3002 tii
Active member
Yes but I genuinely hope it’s not something I get tired of, like how I did with the Supersprint mufflers. I’m not a young kid anymore
Last edited:
3002 tii’s Track Day Journal
- Thread starter 3002 tii
- Start date
Yes but I genuinely hope it’s not something I get tired of, like how I did with the Supersprint mufflers. I’m not a young kid anymore
I personally don't think it will get tiresome, the bonus with the inlet at least is it's only loud on large throttle applications - you can potter about without much noise increase at all 
Anyway enjoy the next practice session, pop some videos up - always enjoy a track vid
Anyway enjoy the next practice session, pop some videos up - always enjoy a track vid
3002 tii
Active member
Today’s focus was to see how the CSL airbox performs. Street cars are required to drive windows down, so my GoPro picked up a lot of wind noise. It doesn’t help the mic is mounted in the rear hatch but I think I have an idea on how to fix that. Importantly, the car felt great, and butt dyno says motor seems to have more top end power versus before.
And lastly, not one of my finer moments. I got black flagged for overshooting the braking zone, twice the same corner during back to back sessions. This is a good demonstration of 200tw vs 300tw tires when pushed to the limit. Only reason I ran my PSS is because as a dedicated 'wet' setup, they never got much use so figured I may as well run them before they get too old.
And lastly, not one of my finer moments. I got black flagged for overshooting the braking zone, twice the same corner during back to back sessions. This is a good demonstration of 200tw vs 300tw tires when pushed to the limit. Only reason I ran my PSS is because as a dedicated 'wet' setup, they never got much use so figured I may as well run them before they get too old.
Last edited:
3002 tii
Active member
With my front RE-71s in need of replacement, I decided to mount my Falken RT660, which I got for 50% off during winter. They're not necessarily my first choice but $600 for a set of 4 tires is hard to say no to. The reason for discount is because they were part of Tire Rack's winter inventory close out sale, which is how I usually try to source my tires for the upcoming season. Older DOT codes (e.g., 3 years) are not an issue since I have no problem using them up in a single season.
In any case, I knew the RT660 ran wide but I was pleasantly surprised to see they run wider than the Bridgestones, which is saying a lot. My back of the envelope math says these run at least 6mm wider than my 255mm RE-71 based on relative difference in strut side clearance.
The only "issue" is that in purposely choosing to step down from 255/40-18 to 255/35-18, my fender gap is little unsightly. I’ll always choose function over form, but even this is a bit much for me lol. So I decided to swap my 6" front spring to a 5", which will not only address the wheel gap but also help in other ways:
As to why I stepped down tire sizes, it's basically a poor man's gearing. The difference in rolling diameter between a 255/40 and 255/35 is about 1" or 4%. For context, a 3.91 final drive is about an 8% difference so just by switching tires, I get half the "effect" of going to a 3.91 (comes out to a 3.76). While that’s not a lot, I’ve done 4.10’s before and concluded it’s not for me. I find the stock ratio of 3.62 works well, so a mild bump that won’t alter my shift points is a welcome change.
With springs fully settled, the front splitter is at about 4” off the ground. I may end up raising this a tad. Might work great for track but I may end up having to raise this another 8-10mm just so I'm not bottoming out on public roads. The fine tuning never ends...
Lastly, if anyone's curious on the math, I've attached my spreadsheet that lets you calculate RPM vs Speed for different gear ratio & tire sizes.
The only "issue" is that in purposely choosing to step down from 255/40-18 to 255/35-18, my fender gap is little unsightly. I’ll always choose function over form, but even this is a bit much for me lol. So I decided to swap my 6" front spring to a 5", which will not only address the wheel gap but also help in other ways:
- Raise the perch just enough to clear sidewall and allow for a thinner spacer
- Add more downforce as the front splitter was sitting a tad high
- Test out stiffer spring rate
As to why I stepped down tire sizes, it's basically a poor man's gearing. The difference in rolling diameter between a 255/40 and 255/35 is about 1" or 4%. For context, a 3.91 final drive is about an 8% difference so just by switching tires, I get half the "effect" of going to a 3.91 (comes out to a 3.76). While that’s not a lot, I’ve done 4.10’s before and concluded it’s not for me. I find the stock ratio of 3.62 works well, so a mild bump that won’t alter my shift points is a welcome change.
With springs fully settled, the front splitter is at about 4” off the ground. I may end up raising this a tad. Might work great for track but I may end up having to raise this another 8-10mm just so I'm not bottoming out on public roads. The fine tuning never ends...
