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Naturally Aspirated Performance ForumDiscussion of naturally-aspirated rotary performance. No Power Adders, only pure rotary power!
From the "12A" to the "RENESIS" and beyond.
Depends on the part, in many instances no. These are pretty robust machines and print pretty slow, its not super thin wall and its not super thick where it is full of heat. We had even done propulsion parts for a spacecraft out of inconel 625 that and was subjected to immense temperatures and we did no annealing or heat treating. does stress relief help? yes, is it necessary always? no. It depends on the geometry too given the the process.
here are the flanges I have on the car today out of inconel:
no heat treatment done or needed.
With DMLS (laser) it does not shrink, the binderjet metal 3d printing process shrinks, you actually print those about 20% larger as they shrink to size (like a traditional MIM or metal powder compaction process). this is literally made out of weld, its just micro welding so the machine and parameters are key to not getting a sad blob out of the printer. Some machines have capability to monitor the part mid print and can alter its settings to try and get the part as close to the CAD model as possible. pretty wild stuff. poorly designed part/bad settings you are going to get build failure and warped part and potentially machine damage. (IE: when a part separates from the build plate and contacts the recoater blade because its 'grown' in the Z height and the machine doesn't realize it)
cheapest was is design it and print it in plastic that can be used in a casting process where the pattern is lost to the molten metal poured. its surprisingly reasonable, even for low volume but then you need to be mindful of the casting process/limitations so you can't do wild shapes like these flanges, that have a floor of triangles and overhangs that are undercut on the mounting flanges shown above.
Very nice on the flange, I'm experienced in microwelding and laser welding, no matter how fine, the powder is melted and it shrinks when it cools. I figured with all the heat for Inconel it might sorta stress relieve while building. We usually don't worry too much fabricating stuff so I imagine it's fine as long as there are no thick sections.
Very cool you get to have access to this, I asked the questions because I'm interested, that's all. Edited to say that I've worked in an investment casting plant, we used the prints for to prove we can make the part and wax patterns from aluminum molds for FAI and production. They make a much better part.
does the metal generally stress test like metal? the plastic has a grain, essentially; so to get a thing that is strong enough you just have to try some different iterations
Yeah its still metal, you get about 99.1-99.7% density out of it, generally speaking it performs better than castings (less porosity) and is almost as good as forging (it has a similar crystalline structure) but due to the forging process you get better durability out of the products whereas the printed variant is more likely to fatigue. layering/shear is a concern on an engineering level really, (like any 3d printed part) the layers get slightly re-melted as it cross hatches across the slices but you can design the part and orient it in a way that its build in a fashion where this is not a concern.
Originally Posted by TonyD89
Very nice on the flange, I'm experienced in microwelding and laser welding, no matter how fine, the powder is melted and it shrinks when it cools. I figured with all the heat for Inconel it might sorta stress relieve while building. We usually don't worry too much fabricating stuff so I imagine it's fine as long as there are no thick sections.
Very cool you get to have access to this, I asked the questions because I'm interested, that's all. Edited to say that I've worked in an investment casting plant, we used the prints for to prove we can make the part and wax patterns from aluminum molds for FAI and production. They make a much better part.
yup same concept but if you print something 1 foot tall it may be a 6 day print because its printing 30-100 micron layers at a time.
using the printed setup for making molds is excellent use of the technology, there are even sand printers that do very large scale used for sand cast molding so you can get a lot of benefits from that.
Well the repair on the rear iron didn't work and it leaks, I'm not opening up the old motor so I've purchased Cosmo 13BRE irons instead and those will get streetported. Time to move away from the T2 stuff and go after the real goal.
okay project no longer on pause time to get crackin'
Cosmo 13B-RE motor on the left (stock ports), turbo 2 motor on the right (ported)
now the actual ports isn't going to be a huge change but because the casting insert to make this port is so much larger it saves me a lot of grinding time and reduce the opportunity for me to poke through.
but when you look at what I'm going to port its not much larger than what is stock currently:
its the same template I have been using on my prior motors but the path of air to this point is far more free flowing, center iron will be a mix of renesis streetport and large streetport
okay so it wasn't THAT weekend but had some misc/random delays and such but back on the tracks for the most part.
good start
uhh too much mad max.
it sticks about 8" out of the hood so this won't do as much as this is really awesome.
the middle straight pipes are coming out which means I need to take double that distance out of the exhaust which I have plenty of room to remove and that way i can keep my primaries "matched"
The intake primaries are half the length of the exhaust primaries but the exhaust runners are too long in general and the manifold itself is difficult to install so that is going to get re-worked a bit too and then the filter should only stick out of the hood 2-3" which is much easier to cowl.
now with heat mitigation (ceramic paint + fiberglass/metal heat deflection)
trimmed a few areas to make it easier to install and all good for the most part.
I managed to save 16.5lbs off the stock intake as well so thats good news.
total intake system now weighs 14.55lbs - not too shabby. Plenty of optimization (thinner block flange, thinner wall sections, fully printed elbows or change to carbon fiber nylon down the road for massive savings)
I was using a S5 NA intake before with some plastic ducting
hoping for first start soon just waiting on a part that DHL lost...
leaks fixed and its running/starting but something is up on the front rotor, may need to break the corner piece free still or something else is wrong:
it hasn't quite seen load yet so some driving around may do it good to help free it up or its pull it and open it. I'm going to pop the exhaust off and check the seals and see but this seems more corner seal/side seal related. Wouldn't be totally surprised if the side seals are too tight and its sticking - the renesis seals are a bitch
:/
yeah, a corner seal and a stuck side seal is my bet.
