Building the 12 Rotor Exhaust with Legos

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[@fordcent]

My depression is cured every time a 12 rotor video comes out.

[@pleite567]

This! But to bad its just temporary 🤪😂

[@brianmunyongani5172]

@@pleite567 😮😊😅😅😅

[@fordcent]

@@pleite567happiness is temporary, 12 rotor is forever

[@phillgizmo8934]

It's not a depression then, it's a addiction.

[@squidikka]

@@fordcent 12 rotor is happiness, therefore happiness is forever

[@matthewdeatsch2787]

Hey I'm a machinist at my day job and just FYI .004" runout on ER collets is WAY more than it should be. If you get name brand collets and holders you should be well under .001". It was cool to see you use the exhaust legos though, Ive always wondered how well they work.

[@robwigglezz944]

Agreed.

[@spdcrzy]

Hell, even a thou of runout is too forgiving at this level of insanity. I'd argue for five tenths, no more.

[@travisolander4749]

I'm pretty sure the guy with the garage and all the one-off, custom builds knows what he's doing.

[@802Garage]

@@travisolander4749 He is the first to admit he isn't a machinist and is always learning. He def won't mind advice from the pros.

[@joealex65]

@@travisolander4749 For the most part he does, but he LOVES good advice from the experts, that's how he learns new stuff, it has always been that way for him.

[@Sebastian-zf7di]

teasing everyone with that "turbo, sorry, exhaust"

[@ScaredEdit]

And the Garrett shirt

[@mildxdrifter243]

In one the first videos with this motor he talks about putting turbos on it

[@fayrebrand1402]

it would make me sad put a turbo on a NA 12 rotor 2000-2500hp (and he said « for boost sorry for exhaust »)

[@christophercantwell1412]

@@fayrebrand1402 he later says turbo at 8:50

[@chris661]

That long header will likely need bellows or something to account for the larger amount of expansion along its length compared to the other runners. I was working in F1 exhaust systems the year we changed to turbo engines and even on those short headers we had bellows. This was mainly due to the tight angles we had due to packaging constraints and the outside of the bends getting much hotter, therefore growing more. Does look a little tight for packaging some bellows in there but I’m sure you guys will manage it! This thing is going to be insane when it’s done.

[@feenyx6394]

Now there's a documentary I'd love to see

[@podulox]

@OP - You Sound Like Rick...

[@tristynleetl]

“For boost.. I mean exhaust” - bro if you boost the 12 rotor, I’ll cry joyous tears of blood

[@halofreak1990]

It's not going to make 5K HP N/A, so for its intended application as a powerboat engine, it'll have to be boosted

[@kabenhanson5878]

at this point, we would no longer be measuring efficiency in miles per gallon, but perhaps gallons per mile haha

[@gordythecreator]

My 85yr old Pops & i don't have much to talk about, but THIS MADNESS always makes an easy conversation starter. Weight is the only complaint from the Old SCA-Racer.

[@Token_Black_Guy]

Talk to that old man more I wish I did the same for mine

[@Jack_Hurst_]

Same me and my dad although ur probably same age as my dad

[@robwigglezz944]

A common machining process to flatten surfaces is to have it on 3 points with a 4th adjustable point to allow the material to spring back in after the first cut. You'd be surprised on how much stuff will move after machining off the scale surface.

[@thomasbaxter8138]

tool maker chiming in id square it off on a bench grinder. lol

[@mostlymotorized]

You'd be surprised at the difference in warpage Machining 303 vs 304

[@thomasbaxter8138]

@mostlymotorized didnt catch him say that now that you mention it

[@thomasbaxter8138]

@mostlymotorized didnt catch him say that now that you mention it

[@gabbermaikel]

stainless wil warp like shit any way. You think you have a flat piece of stainless? Wel try again after machining, or welding for that matter.

[@marktverskoy7927]

Innocent bystander here, but when you make the manifolds don’t forget to account for clearance for wrenches/extensions to get to all the fasteners! It would be a tragedy to go to all the effort designing and building these pieces only to find you can’t get to a fastener because a header is in the way. You’re doing wild stuff guys, keep it up!

[@802Garage]

Interesting to see the approach they took before. Exhaust crossed between the intake runners from the center. Definitely not ideal for heat management. This approach will be much more efficient for the turbo... I mean exhaust... To not heat the intake runners. Really cool stuff as always, Rob and team!

