I know it's cool to clown on the L bodies, but I was pleasantly surprised by my admittedly limited time with various Hellcats at a "defensive" driving course back when I worked for Chrysler. She's a big girl, but she's been to dance classes. I thought the Challenger handled quite well for what it was. Trail brake well and the car rotates right into the corner. In contrast, the GT500 they had there as a competitive evaluation was rough. It just understeered right until it snapped around.

They knew what the platform could and should be, didn't try to compete on lap times with the Mustang or Camaro.

On that note, glad to see you're sticking with the manual. A Miata is a car for the experience, not the numbers. Ripping gears top down with a big honkin' V8 should be much more satisfying than slapping paddles.

 

I agree. They handle better than most give them credit for, but (like my CTS-Vs) there are so many better choices out there for a car if you actually want to turn, so I'm still in support of the crude humor they receive

Did some further refinement on the intake tube. This thing tested every last bit of my surface modeling skills that I need to keep practicing. So many aspects of this design are on different planes or centerlines. The wall thickness is consistent in the main body of the tube, but then varies on the throttle body side which had to have an expanded OD to allow an appropriate surface to clamp a coupler to without impacting the smoothed large radius airflow path in the ID of the tube. On the filter side of the tube, you can see some of the airbox wall that will need to be trimmed away to make room for the big boi air filter.


This will all bolt to the OEM airbox and "float" on the TB side something like this.


So enough virtual talk, make the damn thing! I reached out to a local friend of mine with a higher end Bambu 3D printer last night. 16hrs later, this beautiful specimen came off the print bed. He did run out of his matte material mid-print, so you'll see where he transitioned to a shinier black to finish it up. Either way, it's pretty awesome to see this level of print quality on a relatively DIY budget printer.

Filter fitment was absolutely perfect!


Nice straight through shot looking through the TB side.


We'll see what it makes for power on the dyno soon. Fingers crossed I can make some dollars off of this once word gets out in the Hellcat community that it exists. I'm now almost 4 full evenings into this thing between scanning, meshing, modeling, printing, etc and Daddy needs a TKX

 

I'm going to have to learn how to say "no" here at some point as nearly every night since July 8th has been spent on Mopar things in one way or another.... but that "no" day isn't today, it won't be tomorrow, and it likely won't be any time in the next 1-2 weeks, so let's continue on this train of self-inflicted intake designer misery!

The first print of the intake noted 8 days ago fit really damn well all things considered. I had developed a PDF template that you can print and use to place on the airbox and cut out the appropriate geometry so the new tube fits into place using OE hardware. That worked perfectly. The 1/8" gap on the throttle body side of the tube was also pretty much perfect, but what was slightly miscalculated was the filter base diameter. You can see it is sitting at an angle and didn't quite fit the straight flange it was supposed to seat onto. Disappointing that I didn't nail the design down on prototype #1, but I'll take that L as it's just me being hard on myself.



So what's a guy to do if prototype #1 doesn't work? you go to prototype #2. To further test my surface modeling skills, I figured out I could get rid of a lot of support material (aka wasted material) on the 3D print if I blend the throttle body flange into the tube body where it was previously more of a sharp stepped feature, so that got done, and can be seen here. I'd hate to actually admit how long it took to get this blend to look like this, but I'm learning and this is cool.


the second improvement was to purposely kick the filter away from the front of the airbox to get more clearance. I adjusted my filter model to reflect the actual part and not what was advertised. If you move the 7" hole towards the rear of the vehicle, you start getting really sharp non-desirable bends at the rear side of throttle body opening. You also run into clearance challenges with the filter to the back/lower surface of the airbox... so long story short, purposely angling the filter by about 20 degrees does the trick per my CAD quite well.


We are gambling that prototype #2 is going to fit exactly how we want it to, so we have new more expensive and higher temp capable material received in (which is good to 300F). This is the material that is intended to be used for production. We did some test drives in 85F ambient conditions to estimate how hot the intake tube actually will get and measured it to be around 175F with hot idles being that worst case situation. This supported a level of comfort with the 300F capable material we chose. The material was received on Friday and is currently dehydrating before being printed likely at some point tomorrow.

So then what happens if one hellcat guy is really happy with your 130mm Kong blower to 7" filter design? He sends his demon buddy over...


It's weird making a temporary transition from miata customers who are notorious cheapskates (myself included) to hellcat/demon guys with literal open checkbooks, but I can't say I'm too upset other than this taking away miata build time. It was odd thinking about the fact that I had 2000HP of dodge in the driveway at one point this week...but anyways, the demon guy wants a similar intake as the hellcat one I just got the prototype #2 design done on but instead of going to a 130mm TB on aftermarket blower, he wants it going to a 108mm TB on a factory located blower... so the demon intake will be the "same" but "different"

...then after that, the hellcat owner wants to test a "race only - ram air" design that involves removing the headlight entirely... so I'll be busy on the keyboard and mouse the next week or so developing these designs. It sounds like 4-5 of my 130mm designs are already sold with some big names in the supercharger development space first in line, which is exciting.

