3002 tii’s Track Day Journal

[3002 tii]

I used to hit the race tracks regularly but between life events and what not, I've been out of the game for a while. After spending the last 2.5 years getting my M coupe in order, I've recently started logging more days. So I figured why not start a track day journal to keep track of my progress (and failures) as opposed to the usual build thread.

2006 BMW Z4 M coupe
Imola Red on Imola Red
Carbon fiber trim
(1 of 37)

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[3002 tii]

The goal was to create a capable track weapon that could be driven comfortably to/from the track. Think OE quality, street legal, with full interior, or what I jokingly refer to as my Z4 M GTS. The car will primarily be used for open lapping with the occasional Time Attack events. There are too many mods to list but here's a list of the major ones.

Weight-to-Power	Wheels & Brakes
3230lbs with half tank of fuel 337whp | 256lb-ft See latest dyno here	18x9.5 Apex ML-10RT 255/35-18 Falken RT-660 996 Brembo kit + Hawk DTC 70/60
Engine & Drivetrain	Aerodynamics
Epic Alpha-N tune Euro headers + SS x-pipe TMS CSL intake v2	APR GTC 200 wing APR gurney flap APR front splitter + custom air dam
Suspension	Safety
MCS 2WNR coilovers (600# | 700#) Ground Control camber plates TMS adjustable rear camber arms CSL front sway bar	Wiechers bolt-in half cage Sparco QRT seats Schroth Profi II ASM harnesses Element E100 extinguisher

 

[3002 tii]

I'll start with last Nov 2024 when I visited New Jersey Motorsport Park (NJMP) for the first time in 8 years. NJMP is pretty neat in that they have two different tracks, so there are usually two different events on the same day. That weekend I was at Thunderbolt Raceway with the Porsche Club of America (PCA).

I managed to throw on my APR rear wing just days before so it was be my first time driving with aero. Despite being rusty, the difference between with and without aero was very apparent. High speed corners could be taken much flatter, especially T3 where admittedly, I’ve had my share of two wheels off in the past. But this time around, the car just stayed planted, thus allowing me to get on power sooner. Coming into T4 - same story; with just a slight tap on the brakes, I am able to stick the turn with higher Vmin.

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Best of all, I got to run with a fellow board member Andre, who has 2JZ swap in his Z4 coupe. Andre is an instructor level driver and was nice enough to help me relearn the driving line haha. And yes, those are flames shooting out from his exhaust! By the end of the weekend, I was able to put down a 1:32.4.

Nov 2024
Track: NJMP - Thunderbolt
Club: PCA Schattenbaum
Fastest Lap: 1:32.4


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[Ed Doe]

Cracking idea getting a track journal up, I'll be following with interest Might even make me pull my finger our and get one up for my old nail :lol:

Was this the outing which saw the failure of your rear-end polybushes (per our discussion on Insta a few weeks back)?


One question right off the bat - what do you use for your cam/editing/datalog overlay setup?

I've got an old GoPro which seems to work fine for the actual capturing of video, but I've not yet found a decent bit of software to easily stitch and edit the videos together and/or to overlay the data, and I really don't want o end up filming it on my phone because I think the GoPro does give clearer footage in that application....!

Cheers

 

[3002 tii]

Was this the outing which saw the failure of your rear-end polybushes (per our discussion on Insta a few weeks back)?

No, those poly diff bushings failed more recently in June 2025. I actually did not capture any video that day because my laptimer app was acting up (see below).

One question right off the bat - what do you use for your cam/editing/datalog overlay setup?

I've played around with few different software & hardware but all my videos are processed/edited from iPhone. The videos above were captured using Harry's Lap Timer but I recently switched to RaceChrono. Though I've been a fan of Harry's from the beginning, I encountered increasingly more issues with each software update. It's a fantastic product, but it feels like an app designed by engineers for engineers. On the other hand, RaceChrono's UX may appear more basic but it has ton of features and most importantly, it just works.

I also use an Aim Solo 2 DL that is wired into the vehicle's canbus. It captures way more data than what I can retrieve using mobile but there's quite a learning curve with their desktop software. But at min, I also use it as a backup timing device and it's the "standard" among racers here so it's easy to compare data w/ fellow drivers.