Lastly, if anyone's curious on the math, I've attached my spreadsheet that lets you calculate RPM vs Speed for different gear ratio & tire sizes.
Last edited:
3002 tii
Active member
Great thread, thanks for taking the time with it.
As for whether you’ll get tired of the airbox or not, I can confidently say that in many years time you’ll still be booting it randomly and dropping the windows whenever you enter tunnels!
It’s my pleasure. This forum has tons of great info and the members are what makes this site top notch.
Ha I think you maybe right. It’s probably a placebo effect but it sounds as thought the airbox has “broken in”. Most if not all of the reverberations are gone, and all that remains is an exotic tone.
3002 tii
Active member
I just returned from a fun weekend at the track. Bottom line is the RT660’s are amazing value but they were still 2 seconds slower than my old heat cycled Bridgestones. Two seconds may seem high but keep in mind the course is over 3 miles long. On the plus side, they provide great audible feedback and don’t seem as finicky with tire pressures. On the negative side, my tires showed the infamous “tread splice”. Falken has come out saying it is normal and nothing to be concerned about but it’s something I will keep a close eye on.
The above was my view from my hotel this morning. Weather conditions couldn’t have been better. I wish every day were like this, 72 degrees with low humidity.
Despite the amazing weather, I was surprised to see a small turn out. My friends and I basically had the place to ourselves along with few Miata’s… and a 296 Challenge car. Spoiler alert!!! I was not able to keep the Ferrari behind me
.
But I did manage to keep up with some of my Porsche buddies. My best time of the weekend was 2:43.7, which just goes to show how the RE-71RS are that amazing (see latest TR review here). As for videos, my GoPro was having connection issues due to low battery but I did manage to pull this clip of me going back and forth with my GT3 buddy. This was only the out lap so neither one of us was pushing it that hard.
I knew cracking 2:42 was unlikely but I tried pushing it to see if I could at least get close to my previous best. However, with subsequent lap my brake pedal got little deeper. After my cooldown lap, I came into the pits and inspected my pads. I could see they were much thinner than I expected. Though I started the morning with 50%, I probably got down to roughly 20% just in 1 day. But that’s the thing with race pads, as they begin to wear passed halfway, they generate even more heat and wear down much quicker (i.e., it's not linear).
I probably could’ve done maybe another session but I was feeling a bit lazy and didn’t want to swap back to street pads if these would get me home. I decided to play it safe and sit out my last 2 sessions. These are how the pads looked once I got home. Luckily, I’ll be able to get these replaced under the lifetime replacement program offered by FCP Euro. That includes even wear & tear items, which of course helps with keeping running costs down.
The above was my view from my hotel this morning. Weather conditions couldn’t have been better. I wish every day were like this, 72 degrees with low humidity.
Despite the amazing weather, I was surprised to see a small turn out. My friends and I basically had the place to ourselves along with few Miata’s… and a 296 Challenge car. Spoiler alert!!! I was not able to keep the Ferrari behind me
.But I did manage to keep up with some of my Porsche buddies. My best time of the weekend was 2:43.7, which just goes to show how the RE-71RS are that amazing (see latest TR review here). As for videos, my GoPro was having connection issues due to low battery but I did manage to pull this clip of me going back and forth with my GT3 buddy. This was only the out lap so neither one of us was pushing it that hard.
I knew cracking 2:42 was unlikely but I tried pushing it to see if I could at least get close to my previous best. However, with subsequent lap my brake pedal got little deeper. After my cooldown lap, I came into the pits and inspected my pads. I could see they were much thinner than I expected. Though I started the morning with 50%, I probably got down to roughly 20% just in 1 day. But that’s the thing with race pads, as they begin to wear passed halfway, they generate even more heat and wear down much quicker (i.e., it's not linear).
I probably could’ve done maybe another session but I was feeling a bit lazy and didn’t want to swap back to street pads if these would get me home. I decided to play it safe and sit out my last 2 sessions. These are how the pads looked once I got home. Luckily, I’ll be able to get these replaced under the lifetime replacement program offered by FCP Euro. That includes even wear & tear items, which of course helps with keeping running costs down.
Last edited:
3002 tii
Active member
As expected, I ended up raising the ride height another 6mm. No track events but I will be taking the Z this weekend to on a road trip through the Catskills region of NY. Hence I’ll need some additional front end clearance.