[@brent5832]

“Here’s the first one. The second one is coming up next.” Pure gold.

[@Just_A_MG]

Was so cool meeting you at PRI, crazy to think all of this was going on behind the scenes while you were there. Thank you for the opportunity!

[@eriklarson9137]

Yup, me too.

[@michaelgoldberg4000]

Since you are gonna be making your own crank shaft, or at least working with one where you can change the intervals however you want, you don't absolutely need equal length exhaust headers. Play with the firing intervals to suit your design needs, in a 12 rotor engine it won't matter much anyway and you can save a lot of piping weight.

[@joshuawinegar4303]

Just a thought, and it would mean more machining, but you could make the 4 center exhaust flanges have a built in angle. You could machine the port to come out vertical!

[@Bdude1111]

Glad to see Isaiah in the vid! He hasn't been in/mentioned the last several videos and Rob posted on Instagram a few weeks ago that he was looking for a fabricator. I was getting nervous that he left.

[@nickalderman5943]

I feel like that middle manifold would benefit from a 4-2-1 design that not only allows for scavenging, but also a slimmer form factor. I imagine you've already been down that rabbit hole though as this was filmed months ago and I am no engineer lol

[@2ARM2]

i feel like with the space constraints though getting a nice equal length would be difficult no?

[@michiganengineer8621]

I was thinking the same thing about a 4-2-1 design. And then he "slipped" and said the word turbo. That made me try to picture THAT plumbing job . . .

[@2076649]

​@@michiganengineer86213 100mm snails!?!? Dahmn

[@shize9ine]

4-1 Manifolds would be so much easier but wouldn’t sound or look as cool.

[@DJKr15py]

​@@2076649why not 6 and aim for top fuel dragster territory?

[@scorchpowdispenser]

So happy to see @ fabricationfather ❤

[@taylorpratt6287]

Rob have you considered doing more off a log style exhaust manifold? You’d be able to pull the exhaust further from the intakes and have a bit more room for heat management

[@DustinHasVideos]

I’m not an engineer or exhaust expert, but this was my thought as well. It seems like with the space constraint it would be the best option

[@itsseb359]

I think depending on firing order, there can be some substantial power gains with long tube headers vs log style, (similar argument to equal vs unequal length) if it fires like a cross plane, then I'd agree that a log style exhaust would maybe make more sense, however typically a log manifold is more turbulent leading to less flow

[@Laffatit]

Rob Dahm is the Mike Patey Of automobile. I love to see his passion for the rotary and the meticulous approach to everything!

[@JoeMadds0]

Fabdaddy Isaiah is back! I was getting worried after not seeing him the last couple months.

[@diegofranco8276]

Was wondering what happened to him. Great to see him back tho!

[@hugojeller]

RIGHT? Every video I was scrubbing the entire thing just to check on him lmao I didn't even watch this video and scrolled to the comments haha

[@PaddyQuiggin]

Such a relief, I was so sad when I thought he was gone

[@changes8]

Yes. Make it TT 12 rotor. The mad scientist continues his wild experiments 😂

[@brianrainey2739]

LEGO. There is no S. Ever. BTW, awesome that you have teamed up with RocketBunny.

[@podulox]

EVER!

[@SergeyPupkoMusic]

RocketMoney lol... But I'm sure Rocket Bunny would be open too. 😂

[@TheSilverShadow17]

Then how would you describe multiple of one object if you really believe there is no 'S' in Lego? People say Legos out of habit or because it's plural context.

[@brianrainey2739]

@@TheSilverShadow17 Lego is a brand name. Lego bricks are what you construct with. Bricks is the plural. Saying Legos is primarily an American thing for some reason…

[@TheSilverShadow17]

@@brianrainey2739 As an American myself I've been under that impression myself until upon realization. I don't get why people don't say Lego bricks as opposed to the basic 'Legos'

[@aserta]

This entire process is very entertaining to watch, interesting too. Love it when someone's between "discovering new pathways" and "applying knowledge they learnt". Awesome stuff!

[@killersmith92]

Run ITBs with velocity stacks and turbo the car, enclose the velocity stacks in a ported box(s) and have the turbo(s) feeding air into them.