I've got an old GoPro which seems to work fine for the actual capturing of video, but I've not yet found a decent bit of software to easily stitch and edit the videos together and/or to overlay the data, and I really don't want o end up filming it on my phone because I think the GoPro does give clearer footage in that application....!

I find my old GoPro 4 is still the best option due to its simplicity. The GoPro 3/4/Session are controlled remotely using WiFi only, whereas newer models connect using a combo of Bluetooth & WiFi. This is an important distinction because if you use other external BT devices (e.g., OBD reader, external GPS, etc.), it may cause Bluetooth conflicts. Now that's not to say you can't use newer cameras, but you may either have to limit what other Bluetooth devices you use OR record (and sync) the video manually, which is a little annoying imo.

Lastly, newer cameras boast better image stabilization features which is great if you're walking around with a selfie stick. But the lack of image stabilization on the older cameras is what makes them better for track driving as you don't lose the driving dynamics (i.e., stabilization = smoother which makes videos look slower).

 

[3002 tii]

I just came back from a weekend at the historic Watkins Glen International. For those less familiar, The Glen has a deep racing history, having hosted F1 from 1960-80. Today, major races held at The Glen include NASCAR and IMSA. There's no better rush coming down the main straight seeing the grandstands to your side. With tons of elevation change and banked sweepers, it's easily top 5 on my list.


I was last here 2.5 years ago with my M roadster, which was more of a weekend car. I think a more relevant comparison is my first track prepped N52 coupe from ten years ago. Both cars have very different power outputs, so it’s not exactly apples-to-apples. However, the 3.0si chassis is lighter, more nimble and better balanced.

Whereas with the Z4 M, I can feel that 150lb weight difference, as it’s all in the front making the car nose heavy. It’s really a shame that the engineers at BMW didn’t move the S54 back closer to the firewall by another 2-to-3 inches. That alone would have drastically improved the handling of E85/E86, almost analogous to the 987 vs 996 but I digress…

In any case, don’t let the lap time delta fool you. Hardware differences aside, I was still very green, running in the Novice solo group.

May 2015
Track: Watkins Glen
Club: Genesee Valley CCA
Fastest Lap: 2:31

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Fast forward to July 2025, I just had my speed shop replace my failed diff bushings with solid aluminum mounts. I admit this could be a placebo effect but gear shifts feel crisper under high loads and the car feels more responsive powering out of corners. Additionally, I just finished refreshing the front-end (i.e., tie rods, control arms and FCABs). And so with all this work done, I headed up to Watkins once again with hopes of breaking 2:12 this year.

Till now, I never realized how muddy or vague the steering had become with the original worn bushings. It generally felt "okay", but then again, you don't know what you don't know. With the new setup dialed-in, the steering was now so much sharper, to the point, I found myself turning in too early at T1, T8, and T11 all weekend. However, with each subsequent lap, I started to establish new reference points and find some consistency during the day.




By day 2, the front RE-71RS had over 20 heat cycles so not only did peak grip levels drop, but the tires were getting greasy after 15 minutes. The ambient heat and humidity certainly weren't helping. In order to preserve the outer shoulders, I decided to swap the fronts during the lunch break. It was then, I noticed my front brake pads were quite worn down. While they might've lasted another session, Watkins Glen is not the place to find out the hard way. I was tempted to skip my last session and call it a day. But with the clouds providing temporary relief from the heat, and the track getting progressively emptier as more people started packing up, I said F it! I quickly swapped out my worn DTC-60's for a new set of DTC-70's.




Long story short… you know the DTC-70s are working when can smell that distinct sweet odor when the pads get up to temp. All weekend I was dealing with early turn-in, but now I was over-braking. I reminded myself to stay on throttle longer, go deeper and ease into the brakes. Clipping the T1 perfectly, I found myself using way more of the track limits, riding the NASCAR runoff before quickly tucking back in for T2 leading up to the Esses.

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As a whole, the improved stopping power allowed me to drive with more confidence. Getting able to settle the car sooner allowed me to take a more aggressive line on certain corners. End result, finished a fast lap of 2:13.2.

July 2025
Track: Watkins Glen
Club: Metro NY PCA
Fastest Lap: 2:13.2

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I was three tenths from my goal of cracking 2:12 and my predictive lap was showing I was on pace to do so on my net lap but unfortunately the checkered flag was dropped. On the flip side, I managed to keep the car in one piece and got to catch up with old friends, so all in all, a W still in my books.

