Are the two current wing-planes too close to eachother? Is the gap big enough to feed the underside of the upper wingplane?

The longitud offset of the planes wrong?

With the pressure dropping so fast towards the back of the upper plane, there must be severe separation? It is starting to stall?

And/or the wrong angle of attack relative eachother?

Compare with this...

Another example would be to look at the wing of the old 993 GT2. Obviously, the two planes help eachother.

If these two examples (i.e speculations) are valid, the conclusion must be your upper wingplane must be placed further forward?

Looking at the radiator inlet. It seems to act like a big snow-plow pushing the air infront of it?

1) With a more rounded inlet shape, what happens?
2) With a faster increase of the duct-area from inlet to the radiator (i.e. smaller inlet area), should we not see a static pressure increase directly in front of the radiator?

The current inlet size is significantly larger than those on a F1... Is the current inlet area really necessary?

Lots of great suggestions, thank you

Let me start by pointing out a couple things about the picture:
- This is not the actual position of the wing in the car. This is one of over 100 simulations I ran, I just picked whatever I had open on my CFD machine to picture the pressure differential around the radiator.
- The pressure plot is clipped at a relatively low pressure, again to illustrate the pressure differential around the radiator, so it's not a great representation of the overall aerodynamics of the car.
- The wing was now moved to the rearmost position allowed by the regulations and a little bit upward to try and minimize the suction on the fastback. That didn't completely fix the problem, which also bothers me, but this is the centerline of the car, and that interaction only occurs in the middle 40 or 50cm of the wing, which has a 1.9m span, so while it's definitely not ideal, it's also not as bad as it looks.
- The model in the picture does have a diffuser, you can see the (fairly small) low pressure zone at the throat, it's just very thin. I don't remember if this was the latest version of the diffuser though but even that needs more work. And obviously the flow also changed when I changed wing placement.

Just for reference, here's a picture of the same run, just clipping at a slightly higher pressure, and you can see the difference. The low pressure zones above the windshield is orders of magnitude smaller than the low pressure zone under the wing:


The triple element image you posted is plotting total pressure, while I'm plotting static pressure, so the two images will never look the same. It's also unclear if the wing is in freestream, which changes a lot of things. Here's a total pressure plot for reference:


One thing worth noting is that the fastback was designed and printed before I decided to go down this rabbit hole, so if I had to do it again I'd definitely change a couple things. For one, when I tested with more aggressive triple element wings the effect of the fastback spoiler on the wing was positive, keeping the flow attached, but it wasn't wide enough, so flow separation still occurred about 30cm out from the centerline of the car, then it was attached again on the portion of the wing that was in freestream. So not only it could be lower, the spoiler also needs to be wider.

As for the front opening, it's rough to compare F1 with a production car... everything is so different. But in this particular scenario, F1 has several small inlets for all the heat exchangers, engine intake, etc. while I'm working with a single inlet for the radiator + intercooler which are over 4" thick when stacked together. The curved inlet is an interesting idea, and might be more efficient, but you are also creating a surface with an angle in the opposite direction of what you'd like, so it could create more lift than it'd reduce drag. I tried something similar with the side inlets and it backfired, so I rolled back to the flat design.

All in all, it's been a balancing act between building something that is 1) efficient, 2) looks good and 3) I can actually build in <6 months with my complete lack of experience. I have started learning 3d modeling and CFD just before I started this project a little over 4 months ago, and I have never even touched carbon fiber yet, so I'm trying to manage my expectations. I'm looking at this as a learning experience and if all goes well I'll resume the development soon.

Oh wow, it's been a month already... I've been meaning to update for a while now. The test/media day is getting closer and there's a lot that needs to be done before the car is presentable, let alone ready for the actual competition, but there's been a fair amount of progress too.

There's been some big changes/news, the biggest one is the new title sponsor for 2024: Link ECU. This was just surreal, I wrote a bit more about it on instagram, but the tl;dr was that I had to make the tough decision of selling my other ECU, and then this happened... I feel incredibly lucky and grateful, really can't put into words.



