[priitserk]

Had a track day today and put the G87 truly on test.
Specs: automatic, used manual mode, carbon roof, otherwise bone stock. No mods.
tyres: 19/20 inch wheels, 275 front, 285 back, factory pirelli p zero, TW 300
Pressure: cold 2.2 bar, hot 2.7bar/70-90C
Steel brakes, factory pads.
Drove in M1 and M2 modes.
Driver 90kg, passenger, 70kg

Points to note:
1) The car has a huge torque at low rpms. Getting out from slow corners is a true challenge. 1-2 gears spin the wheels, traction works like hell or if in M2 mode, your gonna drift out. Needs lot of practising. With factory tires, you will not put the power down. Will try again with proper tires later.
2) Brakes... bad, really bad. No feeling at all, really hard to be consistent. They overheat very quickly. I almost smoked them in the first session and its miracle the car did not catch fire... 7-8 fast laps and you need 2-3 cooling laps. Brake duct caps were removed as needed. Is it the traction control that smokes them or the cars weight, don't know yet. Will need to test more.
3) Suspension - we need coils. Stock suspension is WAY too soft for hard tracking and probably gets much worse with semi slicks or even with proper street tyres. On hard brakings nose dives a lot and car becomes wobbly. I got very scared at fast corners where I had to start braking in the middle of the corner (170-180km/h to 80km/h, and braking in the middle of the corner quite heavily ) You don't want to try that, requires big balls. Suspension says WTF and tries to kill you.
4) Pads, 4 sessions, around 2 hour driving, 50% of them is gone. Consider that I was driving the wheels off the car, pushing max out of the vehicle.
5) M1 and M2 mode. M1 is way too restrictive. M2 is better, but you need to be very careful at corners you take with 2nd gear. It will go to drift mode very easily.
6) Fuel, consumes around 1 liter in a minute.
7) Some say steering is vague, I don't know, imo was fine. Brakes are vague for sure ��
8) Factory camber - Tire wear is nearly perfect. But as I cant change camber currently I really cant say if more negative camber would have helped with corner speed.

Other than that, good car. In the same class with Porsche GTS. GT4 and GT4 RS and GT3s run rings around it. To compete with them You will need to find a way how to put the power down and how to get the car more stable. A bit wider tyres(305 square), upgraded pads, coils and some aero and you will be in the same league (around 10k euro investment).

Have fun guys and watch for the brakes! Take cooling laps, they do really overheat extremely quickly.

Also a video of one quick lap and racechrono image of the track and speeds.

[priitserk]

Has anyone done coilovers install? Any recommendations? Did you get the car firmer/stiffer? With stock suspension its way too soft and I need to do something...
HAS kits most probably are not what I want. Yes they lower the car but most probably spring rates dont change.

[BroDoze]

Time to bust out the wallet. And yeah, MPHAS is an extremely expensive, overpriced lowering kit. That why I skipped it. It’s like $3,100 on the 2025s. That’s coilover money.

https://europeanautosource.com/blogs...oilover-system

https://europeanautosource.com/colle...w-g8x-m2-m3-m4

Get different/actual track pads and higher temp brake fluid.

Lots of great knowledge in this and the brakes, wheels and suspensions sub forums to address all of your above concerns.

[BroDoze]

I wonder what your experience would’ve been like on factory Michelins vs factory Pirellis. Obviously neither is a track tire, but I’m curious anyway.

[priitserk]

Originally Posted by BroDoze

Time to bust out the wallet. And yeah, MPHAS is an extremely expensive, overpriced lowering kit. That why I skipped it. It’s like $3,100 on the 2025s. That’s coilover money.

https://europeanautosource.com/blogs...oilover-system

https://europeanautosource.com/colle...w-g8x-m2-m3-m4

Get different/actual track pads and higher temp brake fluid.

Lots of great knowledge in this and the brakes, wheels and suspensions sub forums to address all of your above concerns.

As the track season is over here I have plenty of time to select and install coils for next year. But yeah, for serious track days we need them. These Öhlins are with excellent price compared to KW!

Brake pads - i'll take something from Endless series.

[priitserk]

Originally Posted by BroDoze

I wonder what your experience would’ve been like on factory Michelins vs factory Pirellis. Obviously neither is a track tire, but I’m curious anyway.

Michelins usually are better IMO. Decade ago I raced with superbikes and we truly hated Pirellis. I dont know, but they just were strange and never the best. But of course I have to admit that factory Pirellis are TW300 tyres. Considering that they were up to the task.

I'll get separate lightweight rims for track days and go with semi slicks.

[ZPD]

Originally Posted by priitserk

Has anyone done coilovers install? Any recommendations? Did you get the car firmer/stiffer? With stock suspension its way too soft and I need to do something...
HAS kits most probably are not what I want. Yes they lower the car but most probably spring rates dont change.

