Saw the pictures on Facebook and was going to ask what was up with the intake runner length. I know from first-hand experience that big, long intake manifolds aren't great for top-end power. The "printed" pieces look great though. Can't wait to see how this motor turns out!
In reply to infernosg :
I was hoping for long runners for as much torque as possible and went through a few different iterations then decided to scrap that and go with something more realistic then just modify the exhaust accordingly. more top end power for the rotary it is!
What is that air cleaner shaped like inside, is it two separate holes or one big cavity that both throttle can share from?
What inspires me to ask this is that I had two Spectre air filters on my peripheral port 12A and they were causing about 10-15kpa of pressure drop vs. running with no filters at all. This is like the difference between full and half throttle, that engine never made more than about 150hp as a result.
I am using ONE of those filters on my bridge port, and there is no measurable pressure drop until the very high end.
The difference is that an individual filter right there on the throttle needs to be able to flow the instantaneous demand of the port, while having a shared filter with a decent plenum volume between the throttles and the element smooths out the flow requirements significantly.
In reply to Pete. (l33t FS) :
one big cavity, but the filter housing is raised because of the air horn height because otherwise it is just a flat sheet for the filter to attach to, so there is more volume in there.
the oversock filter is what ITG recomended for rally car application/dust - I will definitely do some dyno runs without the filter, 1 filter, filter + overfilter and see how much power gets sapped.
okay a bit more realistic now:
and here it is all assembled:
I can't remember, have you had the car up and running on a EFI Hardware throttle body? I know I'm definitely not the only one but I'm apparently the only one complaining about the weak throttle return spring. Curious if you're going to run just the spring EFI provided or if you have plans to add others, like I did.
I had not had it running this throttle body on the old motor - that was the original plan but the old motor ceased to start and I had to hope for the best on the new motor. By hand i don't see any issues but also with the placement of this I need to run a custom throttle linkage, 12A FB one is too short and the t2 is WAY to long and the S4 NA one is way too short, luckily there are hot rod shops in the area that I can get this done quickly.
remember folks, before welding anything triple check that the parts are correct. I swear I did this but yet here we are:
I know I run an vented catch can for the crank breather but this is not a shortcut I intended.
going to try and get some small pieces machined, welded on and then get the flange straightened again otherwise its a lot of grinding and a big saw to cut this off and have them weldable onto another flange...
In reply to fidelity101 :
A short screw partially installed, a glob of knead-together two part epoxy (the stuff like smelly Silly Putty), then filed flat, will work just fine too 
I mean, I do understand the disparity between 3d printed and CNC machined bits, and then globbing some JB Stik over it...
fidelity101 said:remember folks, before welding anything triple check that the parts are correct. I swear I did this but yet here we are:
I know I run an vented catch can for the crank breather but this is not a shortcut I intended.
going to try and get some small pieces machined, welded on and then get the flange straightened again otherwise its a lot of grinding and a big saw to cut this off and have them weldable onto another flange...
For a piece that small, I wouldn't have pieces machined. I would surface up as needed with TIG and filler, then machine acccordingly. Tiny aluminum pieces welded to big heat-sinky pieces such as your manifold flange have a way of liquefying under the arc and turning into ugly bags of mostly aluminum.
Just build it up and machine it down. It will be stronger, easier, and cheaper. Think of it as printing--GTAP.
If the headers were 3D printed metal, is building up material by hand 3D calligraphy?
In reply to GasTungstenArc :
welding the 3mm thickness transition pieces to a half inch flange was pretty crazy enough as it was. but building several mm of tig/filler to close a gap seems like a stretch too.
Pete. (l33t FS) said:
If the headers were 3D printed metal, is building up material by hand 3D calligraphy?
if funny you say that because I use that example on compare the different styles of printing in some machines...
fidelity101 said:In reply to GasTungstenArc :
welding the 3mm thickness transition pieces to a half inch flange was pretty crazy enough as it was. but building several mm of tig/filler to close a gap seems like a stretch too.
It's a cakewalk. Aluminum freezes and builds so nicely. It is easier to build up some 4043 there than it would be to get a quality weld on the little sliver you would whittle to weld to it. Of course, it's your project and you're doing a fine job of it. But in your position, a position I have been in many times, I would build it up and machine it down.
GasTungstenArc said:fidelity101 said:In reply to GasTungstenArc :
welding the 3mm thickness transition pieces to a half inch flange was pretty crazy enough as it was. but building several mm of tig/filler to close a gap seems like a stretch too.
