F82 M4 light weight measurement and Road Atlanta review observations

[karussell]

     Featured on BIMMERPOST.com

So this past weekend I took the M4 for its first stateside track visit. I was instructing with Chin Motorsports, a very competent group. All of the drivers are top notch from weekend warriors to pro's and club racers.

As you may know I organized and drove at SPA and the Nurburgring during our epic Bimmerpost sponsored - I'm Delivered event back in June. Changes I made to the car for this trip was Carbotech XP10 brake pads front and back, studs, 12.5mm spacers front, 10mm spacers rear, removed the rear seat (top and bottom). thats it. even had the same brake fluid from delivery and previous track days. The M4 currently has 3400 miles on it.

Ok so first the weight of the car. My car has the following options.

YMB paint
Adaptive Suspension
USB bluetooth

Thats it. I have cloth seats and 18" wheels. It is running the same MPSS tires in original sizes from delivery. I maybe saved a pound on tread from Europe already


Here is the the weight with 1/4 tank of fuel and just the miscellaneous crap pulled out of the car that isn't attached like floor mats and that ridiculous cup holder cover. 3416 lbs.



After the baseline measurement, I removed the rear seats just to see what we could easily drop the weight down to.
The thread on removing the seats is here. http://f80.bimmerpost.com/forums/sho...3#post16695193

After just taking out the seats i'm left with 3376lbs which is not bad at all. The rear seats weigh 40lbs btw. (cloth in coupe)



After playing with the weight I then had the carbotech XP10's installed provided by IND. My review on just the brakes is also separately posted here. http://f80.bimmerpost.com/forums/sho...6&postcount=56

Road Atlanta... If you haven't been and you can make it out I highly recommend trying this epic Petit lemans track out. Its gotta be one of the fastest courses in the country and at the speed you carry in several in the corners its highly technical. This track is ideal for the F8X platform.

Revisited Brakes: 9/10 (50% used front 30% used rears, original fluid)

So I had my friend come out in his F80 M3 and we went for a hot session with it being bone stock except for a set of aftermarket 20 inch wheels and Hankook tires. The same brake pads from factory with same fluid and these were well used and abused in europe on our delivery at SPA and the Nurburgring. Examining the fronts there was about 50% of material left before we began. The brakes still held their own on a very hard track for brakes. we have a back straight approaching a tight left right combination from 150mph down to about 50mph. Its brutal in 300 meters which is about the same brake point as the gt3's that day. Lap after hard lap these brakes just amaze me. only after 20 minutes into it did my colleague notice a hint of sponginess in the pedal. still perfectly able to complete laps but also predictable considering their condition to begin with. Have a cool down lap and likely they would be back for next session although we didn't have an opportunity. We did try a nice easy back straight scrub of material on the disks and cooling before coming into the pits rather than a hot pit in. There was still some noticeable pad deposit on the rotors but very minor. That should wear off in a few days of driving.

Revisited Adaptive Vs. Passive Adaptive 9/10 Passive 8/10

Trying to be unbiased here but i noticed with the passives in my friends car a distinct squat when threshold braking momentarily delaying throttle application as the car was settling. I believe the passive shocks are just a tad too soft for such a smooth fast course requiring very rapid weight transfer to occur that the passives simply could not keep pace with.

On adaptives i had a much more linear transition. My only limiting factor is too narrow tires for the exit of turn 7 (right angle bend leading to front straight) this was a key point as I noticed in the passive suspension equipped car we had to ease throttle input by another ten feet as we unwinded the wheel more. That extra time spent settling the car possibly means a gap of 50 meters in the end of this straight. I experimented with sports and sports plus settings. sports plus was definitely more responsive for me. and even in sports plus when you attack a burm like on turn 3 the suspension soaks it up so well and you can continue to apply maximum pedal through it.

DSC Off MDM and DSC On Revisited.

DSC On - Still useless on track even for a new student after their first session it cuts in way too aggresively.

MDM - Quite intrusive actually on this track. Its such a fast course with rapid transitions in weight that I think it just freaks out too easily. For an average student they would still cause the stability control to spark in several areas of the course while being about as smooth and gradual as possible. Leads me to wonder if we have a US version that is "dumbed down" versus the EU spec.

DSC Off - Old School and the only way to drive this car fast on this course.


Manual Transmission Revisited 9/10 - still great. still very easy to throttle blip manually. shifts are clear. no worries on misshift at all. its not the rifle bolt from the porscche gt3 but its no wood spoon in bucket of cake batter either. It could still use more weighted shifts. I will be working on resolving that shortly.