Hard to compare as I’ve temporarily mounted my 19” street setup, but I am no longer scraping the splitter. If was fun while it lasted
Hard to compare as I’ve temporarily mounted my 19” street setup, but I am no longer scraping the splitter. If was fun while it lasted
Last edited:
3002 tii
Active member
As promised, I got a chance to re-dyno my car with the CSL airbox. I don’t have a stock baseline so we’ll have to use my header tune from April 2024 as a relative starting point. It’s worth noting all runs were performed at the same Dynojet facility and ambient temps were pretty similar (spring 2024 vs fall 2025), so I consider these runs comparable. Lastly, all figures below are stated on a corrected basis (i.e. SAE 5).
TLDR; The gains with this box are real so long as you go with a quality tuner. In my case, I went with Randy at Epic Motorsports but I'd imagine you'd see similar results with other quality tuners such as Josh at Severn or Martyn at ECUWorx.
Baseline - 298whp | 237lb-ft
CSL Airbox - 318whp | 242lb-ft
With the following hardware changes & updated reflash…
It’s hard to discern how much of the 20whp gain is attributable to airbox only. My best guess is pulleys, flywheel and exhaust freed up 7-10whp, but not sure it matters. The gains from the CSL airbox + Alpha are certainly double digits, but it gets better…
The Alpha-N map was a canned tune initially uploaded just so I could drive the car and eventually make my way over to the dyno. But the intent was to always get a custom dyno tune. I can’t say for sure what tweaks were made but at minimum, the IAT was rescaled to help lean out the car. After about an hour of trying 3 different maps, the final result was 337whp | 256lb-ft, an incremental gain of 19whp.
Needless to say I’m quite satisfied with the overall results. Knowing our cars tend to come in lower than our M3 counterparts, I went in thinking 320whp was an optimistic number, so a net gain of 40whp (or ~60whp over stock) surpassed my expectations.
TLDR; The gains with this box are real so long as you go with a quality tuner. In my case, I went with Randy at Epic Motorsports but I'd imagine you'd see similar results with other quality tuners such as Josh at Severn or Martyn at ECUWorx.
Baseline - 298whp | 237lb-ft
- Epic Off-road (OTS)
- OEM Euro headers
- DKF section 1 w/ 100 cell hfc
- Stock intake + charcoal filter delete
- Est. delta of +23hp (based on research, a healthy stock Z4 M puts down ~275whp)
CSL Airbox - 318whp | 242lb-ft
With the following hardware changes & updated reflash…
- Epic Alpha-N (OTS)
- TMS CSL airbox
- TMS underdrive pulley
- Supersprint x-pipe
- TTV Racing flywheel
- Incremental delta of +20whp
It’s hard to discern how much of the 20whp gain is attributable to airbox only. My best guess is pulleys, flywheel and exhaust freed up 7-10whp, but not sure it matters. The gains from the CSL airbox + Alpha are certainly double digits, but it gets better…
The Alpha-N map was a canned tune initially uploaded just so I could drive the car and eventually make my way over to the dyno. But the intent was to always get a custom dyno tune. I can’t say for sure what tweaks were made but at minimum, the IAT was rescaled to help lean out the car. After about an hour of trying 3 different maps, the final result was 337whp | 256lb-ft, an incremental gain of 19whp.
Needless to say I’m quite satisfied with the overall results. Knowing our cars tend to come in lower than our M3 counterparts, I went in thinking 320whp was an optimistic number, so a net gain of 40whp (or ~60whp over stock) surpassed my expectations.
Last edited:
That's a bloody good result, considering the book bhp figure is 343(!)
How do you find the lightened fly and under-drive pulleys? Partly ref my previous thread querying it, are you finding any issues resulting from the change in harmonics from these components?
How do you find the lightened fly and under-drive pulleys? Partly ref my previous thread querying it, are you finding any issues resulting from the change in harmonics from these components?
3002 tii
Active member
Agreed, not bad at all for a nearly 20 year old motor. The gains were really noticeable on track where I'm generally keeping the revs above 6k.
The pulley is most noticeable vis-à-vis heavier steering feel, which is something I quickly got used to. The lightened flywheel is very much drivable on street and track. Biggest difference of course is how quickly the revs climb and drop so you can't fall asleep on your heel-toe or rev match.
NGL you can certainly hear the flywheel but it's nowhere as bad as JB Racing flywheels, which sound like bag of bolts and nuts thrown in a blender. For those wanting a factory (i.e., virtually silent) experience with the DMF, this mod probably isn't for you especially when you factor the very modest gains. But I'm also at the point where combining these marginal gains is the only way to unlock more power. But to answer your question, being fully honest -- the flywheel rattle is more noticeable from the outside of the car. In-cabin NVH however, is on par with a louder exhaust which is why I am fine staying with stock mufflers. In fact, my only complaint with the oe backboxes is their weight, but there is absolutely no drone or harsh NVH as a result of the TTV flywheel. Best analogy I can think of is the feedback you'd hear in driving a mid-engine car.