 

This thread continues to be a great read no matter which curveball it throws at us. I don't think anyone is complaining about all the V8-ness going on here recently lol.

Super sick how quickly your design gained traction with the Mopar crowd!

 

I'm glad this iterative design torment is good for something... so without further ado


We got the second iteration printed. TLDR as the meme suggests, it was a nice learning loop but still not quite there.

It was the first time we tried using a glass filled PA6 nylon material. It's a more challenging filament to print for a variety of reasons, but the temperature resistance is good for up to ~350F, which makes it good for engine bay applications if you are intending to use the printed part as a production part (which we are here). Jumping straight into things, you can see how the external surface finish actually looked quite good. If you didn't know any better you'd think the finish was a textured injection molded part.


The internal finish has a bunch of random "dots" that need to be cleaned up. Still haven't figured out what setting this is, but light work with high grit sandpaper does clean it up quite well.


Splitting the main mounting flange was a good idea as we drastically reduced the amount of material to print the part, but life is full of consequences. The consequence here was that the flange was a bit too thin on the throttle side of the intake tube for this material's properties (or our printer settings) and the flange warped a bit during cooling. When you go to mate up the 2 halves, you get something like this. We also found that this material was a bit more brittle off the printer, specifically where the tube met the flange so we are investigating methods to hydrate/anneal the material to bring back a bit more overall strength.


So all of this led to tonight's iteration #3 updates. I made the mounting flange thicker and added beefy chamfers from flange to main tube body to promote more strength as shown below. Iteration #2 above physically fit spot on which was awesome feedback to get, so the scanner has shown it's value. Something like this would have taken at least 5-10 iterations to get this close otherwise with all the complex angles in play. What I'm stuck in now is the oh so joyful 'design for manufacturing' loop where I have something that fits the space, but now I need to make tweaks so it's easily made by the printer without issue/risk. Fingers crossed we get there on this print tomorrow!


Oh, and to make things more fun, I'm doing all of this remotely in the middle of a freaking southwestern desert. I'm spending the week to specifically find wind-free 100F+ heat at a test track to complete data acquisition on 5 prototype bikes that I can't speak details on. Enterprise gave me a new Elantra limited rental, which I can't say I'm really that upset about for a commuter car... Would I own one? No, but maybe the N trim. Is it probably one of the better mid-size rental sedans I've had? Probably. Very nicely spec'd interior for what it is. Mountain views beyond the steering wheel don't suck either. Nice change of pace from Midwestern corn for a bit.

 

Cool stuff! Random dots is most probably seam position set to "random" in your slicer. Aligned gets rid of them, but produces a clearly visible seam, not sure which one you would prefer. On the flange, consider adding a metal plate on top; you can get away with a thin flange and the metal will pull it back to flat while spreading the load (which helps with creep over time).

 

Nissan proving grounds?

That's not far from Podium Club, one of my regular tracks. You shouldn't have any problems getting your 100* tests later this week, though the next couple of days are cooler than normal here for this time of year.

 

Yeah, we are 99% certain that setting is what the dots are coming from, but are more-so curious as to why they are existing to begin with. They do not show on PLA or ASA materials with the same slicer settings, just on PA6 attempts thus far... more to come on that front, but in the meantime, the PA6 dots are quite simple to remove with a light scuff of sandpaper. Funny you mention the metal plate. we considered something like that, but the thicker flange seems to be doing the trick right now. We are attempting to avoid additional costs with a metal flange if we can avoid it. Additional plastic thickness on the flange is cheap in comparison.

Yessir. I'm on my semi-annual pilgrimage out here. Generally we come about 2-3x per year to stress test in the heat. It would be awesome if there was a podium club event during one of the business trips that I could plan ahead on as I would gladly jog down on a Saturday afternoon or Sunday to spectate or hang out in a paddock for a change of pace from what is generally very monotonous and repetitive days.

 

Holy updates! Man I love your content here, so thanks for keeping it going. The mopar stuff was a fun read. Awesome cars too.

These 5 prototype bikes you speak of, would any of them happen to be of the sportier variety? I gotta say, I'd love it if HD made something akin to an old Buell or an FTR. I like the panam but it was a bit big for my tastes of a "fun" bike.

 

I was expecting it to be the Chrysler facility out in Yucca. I saw a lot of H-D testing going on when I worked out of the Naples FL facility, I figured the rental might have gone to other facilities as well. Thankfully I didn't spend too much time on the grounds at the Yucca PG, it was more of a base of operations we got our cars shipped to.

I loved going on cal trips, except for the part where we were in Yucca. Yuck-ah.

 

We have multiple locations we can test. It just depends on the type of testing we want to do. For torture testing cooling system (and powertrains), it's hard to consistently beat the heat (and lack of wind) that you can get south of Phoenix. Here is where I have to give my canned boring employee response because I like my job. "I cannot speak about future HD product".

