[GeraldM2]

Just upgraded to MCS 2WNR from Ohlins R&T. I went with some pretty conserative spring rates (7k F, 14k R) since i found the Ohlins to be really over sprung. (Ohlins will be listed for sale on members classified later this week)

What I want to know what are some good baseline settings I should play with for a back roads/street set up and what are some good settings for the track (buttonwillow and streets of willow).

ps.

Shoutout to Harold from HP autosport for hooking it up with the coilovers, educating me on what springs i should go with and helping me get them quickly after i waited months for ST suspension that never even left the factory. Would never have imagined i'd end up with MCS suspension till he made it a reality.

[ThreeStripes]

Don’t have any personal experience them but our race shop that runs MCS on everything including their WRL cars sets them up in the middle for both settings to start and then adjusts from there.

They advise that a single click adjustment with MCS is a big one, so large scale adjustments are uncommon fwiw.

I’ve also heard them say that spring rate, sways, and alignment control how the car behaves and MCS settings control how quickly or slowly that behavior is realized.

[AlpinewhiteM2C]

@GeraldM2 - I too have recently moved to MCS 2WNR. My setup is as follows for the street:

Springs: 450 front/ 750 rear (Eibach ERS)
Height 595 front/ 600 rear (similar to M Performance suspension height recommendations from BMW)
Aligment: -2.9 front/ zero toe; -2.0 rear/ 1/16th toe in.
Swaybar: Hotchkis front swaybar set at 2nd from the softest setting
MCS settings: started at 4C/ 8R front and rear as MCS suggested. It's been a good on the streets in that it absorbs the irregularities really well and keeps the car composed while still being relatively comfortable for daily driving. I'll be doing my first HPDE at The Ridge w/ this suspension set up later this month where I'll play with the settings.

[GeraldM2]

what are the driving characteristics like? Im trying to dial out some of the cars natural understeer (currently on 275 square) and im trying to just make the car feel more settled over large bumps

[AlpinewhiteM2C]

Originally Posted by GeraldM2

what are the driving characteristics like? Im trying to dial out some of the cars natural understeer (currently on 275 square) and im trying to just make the car feel more settled over large bumps

The car handles pretty well on the streets. Turn is is much better which I think is a function of the front bar and added camber. The MCS shocks handles bumps really well. I have an HPDE w/ the local BMW club lined up as well as an auto-x event later this month. I suspect that even with the updated suspension, the car will still exhibit some understeer at mid corner which is fine with me as I can drive around that (try not to carry too much speed into a corner and be really smooth with my transition/ trail brake going into high speed sweepers).

[FaRKle!]

Originally Posted by GeraldM2

what are the driving characteristics like? Im trying to dial out some of the cars natural understeer (currently on 275 square) and im trying to just make the car feel more settled over large bumps

Understeer with 275 square was with the Ohlins? If you want to dial that out you need to go to a higher rear spring bias than the Ohlins had, decrease the rear tire width relative to front, go to a softer front sway (keeping the rear the same), or a stiffer rear sway (keeping front the same).

[RugbyBro]

Originally Posted by AlpinewhiteM2C

@GeraldM2 - I too have recently moved to MCS 2WNR. My setup is as follows for the street:

Springs: 450 front/ 750 rear (Eibach ERS)
Height 595 front/ 600 rear (similar to M Performance suspension height recommendations from BMW)
Aligment: -2.9 front/ zero toe; -2.0 rear/ 1/16th toe in.
Swaybar: Hotchkis front swaybar set at 2nd from the softest setting
MCS settings: started at 4C/ 8R front and rear as MCS suggested. It's been a good on the streets in that it absorbs the irregularities really well and keeps the car composed while still being relatively comfortable for daily driving. I'll be doing my first HPDE at The Ridge w/ this suspension set up later this month where I'll play with the settings.

I'll be at Ridge 2x this month and have a similar set up to you. MCS 2WR w/ 550F/450R true coil. I also have the GTMore sways set to stiffest front and middle rear. Square setup for tires. My settings for a smooth track (like Ridge) are:

F: 9C/10R
R: 8C/9R

The low spring rates are great for the Seattle streets but I feel that these dampers can still be smooth/livable with higher rates, will be bumping those up next season.