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[3002 tii]

Reserved

 

[Z4Dude]

Great video and journal ... massive improvement in timing with the upgrades!

 

[Ed Doe]

No, those poly diff bushings failed more recently in June 2025. I actually did not capture any video that day because my laptimer app was acting up (see below).



I've played around with few different software & hardware but all my videos are processed/edited from iPhone. The videos above were captured using Harry's Lap Timer but I recently switched to RaceChrono. Though I've been a fan of Harry's from the beginning, I encountered increasingly more issues with each software update. It's a fantastic product, but it feels an app designed by engineers for engineers. On the other hand, RaceChrono's UX may come appear more basic but it has ton of features and most importantly, it just works.

I also use an Aim Solo 2 DL that is wired into the vehicle's canbus. It captures way more data than what I can retrieve using mobile but there's quite a learning curve with their desktop software. But at min, I also use it as a backup timing device and it's the "standard" among racers here so it's easy to compare data w/ fellow drivers.



I find my old GoPro 4 is still the best option due to its simplicity. The GoPro 3/4/Session are controlled remotely using WiFi only, whereas newer models connect using a combo of Bluetooth & WiFi. This is an important distinction because if you use other external BT devices (e.g., OBD reader, external GPS, etc.), it may cause Bluetooth conflicts. Now that's not to say you can't use newer cameras, but you may either have to limit what other Bluetooth devices you use OR record (and sync) the video manually, which is a little annoying imo.

Lastly, newer cameras boast better image stabilization features which is great if you're walking around with a selfie stick. But the lack of image stabilization on the older cameras is what makes them better for track driving as you don't lose the driving dynamics (i.e., stabilization = smoother which makes videos look slower).

thanks for the detailed reply man ref your last point, last thing I want is to make my videos look any slower :lol:

Without wishing to appear dense, how do you edit the videos from your GoPro on your phone? I've got a hero 3 which is admittedly a bit ancient now but works really well in terms of the field of view etc. I don't want to get too involved in it all, I frankly don't have the time for cocking about with stuff, I just want to be able to stitch the videos together to get the sessions in one hit, and add a short intro type thing. The data overlay would be great because for my own interest it'd be great for chipping away at times etc and improving consistency. What phone software do you use to edit your videos - does Racechrono have the ability to import your video from Go Pro to edit/overlay your data to?

More than happy to discuss this further via PM to avoid clogging your thread if you prefer dude

 

[AndyBeech]

thanks for the detailed reply man ref your last point, last thing I want is to make my videos look any slower :lol:

Without wishing to appear dense, how do you edit the videos from your GoPro on your phone? I've got a hero 3 which is admittedly a bit ancient now but works really well in terms of the field of view etc. I don't want to get too involved in it all, I frankly don't have the time for cocking about with stuff, I just want to be able to stitch the videos together to get the sessions in one hit, and add a short intro type thing. The data overlay would be great because for my own interest it'd be great for chipping away at times etc and improving consistency. What phone software do you use to edit your videos - does Racechrono have the ability to import your video from Go Pro to edit/overlay your data to?

More than happy to discuss this further via PM to avoid clogging your thread if you prefer dude

I use a GoPro 7, pretty old now and cheap to pick up but takes decent enough footage. Use it with a bit of software called Dashware, takes out the GPS data and you can use it to overlay a speedometer, track map, G force etc.
Stitches all the parts together for you and is pretty easy to use once you know how. Does require a little cocking about but not much if your handy on a PC. Might work with a 3 though not sure if that has GPS data?

 

[3002 tii]

What phone software do you use to edit your videos - does Racechrono have the ability to import your video from Go Pro to edit/overlay your data to?