Besides that it's a lot of smaller progress updates:
- The fastback is out of the car, only missing now the internal reinforcements.
- The cooling system is done
- The plumbing between the intercooler and throttle body, including the Nuke blow-off valve is done. The turbo manifold should be here very soon and then I can finish the other side as well.
- The wiring diagram is finalized and the mock harness is done. Everything is ready to start the wiring, just prioritizing the bodywork for now
- All the fuel components are in place, just need to make the hoses now
- All the wing components are ready for assembly
- 99% of the carbon work is still left, but most things are prepped for the carbon, the only missing parts are the hood and quarter panels. The first quarter panel just finished printing, I'll assemble it this week, and I just finished modifying the hood so it no longer hits the engine, but it will require a little bodywork before it's ready for the carbon.
- The tires are here, just mounted the 2 wheels I have. The other 2 wheels are stuck in transit, but hopefully should be here soon.
- The steering wheel prototype is printed, just needs the hardware and soldering the wires



I'm sure I'm missing something, but I think that's the gist of it. It's been super intense to try and get the car done in such a short time, but it's also been a ton of fun and I already met a bunch of amazing people, so I wouldn't take any of it back. I hope that once the initial thrash is over and the car has turned some laps I can have more regular and detailed posts here.

Oh, somewhere in there I also printed this little miniature of the car, maybe someone here saw it at Speeding's booth at the Custom Motor Show.

Good progress

Hello folks!

It's been a while, but it's time to revive this thread. The good news (for me at least) is that the updates stopped, but the work didn't. I just got a bit too busy between the car, my day job and life in general and decided to focus all updates into one place (Instagram). But anyhow, it's the off season again, and as I'm about to start working on the car again I figured it was a good moment to bring this thread back to life, so here's a very brief recap:

First of all, a few pics of the car:





To nobody's surprise, the car was late for the season, but at the very least we managed to squeeze 2 events this year: the final TANU round at Gelleråsen and European Time Attack Masters at the Nurburgring.

At Gelleråsen the test was positive, we got some good base data on Friday and Saturday and worked through some minor teething issues, but we had some wild drivetrain vibrations and ended up splitting the gearbox in half on the last session of Saturday. In a true team effort Rhys and Daniel drove 7hrs to pick up a new gearbox while my brother and I worked until late to get the broken box out. We manage to complete the swap just in time for the last session of Sunday, but unfortunately the vibration was still there. Here's my best lap from that weekend, but far from fast as I was still on low boost, had to lift on the straight due to the vibrations and there was some air in the ABS solenoids which led to a very inconsistent brake pedal:

Eventually we figured out we had some driveshaft issues, and also ended up changing the gearbox mount to soften it up. The wing also had a little too much movement with the original pylons (6mm aluminum), so we fixed those things and headed to the Nurburgring for ETAM. That was a wild trip, met some really awesome people, including the folks at One Lap Heroes who recorded an awesome build breakdown of the car ( https://youtu.be/l9JEQFmdu4I ) and the car was also featured on Misha Charoudin's video, which was crazy.

The actual driving was less than optimal though... after Gelleråsen we bled the brakes using the INPA software to try and get the air out of the solenoids, but something went very wrong because I started the day with only rear brakes. The ABS also wasn't working, and the track was wet and very slippery, so that was fun... fortunately no mishaps though. We kept bleeding the brakes after every session, and continued to fix other little teething issues like at Gelleråsen (it was still only the second test event after all), until at the very last session the brakes felt great, and the ABS came back to life so I tried pushing a little more, but the ABS decided to not work on a very big braking zone and I ended up in the gravel. Fortunately the car was unscathed, but it was enough for me to decide to ditch the mk60 for next year.

During this whole process I started a company called Forza Racing together with Rhys from Link ECU (forzaracing.se) and we also started a little YouTube channel which includes a more in-depth recap of the Nurburgring trip:

I'm currently in the process of revising all the aero for next year, acquiring the necessary parts for the upgrades and just dropped off one of the engines at MotorNord to get built for next year, so things are starting to pick up for the winter. I'll try to keep up the updates this time around.

Cool!

The company name, is it really registered in Sweden? Bacause there is a Forza already, quite well known too: https://shop.forza.se/

MaZ skrev:

Cool! The company name, is it really registered in Sweden? Bacause there is a Forza already, quite well known too: https://shop.forza.se/

Yeah, it's registered in Sweden. Unfortunately we only found out about that shop after we had already registered... oh well, there are 13 pages of companies named Forza on allabolag, now there's one more 🥲

Just answer emails and phone and there will be no confusion which is which...