[@mickaeldrouin9452]

Yoooo it's so gooood to see Isaiah back

[@zeadlots]

The heat is going to be crazy. Best of luck!

[@trevormoore4456]

It's cool as heck watching you run CNCs!! I CANNOT wait until you start thinking in the world of metal AM!!

[@ttsupra87]

I've wanted this kit for a while. The money saved in time for design is so worth it

[@krusher74]

should have designed it in cad, you could 3D print prototypes and cost less than $750.

[@trustfire]

Exhaust legos are genius!

[@Musclecarera69]

Love this, can’t wait to see how you deal with the collector and how you’re going to deal with scavenging of the exhaust pulses. Don’t know how much scavenging affects Wankel engines.

[@randominternetguy]

Why scavenge when you could boat motor?

[@Big_Fe11a]

No need to scavenge if it's going to be forced induced.

[@Musclecarera69]

@@Big_Fe11a engine pulses still cause issues with forced induction.

[@ImKairyu]

Saw DDE using these and I knew you would get your hands on them for this project!

[@Zdub811]

I thought the same thing… Mike Essa is a DAWG

[@MattMoeMedia]

I think I’ll have a stroke hearing this start up for the first time, very excited rob! Been watching all these videos!

[@ftovr2957]

Seeing where the runners have to go, you appreciate the insane difficulty of packaging this. It's like trying to cram a V12 into the space of a V8.

[@Grimm-Gaming]

How about the kid sticking the v12 in his miata? Hahaha

[@ftovr2957]

@@Grimm-Gaming True! But at least in that case, there aren't any exhaust ports in the valley 😂

[@Sun-ut9gr]

Not as far-out as you'd think, cause making a V12 the size of a V8 was done! Look up the W12 from VW/Audi. It's wild, and it's not even the biggest one--they made a W16 and stuffed it in a Bugatti 🤣

[@jimhimes3506]

Ethan good job having your hand on the estop. You never know when something can go wrong on a newish setup and finding the estop when you’re panicking due to a crash can be a bit daunting

[@yutub561]

Clean your table before your second op on the mill! any tiny chips or coolant underneath will throw off your flatness

[@hunterjames8251]

I enjoy Ethan’s segments and hope he gets more comfortable with the camera. Also good to see Isaiah back, maybe he’ll help with that lol

[@LavshBeatsTMlavishbeats]

Can’t wait to see how much power this thing makes

[@Tclans]

That is so cool. It is Lego actually, it says on the box 😆👍🏼

[@kennethparker573]

Make a log manifold for the center exhaust and keep a lower profile for the intake

[@PossumSwanger4]

Been watching for awhile now since I saw you on this vs that.. the stuff you do with these rotary engines absolutely amazes me man! Great stuff!

[@easygoingdude9990]

So happy to see Isaiah dude

[@bobby43rocks]

Rob and team, I'm BEGGING you to try to get a 12 to 1 exhaust for this thing. I know that the engineering challenge will be near next to impossible, but based on the videos that you guys put out, I'm certain you guys can do it

[@TheBCninja]

If it's going turbo, I don't know if it would be possible to go 12-1. First off those primaries are large so the collector and subsequent flange would be massive. Second, the turbo would have to be off of a space shuttle to be sized for 12 rotors.

[@floodo1]

This is gonna be 3 turbos watch

[@TheBCninja]

@@floodo1 Specifically three Garrett G57-3000 106mm turbos :)

[@thefunniestfarm4731]

@@floodo1 Yup, I expect no less than 3 turbos.

[@boxcarbro3043]

Exciting to think what this engine will sound like.

[@ethanruedinger1630]

Let’s go Rob! I have been absolutely loving the content lately and I’m super excited for what comes next

[@ethanruedinger1630]

Someone who comments “I’ll do as many push ups as this comment gets likes” or a fun fact of the day would probably get more traction than this

[@clearskies8098]

Great video Rob, keep up the hard work. It’s definitely paying off. Cant wait to see it finished!!!!!!!!!!😊

[@savydude1]

Great build... :) *Check out the Mercedes Gtr....the intake is the exhaust and they run outside air over the centre "V" to cool the turbos and exhaust.* You could do something similar.

[@mccullummedia]

Those lego like exhaust pieces are so cool!