More than happy to discuss this further via PM to avoid clogging your thread if you prefer dude

No worries! To the extent this is helpful to others, happy to discuss here. The process for your camera should be the same as mine. The specific steps will vary by app of of course, but the general process is as follows:

1. Connect phone to GoPro WiFi network
2. Launch laptimer app and ensure it sees the external camera
3. Begin driving; data & video recording should occur in background.
4. After session is over, import the videos from the GoPro to phone. Two easiest ways to do this are:
   1. Transfer files from within the laptimer app, using the GoPro's WiFi connection or
   2. Copy the files using a Lightning/USB-C to microSD adapter
5. Once videos have been transferred, the laptimer app should now be able to determine which videos correspond to which laps
   1. Note THIS is the whole point of using the GoPro's WiFi connection; seamless linking between video and lap data. If you don’t rely on WiFi and record videos 'normally', you can still import the videos but it then requires you to manually sync the start/end points, which can get quite tedious.
6. To overlay the actual video, this is ALL done within the Laptimer app. You typically choose which laps you want to overlay. If you have OBD data, it will include those parameters as well.
7. Once the overlay is complete, there is usually then an option to export the overlaid video to your Photos gallery.
8. From there if you want to do any further editing, you have your pick of desktop softwares. But for anything basic (e.g. adding an intro), you can easily do that in YouTube after you upload the video to your account.

The Laptimer app I use is RaceChrono Pro. Here's their DIY tutorial which should help visualize how the above works. But to be clear, I do not need any other mobile app. The GoPro ‘Quick’ app is only used once to initially setup the WiFi network. After that, it is no longer required for GoPro 3 and 4.

 

[3002 tii]

I use a GoPro 7, pretty old now and cheap to pick up but takes decent enough footage. Use it with a bit of software called Dashware, takes out the GPS data and you can use it to overlay a speedometer, track map, G force etc.
Stitches all the parts together for you and is pretty easy to use once you know how. Does require a little cocking about but not much if your handy on a PC. Might work with a 3 though not sure if that has GPS data?

If I had to pick a more recent model, I’d go with the 7 Black as well since you really don’t benefit from the other features on later models when it comes to this type of stuff.

For my use case though, I will sacrifice a little video quality (i.e. 1080p 60fps vs 2.7k) if I can do everything from a single mobile app.

 

[3002 tii]

Nothing too exciting but some post-track day maintenance, which generally consists of:

1. Check for loose components underneath the car
2. Inspect rotors & pads
3. Rotate wheels; remove any marbles
4. Oil change (every 4 track days)
5. Basic car wash

I usually leave my track pads on during the season but certain compounds (e.g. DTC-70) are known to be very harsh on wheel finishes. Plus it just makes things easier down the road. Luckily, I applied ceramic coat when I first bought these, so everything came off pretty easily with a brush and wheel cleaner.

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Then removed any marbles I picked up during my cooldown laps. With an oscillating tool the clag comes off like butter!




Also noticed my wheel liner rubbed through on the backside, which is pretty typical. Usually it's on the front where the bumper clips in but I've been able to avoid that ever since raising the ride height. Either way, the generic liners only cost $20/ea so not big deal.

 

[3002 tii]

Got a chance to take the M to Monticello Motor Club (MMC), a private, members only track. At 3.3 miles, it’s a very long flowy track with nice balance of elevation changes, tight hairpins and one of the longest straights in the east coast. The cars that show up are pretty insane, from factory clubsport race cars to exotics. Last time I was here, a guy was doing hot laps in this:

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Other than replacing a faulty TPS (the one under the manifold), the car was in the same condition as how I ran it at Watkins 2 weeks ago. Front tires now have 30+ heat cycles, rears are still fresh with only 1 weekend on them. My best lap time till now was 2:43, so my goal was to crack 2:42 this weekend. My ultimate goal is to crack 2:40 before end of season (cool temps and fresh tires).

The east coast finally got a break from the heat wave and flash flooding storms. Morning started out in hi 60’s and temps were going to peak in mid 80’s, so I knew my morning session was my best shot of setting a PR.

First session was 9am and unfortunately it’s never my best. I admire drivers who can go balls to walls and set a ridiculous pole position worthy time. I am not that guy — I usually have to ease my way into it. But it’s also because I try to preserve tires so I usually set pressures higher in first session to get them up to temp quicker. Then I’ll come into the pits, bleed them down and maintain for rest of day. So not surprising, I was doing 2:45-46 in my first session.

However, by the 2nd session (10am) my brakes and tires felt good and by lap 3 there was very little traffic so I got focused for lap 4:

Jul 2025
Track: Monticello Motor Club
Club: Member Day
Fastest Lap: 2:42

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I struggled to find some grip in the final few corners. I suspect there may have been a slick spot (got same feedback from other drivers). But to my surprise, I was able to put down a 2:42.7 despite my over-tendency to turn in early. My theoretical optimal time is 2:41.9 so who knows, but I will be back in 2 weeks to give it my best shot.