Engine Revisited 9/10

Engine sound to me has slightly changed after 3000 miles. The car is even more angry hungry with the valves open. god the wastegate swhoosh noises and back burbles this car makes on throttle lift are fucking awesome.
Engine what can i say.....my favorite BMW engine ever! revs like a NA motor so much torque though. gobs of it. true story. upload video later. it will keep pace with a 997.1 Turbo running R comps on the back straight. in fact i'm pretty convinced this car is faster from roll. also GTR's used to be pinpoints on long straights. they still stay ahead but now they crawl rather slowly away from a MT M4. what the hell is in this motor! I would give it a 10 honestly but hoping the M4 GTS will be the highest mark. GT3's on straights not really got much going for them compared to the M4. of course they rule in the corners and rightly so.

Michelin Pilot Super Sport Tires 8/10

I am only giving these tires an 8/10 instead of higher marks because I think BMW really should have offered a wider tire for this car. 275 really is way too narrow for a car putting this much power to the ground. It is my opinion that all the major reviews mark this car slightly lower on their relative rankings because of this one parameter. The tires are the most important part on any vehicle especially one that has to navigate around a closed course in all conditions and get you home afterwards. I have been part of the group of GT3 owners that begged Michelin to make this amazing tire in our sizes so I am a long time user and fan. To date I have owned and tracked 5 sets of these tires on 3 different cars plus driven in countless other cars running them. There is no R compound tire that matches this tire in the rain or damp conditions. In the dry this tire is slightly slower than a Toyo R888 but will last 3x longer if heat is managed. The key is these tires do heat up quickly and you can't drive them over heated. On Road Atlanta even in cool weather they work well for 20 minutes. then you must cool them down. wider widths likely will greatly fix this. The MPSC and MSPC2's are hands down much much faster but even the slightest hint of rain and every GT3 equipped with them is grounded unless the drivers are Scandinavian. for the F8X platform I find hot pressure optimally at road atlanta is 36F/35R. that will utilize the entire tread block and maximize contact patch which is critical. I'm still debating what to switch to as my oem tires are about due for replacement now. i would like to get a set of wheels that are wider and run 275/295. before all M3's loved a square setup. I don't think this car needs it as its so neutral already.

Overall 9/10

I'm still amazed this car is pretty much stock. hell its nice to know i just rolled up took my bag out the trunk and was ready. i think 9/10 cars in my group are running R compound or full slicks. many fully dedicated track cars that are towed to the track in trailers. and you know what the M4 can hang with most of them if not outright go right past them. the only limiting factor is the MPSS tires get greasy quite quickly on such a fast course. after about 20 minutes the car will get quite loose. She needs 275/295 setup i think if going to stick with street tires. its so easy to get the tail out on exit of turn 7.
also this car is not as easy to drive at the limit as previous M3's. just like some much more expensive sports cars it transitions from understeer to oversteer quite readily. 4th gear counter steering is normal on road atlanta with street tires in this car. buyer beware. build up speed gradually.

respect required.

some photos from the day. love this car! enjoy in good health ladies and gentlemen!

Thanks to the fine folks at IND for the superb support getting my parts i needed just in time!
Thanks also to my technician at our very own shop still getting started... RSAugusta
And finally Terrence with our other joint venture that organized the euro delivery tour... RSTouring.
more to come!!!

[SakhirM4]

Great posting!! Thanks.

[Suave]

Outstanding write up and review as usual. I am always learning something from your articles on the forum and a pleasure to have worked with you on the ED trip and with big things to come in the near future. I was just thinking how amazed I am that you are still using the original 18s that were delivered with the car in Munich. I mean nobody ran the car harder, longer, or drifted more than you did by a huge margin and these tires just keep performing. I need to stop being such a wuss and drift my M3 a little more and stop worrying about early tire wear

[karussell]

Originally Posted by Suave

Outstanding write up and review as usual. I am always learning something from your articles on the forum and a pleasure to have worked with you on the ED trip and with big things to come in the near future. I was just thinking how amazed I am that you are still using the original 18s that were delivered with the car in Munich. I mean nobody ran the car harder, longer, or drifted more than you did by a huge margin and these tires just keep performing. I need to stop being such a wuss and drift my M3 a little more and stop worrying about early tire wear

The ED trip will live on forever in my memory as the most epic trip.
You reminded me I left out the review on these fantastic tires. I will update the original post.

[Lynchmob6]

Thanks for the great post...excellent!

[JoeFromPA]

Weight: Awesome comments. Your car, without floor mats, weighed ~34 pounds less than my f80 m3 with almost identical setup when weighed. Nice to see consistency there. Great info on the rear seat too!

Tires: If I've read you correctly, you've got 3400 miles on the rear tires with alot of that being on the ring and various U.S. tracks. How's the tread/treadlife looking?

I really didn't want to "want" more tire in the rear, but I find myself agreeing. That being said, I love how the M3 can both hookup beautifully, wiggle its tail alot in MDM mode, or do full on slideways....and perhaps M liked that character too and decided not to equip the rear with, say, 295 wide for that reason. Maybe it wasn't as willing of a dance partner.