MaZ skrev:

Just answer emails and phone and there will be no confusion which is which...

Insane build!

What's the reason for so big wheel wells and at the same time so small wheels?

stilldouble skrev:

Insane build! What's the reason for so big wheel wells and at the same time so small wheels?

The car is meant to run 18" wheels, but I ran out of time this year. The wheels are ready to go for next year though, 18x10.5" wheels and 295/30/18s all around.

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, but rest assured I haven't abandoned the thread again, I just don't have too much to show yet. 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 BroFab made for me to arrive, should be here next week. The rear still needs a fair amount of work to improve the quality of the surface.

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. Thanks to Wiborg for helping me sort out the wheels and tires: 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 weigh 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 from Supermiata pointed out in another forum. 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 my 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 (23.2kg/mm front, 14.2kg/mm rear), downforce and aero balance at 160km/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 model had more static rake than actual car 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 for a Miata: 20.5f/23.2r. Obviously that will throw the front roll couple completely out of whack, so to fix that I'm then taking this data and using another online calculator from fatcatmotorsports. 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 from BroFab 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, I can't test on track, 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 partner for next season! 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.

After a few hundred hours I'm done with the aero design for next year, here's what it'll look like:



I'm pretty happy with the results, in the high downforce configuration it has 20% less drag and 8% more downforce than the previous model. L/D ratio puts it close to a prototype. Hopefully I can build it the way it deserves and then we can see how the real world numbers will compare to the simulation.



I got the wheel mounted this weekend, now I just need to scan it and verify the wheel fitment, split the model into separate body panels, then further split 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 haven't had much luck so far.

On a different note, our latest YouTube video is out! We took a trip to MotorNord to get started on the engine build and covered the disassembly as well as what parts are going in and why. For folks building an engine this off-season, check it out as MotorNord was kind enough to offer a discount to all our subscribers:

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!

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 😅[/youtube]

I got the wheels mostly fitting! It was a fair amount of cutting... I started in the front, initially just cutting the minimum necessary. The idea is for the static ride height to be 120mm at the pinch welds, and aiming for 50mm of wheel travel in bump. I started with fairly rough cuts, as I'll want to cut some more later, then I can clean it up a bit.




For the most part it's not too bad. Gotta cut out the tub, but that's easy. The biggest issues are cutting the area behind the tire, and the clearance to the shock tower. The area near the firewall has several layers, and it's a massive pita to cut. I was trying to not remove more than necessary, but will eventually trim a little bit more for aero reasons. As for the shock towers, I'm test fitting with Konig Hypergrams 18x10.5 et25 and 280/650-18 Yokohama A005s. Even after cutting flush with the shock top hat it was still too tight, so I added 10mm spacers. Now it clears in bump, but still makes contact when turning. I destroyed my ball joints when swapping the uprights, so everything has been fairly loose, which is obviously not good for these measurements, so I ordered a front-end service kit from Supermiata, and while I wait for it to make its way across the pond I moved to the rear. When that gets here I can do the final trimming, then I'll plate it all back up as well as tie the shock towers to the roll cage.

The rear was a lot easier, unsurprisingly. With the same 10mm spacers the clearance to the shock tower was fine, but the tub has to go. I ended up getting a little carried away and cutting most of what I believe I can get away with. For now I'm leaving the "outer frame" if you will, both front and rear, but that's just in case I need to mount the old body panels. Once we're done with that, and I triple checked all the 37 rule books we care about, then it's all coming off.



The garage is absolutely chaotic, and that's because I just spent a full week adding more shelving and cleaning it up. I still want to optimize the space as much as possible, but there's no miracle that will make it pleasant to work on a single car garage, while trying to fit: a spare engine with stand, a gearbox, an engine hoist and all the tools, parts and metal stock, etc... oh, and the actual car lol

Tomorrow we cut some more! Time to drop the rear subframe, remove the OEM tank and  make some room for the fuel cell.

This is so incredibly unreasonable

I love it!