M3/M4 CS Owners Thread

[RugbyBro]

Originally Posted by Nyc911

Is anyone running wider tires in the rear on stock wheels or are 285 the widest you can go? I’m going to need new tires soon and wanted to know if I can go to 295 or even 305 in the rear

Unfortunately 285 is really the widest you should go assuming the tires aren’t running narrow. You can squeeze on 295 or even 305 but it’s not advisable - there are plenty of people who’ve done that on the 437Ms… 295 seems to work okay but 305 will definitely bulge way too much.

My number one pet peeve about the CS is that 763Ms came in a 9 & 10in setup instead of 9.5 & 10.5 in. It’s probably due to the legality around wheels needing to be set narrower than the fender - that’s pure speculation on my part.

[RugbyBro]

Originally Posted by M3CSinWisc

I'm not chasing a solution, nor do I think there is a problem I'm just intrigued by the engineering and design, it's resultant aesthetics, and how subsequently owners upset that original design by trying to "correct" those aesthetics. Been down that road myself with my previous car, never going to do it again. My CS will remain bone stock.

Yeah being designed as a street car there is more suspension travel engineered in purposely. I’d think that the desired ride height would be one of the initial parameters and the suspension is designed and optimized around that. Plus F8X suspension components were designed back in 2014, so there’s probably some mechanical limits to the hardware that impact ride height relative to the desired damping characteristics.

[jmg]

Originally Posted by Nyc911

Is anyone running wider tires in the rear on stock wheels or are 285 the widest you can go? I’m going to need new tires soon and wanted to know if I can go to 295 or even 305 in the rear

I've run MPS4S 295/30/20 lowered on MP HAS no rubbing.

[slcook54]

Given we're on the topic of wheels / tires, are there any specific considerations if swapping the rear wheels from 20 inch to 19 inch?

I was thinking of something like

19x9.5 (F) and 19x10.5 (R)

275/35/19 and 295/30/19

[Nyc911]

Originally Posted by jmg

I've run MPS4S 295/30/20 lowered on MP HAS no rubbing.

Thanks!! 👍🏼

[Gtracer]

Originally Posted by jmg

I've run MPS4S 295/30/20 lowered on MP HAS no rubbing.

Any pics of the car?

[jmg]

Originally Posted by Gtracer

Any pics of the car?

Here you go:

[Mic3]

Does someone know the actual weight saving on an M3 CS over a standard M3 DCT with CF roof?

The data I’ve found from BMW is a bit confusing.

M3CS 1585kg without driver and 1660kg with driver. But for standard M3 BMW writes 1610kg for 6MT and 1635kg with DCT. And this is with 90% full tank, 68kg driver and 7kg luggage. So according to this the CS should be 25kg heavier.

[CanAutM3]

Originally Posted by jmg

It's a compromise between aesthetics and performance. Most street driven cars won't mind a bit of forward rake. Best bet is a corner balance with the driver at the wheel. Each corner is on a scale and ride hight is adjusted to balance weight to the driver's liking, ideally an even distribution, including left to right accounting for the driver's weight. It's a bit excessive for street cars, but if you are a stickler for performance and chasing 10ths of a second, it's pretty much the SOP.

FYI, corner balancing and rake are not directly related. You can set the front and rear ride heights as desired and then fine tune the corner balancing. Ultimately, the only thing corner balancing does is even out left and right turn handling. IMO, properly adjusting rake, i.e. relative front and rear ride heights, is much more critical to handling than corner balancing. Changing the relative ride heights changes the roll centers and how much each axle resists roll respective to the other and this has significant incidence on handling characteristics. On my CS, I originally had the front set too low, which limited the ability to put the power down on corner exit. Raising the front a tad got the front axle to take more of the roll resistance and improved rear axle grip under power coming out of corners.

[jmg]

Originally Posted by CanAutM3

FYI, corner balancing and rake are not directly related. You can set the front and rear ride heights as desired and the fine tune the corner balancing. Ultimately, the only thing corner balancing does is even out left and right turn handling. IMO, properly adjusting rake, i.e. relative front and rear ride heights, is much more critical to handling than corner balancing. Changing the relative ride heights changes the roll centers and how much each axle resists roll respective to the other and this has significant incidence on handling characteristics. On my CS, I originally had the front set too low, which limited the ability to put the power down on corner exit. Raising the front a tad got the front axle to take more of the roll resistance and improved rear axle grip under power coming out of corners.

