been able to get things right at the start. It is a lot of trial and error for me. We will see what stiffer springs yield and I did go ahead and ordered a heavier FSB. With it being a short season here I felt it was better to have the bar here to try. Its a good thing I consider the garage work to be the hobby!

 

Sorry, I missed this post while I was writing the one above.

Not sure if I missed it, but what year and model Cooper do you have? And what is your experience with Autocross?

The Ohlins are a great coilovers. Good choice.

The spring rates seem to be very odd. I would have expected that the fronts would have been stiffer than the rears. I seem to remember that being the case for their R56 application.

It would seem that their spring rates are designed for an application where the stock sway bars are being used. That is, with the spring rate of the Ohlins rears being that much stiffer than the fronts, then that would be the same as putting in a stiffer rear swaybar with respect to handling. This would tend to reduce the understeeer. This is assuming that the difference between the front and rear stock spring rates is proportionally less than what is on the Ohlins.

This might explain the difference in wheel lift between your car and Charlie’s. If your rear springs are stiffer than the MINI Pro suspension and with the same sway bar, your wheel droop should be less. Hence more space under the tire. The real tell would be a front end picture that shows the roll angle of the car.

That all aside, as there is little to be done with it at this point.

The Ohlins are adjustable and their range of adjustment can make a huge difference in the handling of the car. Have you set up your own autocross course and made changes in their adjustment to determine how the car’s handling changes? For example, set the fronts at 2 clicks from full hard and the rears 2 clicks from full soft, run the course a couple of times. Then repeat this with the rears stiffer by 2 clicks each time until the rears are at the same setting as the fronts. Then start over, but this time with the fronts 2 clicks from full soft and the rears 2 clicks from full hard. Run the course, then repeat but with the fronts 2 clicks stiffer. Keep repeating until the fronts are at the same stiffness setting.

It will be interesting to hear how you make out with the stiffer front springs.

 

Once again you and I are typing responses at the same time, and I missed this one too. Sorry…

It is good you asked and are interested in the subject. As for suspension design and setup there is no “absolute” how-to manual. But there is a lot of “conventional wisdom”, which, at best is incomplete, and, unfortunately, that is the information that most of us hear. In my case, conventional wisdom didn’t end well for my first MINI. The school of hard knocks. I think we have all been where you are at. Hang in there.

I have setup my R56 to be a track car that is still useable on the street. It is based around MINI’s design with enhancements (mostly the sway bars). My thought in doing it this way is to retain a bit of safety/stability that MINI designed into their street cars. I would like to refrain from hitting a guardrail at 80 mph because the back end wanted to step out. I have also done autocross with this car and it does pretty well at it. However, I also understand that this suspension setup is less than optimal for autocross. Ideally, it would need to be less stable than it is in order to be competitive at autocross. Typically this done by making the rear of the car proportionally stiffer than the front. I say proportionately because, as I think you are finding out, making the car too stiff in the rear can lead to detrimental issues in the front. Balance is the key.

I point this out as my experience is with cars on the track. While the fundamentals are the same for setting up a car for the track and autocross, the detail application of those is different. I may/will quickly hit my limit with respect to being able to be any more help and you will be on your own. Or you may say - I have a better idea. At that point, just try one thing at a time so you know exactly what the change did to the car. If you do 2 things at once and there is no change, how will you know if one thing was helpful and the other was hurtful, cancelling each other out.

One last thing. As you set the car up for autocross, it may not have the stability to be safe on the road, especially when things get slippery, like in the rain. I would strongly suggest shock and, maybe, rear swaybar settings for the street to make the car street stable. The advantage of those shocks and adjustable swaybars.

 

One difference I embrace is the RSB setting. I ran it stiff in DS and STU, but now that Gollum and I are retired I run it soft.

Another is the split on tire pressures. I would always run +5 lbs out back - to reduce the contact patch slightly, and encourage the car to rotate.

That balance helped on course, but as you say Jon I'd not like it in a decreasing radius off ramp!

That photograph stumps me. I've downloaded it, examined it closely, and applied the "Protractor" java class to it to guesstimate angles.

The car seems to have about 3 degrees of roll at that moment,, but also 2-3 degrees of pitch! In addition, the outside edge of the INNER front tire appears off the ground. I'd guess the weight distribution at that moment would have almost three quarter ton on the left front ALONE. Given that the car is apparently stopping HARD, I also note that there appears to be quite a lot of steering lock applied. I wonder at the course layout that would result in such a dramatic maneuver. It may be that the surface is not as flat as it appears,






Cheers,

Charlie

 

Not sure but I believe I was coming in way too hot into a slalom section. In later runs I smoothed things out but not sure. I still have a lot of work to do as a driver.

 

They are made by KW for MINI, like a KW V1 but tuned to the car more i bet.

https://www.ecstuning.com/b-genuine-...t/33502361197/



Reviews:
https://www.northamericanmotoring.co...-unboxing.html




One of the promo cars was in Cleveland for MTTS back in the day and I was there near downtown. One of the product managers for MINUSA was driving it and i was chatting up about it. I did not ask the spring type at the time. I was more concerned about ride, drop, and truly adjustable.