It's a cakewalk. Aluminum freezes and builds so nicely. It is easier to build up some 4043 there than it would be to get a quality weld on the little sliver you would whittle to weld to it. Of course, it's your project and you're doing a fine job of it. But in your position, a position I have been in many times, I would build it up and machine it down.
I talked with my welder buddy about this - we are going to give that a try first. meanwhile the machinist said he would make small pieces or a new flange if needed so thats good option too.
also - thanks Chris!
fidelity101 said:GasTungstenArc said:fidelity101 said:In reply to GasTungstenArc :
welding the 3mm thickness transition pieces to a half inch flange was pretty crazy enough as it was. but building several mm of tig/filler to close a gap seems like a stretch too.
It's a cakewalk. Aluminum freezes and builds so nicely. It is easier to build up some 4043 there than it would be to get a quality weld on the little sliver you would whittle to weld to it. Of course, it's your project and you're doing a fine job of it. But in your position, a position I have been in many times, I would build it up and machine it down.
I talked with my welder buddy about this - we are going to give that a try first. meanwhile the machinist said he would make small pieces or a new flange if needed so thats good option too.
Good call. Just as a "for instance," here is an edge that I built up on a piece of 16ga aluminum tubing. I built about 1/2" at the tallest point. Please disregard the ugliness resulting from hammer strikes below the beads. Any material can be built in this way, but aluminum is by far the fastest and easiest.
Meanwhile I wait on DHL's berkeleyup of loosing my fuel rail I finished the heat shield for the intake manifold. spray painted the steel sheet with ceramic header paint and baked it then added to both sides the heat deflection material (metal with fiberglass)
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)
The flange gets fixed tomorrow so just hurry up and wait now, the to do list to get it started is basically done pending the fuel rail's arrival then I can get working towards getting it broken in and stage worthy again.
Ooooh, complete engine package weight could be really interesting.
In reply to ¯\_(ツ)_/¯ :
ballpark:
plus fluids and exhaust manifold would put you under 250lbs id say. these may be a little light but 200-220lb dry engine with intake sounds about right. I forgot to add the stationary gears and oil pump stuff too so 240-260lb would be my guess with the intake.
however you can make the exhaust manifold super short or extra long so that really plays into the mass a lot so i left it out. still not considering accy drive/waterpump either but you get the idea
In reply to GasTungstenArc :
just a bit of weld and then all better:
time to clean up the center port excess weld and give this manifold a final cleaning so then I'm all set to continue.
lots of hiccups along the way causing delay after delay but here is the bundle of tubes all set and ready for action:
Just need to set the base timing then adjust the tune and fire it up ...right?
well that's the idea but it hasn't happened yet - need to check a few things as it keeps flooding. I'm either fighting a trigger problem (which makes no sense) or a compression problem. motor has been sitting I wonder if some of the seals are sticking or if even a compression test is valid at this moment since the motor is full of (well probably not anymore) petroleum jelly.
good news though is that I got the keyway on the oil pump correctly because I am making oil pressure during cranking so I got that going for me, which is nice.
Yup I wasn't crazy - I set the base timing correctly. Dead/Bad battery and loose terminals were the culprit; I used my trailer battery (1000CCA) to omit this variable and tried again. Because I was thinking a compression problem I used an old rotard trick of adding ATF to the chamber to help build compression and it fired right up!
have a few problem to address then I can begin the break in (and get that windshield fixed)
Great success! I can now breathe a sigh of relief and work towards the next event.
2 steps forward. 1 step back;
I got it warmed up and running at least and fixed the leaks and proceeded to dial the cal in a touch. however one of the apex seal corner pieces hasn't broken free or something is wrong on the front rotor. I am going to pop the exhaust off and check the apex seals and see how the springyness is across all 6 but I hope I don't need to tear it down again. HOWEVER now I have all the fabrication done for all the misc pieces I don't need to wait on other people to do things which is nice but not thrilled having to tear it down but that option is still on the table.
possibly I need to drive it some more (or drive it at all) and break those seals free. the side seals may be clearanced too tight? but tuning it right now with the compression so far out of balance is a moot point. Test was done while the engine was warm.
one thing I didn't notice though is that I need a FD or cosmo dip stick. I managed to install it while the engine was apart but now I cannot get my FC one to fit at all lol, very weird. it wont go past the baffle at all. #lessonslearned
compression will increase with break in but i would expect the mid 90s crest just over 100 but its not going to jump 30-40psi...
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.
(example orientation)
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.
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.
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