I remember my 99 boxster, a fairly underpowered car already, on 265/30/18 michelin pilot sports. It had endless traction considering that width, the engine power, and the mid-engined design.....but it was less playful for it. I found myself wishing I had the compliance of the original tire spec for that car: 225 wide on 16" wheels.

Anyway, just speculating. How do you like the spacers when it comes to track use?

[karussell]

Originally Posted by JoeFromPA

Weight: Awesome comments. Your car, without floor mats, weighed ~34 pounds less than my f80 m3 with almost identical setup when weighed. Nice to see consistency there. Great info on the rear seat too!

Tires: If I've read you correctly, you've got 3400 miles on the rear tires with alot of that being on the ring and various U.S. tracks. How's the tread/treadlife looking?

I really didn't want to "want" more tire in the rear, but I find myself agreeing. That being said, I love how the M3 can both hookup beautifully, wiggle its tail alot in MDM mode, or do full on slideways....and perhaps M liked that character too and decided not to equip the rear with, say, 295 wide for that reason. Maybe it wasn't as willing of a dance partner.

I remember my 99 boxster, a fairly underpowered car already, on 265/30/18 michelin pilot sports. It had endless traction considering that width, the engine power, and the mid-engined design.....but it was less playful for it. I found myself wishing I had the compliance of the original tire spec for that car: 225 wide on 16" wheels.

Anyway, just speculating. How do you like the spacers when it comes to track use?

haha, well that is a boxster and this car has nearly 100ft lbs of torque over a 3.8RS with 325's. I am pretty sure i can slide around in a perfect figure 8 with 275/295's if someone is willing to loan me a set.

tire wear appears pretty good so far on the rears. fronts still look new. I will measure tread depth maybe tonight when we are working on the car some more.

MDM does not allow for much tail wagging. I find its intervention actually more of a hindrance than an aide. I think really of it as a comfort blanket. Its a useful tool for someone learning the car considering the power this motor has but I think its still completely safe to learn to drive in this car with DSC off and gradually build up along with going to plenty of autocross events to work on maximum car control.

[JoeFromPA]

Originally Posted by karussell

haha, well that is a boxster and this car has nearly 100ft lbs of torque over a 3.8RS with 325's. I am pretty sure i can slide around in a perfect figure 8 with 275/295's if someone is willing to loan me a set.

tire wear appears pretty good so far on the rears. fronts still look new. I will measure tread depth maybe tonight when we are working on the car some more.

MDM does not allow for much tail wagging. I find its intervention actually more of a hindrance than an aide. I think really of it as a comfort blanket. Its a useful tool for someone learning the car considering the power this motor has but I think its still completely safe to learn to drive in this car with DSC off and gradually build up along with going to plenty of autocross events to work on maximum car control.

Yes, I use MDM as a learning tool myself - so I totally agree with you. I actually just realized that i'm not redlining it nearly enough since break-in service was done....because I find myself so readily shifting early

Good stuff on the fronts...if they look new, that speaks volumes about their ability to handle the front weight of the vehicle and I think 255 wide fronts are perfectly suited to this car.

You are probably right about tires, width, and power I'm not finding too many problems with daily traction (non track) with roll-on power application. So far I'm actually a better driver with smoother inputs on the f80.

Anyway, how do you feel about the spacers? Any changes to driving demeanor? I do like the look but historically not a huge fan of spacers, but I take your experience with some hefty weight, so I ask.

[karussell]

Originally Posted by JoeFromPA

Yes, I use MDM as a learning tool myself - so I totally agree with you. I actually just realized that i'm not redlining it nearly enough since break-in service was done....because I find myself so readily shifting early

Good stuff on the fronts...if they look new, that speaks volumes about their ability to handle the front weight of the vehicle and I think 255 wide fronts are perfectly suited to this car.

You are probably right about tires, width, and power I'm not finding too many problems with daily traction (non track) with roll-on power application. So far I'm actually a better driver with smoother inputs on the f80.

Anyway, how do you feel about the spacers? Any changes to driving demeanor? I do like the look but historically not a huge fan of spacers, but I take your experience with some hefty weight, so I ask.

we have spacers on our N24 race cars and the wheels have not fallen off yet....well not because of the spacers at least

wider track is always preferred. i think the heavier the car the more width it can use.

i use studs prefer them. check multiple times with torque wrench however.

[von_zoom]

How are the seats? Assume they were stock with factory belts. Do you stick to the seat, proper support.... or like my E92, I had to ware knee pads to prevent my legs from brusing from the pressure of resting the against the door and center to hold me stable. Never did like that. Six point belts and proper seats are the way to go.
Thanks
vz

[karussell]

Originally Posted by JoeFromPA

Yes, I use MDM as a learning tool myself - so I totally agree with you. I actually just realized that i'm not redlining it nearly enough since break-in service was done....because I find myself so readily shifting early

Good stuff on the fronts...if they look new, that speaks volumes about their ability to handle the front weight of the vehicle and I think 255 wide fronts are perfectly suited to this car.