 

[3002 tii]

Despite my best efforts to avoid going CSL, the temptation was too strong with Turner’s flash sale. I decided to go with the less popular matte finish…

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What appealed to me about the TMS box (in addition to price) was its large mouth velocity stack that supposedly allows more air to be fed in vs the traditional snorkel. I don’t think anyone’s done independent testing so I’ll just have to take their word for it.

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The box itself seems to well-constructed. Fit and finish are good, probably not as nice as Karbonius but everything lines up and the bungs seem to have a healthy amount of epoxy. My only complaint is that the interior walls were quite rough and I could feel random sharp bits; the concern being they may get dislodged over time (like this). So I spent a few mins sanding it down and then applied 2 coats of epoxy. The resin takes a day to cure, so I let it sit overnight while waiting on some other parts to arrive. Note the trumpets have a smooth finish so no issue there, but these are some of the bits that came off when sanding the main box.

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With the epoxy resin fully cured, the walls are now reinforced and smoother.

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To help keep IAT’s down, I also applied reflective heat tape on the hot sides of the plenum.

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Almost ready for the transplant. Per a fellow member's suggestion, I cleaned the ICV while the manifold was already out. Just disconnect the plug, undo the 3 bolts and remove one of the hose clamps (note these are 1x use so either replace with worm clamp or new oe clamp p/n 13417831793). After hitting it with some throttle body cleaner and letting it dry out, I reinstalled the ICV along with the CSL airbox.

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With airbox temporary in place, I added the Turner bracket which goes underneath the box. I'm not sure why the bracket was designed to sit flush but I added rubber spacers (red arrow) so there was enough enough clearance to attach the air valve onto the tab (green arrow).

(View from other side with air valve secured)

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I went with Turner’s dry” panel air filter since it was less than half the cost of the OEM BMC filter. Also I swapped the brake booster plug from the original 45 degree connector to a 90 degree for better fitment under the hood.

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With everything buttoned up, I uploaded the Epic Motorsport 'base' Alpha-N tune. I plan to drive on this for a week or so before I schedule a follow-up dyno tuning session.

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[Ed Doe]

Loving that dude! Keep us posted ref dyno results. Mine definitely feels like it's pulling harder right to the redline, and the noise is epic
I've got a few more iterations of the map to come I think but I'm well chuffed so far!

Where did you get the reflective tape from? I'll probably do something similar when I take the car off the road for winter - I was too excited to get it on to bother with it first time round lol

 

[3002 tii]

Where did you get the reflective tape from? I'll probably do something similar when I take the car off the road for winter - I was too excited to get it on to bother with it first time round lol

Amazon where else?

There’s cheaper options but I find DEI has better quality adhesive. 2”x30’ was more than enough to cover 3 sides (back, bottom and throttle body).

 

[Ed Doe]

Haha perfect that's the answer I was hoping for I'll be on that as a little winter project I think (in addition to the rear end rebuild and a few other odds and sods!)

 

[3002 tii]

Before taking the car out on road, per @maupineda suggestion I cleaned the ICV while the manifold was already out. Then I cleared codes, reset adaptations and took her out for a spin. During the first few mins, the throttle was quite twitchy as the ECU was clearly re-learning throttle inputs. But after two miles, things started smoothing out and I was ready to start pushing. All I can say is the hype is real.

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I used to roll my eyes whenever I read something along the lines of “the sound alone is worth the price of admission.” But in all honesty, it’s abso-f’ng-lutely true. I felt like a 12 year old first getting his hands on a copy of Playboy magazine. I could not stop smiling for a good twenty minutes. The carbon airbox truly takes the M to the next level.

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All of this could be attributable to myriad of factors (e.g. cooler temps, tuning, etc.) and I promise to throw it on the dyno. But I know this much — the car pulls stronger across the power band, almost like sport mod engaged but much smoother. And the induction noise is just bonkers. My iPhone doesn’t do it justice but calling it aggressive is an understatement. I had an Eventuri intake before and this is easily twice as loud. I’m not exaggerating when I say my hatch was rattling as I got closer to redline.

 

[Ed Doe]

The sound is mad isn't it?! I was exactly the same, couldn't stop grinning first time I drove it with the box fitted lol