[D.Yooras]

Originally Posted by FaRKle!

Understeer with 275 square was with the Ohlins? If you want to dial that out you need to go to a higher rear spring bias than the Ohlins had, decrease the rear tire width relative to front, go to a softer front sway (keeping the rear the same), or a stiffer rear sway (keeping front the same).

For a proper racing chassis that is generally true. However, because this chassis is compromise setup due to front struts, it doesn't play by the standard rules.

The most important aspect of optimizing this chassis is front camber and roll stiffness. Since strut suspension doesn't gain much negative camber in compression (and at lowered height it's basically none) the most important aspect of setting it up is ensuring the outside front wheel has sufficient camber when the car is cornering. The easiest way to achieve this is with camber plates and/or a stiff front sway bar.

The camber plates do two things, one they give more static camber but they also change the camber curve through changing the SAI (steering axis inclination). The front sway bar limits body roll to minimize camber loss during cornering AND also assists in lateral weight transfer to the outside wheels (mainly front but also the outside rear). This is especially beneficial since the front inside wheel isn't doing much in terms of grip anyway. The main drawback to tuning this way, though, it does require more diligence on turn in to ensure the lateral load transfer happens properly (too fast and outside front will lose traction before the transfer is achieved). Other than that aspect, the rest of is generally beneficial.

Overall, that is the easiest, most cost effective way to get front grip out of a chassis like this. Once front grip is maximized, then fine tune with minor changes in the rear, like springs and sway bars.

[FaRKle!]

Originally Posted by D.Yooras

For a proper racing chassis that is generally true. However, because this chassis is compromise setup due to front struts, it doesn't play by the standard rules.

The most important aspect of optimizing this chassis is front camber and roll stiffness. Since strut suspension doesn't gain much negative camber in compression (and at lowered height it's basically none) the most important aspect of setting it up is ensuring the outside front wheel has sufficient camber when the car is cornering. The easiest way to achieve this is with camber plates and/or a stiff front sway bar.

The camber plates do two things, one they give more static camber but they also change the camber curve through changing the SAI (steering axis inclination). The front sway bar limits body roll to minimize camber loss during cornering AND also assists in lateral weight transfer to the outside wheels (mainly front but also the outside rear). This is especially beneficial since the front inside wheel isn't doing much in terms of grip anyway. The main drawback to tuning this way, though, it does require more diligence on turn in to ensure the lateral load transfer happens properly (too fast and outside front will lose traction before the transfer is achieved). Other than that aspect, the rest of is generally beneficial.

Overall, that is the easiest, most cost effective way to get front grip out of a chassis like this. Once front grip is maximized, then fine tune with minor changes in the rear, like springs and sway bars.

For a suspension like the MCS or Ohlins you're already inducing a lot of understeer by having too much front spring relative to rear. Adding more front sway bar to that only makes it even worse. You're not going to gain enough of that back adding static camber and will be forced to reduce rear axle grip to balance. I've tested quite a few things with the Ohlins, and the stock springs/dampers are still faster around my testing track.

[GeraldM2]

Originally Posted by RugbyBro

I'll be at Ridge 2x this month and have a similar set up to you. MCS 2WR w/ 550F/450R true coil. I also have the GTMore sways set to stiffest front and middle rear. Square setup for tires. My settings for a smooth track (like Ridge) are:

F: 9C/10R
R: 8C/9R

The low spring rates are great for the Seattle streets but I feel that these dampers can still be smooth/livable with higher rates, will be bumping those up next season.

Awesome! What height did you set your coils at? I am a bit confused as to how i should set the height/pre-load for the fronts. As of rn they're way too high and it makes the front end feel unstable and floaty. might turn the compression up in the front and see how it feels after the springs settle and i get an alignment.

[medphysdave]

Originally Posted by FaRKle!

For a suspension like the MCS or Ohlins you're already inducing a lot of understeer by having too much front spring relative to rear. Adding more front sway bar to that only makes it even worse. You're not going to gain enough of that back adding static camber and will be forced to reduce rear axle grip to balance. I've tested quite a few things with the Ohlins, and the stock springs/dampers are still faster around my testing track.