Just TBC, the pulleys are water pump and steering only; harmonic damper is not touched. The TTV Racing flywheel is actually made of forged steel (as opposed to aluminum), so the harmonic damping is much better and why it is well-suited for the stock clutch. Here’s a clip of how the flywheel sounds from the cabin. You can hear the rattle when I clutch out.
Here’s a clip from the outside
Last edited:
3002 tii
Active member
Each October my best friend and I do our annual track outing, a tradition we’ve held for few years now. Last time I drove the Z was a few weeks back when I took her out on a road trip: So this past week I threw my track wheels back on, put on new pads and did a quick lookover. I noticed my front right caliper has a torn boot so I’ll need to address that soon but one day should be fine.
Track temps were as low as 45 °F but there was still a decent turnout. Guessing everyone is trying to squeeze whatever remaining weekends left before the season wraps up.
Neither one of us were really pushing it. For one his Honda was bone stock and two, it was raining on and off. But once we got passed the Miata’s we put down some respectable times.
Overall I had a lot of fun but it’s clear I won’t be setting any PB’s with RT660’s. Don’t get me wrong, they’re great value considering how well the shoulders are holding up. Finding the limit is quite easy and when they fall off (~20 mins), it’s very gradual so it makes for a great practice tire. In fact I have more fun sliding around in these than any other tire I’ve drive so far. But for any street class competition, it’s clear the RE-71RS remains top contender.
Track temps were as low as 45 °F but there was still a decent turnout. Guessing everyone is trying to squeeze whatever remaining weekends left before the season wraps up.
Neither one of us were really pushing it. For one his Honda was bone stock and two, it was raining on and off. But once we got passed the Miata’s we put down some respectable times.
Here’s a clip of some lead/follow from our warm up session.
Switching places and pushing a little harder now that the tires are warmed up.
Switching places and pushing a little harder now that the tires are warmed up.
Overall I had a lot of fun but it’s clear I won’t be setting any PB’s with RT660’s. Don’t get me wrong, they’re great value considering how well the shoulders are holding up. Finding the limit is quite easy and when they fall off (~20 mins), it’s very gradual so it makes for a great practice tire. In fact I have more fun sliding around in these than any other tire I’ve drive so far. But for any street class competition, it’s clear the RE-71RS remains top contender.
Last edited:
3002 tii
Active member
Track season typically wraps up 1st or 2nd week of Nov in my neck of the woods so a lot of fast cars showed up this past weekend, for what was likely the last event of the year.
I've always wanted a swan neck rear wing
It rained for 2 days straight so morning conditions were still damp. And with temps on the colder side, it took a little longer to get the tires warmed up. But I did manage to stay on the 458's bumper. I’ll give him the benefit of doubt that it was his first time at this particular track. Not knowing his resume, I was unsure if he'd leave me space for an inside pass, so I returned to the pits to get re-released. Best time of the day was 2:45.9 (vs 2:43.5 with same tires back in Sept)
I've always wanted a swan neck rear wing
It rained for 2 days straight so morning conditions were still damp. And with temps on the colder side, it took a little longer to get the tires warmed up. But I did manage to stay on the 458's bumper. I’ll give him the benefit of doubt that it was his first time at this particular track. Not knowing his resume, I was unsure if he'd leave me space for an inside pass, so I returned to the pits to get re-released. Best time of the day was 2:45.9 (vs 2:43.5 with same tires back in Sept)
Last edited:
3002 tii
Active member
Looking back at this year, I'd say the car was pretty reliable. The only piece I need to sort out is brake cooling. While I've not had any fade issues, I've noticed the fronts have show signs of overheating ever since switching to DTC-70s. Some of it is certainly technique (i.e. bad habit) as I got so used to DTC-60s, which required braking earlier. However, the calipers themselves don't seem to be up to the task of repeated track use.
For context, this is a known issue among M3 owners who also track their cars using the same 996 Brembo kit. The boots can't withstand the heat and can eventually lead to brake failure if water and debris make its way into the piston bores. Knowing I wouldn't have time to rebuild the calipers before my last event, I ordered a set of titanium brake pad shims in hopes it would at least buy me some time and prevent the boots from getting any worse.