I have MCS coilovers, 305 square tires and a bunch of other good stuff. The MCS coilovers are covered here: https://g87.bimmerpost.com/forums/sh....php?t=2081879

The M2 is a fun track car in base form. It is a track monster after some good mods. I frequently pass Z08's, GT4's and GT3's of course they could be driving conservatively.

Where do you have MDM set?

[ZPD]

Originally Posted by priitserk

2) Brakes... bad, really bad. No feeling at all, really hard to be consistent. They overheat very quickly. I almost smoked them in the first session and its miracle the car did not catch fire... 7-8 fast laps and you need 2-3 cooling laps. Brake duct caps were removed as needed. Is it the traction control that smokes them or the cars weight, don't know yet. Will need to test more.

If you have traction control set to one of the higher numbers, you will burn through your rear brakes quickly. The car will activate your brakes when you come out of corners reducing your exit speed. The higher the setting the more the brakes will intervene. If I understand it correctly if traction control is set between 0-4 then the rear brakes are not used (or rarely).
If you are driving right your rear pads will last 4-5 times longer than your front.

[vranko]

Originally Posted by ZPD

If you have traction control set to one of the higher numbers, you will burn through your rear brakes quickly. The car will activate your brakes when you come out of corners reducing your exit speed. The higher the setting the more the brakes will intervene. If I understand it correctly if traction control is set between 0-4 then the rear brakes are not used (or rarely).
If you are driving right your rear pads will last 4-5 times longer than your front.

This was not my understanding of how the latest generation M car's stability and traction control systems work. This is based upon watching the BMW M Videos (https://www.youtube.com/@BMWM). Unlike Porsche, which uses the rear brakes for stability control in all modes (even in off, a bit). BMW with Stability On or in MDM uses rear braking to control the cars yaw / attitude. When OFF the car 'only' uses the rear, electronic differential to control traction and how much yaw the car is allowed.

So, I'm not completely sure this is how it works, but this is what I've gathered from reading and their videos.

[ZPD]

Originally Posted by vranko

This was not my understanding of how the latest generation M car's stability and traction control systems work. This is based upon watching the BMW M Videos (https://www.youtube.com/@BMWM). Unlike Porsche, which uses the rear brakes for stability control in all modes (even in off, a bit). BMW with Stability On or in MDM uses rear braking to control the cars yaw / attitude. When OFF the car 'only' uses the rear, electronic differential to control traction and how much yaw the car is allowed.

So, I'm not completely sure this is how it works, but this is what I've gathered from reading and their videos.

I think that we are saying similar things. I said that if you have traction control set at the higher settings then the rear brakes intervene when coming out of corner quickly (which creates yaw). Somewhere between 0-4 (0 being off) the brakes don't intervene.

This much I can tell you from real-world experience: Coming out of turn 11 at COTA, if my traction control is set to 6, my rear brakes will activate, the engine cuts power, and I exit the turn at around 30 mph. If I have my traction control set to 3 then the engine doesn't cut power, I don't notice the rear brakes, and my exit speed is closer to 45 mph.
Also, I will get 6-8 track days out of a set of rear pads. Most people who have their traction control set to a higher number get 1-2 track days out of a set of rear pads. YMMV

[Biglife]

In the stock form, it's not incredible. Too much understeer too - to add to your list. The bare minimum "mods" will make it feel like a much different vehicle:

1. Track alignment
2. Brake pads
3. Brake fluid (SRF)
4. 200 TW tires

It's a night and day difference.

[TallGibbs]

Can someone educate me a bit more on why the stock pads do not feel great initially at the track? With their G-G temp rating I think they would feel awesome for at least a few laps or even in fact the whole time but they would just wear through quickly. Why is the hot temp friction coefficient inadequate? Does track temp loading go even above that and then their bite falls away?

Several of the track pad compounds I looked at (that publish any temp vs friction data) actually show lower friction. So my assumption is that the track compounds just offer more life at the higher temps and not actually much fade resistance compared to a G-G rated pad.

[ZPD]

Originally Posted by TallGibbs

Can someone educate me a bit more on why the stock pads do not feel great initially at the track? With their G-G temp rating I think they would feel awesome for at least a few laps or even in fact the whole time but they would just wear through quickly. Why is the hot temp friction coefficient inadequate? Does track temp loading go even above that and then their bite falls away?

Several of the track pad compounds I looked at (that publish any temp vs friction data) actually show lower friction. So my assumption is that the track compounds just offer more life at the higher temps and not actually much fade resistance compared to a G-G rated pad.

I think that it depends on the track. If you are on a milder track without ~100+ mph deltas in speed at a braking zone then stock pads will probably be fine. Honestly, I am impressed with the balance that BMW struck with the stock pads regarding often competing characteristics of brake dust, noise, aggressiveness, modulation, etc. It is a decent attempt at a one-pad-fits-all driving condition. I think most of the complaints I have read were about how quickly they wear out in aggressive driving.

With that said- the pic below is not on stock pads; I wouldn't put the stock pads through hard braking like that. If you want a track-focused pad there are better track options but these will have downsides for day-to-day driving.