Your last statement about the stock suspension is interesting. Does that mean that keeping the stock ride height vs changing to lowering springs like Eibach or HR isn't too detrimental? I follow a lot of your videos and am changing quite a few things, but I'm leaving my dampers and springs alone for the time being. Thanks!

[FaRKle!]

Originally Posted by medphysdave

Your last statement about the stock suspension is interesting. Does that mean that keeping the stock ride height vs changing to lowering springs like Eibach or HR isn't too detrimental? I follow a lot of your videos and am changing quite a few things, but I'm leaving my dampers and springs alone for the time being. Thanks!

It has more to do with flat ride/rear freq bias rather than ride height. Aftermarket springs generally still maintain flat ride, but to a lesser degree, while coilovers typically change it to non-flat ride/ front freq biased.

[D.Yooras]

Originally Posted by FaRKle!

For a suspension like the MCS or Ohlins you're already inducing a lot of understeer by having too much front spring relative to rear. Adding more front sway bar to that only makes it even worse. You're not going to gain enough of that back adding static camber and will be forced to reduce rear axle grip to balance. I've tested quite a few things with the Ohlins, and the stock springs/dampers are still faster around my testing track.

There are different ways to approach tuning that can yield similar results but require completely different styles of driving and conditions to get there. The approach you're taking could produce results similar to the method I'm talking about in one instance/track/configuration but not work as well in others due to the nature of the compromise. Again, since we're dealing with strut front suspension there isn't a one size fits all approach.

That said, there has been a lot of development put into these cars over the decades and the best all around, all condition, compromise setup always involves a larger front sway bar. This started with the E46 M3 CSL which was a huge improvement over the regular M3, especially when it comes to front grip. This front grip improvement was the culmination of a couple aspects but the one with the most affect was the front sway bar. The regular M3 had a 26mm bar while the CSL had a 30.8mm that (although hollow) was significantly stiffer than the regular M3 bar. This greatly improved front roll stiffness which, in turn, retained front camber better in heavy cornering situations in addition to the advantageous weight transfer.

Second example, the F8X chassis. BMW made one sway bar for all F8X chassis which, educated guess, was the max size BMW would ever want to put on a factory spec/trim. This allowed BMW to make one bushing and bracket set for all F8X chassis while at the same time allowing them to tune roll stiffness anywhere from 28mm down. On the F87 the front sway bar is 28mm bar but, to de-stiffen it, BMW milled the center down to 24mm (plus paint). Sway bars are like chains, the weak link establishes the total strength of the chain. In this case, the smallest point (especially if it's in the middle) is the torsional stiffness of the bar which, in this case, is 24mm.

Third example, the M235i Racing which comes stock with H&R sway bars 28mm front and 20mm rear (among other things as well). Example four, Spec E46 where nearly everyone is running the Hotchkis front sway bar (30.2mm hollow) if not the whole set (though most people keep the OE rear sway bar because they claim it's too stiff relative to the front).

Front roll stiffness on this chassis is critical. In fact, it wouldn't surprise me if the reason the springs are stiffer in the front relative to the rear on Ohlins and MCS, is to deal with the extra weight being transferred to the outside front wheel of a properly setup track car. Since the stiff front bar allows for more grip, there is more load transfer which means there will be more weight being transferred to the outside wheels.

The last thing you want in a car like this is to have too much weight transfer to the front axle on the whole through excessively stiff rear springs and/or rear sway bar. Going back to the Spec E46 example, most of those cars are setup to where the front axle under heavy cornering has 100% lateral load transfer, meaning the inside front wheel is off the ground. Obviously having wheels off the ground isn't ideal, but again, compromise setup means compromise tuning. If you run too stiff of a rear bar, the inside rear wheel will try to lift off the ground shortly after the front one and you'll lose grip on the rear axle, possibly even cause a snap oversteer situation.

To the original point, stiffer front sway is the most important part of this equation. Put a bigger front bar on first, maximize front grip, THEN fine tune rear axle handling characteristics through aspects like springs and sway bar. It’s possible to get the weight where you want it through very stiff rear springs and/or rear bar, but you could have a car that’s a handful on the street, especially in emergency situations.