[@Hero3life]

So damn excited to watch this thing fire up

[@mrsomething0075]

Wow! Im so amazed to see the progress of this engine. I am super invested to see the future of rotaries! Cant wait to see this in a car and hear it run! Regards from South Africa.

[@vadimm6432]

I really hope this is going to be a TRIPLE TURBO setup!

[@billyking722]

Again another very interesting video on a very complicated inlet and exhaust system more to come I am sure thanks

[@KaineVarley]

@Rob Dahm, it's always such a surprise when your videos end... Always makes me laugh... Love it.

[@Jrakula10]

always a joy to see uploads on this channel

[@emailformosa]

3:23 - _”What happens when a tool snaps?”_ A machinist’s heart skips a beat, an angel sheds a tear, and a Purchasing Manager gets their wallet out.

[@jonasjohansson1511]

Never have i repeated the words "log style manifold" in my head before in 20 minutes.

[@animal_engineering]

Looking good. when it comes time to transfer the bends to tube, keep the ice modelling kit away from acetylene. I accidently spilt my bottle over and it fused a bunch of them together. It is good for when they split in half to join back up though.

[@BorisSpark]

Avoid Pi cuts like wild fire, lose of flow velocity due to imperfection on the inside, each weld brings a weak spot (a point of possible failure) due to the heat affected zone and there is so much more, building an exhaust system that makes power is an absolute art and it difficult af. Have fun lads and its an absolute pleasure witnessing the build! Thank you.

[@tekia9233]

This man is carrying rotary's legacy on his back❤️❤️❤️❤️ Love you Rob.

[@AndrewRzymski]

cant wait to hear it run!!

[@brianouwersloot]

Great stuff as allways sir

[@gabrielnhn1558]

Hey Rob, why don't you "just" 3D print in inconel some exhausts manifolds ? There could be a gain of space and better heat management this way i guess ? ( Something like an Artec manifold ) Plus you could model one and print it three times assuming the spacing between rotors is the same on each bank. Keep up with the good stuff, cheers !

[@mostlymotorized]

Because it's heavy enough already as it is

[@krusher74]

yeah, i though for $750 of that lego kit, instead 3D scan the engine, build a manifold in CAD, have flanges with stub 3D printed and then have the tubes CNC bent and weld it all up.The get one of the motorsport heat shilding companys as a sponsor to shieldit. He needs to watch some papadakis racing vids and move into the tech of the future. its all there in LA.

[@gabrielnhn1558]

@@mostlymotorized The 3D printed part would actually be lighter than all the welded tubing, that's one of the benefits of working with inconel

[@medalami17]

I love these cnc videos, because I recently had classes of g code. I haven't studied it for like 3 years, so this combination of classes and rob's videos is a great refresher lol

[@NagronCZ]

I dont have notifications on this channel, yet somehow I still click on all the vids the minute they drop. Always makes a day better

[@jgq5]

Man please cure my addiction to your 12 rotor😂

[@jacobnewman3152]

Can't wait to here this thing start!

[@mecabe5137]

Been crazy weeks of work and Rob's videos just recharge and boost back up my dopamine level for real! So happy to see Isiah back to action after so long and dayum! Rob should get Ethan talk more in the camera, it's good to see him more instead of just silently working behind hahaha

[@tiagoteixeira8415]

Brutal! Mal posso esperar para ouvir esse motor a trabalhar outra vez... Não ah nada igual no mundo. Boa sorte 🤞🍀

[@leonanthony7007]

Only channel were i drop everything to watch

[@Digimanis]

What a beauty!!!

[@MikePruszkowski]

Aluminum composite sheet is in your future (heat shield) Banger video 👍

[@grantbuxton]

You guys are awesome

[@TofuRabbit]

The mock-ups look great, it's gonna look SO awesome when it's real, super stoked!

[@StarPower999]

Seeing rob put his fingers down there to grab the tool really shows how big this motor is, easy to forget how big it is in the video

[@levilueth7778]

Can't wait to see more

[@corporaldestroyer2811]

I’m a machinist for Pratt, just a little advice you should get some shim tape, .001 - .010 it’ll help you gauge just how flat your face is sitting against the table and if needed you can put the shims under the part to get it to sit flat when you clamp it down

[@Silvia_Jay_S14]

The Rotary king 👑 at it again.Like they say only Rotary be long in a RX7 or RX8.

