[ndyvidual]

In an earlier post, I was struggling to get the corroded brake dust form my beautiful street wheels. I decided just to get them refinished. The shop did not spray the lug nut or the mounting surface, but here's evidence that the small overspray was present and it does indeed compromise clamping strength.

When removing the wheels to prep for my upcoming track event, There was a thin layer of power coat present as you can see with this flaking. The front nuts came off easier than expected which means after my last fastening, they loosened up due to this flaking become mobile.

So the point is: clean your wheel mating surfaces and check your lug nut torque after some distance when mounting new wheels.

[ndyvidual]

A few months ago, I noticed a louder than usual clunking from the front suspension. The TCK's have a subtle clunk which I've accepted, but this recent noise was quite louder. Something 'loose' while on track would not inspire confidence. I located the source though: corroded thrust bearing which was notchy when articulating and binding.

I used the Fall Line tension strut bearings because options were limited at the time. Now Bimmerworld has reused the OE ball joint into an assembly that gives me precise articulation and protection from the New England elements. So I switched to them and have been very happy.

You can see the difference....

[ndyvidual]

Small update:

I'm constantly trying to work on cars more efficiently. During my last brake fluid flush, I was reminded of how much 'gymnastics' my usual Blue Point flex head requires to open and close the bleed screws...particularly the inside screws while my bleed hose is connected

Over the years, I've been buying less Snap-On/Cornwall/Mac tools and moved to Icon and most recently, Tekton with very good results. The latest arrival is a new Tekton 11mm wrench that has more head angle to better access the bleed screws with ease. I recommend it.

[ndyvidual]

I'll be at Road Atlanta and Barber Motorsport Park [in Alabama] in June. Before I cover the car with every bug along the east coast + someone's Hoosier track tire rubber, the car was in need of a cleanup. So I bought out a different set of tools.

After using the clay pad and detail spray, I used Menzerna high cut compound and then followed it up with Sonax's Polymer Net Shield. I use this compound every two years; I usually try get away with the less aggressive cut of the Perfect Finish to preserve my clear coat thickness.

No need to use the Sonax Paint Cleaner since the clay pad cleaned up so well. It's a great product. I only use my 3M clay when I need to clean small areas. Overall, the results were very good.

[ndyvidual]

I had one rotor screw seize. Had to drill/cut/tap. I'll need to make a note to get some stainless steel screws that F87source had reviewed.

[F87source]

Originally Posted by ndyvidual

I had one rotor screw seize. Had to drill/cut/tap. I'll need to make a note to get some stainless steel screws that F87source had reviewed.

Yeah that sucks man, these factory screws really are sub par... The stainless steel rotor bolts will really help fix that issue.

[ndyvidual]

With the M2 waiting for the epic road trip in a few weeks, I turned my attention to some routine maintenance on the Porsche. With its tires needing replacement, I removed the wheels from the car to prep them before taking them from the tire shop.

I pried the weights off to clean up the new (and old) adhesive with my handy adhesive wheel that I used for removing the wing earlier in the journal.

I followed it up with Stoner's Tar and Sap remover and it was done. I recommend it.

[ThreeStripes]

Originally Posted by ndyvidual

I'll be at Road Atlanta and Barber Motorsport Park [in Alabama] in June. .

I’ll try and stop by and say hey. Interested to see what kinda pace those Hoosiers bring.

[ndyvidual]

Originally Posted by ThreeStripes

I’ll try and stop by and say hey. Interested to see what kinda pace those Hoosiers bring.

Oh, nice...it's great to meet new car people! My schedule is:

June 13: Road Atlanta (Racing for Carolyn)
June 15, 16: Barber Motorsport (Porsche Club of America, Alabama Region)

I'm not running Hoosiers though....Nankang's CR-S V2 are my 2023-24 season tire of choice

[ndyvidual]

What went well
• The trip from Boston to Atlanta metro is LONG. Taking two days to get there was a good decision to pace myself.
• Adding a third brake light to the trailer I’m sure avoided several rear end collisions through the congested highway sections.