Good to know. I usually group them together since adjusting the rake is all part of the alignment and corner balancing service at the alignment shop.

[RugbyBro]

Originally Posted by Mic3

Does someone know the actual weight saving on an M3 CS over a standard M3 DCT with CF roof?

The data I’ve found from BMW is a bit confusing.

M3CS 1585kg without driver and 1660kg with driver. But for standard M3 BMW writes 1610kg for 6MT and 1635kg with DCT. And this is with 90% full tank, 68kg driver and 7kg luggage. So according to this the CS should be 25kg heavier.

It’s around 3600lbs w/ half tank and steel brakes - no real weight savings over a comparably equipped Non-CS F80. 4CS is a little lighter than and normal F82, I vaguely remember CanAutM3 posting that his car scaled in around 35XX

[CanAutM3]

Originally Posted by Nyc911

Is anyone running wider tires in the rear on stock wheels or are 285 the widest you can go? I’m going to need new tires soon and wanted to know if I can go to 295 or even 305 in the rear

295 is the max recommended for a 10" wide wheel. On my 2015 M4, I ran the F10 M5 295/35R30 star spec tire in the rear, but that tire was specifically designed for a 10" wide wheel. Other 295 tires might "bounce" more due to sidewall spring.

[CanAutM3]

Originally Posted by RugbyBro

It’s around 3600lbs w/ half tank and steel brakes - no real weight savings over a comparably equipped Non-CS F80. 4CS is a little lighter than and normal F82, I vaguely remember CanAutM3 posting that his car scaled in around 35XX

Correct. My M4cs was weighed at 3,537lb with 95%+ fuel.

[CanAutM3]

Originally Posted by jmg

Good to know. I usually group them together since adjusting the rake is all part of the alignment and corner balancing service at the alignment shop.

Wow, you found an alignment shop that has enough knowhow to fine tune ride height? That is rare. Just finding a shop that will do a "good alignment" to my spec is already hard to find. What I mean by a "good alignment" is a technician that will go back and forth between the various adjustments until all the parameters are "exactly" to my spec, not just within tolerance.

As a tidbit, I was quite impressed with the alignment service I got at my Porsche dealer, every parameter was bang on what I had specified. I've never gotten anywhere near that with BMW dealers and used independent alignment shops because of this.

[jmg]

Originally Posted by CanAutM3

Wow, you found an alignment shop that has enough knowhow to fine tune ride height? That is rare. Just finding a shop that will do a "good alignment" to my spec is already hard to find. What I mean by a "good alignment" is a technician that will go back and forth between the various adjustments until all the parameters are "exactly" to my spec, not just within tolerance.

As a tidbit, I was quite impressed with the alignment service I got at my Porsche dealer, every parameter was bang on what I had specified. I've never gotten anywhere near that with BMW dealers and used independent alignment shops because of this.

Yup. Several good track oriented shops in the Los Angeles/Orange County area. They will corner balance with the driver in car and the techs are all racers and HPDE regulars, so setup is not just their job, it's their hobby too.

[slcook54]

That's better.

[e90335e36m3]

My CS…MP HAS w/295s as well. Tested on the Tail of the Dragon, no rubbing. Handles like a dream, better than my E92 M3, my old E36 M3.

[THEROK]

Originally Posted by e90335e36m3

My CS…MP HAS w/295s as well. Tested on the Tail of the Dragon, no rubbing. Handles like a dream, better than my E92 M3, my old E36 M3.

That m4 CS rear end is perfection

[slcook54]

Suspension issues solved

https://f80.bimmerpost.com/forums/sh...2&postcount=16

[falconey]

Curious what tires folks are going with when replacing the oem set? I'm not looking to track my CS.

[11LMBiSTT]

Originally Posted by falconey

Curious what tires folks are going with when replacing the oem set? I'm not looking to track my CS.

Michelin Cup 2's or 4s'.

The 4s's specifically from the new G8x - star spec are very good and as good as Cup 2's in an all season tire.

[jtskariah]

Hi everyone, I asked this in another thread but I believe it may be more appropriate in a thread for CS owners. Do you guys think an Alcantara headliner retrofit is an appropriate mod for our cars? Or do you think that this is a bad idea for a limited-run car (essentially keep it as stock/reversible as possible)? I think it would look great with all the Alcantara pieces that we currently have but I don't want to push the envelope and change the car "too much" if you know what I mean. Here are a few pics for reference