Corner seal or apex seal affect compression on 2 rotor faces, side seal 1 face.
1 stuck corner seal between 75 and 60 psi faces and a side seal stuck down with it on 60 psi face.
Though that 80 psi face could show corner seals stuck down on both ends of the stuck down side seal.
before teardown I checked each apex seal as it passed the exhaust port and all of the corner pieces were definitely free.
This one is on me; it looks like I installed one of the apex seal springs incorrectly on the front rotor.
The spring wasn't seated against the tang so the short seal was limiting the travel of the long seal which made it less springy/not good compression and affected both faces. time to re-go through and double check everything clean and inspect as well as give the housings a 2000grit light polish treatment to help build some compression. Also these are rotary aviation apex seal springs which I'm going to ditch those for OEM ones as they may fit better as well. I didn't like the way one of the corner seals felt either so that may have been that 80 value on the front rotor.
good seal has spring witness marks where they should be along the tongs/tabs of the apex seal
and here is where I found the suspect seal, the EGTs and AFRs were quite a bit different between the two rotors and this confirms the theory.
but now that all the fabrication and puzzles pieces are sorted this should go quickly but I'm going to go through and triple check my side seals as well while I'm here. Not a fan of the renesis in this aspect, rx7 side seals are much easier/simpler.
ended up fixing it, putting it back to together and damaged an o-ring on the front inner so it wouldn't hold coolant - I figured if I had to open it one more time I was going to put new housings in to match the effort of all the other parts so I went with full length dowels and new FD housings and gave them the extreme rotaries port job from Australia. I ended up making a jig to help the porting and prevent me from making a mistake because of trying to hold the housing and port much more stable and less awkward
I do hate tearing into new housings was tempted to run them as is but nahh.
this is better suited for my non turbo application and doesn't really change the port opening but increases the duration for more overlap. Here is the port marked on the FD rotor housing.
and a rough cut done hopefully get a chance to get these inserts swapped out for my printed inconel ones and get this motor assembled this weekend - the EGR port needs to get welded still (underneath the insert) then do a deep cleaning on these housings then it should be ready to rock!
Plug the hole and tap the hole for m6 thread to use set screws instead of rollpins. good with and without the printed inserts.
these came out much better than the other housings.
this is no longer a frankenwankel - its truly a dankenwankel now.
Renesis Rotating, fully cut
Custom streetport
Cosmo 13B RE front/rear irons
20B center iron
FD housings w/ printed inserts (Inconel 718)
Printed metal intake/exhaust manifolds
Haltech elite
EFI Hardware ITBs
Cool build!
How is the quality of the EFI hardware intake? I'm planning on buying their 20b setup.
very nice, good finish - very tidy but the way it bolts down on my outboard, in car position, needed a specific height stud and the hardware isn't supplied. It wasn't the easiest to install because of where the fuel rails bolt to the body on of the throttle body assembly which seems like a basic design flaw but not a big deal in the grand scheme of things.
i'm really liking your manifold - the finished product. kudos to you.
is it in the car and running yet?
yup! been busy so my internet log has been a bit of a delay - started up on 7/5 and I put about 200 miles on the break in so far, got some more miles to work in the sub 5k window then start working the 5k+ break in, try and do about 500-700 miles on the break in and then do an oil change and start floggin it.
working on a new hood so I can keep rain out and improve my radiator cooling, I can still use this current one as a backup if need be but the plan will be to hack up an aluminum non turbo hood.
about 500 miles done on the break in so next week we go in for dyno testing and see what this is all about.
Same dyno as the last motor, same car/setup just new motor/intake and a small adjustment to the exhaust. should be a good comparison, aiming for 200whp.
car show went good! yeah that is a roof scoop on the hood, I'll work on printing a more sleak design but this buys me time and I can toss this cowl on the other hood for a backup/party hood.
I have got about 500 miles on the motor now so dyno is coming soon to quantify the horsepower. Curious to stack it up over the past few motors, should be an improvement!
I got some latergram to catch up on but the results are in! and the engine is... well kinda lack luster to be honest. Lots of R&D/$$$$/efforts to go backwards in horsepower. The old t2 motor on the stock non turbo intake was peak 184whp/127tq this new motor is 170whp/130tq. So I have heavily invested into a motor that should be capable of 10k RPM and barely spins to 8500 but that does give me a large ceiling of safety, so I got that going for me... which is nice.
how to read: solid line is baseline, dotted line is leaving dyno with improvements to the calibration:
OLD MOTOR:
New fun motor with cosmo and rx8 bits
time to do a compression test and see whats the deal, side seals clearanced wrong? too much porting? data shows no intake/exhaust restrictions and the spark plugs show that the engine is burning properly.
but I had no time to dig into this as the next morning I packed up the car and headed north for the Lake Superior Performance Rally up in the upper peninsula of Michigan.
12-29-21, 02:23 PM