What didn’t go well
• I have a track prep spreadsheet that I always follow. One item is to install race pads before starting the trip. Because of the long drive, I didn’t want to put 1k street miles on them so I packed the tools to change the pads in the hotel parking lot once I arrived in ATL. But I forgot to pack the pads! So I had to use the stock OEM pads. Lesson learned: establish a process and follow it.
• It was 95degF air temperature. I changed my shelter approach from a 10ft square canopy to a two person tent. Great idea (quicker setup/breakdown, smaller to pack), but air doesn’t flow through it very well when the run/sun layer is added. I’ll add two large clothes pins to my pack list to hold the side flap up to allow air to travel though.

What would I change to improve performance at this track?
My 2024 suspension settings worked great here. I was able to get up on the curbing on the exit at the top of the esses with complete composure. Also, the bumps on the back straight didn’t disturb the chassis much at all. Soft springs for the win; I wouldn’t have changed anything other than more seat time (and my race pads installed) to find another 3 seconds.

Closing thoughts

This is my first time at this track and I learned it quickly and refined my technique after chatting with a local instructor while we reviewed my VBOX data and video. Since I was new, they placed me in the Intermediate group. I love this track; I wish it was closer to me. It’s like Lime Rock and Club Motorsports had a baby named Road Atlanta.

The Nankang CR-S V2's have soft sidewalls when pushed. You can see where my witness mark is rubbed off. Something to watch...

In an earlier post I talked about coding my braking settings. I suspected that my change to a different race compound (Porterfield to Cobalt) could have been more effective [in preventing rear instability at high speed braking zones] than the coding was. Since I left my Cobalts at home for this trip, I could confirm that I DIDN’T need to wrestle the car in the braking zone on stock pads. So, to me, the coding changes were quite effective.

And, lasty, I’ve seen many Internet comments criticizing the stock brake pads for track use at faster paces. I was hesitant to push once I found my racing line, but these pads impressed me by taking everything I threw at them in the afternoon... even in the extremely hot track conditions. I NEVER lost my pedal.

I use Castrol SRF so I’m sure that was the key. My personal best here was 1:45:83; on pace with the advanced group (which I probably should have moved into based on the number of point by’s received). Good job BMW….they worked great for my driving style and I was working them like my Cobalts. Takeaway: don’t think you need to spend $1000 USD on track pads to be competitive at DE events; start with just some good brake fluid.

My conclusion: On a scale of 1 (worst) to 10 (best)… I gave the track a 9; the facility a 7.

[medphysdave]

Any thoughts on the soft sidewalls and what could be done to avoid getting over on the edge? I'm seeing similar with my setup

[ndyvidual]

What went well
• Same as Road Atlanta: the stock brake pads and rotors (with Castrol SRF) handled everything I subjected them too despite over 100degC air temperatures.
• The PCA Alabama chapter members and the Barber staff workers were super friendly and accommodating. Challenging track; requires a new suspension setup. The facility is top notch and the art throughout was impressive…including the Attack On Titan-like woman in the pond.
• The car itself made it through without incident/failure for 51hrs of driving along the east coast, multiple track days all while pulling a full trailer from state to state. BMW did well. The ownership trauma from my previous E46 M3 in post #1 are melting away every month I own this car, haha…

What didn’t go well
• It was as hot as a furnace set to broil. It was difficult for the body and the tires/wheels/brakes.
• Sidewall rolling on the outside, left front tire failure on the inside

What would I change to improve performance at this track?
More seat time. Maybe a little more camber on the left side only. A pyrometer would be helpful to optimize the final setting.

Closing thoughts

All things tires…
Despite its beauty, this track is brutal on tires. It was worse than any track that I’ve encountered. Long, off-camber right hand turns just aggravated my CR-S v2s’ sidewalls. There was ONE INCH of rubber between the wheel rim itself and the top of my sidewall witness mark. And the terrible heat amplified things. My paddock neighbor (local guy) brought front and rear LEFT’s with him as a precaution for his Carrera…as did others.