You are probably right about tires, width, and power I'm not finding too many problems with daily traction (non track) with roll-on power application. So far I'm actually a better driver with smoother inputs on the f80.

Anyway, how do you feel about the spacers? Any changes to driving demeanor? I do like the look but historically not a huge fan of spacers, but I take your experience with some hefty weight, so I ask.

daily traction of course there is no issue unless you want to have police lights and neighbors shaking their fists at you. 255 i agree are good size. 275 better. the e9x could heat up 275 fronts quite well. actually its most preferred spec is 275's squared. on the e46 it was 265 square. this car i think 275/295 would be very nice indeed. and also i think going up on the fronts will keep it proportionally neutral. just it will launch harder on late apex low speed turns. look at road atlanta's track map. turn 7. if you can get just 1mph faster on exit of that turn you can carry that faster speed for that entire damn straight. thats seconds off a lap time. and i think this change alone will net more than a 1mph gain. more likely 5-10mph using same tire compound.

[karussell]

Originally Posted by von_zoom

How are the seats? Assume they were stock with factory belts. Do you stick to the seat, proper support.... or like my E92, I had to ware knee pads to prevent my legs from brusing from the pressure of resting the against the door and center to hold me stable. Never did like that. Six point belts and proper seats are the way to go.
Thanks
vz

stock seats especially with the fabric hold you in quite well. the bolsters are generous. its much better than the e9x design which in US form used the standard 3 series base cushion. i didn't find myself fatigued from holding myself in the seat. this car is just begging for some fixed back buckets, a roll bar, and 6pts though.

[X2Board]

Originally Posted by JoeFromPA

I remember my 99 boxster, a fairly underpowered car already, on 265/30/18 michelin pilot sports. It had endless traction considering that width, the engine power, and the mid-engined design.....but it was less playful for it.

Joe, you just brought back a lot of memories of my '99 Boxster. I ruled the Northwest Hills of Connecticut with that car. It was playful enough when fall came and the temps were low. I got caught out in snow once and that was more "play" than I wanted.

I had a GHL Exhaust that you could hear from a mile away.

http://vidmg.photobucket.com/albums/...rs/GHL1MOV.mp4

[myzmak]

Great post and fantastic pics.

It is nice to get consistent respect from a driver with your background.

[///M///]

Originally Posted by karussell

Revisited Adaptive Vs. Passive Adaptive 9/10 Passive 8/10

Trying to be unbiased here but i noticed with the passives in my friends car a distinct squat when threshold braking momentarily delaying throttle application as the car was settling. I believe the passive shocks are just a tad too soft for such a smooth fast course requiring very rapid weight transfer to occur that the passives simply could not keep pace with.

On adaptives i had a much more linear transition. My only limiting factor is too narrow tires for the exit of turn 7 (right angle bend leading to front straight) this was a key point as I noticed in the passive suspension equipped car we had to ease throttle input by another ten feet as we unwinded the wheel more. That extra time spent settling the car possibly means a gap of 50 meters in the end of this straight. I experimented with sports and sports plus settings. sports plus was definitely more responsive for me. and even in sports plus when you attack a burm like on turn 3 the suspension soaks it up so well and you can continue to apply maximum pedal through it.

Great thread So based off your review on the adaptive suspension, is that option really needed on a car that will primarily only see the street and never the track? What setting on the adaptive does the passive most feel like? Sport?

[Needsdecaf]

Originally Posted by X2Board

Joe, you just brought back a lot of memories of my '99 Boxster. I ruled the Northwest Hills of Connecticut with that car. It was playful enough when fall came and the temps were low. I got caught out in snow once and that was more "play" than I wanted.

I had a GHL Exhaust that you could hear from a mile away.

http://vidmg.photobucket.com/albums/...rs/GHL1MOV.mp4

\

Arena Red. My friend had a '99 Boxster in same color. We had some fun in that car.

[Needsdecaf]

Karussel:

What made you choose the MT over the DCT? For someone who is going to track the car often, I would have thought it would be opposite.

[Boss330]

Great write up!!!

[solstice]

Originally Posted by Needsdecaf

Karussel:

What made you choose the MT over the DCT? For someone who is going to track the car often, I would have thought it would be opposite.

That's easy. He don't want to give the MT guys on the track any excuses when he blow pass them

[RocketBoots]

Thanks for the follow-up reviews. Would you say there was a noticeable difference, for YOU, after shedding the ~40lbs of rear seat?

[Sean@PSI]

Great write-up. Hopefully I will see you on the track soon!

[gthal]

Great review... your pics are HUGE!! I can't see all of them without scrolling. Maybe just my computer.