Color change indicates temps are exceeding 600 °C
In addition to rebuilding the fronts, I also plan to add some form of brake cooling. I've already ordered a set of backing plates from Westersund but I need to figure out how I'm going to route the hoses. I've done the typical install before drawing air from the bumper inlets. However, I'm going to try something this different this time around that won't require lengthy hoses or cutting factory plastics. I'll post an update in a few weeks after I've acquired all my parts.
For context, this is a known issue among M3 owners who also track their cars using the same 996 Brembo kit. The boots can't withstand the heat and can eventually lead to brake failure if water and debris make its way into the piston bores. Knowing I wouldn't have time to rebuild the calipers before my last event, I ordered a set of titanium brake pad shims in hopes it would at least buy me some time and prevent the boots from getting any worse.Color change indicates temps are exceeding 600 °C
In addition to rebuilding the fronts, I also plan to add some form of brake cooling. I've already ordered a set of backing plates from Westersund but I need to figure out how I'm going to route the hoses. I've done the typical install before drawing air from the bumper inlets. However, I'm going to try something this different this time around that won't require lengthy hoses or cutting factory plastics. I'll post an update in a few weeks after I've acquired all my parts.
Last edited:
3002 tii
Active member
Can’t believe it’s been 3 months since I’ve properly driven my car. This winter was brutal so the car really didn’t see much use as I generally try to avoid road salt. But temps finally cracked 50s this weekend so I decided to take her a local touchless wash to get the undercarriage rinsed off.
I have about 4 week before my first event. Luckily I addressed the caliber rebuild at the end of last season so the car shouldn’t need much work. I will do a full lookover next weekend but at minimum, looking to do
- oil change
- brake fluid
- pad swap
- brake cooling
- recharge a/c
Oh and I finally got to installing an F-series dual USB C port.
I have about 4 week before my first event. Luckily I addressed the caliber rebuild at the end of last season so the car shouldn’t need much work. I will do a full lookover next weekend but at minimum, looking to do
- oil change
- brake fluid
- pad swap
- brake cooling
- recharge a/c
Oh and I finally got to installing an F-series dual USB C port.
Last edited:
3002 tii
Active member
Work has been insanely busy but things are finally slowing down so I’ve been able to focus on the Z. What should’ve been my first event got rained out, so that gives me 2 weeks to knock out a bunch of small jobs before my next event. First on the to do list is replacing the air compressor and recharging the system.
The job is very straightforward given how accessible everything is in our cars. I’ll just say be prepared to deal with a stripped coolant line hex bolt.
Figured may as well replace the belt since it’s coming off anyway.
Old unit only has 20ml of oil so guess it’s not surprising it was on its last legs. Filled the new one with 50ml of PAG-46.
Old receiver drier vs new. This should always be replaced whenever you touch the compressor.
4.5 hours later ice cold a/c without any leaks. I spent $120 on tools (pump and gauges) and $480 on parts (compressor, receiver drier, belt, cabin filter, replacement bolt and freon). Dealer would’ve charged over $1600 all-in just so buying new tools to DIY was money well spent/saved imo.
The job is very straightforward given how accessible everything is in our cars. I’ll just say be prepared to deal with a stripped coolant line hex bolt.
Figured may as well replace the belt since it’s coming off anyway.
Old unit only has 20ml of oil so guess it’s not surprising it was on its last legs. Filled the new one with 50ml of PAG-46.
Old receiver drier vs new. This should always be replaced whenever you touch the compressor.
4.5 hours later ice cold a/c without any leaks. I spent $120 on tools (pump and gauges) and $480 on parts (compressor, receiver drier, belt, cabin filter, replacement bolt and freon). Dealer would’ve charged over $1600 all-in just so buying new tools to DIY was money well spent/saved imo.
Last edited:
3002 tii
Active member
No lap times recorded but I did wrap up an epic 1000 mile road trip hitting the best mountain backroads the northeast has to offer. The mix of cars ranged from lifted 4Runner to Emira.
Even with all the upgrades, the Z is still pretty civil on public roads. Only towards the final leg of the trip did my back start getting a bit tired. But the Sparcos are still way more supportive than the factory seats imo.
All in all, it was a good group of car enthusiasts with a common interest in money pits.
Even with all the upgrades, the Z is still pretty civil on public roads. Only towards the final leg of the trip did my back start getting a bit tired. But the Sparcos are still way more supportive than the factory seats imo.
All in all, it was a good group of car enthusiasts with a common interest in money pits.
Last edited: