Funny enough, I'm in that video as well. Hair dressers unite!

 

I can’t speak from experience, but from what I read you really don’t want to use 7th and 8th for real on track. I should probably do more research, but to be safe I decided to avoid it. I think between raising the rev limit to 8500 and moving 18” wheels that should give me enough top speed even while keeping the 3.55 diff.

oh, that’s cool. I really wish I had more time to go around and chat with folks, but it was such a hectic day from start to finish (hell, week, month, year… &#128517

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I finally got the car on the scales today: 1036kg/2284lbs as it came back from Germany. Full fluids and some fuel left, give or take 10L/2.5gal is my guess. Overall, I find it a bit underwhelming, but it’s within what I expecting. The gearbox is super heavy, the splitter is ridiculously overbuilt, so I knew it would be up a fair amount from the last weigh in (890kg).

As far as weight distribution goes, left/right is pretty decent, slightly heavier on the right without me in it (50.6%), and should be even better when I place the dry sump tank there. Front/rear isn’t quite as nice… even though the wing is quite big, it’s (thankfully) no ballast, so the scales showed 56.5% front.

As nice as it’d be to shed a few kgs and get it sub 1000, that might be tricky considering a lot of the items on the list for this winter add weight to the car (like bigger wheels, bigger brakes, bigger turbo, all the missing aero bits, etc)… so maybe it’s more realistic to aim at breaking even, but we’ll find out in a few months.

 

Ha... me too...

 

In case anyone is interested, we finally managed to finish editing the Nurburgring episode:


The OneLapHeroes video should be coming out soon too.

 

Wow that wing is something haha. Cool build.

 

Video going into T1 at the GP track looks like the wing might be changing the pitch of the car too much, lifting the nose. We had that on our 2018 Super Lap car and had to dial the wing down during the event. Ended up removing an element to get the aero balance.
That was with 1800/900 (32/16kg) springs

 

You mean on the front straight? I honestly can't see it, but I did end up dialing the wing down from 5º to 0º (measured at the main element). I'm running 1300/800 and the car feels quite soft, but not bad. Unfortunately I just haven't had enough quality seat time to dial it in though.

Eventually I found the cause of the boost leak we mentioned in the video: the wastegate boost pipes/tubes came loose so we weren't running full power, which we saw in the logs on the day, but it's good reassurance since the car felt a bit sluggish compared to last time, and as a result our top speed was only 210kmh (130mph). I bring that up as I imagine that next year with the higher speeds we might need to increase the spring rates.

I just started the first few iterations for the aero upgrades, and it's looking like there'll be a lot more changes than I originally planned. Even though I left so much margin in the fenders, time was running short so I didn't carefully measure it with the 18" wheels, and obviously they'll need to be remade. On top of that, the hood was too close to the turbo and got a bit melty on the last event, so that too will need rebuilding. Add that to the fact that the front splitter weighs about as much as a baby hippo, and it's looking like not much of this year's aero will be left. Anyhow, was up till 3am last night working on the diffuser and some other bits, lots to change still, but here's a little sneak peek of where I'm at:

 

Yes, front straight. That nose up attitude reminded me of Vegas until we made adjustments. Do you have shock pots at all four corners? Might be useful data.
My gut feeling is that you'll make too much downforce for a simple 4 shock system and have to go with some sort of 6 shock system or maybe hydraulic preload to deal with it. On Bullet, we had to run almost 15psi (1 bar) more tire pressure than a normal road race downforce setup. That was to deal with all the extra load. Some rough calculations and we figured were making somewhere above 1500lbs ( ~700kg) downforce at 120mph (200kph). That set up had maybe 1/3rd the effective surface area that you have. Really interested to see how you work though that.

 

No shock pots this year yet unfortunately, but it's already in the shopping list for this winter, should be coming soon. Should be useful for some CFD correlation, together with some flowvis.

Yeah, according to the CFD the car was supposed to produce ~1100kg of downforce at 200kph, but that included some pieces of the aero kit that weren't completed, and it's a bit optimistic. Regardless, the goal is to beat that for real soon, so I agree it will be less than ideal with a standard 4 damper setup. The mid/longer term the plan is to build a second chassis with a proper 3rd damper setup while I race this one, but one thing I considered for next year was moving to a simple pushrod setup, keeping the OEM arms, but using a rising rate bellcrank. I ended up postponing that as the upgrade the list is already much too long, so for now I'll continue pushing the Xidas as far I can lol, but I will come back to that. Might be time for sending the Xidas for a rebuild though, and maybe revalving too, I've had them for a few years, although they've seen less track time than I'd have liked.

 

One Lap Heroes has released the build breakdown video. Can't thank them enough for such a cool video:

 

Happy new year folks! Things have been quiet as I have been spending every free minute on the computer working on the new aero package, so rest assured I haven't abandoned the thread again, I just don't have too much to show. This is where things are at:



The goal is to keep about the same level of downforce, but reduce drag. I also simplified a few things. The front end is mostly done, just waiting for the new uprights with the 5x114.3 hubs that Bronson made for me to arrive, should be here next week. The rear still needs a fair amount of work.

Once the hubs arrive, it's time to mount the new wheels and give it a quick scan to ensure no whack fitment this time. Will also be working on the custom mounts for the new brakes. Wheels are Konig Hypergrams, 18x10.5 et25, wrapped in Yokohama A005 280/650/18. Alternatively we'll also be using the 295/30/18 A052s. Calipers are Alcon CAR8949, absolutely massive and weight only 2.7kg. The front discs haven't arrived yet, but will be 378x32mm, and in the picture you can see the rear discs, 350x32mm, compared to the current 11.75" (298mm).






Once I'm satisfied with the fitment I'll just add some final details to the front clip and it's ready to print. The goal is to add small features that make it resemble a Miata a little more. Obviously the shape is quite different, so it will never look like a stock Miata, but I'd like to have at least something that suggests it's a Miata lol.

Another (quite nerdy) thing I've been working on in the meantime is addressing the negative rake caused by the aero loads as Emilio pointed out. The long term goal is to have heave springs (I even got side tracked and bought 6 Öhlins TTXs in a garage sale), but that will be a project for 2026. For the time being I wrote a small calculator that takes in the data from one of CFD post processing scripts and computes how much shock and wheel travel it will have with a given spring rate:



With the current spring rates (1300/800), downforce and aero balance at 100mp/h, the front wheels would compress 12mm and rears would compress 28.2mm, resulting in 0.41º of negative rake. That was based on CFD data, but in practice it was likely even worse, as the data was assuming the car had a more static rake than it ended up having. This is bad in many ways, including how difficult it becomes to simulate the aero of the car as the rake is always changing, so at every speed the car will have a different aero balance.

It's still preliminary, but plugging in the data for V2, and trying to keep the car from pitching, it will require some pretty unusual spring rates: 1150f/1300r. Obviously that will throw the front roll couple completely out of whack, so to fix that I'm then taking this data and using the FCM calculator. It seems it'd require removing the rear bar and adding a 45x2mm front bar. I'll likely go with an even stiffer front bar with blades to be able to fine tune it. Thanks to Bronson once again for helping me figure all this stuff out, as it's very far from my comfort zone.

A disclaimer that should be obvious, but people always point it out for me, so I'll say it upfront: all of this will be validated on track, CFD isn't always correct at any level, let alone on my level, so I'm not blindly taking all of these numbers as gospel. But... it's winter in Sweden, we have about 1ft of snow outside, and I don't happen to have access to a wind tunnel, so this is all I have to go by for now. My only expectation is that it's a decent starting point, better than if I was just guessing. I already have the shock position sensors ready to go for next season, and I hope do a mix of coast down testing, downforce estimates based on shock travel, and some flowvis to correlate back to CFD.

In parallel, we dropped off the engine at MotorNord last month, and they started working on it. We'll have a video on the engine teardown and showing what's going into it soon.

And, as I was about to wrap up this post, I realized I forgot to share some pretty big news here haha. Turbosmart has come onboard as sponsor! I'm gonna be running the 6466 turbo, ProGate 50, ALV40 fresh air anti-lag valve, RacePort blow-off valve and OPR V2 turbo oil pressure regulator. Can't wait to get it all installed and see the first pulls on the dyno.

 

Are the brake discs custom? Those things are gonna be massive!

Interesting to see that the turbo is air cooled. I'm not familiar with the latest and greatest pro level stuff, but is it common to have an air cooled turbo making that much power?

Congrats on getting a new sponsor onboard!

 

Thanks

The discs themselves? It all came from a touring car, but the discs I have are not the correct ones, that's why I'll move them to the rear. The 378x32 are the standard touring car spec from Alcon, and the only recommended size for these calipers (I think technically it's 378x32 - 380x36, but it's a bit hard to find the info online, and I've been emailing with Alcon, but their replies aren't exactly speedy). I'll make custom brackets for the calipers and custom bells/hats for the discs.

You mean the Turbosmart turbo, or the current Garrett one? The Garrett is oil cooled, the Turbosmart is oil and water cooled IIRC. I'm by no means an expert either, as the project advances into another level I've had to rely more and more on others to help me in certain areas, and this has been one of them. Both MotorNord and Turbosmart helped me spec everything, I'd have no idea otherwise.

 

I was talking about the Turbosmart unit. I just looked it up because I hadn't seen that turbo before and was curious about it.

Maybe you're running something else, but all I was finding was the Precision brand turbo of that model number which mentioned it was air cooled. That was still quoted to be a ~900hp turbo, so if that is the case I assume it's adequate cooling.

 

I'm done(ish) 3D modeling! Time to grab a wrench and actually make this thing happen in real life now! Pretty happy with the results, in the high downforce config it has 20% less drag and 8% more downforce. L/D ratio puts it close to a prototype. Hopefully I can build it the way it deserves and then we can see how close the real world numbers will be.



I say done-ish with the modeling as I still need to verify the wheel fitment with a 3D scan and split the model into separate body panels, then further into printable pieces. Last year I printed about 30kg of plastic in a single BambuLab, this year it will likely take at least twice as much plastic, and if we don't want to be late for the season again we'll likely need multiple machines to speed up the process. I'm still trying to find a 3D printing partner to help with that, but had zero luck so far.

The BroFab hubs arrived yesterday, so the plan for this weekend is to get them in place, mock up the new wheels and tires and start cutting. I also need to have a first look at here the rear radiator is gonna sit, and where the intercooler is moving, there's very little margin with the front being that low, and the rear isn't much better since the side ducts need to reach the radiator too, but it's all included in the model, so it should be fine (famous last words, I know).

I'm just so excited to bring this thing to life!

 

That thing has serious 935 vibes; loving it. I would be glad to help with printing, and shipping from Greece to Sweden should not be expensive. Let me know if interested!

 

Thanks man, the 935 was one of the main inspirations haha so glad to hear some of it came through. That could work, and it'd be a great a help! What's the best way to chat about that?

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In the meantime, our latest YouTube is out! We got started on the engine build and covered the disassembly as well as what parts are going in and why. If there's any Swedish folks following the thread here also check out as MotorNord is offering a discount if anyone needs parts for their engine builds!

 

Sending you a PM

 

The past couple of months have been busy, but not too much to show for it. Lots of planning, organizing things, accumulating parts, and lots of work on the computer, slicing 3D prints, then the actual printing, which we'll have some more content to show soon.

We partnered with AddNorth, a Swedish 3D printing filament manufacturer, and also bought an extra 4 printers to speed things up. We printed the whole body, using ~50kg of filament, in about 2-3 weeks. We started building the first mold, but we'll have to take a break from that for a while and I'm moving back to wrenching on the car for now.

We just finished building the new engine, and it looks so good. It's my first ever built engine, only had junkyard specials before, so I'm really excited to get it into the car. A couple things will likely need some trimming, but we'll make it work!
https://www.youtube.com/watch?v=nu4NhV_9-8w

We also picked up some new products with Nuke performance as we continue to partner with them for this year. I'm replacing the OEM tank + surge tank with a fuel cell. Also moving to their new high pressure air jacks which gives us a lot more space around the pedals. Just picked a couple air bottles and all the accessories too, so the air jack setup is ready to go, just need to weld the mounts.

It's now time to spend some time in the garage. It was an absolute chaos, so first things first I need to spend a little time organizing it, which was long overdue. After that I can finally start cutting everything to make up space for the big tires. The plan is to cut most of the sheet metal around the shock towers and behind the front wheels. Then rebuild the firewall and add extra bars from the cage to the shock towers. The exhaust manifold might also require some very minor notching of the frame rails, but we'll make it work. The dry sump is the biggest worry, the engine is very tight to the steering rack, but I'll get around to testing that very soon.

On the rear of the car, I'll cut out the sheet metal around the oem tank, and most of the wheel well and metal around that area. Lots of things are moving to the rear: radiator, water pump, coolant tank, transmission cooler, alternator, fire system, maybe the battery... we're also moving to 3 separate PDMs to simplify the wiring:
- a rear pdm that supplies 12v to the fuel pumps, lights, fans, water pump, etc.
- a cabin PDM to supply the dash, ECU, abs, TCU, etc
- a front PDM to supply everything around the engine

The plan is to have the car on the dyno in a couple months, and on track in 3 months. It will be tight, again, but we'll see. At least there's less to do this year 😅

 

Are you going to make a real mold out of the plug this time?

A mold will be handy when you inevitably crack up body panels. Lay in coremat. I wouldn't bother with infusion either, IMO it isn't worth the extra hassle.