That said, I can talk about current product. For those reading that will be at MATG, seeing as my car is obviously in jack stand land for the foreseeable future, I will be driving down in what is my favorite bike in our 2025 lineup, the Pan America ST in black/red. I can almost guarantee I'll be the only one there on one of these because 1) its a miata event and 2) these things are fairly new to market. 542lb wet, 150hp/94tq, and really nice rider triangle. The ST (sport/street touring) sits about 2" lower than the Pan America Special that is a bit more adv touring spec in wheel/tire/suspension/seat department. The 17" street tires and retuned 1" lower suspension really make this chassis shine. What it gives up in nimbleness from my ZX6R, it definitely makes up for in long distance touring comfort and having tech features like cruise control, navigation, etc for a trip like this. While I will miss having the miata at a miata event, being "stuck" with this bike isn't exactly a not-fun situation. If you see me out there, feel free to say hi.

 

I had to poke, though I expected this answer!

I hadn't actually seen the ST, it's way more my style. I'm not a fan of the trend of 500+lb offroad bikes, they give up too much street performance for looks and the ability to go off road that most people don't use. I know a few people that use them for their purpose and they are cool when you actually do it, most just don't (myself would be included). And if I were doing any serious offroad I'd pick something more akin to an africa twin or T7. It just isn't what I'd choose if I were doing that kind of riding. I LOVE sport touring bikes though. Bags for camping and luggage, can still bomb a fire road or get to pretty much any camping without issue, 2 up pleasures for the wife and good handling while loaded. When unloaded can hang with sport bikes in the twisties and still cruise long distances. I still haven't given up my 09 Ulysses but maybe one day I'll step into one.

I sure wish I could make MATG this year. I keep saying someday, so.. maybe someday.

 

Very cool on sharing how you develop a product. A buddy of mine had a Hellcat and a red eye and those things are nuts. Supercharger whine is fun. Not terrible on track for how big they are and a nice cruiser. Of course he had to get these tags and every Tesla tried to race him.. lol



On the topic of Hyundais/Elantras. They are definitely nice cars... as long as they're under warranty. I was helping a friend look for a used/affordable car recently and it seems like Hyundai/Kia have some issues with their engines as they seem to have failures that aren't uncommon around the 100k+ mark. So resale value is s**t on them. Hopefully they get it sorted out as they seem like nice cars (my wife's on her 2nd Tucson) and I'm a little wary about purchasing another new one.

 

A-ha, then I may be wrong; start-stop blobs should depend mostly on machine paths rather than material. Suppose you have thoroughly dried and monitored humidity in the material before printing?

 

This,
Nylon is notoriously Hygroscopic.
if you're not printing FROM a dry box you can easily get issues, even with freshly dried filament if the print is long.

 

You and me both here. Having grown up on light weight dirt bikes, the idea of purposely wanting to wrestle a 500+lb bike in loose uneven terrain has never seemed that appealing to me, but I depends how crazy you go with it. If you just want something that can more comfortably manage a gravel road than a more street oriented bike, I get it. If you are doing gnarly offroad only adventures, I'd lean towards something more nimble than the heavyweight adventure segment.

 

we are printing from a dry box, but its possible it wasn't dry enough at the start of print. We will keep this one in mind the next run of PA6 that we do.

 

Been having a lot of "fun" with intakes the last 2 weeks, but it's pretty awesome seeing this all come to light.

The first intake design is built for a hellcat (or demon) that uses the Kong 2650 supercharger (an upgrade) with the 130mm throttle body and flows to the 7" air filter in a modified factory airbox. It is a beast.


After beefing up the bolt flange on the airbox, we are able to split the print in half along that flange for 2 reasons. One, it allows some future customization ideas. Two, it makes it printable with the printer we have as it would otherwise be too big. With all that back and forth done (I kid you not, probably about 30 hours of scanning and modeling to get to this point), the hellcat owner had already sold 3 of them between his uses and some friends of his in the industry, so let that printer go brrrrrrrr and start making money! Really happy with the surface finish on these parts overall. Shown below is the larger throttle body half. It is a perfectly smooth internal transition from throttle body to filter which was not easy to achieve.


...but because one intake isn't enough and cornering the market off the bat is important with ideas like this, we decided to build a similar intake for the demon owner who still had the factory IHI supercharger (same as hellcat factory blower) with a 108mm throttle body (a very common upgrade). So here you can see the same concept, but now it goes to a throttle body in a slightly different location. This one went much quicker as I was able to just modify the Kong blower intake and update the size/orientation of the new TB.


Here you can see the difference between the two designs. The IHI blower intake is the longer more slender one, whereas the Kong blower intake is more chubby and short. They both utilize the same air filter box half which makes things simple.


So now the printer continues to go brrrrrrrr as we have a couple of the IHI intakes tentatively called for.



So now that all takes me to tonight. I haven't honestly had any time to look at the miata with all this intake stuff going on and MATG is already on top of us! These intake designs should help fund the LS swap, so I really can't complain about spending design time now for what will be easy money going forward. Will be leaving at 4am tomorrow morning on the company bike and be on the tail by around 5pm local time! See you there if you show up!