Leafy

iTrader: (1)

Any reason you're not just using the NB throttle body instead of the NA? No need to put a breather on the idle valve.

nitrodann

Because breather filters are 2 bucks and already have the NA engine..?

It will actually go on a 1.6 first.

No idea on cost yet, but.. mates rates.

So... how do I AIT? I was thinking just into the radiator support panel, let it sit there, close enough.

Dann

asmasm

iTrader: (1)

I am planning to put a fitting in my silicone elbow for the IAC hose. I am also going to add one for the crankcase breather hose. I had really bad oil consumption before adding the orifice to the breather hose and I don't want to disturb that airflow since the orifice had a weirdly large effect.

Dunning Kruger Affect

That's what I'm doing currently: ziptied to the MAF harness pointed towards the air filter. Close 'nuff.

With this intake, I'll move the AIT into the bumper cover.

asmasm

iTrader: (1)

New version is up:
NA miata intake duct by AlecMoody - Thingiverse

Nitrodann,
I haven't test fit this version yet but I am 99.9% sure it will still work.

thasac

iTrader: (3)

Rapid-proto'd ABS parts are going to be FDM'd - the process doesn't create water tight parts since it is basically molten ABS squirted out as a continuous bead ... lots of pin holes which are unavoidable.

Another option is SLS (selective laser sintering) which can produce water tight parts in various nylon plastics, as well as SS, titanium, etc. The price will give you heart failure which is why I only use the process when the client is paying or my part is tiny (i.e., not a ******* intake).

SLS Materials | Solid Concepts Inc.
DMLS Materials | Solid Concepts Inc.

Solidconcepts has a wide selection of materials.

Immediate baller status for SLS PEEK intake.

-Zach

asmasm

iTrader: (1)

You can apply an epoxy sealant if water tight is critical. For this application, it is not.

I am looking into different epoxy coatings since some have much higher temp limits and will provide some additional strength to the part. Also, there version I have here has been acetone vapor treated (on the inside), which should significantly reduce pinholes.

SLS is certainly an option but shapeways quotes me almost $400 to print this part.

Leafy

iTrader: (1)

IMO air tight is more or less required for this. , like well enough to use RP ABS for an intake manifold.

asmasm

iTrader: (1)

The percentage of air leak is going to be fractions of a decimal point. Any pinholes in this are theoretical. None of them allow a visible amount of light through or any amount of water through the part. I can try pressurizing it with air.

thasac

iTrader: (3)

Regardless, why not seal the components? FDM is great for creating structural components, however, the process is an inherently terrible method for creating air tight walls.

Just spray the outside of the tube with a two part urethane and be done with it.

asmasm

iTrader: (1)

Hopefully I can find an epoxy that makes the part significantly stronger and temp resistant at the same time. I found one yesterday but it was $600 a pint. Perhaps I am over thinking this, but it would be nice to find a coating negated the need to do any kind of fiberglass work.

Leafy

iTrader: (1)

You're not going to make the part significantly stronger with just a think coating of resin. You need the fiber to add the strength or you have to put on a thick coat of resin, but at that point you might as well just print the part thicker and spray the sealant on.

thasac

iTrader: (3)

They can FDM Ultem, which has about 35% more heat resistance compared to ABS. It's a great material but it is not cheap (but cheaper than FDM ABS + $600 resin).

-Zach

Leafy

iTrader: (1)

I wouldnt worry about the heat resistance of ABS. I've used; straight abs, FG over abs and carbon over abs for intake manifolds. Its going to be fine this far from the engine. Though I've never run one of those manifolds for longer than an hour and thats on the dyno, the carbon one was actually run for half an hour on the dyno before we remember to turn the dyno fans on, lol. The radiator on that car was WAY too big.

asmasm

iTrader: (1)

I didn't realize you could FDM Ultem. I'll talk to my printer about that.

My concern is the ABS getting heat cycled from where it touches the radiator end tank. I am sure it is fine in the short term but I worry about it breaking up after a year or two of use.

Dunning Kruger Affect

I really want to see you explain this one. As to why "air tight" is "more or less" required pre-MAF or MAP.

Leafy

iTrader: (1)

Well if this intake actually ends up getting tuned to length, the air leaks will weaken the resonance effects. And its also going to do odd things with the airflow at the surface that I hadnt even considered analyzing, because it'd be too complex and unpredictable. Its probably fine to run unsealed, but its not like its expensive or hard to seal it up.

Dunning Kruger Affect

Does it have anything to do with the Doppler effect and why it sounds like you're talking out of your ***?

Leafy

iTrader: (1)

Does the wacka wacka sound like its changing pitch?

asmasm

iTrader: (1)

Speaking of length, I took almost an inch off of the inlet side. I want to see how well the filter clamps on before going any shorter. It is somewhat difficult to measure the length of an intake that makes several turns. However, the center line through this duct is currently 15.5". After that there is about 11" of intake path (including the turn for the elbow). Getting it any shorter is going to be a challenge with a stock radiator. If I had an aluminum rad I could probably use a 45" degree elbow instead of a 90 degree and come across at an angle. That looks like it would be about 2" shorter.

It will be interesting to see the dyno results and if grabbing ambient air is worth an intake that is a few inches longer than what might be ideal. I know Emilio and Schenker have both done testing on intake length and I wonder where they are starting and stopping their measurements.


Edit:
To make this a lot simpler:
Not including the throttle body elbow, it's 24" to the tip of the duct.