Though rolling on the sidewalls never posed an issue and I do not think it was related to the inside edge failure. I had a few things came to mind to limit this tendency though:
• Run slightly higher front pressures. I normally run 34psi. A few more pounds could help.
• Add more cool down laps during a session to give the tires a rest. I’m really bad at backing off during a session. It’s not like I’m going chase down a run group full of GT3’s anyway.
• Increase spring rate to limit the ease of weight transfer laterally. I'm running 400lbs front, 700lbs rear. Maybe +100lbs?
• Increase rebound on the right side only to add resistance of weight transfer from the right to left.
• Switch back to AR-1’s (which were not as soft) or try another tire model in the future. I have some ideas for this.
• Move to 35 series tires instead of 30's so that % of sidewall that is rolled is reduced.


Another new observation: Tire rotating on the wheel…all four were moving as shown by witness marks across the tire and wheel. Root cause: excessive heat and heavy braking. I run TPMS in my track wheels to get an advance notice of any issues. During the last few laps of the late morning session, the front left sensor was reading 97degC/34psi while the other three were in the lower 80's. During the next session, the left front tire failed. When I was switching over to the Michelin’s, the tires and wheels were so hot I couldn’t hold either surface without pain despite waiting 20min to allow the lug nuts to cool down.

My conclusion: On a scale of 1 (worst) to 10 (best)… I gave the track a 6.5, the facility an 11 and Alabama’s weather a -3.

[ThreeStripes]

Great read. Glad you enjoyed it. I passed through briefly but missed ya.

Re: the left side rubber taking a beating… Some locals even run a hair more camber on the driver side to mitigate that uneven wear. Weird the CR-S failed like that.

What sort of lap times were you managing with the insane heat?

[ndyvidual]

Originally Posted by ThreeStripes

Great read. Glad you enjoyed it. I passed through briefly but missed ya.

Re: the left side rubber taking a beating… Some locals even run a hair more camber on the driver side to mitigate that uneven wear. Weird the CR-S failed like that.

What sort of lap times were you managing with the insane heat?

This should more than answer that

[ThreeStripes]

Very cool. Thanks for sharing.

[ndyvidual]

Next week I'll be at WGI hosted by Ferrari Club of America's Empire State chapter. Three days will really push consumables. I finished a thorough inspection on both the M and my track trailer and found a nail in one of the trailer tires. So the trailer is up on a bucket with no wheel on while I wait for my Tire Rack delivery.

Don't overlook your trailer during tech inspections!

[ndyvidual]

What went well
•I had a lot of fun as usual and I was able to keep a very healthy pace and with the help of a friend, I found time in a few corners. And the bus stop's entry has been modified this year to it's flat curbing on the right side. So I started to enter it like Mid-Ohio's bus stop.

What didn’t go well
• Engine belt failure took the entire car down. Too long of a story. See photo.
• Sidewall left front tire failure on the inside...again. Alignment is confirmed OK.

What would I change to improve performance at this track?
This track is so smooth, I could go up on spring rate with no ill effects. More WOT, commit. Find how to get more grip on this chassis. I'm pushing the TW200's to their slip angle limit. Brake compounds are great. I don't need more power.

Closing thoughts
So let's find the true root cause of the tire situation because these tires aren't free nor is the lost track time due to these issues:

Problem Statement: The left front tire lost pressure.
Why?: The side wall edge had ruptured.
Why?: It came in contact with the spring perch ring edge and was compromised due to be cut.
Why?: Cornering forces during right hand turns caused excessive tire deflection (e.g. sidewall rolling over on the outside edge which results in sidewall extending inward on the inside edge which could make contact with the spring perch).
Why? Soft side wall construction combined with tight clearance.

Corrective Action: Find a tire that has a stiffer and taller sidewall and also is slightly narrower to allow for my spring perch clearance. Add witness marks to the INSIDE of each tire (in addition to the usual outside) to get confirmation that clearance is maintained (or not).

I have an exciting solution in my possession and that's got very good fitment. My next track event is VIR with Chin on November 18, 19th. Will report back after the event...wish me luck and I hope the temps stay above freezing.

[Nuggs]

I loved reading your thread.
I just purchased a '19 M2C and I'm curious what fluids I need to look at and flush. I'm handy, but never have fully done fluids on a car and am unaware at why I need to.

FYI. THAT TRAILER IS the opposite of hillbilly.