[@hahaha12345678993]

man, i cant wait to hear this thing run

[@kita1318]

the definition of "trust the process"

[@GoneAsGoneCanBe]

Saw Mike Essa on DDE using the manifold mock up kit recently, and I was blown away by them. Such a simple, amazing, idea.

[@nickcollins1528]

Mike Essa is God

[@nexrace]

Those lego looking things are not cheaply priced! You can spend a grand on them no problem.

[@joeykeegan6909]

@@nexracestill cheaper and easier than experimenting with metal, but yeah kinda crazy just for plastic but definitely worth it at this build level

[@lolly77]

They are more for shops who sell stuff they can afford it if a single manifold cost the same​@@nexrace

[@nickcollins1528]

@@nexrace probably could 3d print them yourself for cheap if you bought one of each

[@jamesh5460]

The whole engine just looks amazing beastie!

[@mrsquirrel8079]

@17:25 this moment of "DERP" is brought to you in part by oops.. because oops in the (building with your hands) world happens quite often.. lol

[@danielbieda5413]

A bit of advice for the future. I found that when doing some heavy roughing with 16mm carbide endmills they can actually pull out of the hydraulic and collet holders. For heavy roughing in stainless I use a side lock holder to make sure that it doesn't pull out, and then finish using a hydraulic holder to get a good finish cut

[@lameboysmtb6705]

Omg omg more 12 rotor content from the man the myth the legend yessir

[@gnydick]

One thing it seems a lot of car guys don't realize is that flowing gas doesn't like corners. It doesn't matter how smooth the path is, if the bend is basically a tight corner, it makes a lot of resistance.

[@weedfreer]

Hey Rob if youre chasing microns,.you probably want to get yourself a tool presetter device. It allows you to check your tool is seated correctly in the collet/tool chuck. Not only that, some of them can look at your tool and make sure that the tool/bits mounted on it are not damaged...down to microns of precision...also. You'd be surprised what gets missed setting tiols by eye only.

[@illuminatikiller1]

Should have made the radius piece different colors

[@doctordak7971]

Absolutely bonkers! Your content never ceases to amaze me.

[@adamlancaster5364]

love the N. Custer Rd sign 😂😂😂 gotta keep some Monroe with you!

[@roboman2444]

A scan of the engine (or a quick and dirty model just made with measurements) and some cad for tubing would work great here.

[@boochasaorusrex8231]

Best rotory channel hands down!

[@bencarignan2711]

It's been 4 months. We need an update on the 12 rotor!

[@jpdthe3rd]

take the time to put a real heat shield between the exhaust and the block/manifold. any sort of air gap and physical barrier will keep temps much lower. i under stand you ceramic coat parts or whatever else it will not beat the air gap and physical barrier; use them in conjunction. also it would be worth planning some sort of ducting/air low for that area. I'm sure there's a way way wo wire up a small fan on a relay or have an engine driven option

[@justbaumwolle1105]

Good job im hyped and great to se the fabdaddy again and a also can see 3 huge turbos😂

[@rhoninence4654]

I could not imagine trying to get an equal length for the exhaust with all of those tubes. it'd look insane

[@jans9426]

Didn't feel well this morning, then I saw another 12 rotor upload and started feelings better. :D

[@FreddyKrugerGloves]

Cant wait to see this engien in action 🤩🤩

[@marcomansi]

@Rob Dahm As your firing the 12rotor as a twin fire 6rotor, maybe consider running 2 huge(110mm+)turbos, with even firing 3(aka6)rotors to each turbo.

[@burningdieselproduction5498]

I love you Rob! You’re bringing back Built Not Bought a true meaning and value in t o day’s society. I truly believe that the impact that F&F had on the young car enthusiasts can be repeated. And you’re the one making it! I love you for that! Oh, would you please change that coolant or at least tell us it’s chocolate based and it smells nice so we don’t freak out. Be safe! I love you Rob!

[@Rhainee]

He said boost. What insane turbo setup is this mad man planning!?

[@matklm]

This project ❤

[@mtech1961]

Cant wait for another Video. Heat SHielding is going to be very critical though, with so many Exhausts and inlets so close? I am sure you will come up with a creative way of handling it. Love the Use of Lego btw.