Ideal Vacuum Pathway from ITBs to Block
 

Looking to see what is better to run:

Start from the 4 nipples from the ITBs, then merge into 1 tube, and go into the vacuum block.
https://cimg9.ibsrv.net/gimg/www.mia...0a11b54316.jpg

Or
Start from 4 nipples and do not merge, plug all 4 into the vacuum block.
https://cimg3.ibsrv.net/gimg/www.mia...6e5249c018.jpg

It seems like maybe the second one is better for MAP response and achieving equilibrium faster. But the first one would already have the average vacuum as it goes into the block.
I'd appreciate any explanations as to what and why.

Thanks

Average is better than fluttering and pulsing. Response won't be a problem with the volumes that are being moved.

The second one is better. You need a large chamber to dampen the pulses and feed a brake booster. OE's applications (like the 20V 4AG) have really large cambers fed by the runners.

Yeah that's what I thought, good thinking on the 20v setup. Six apparently says otherwise? Lol not sure still

I'd see if you can study some OEM ITB applications of the era, like the AE101 factory setup, or the EUDM e36M3 setups. But yeah, larger chambers will be the MAPs friend. Also, maybe a small orifice between the vac block and the MAP, so its not trying to contend with each individual vac pulse as much. Kinda like vac sync gauges for motorcycles have, they usually have a variable orifice choke point before the vac gauge to smooth out the pulses.

A bit late, however i'm just curious.
Which kind of material could be that black manifold? It seems to be 3d printed but i can guess wrong.

looks to be anodized aluminum. 3D printed parts won’t hold vacuum well, so I highly doubt it’s been printed

It's 3D printed carbon fiber nylon. Seals great and withstands the temp great too. SEMA uses this material for a print service to customers, and it's kind of grown ever since. I did look at metal sintering as a form of printing my manifold but it is big bucks $$$. Pretty nice way to achieve complex geometry on certain parts

Ohh, first pic manifold, yes that is printed. Missed that pic on mobile and thought he meant the vacuum manifold in the lower pic.

No worries. Although I will say the printed manifold experiences the same vacuum as that block you were talking about

Oh yeah of course. I was unaware they'd solved the porosity issues. But that also doesn't look to have been printed on a reasonably attainable hobbyist printer either (?)

Apart from the hardened nozzle and heating upgrades it is a decently nice printer, but obtainable.

Which printer is it? Did you print that at home? Is that filament expensive?

It's a Tevo Tornado which is a Chinese copy of a CR-10. Yeah it was printed at home and filament is ~$70 for 1kg (2.2 lbs). I used about 80% for one manifold.

Mind sharing the stl? I would totally print one out for shits and giggles on my CR-10.

Yeah I can share it sometime. Probably when I get home to my computer tonight. It is an adapter for a Yamaha R6 set of throttles to an NB Miata flange. It is however a bit restrictive as the port size of the R6 is not big enough. But it still manages to put out 5-10 more whp and wtq. The R6 flange itself in the file is flipped 180* and won't line up (I had caught this mistake right when I was about to print it so I didn't save the final copy). I have the solidworks file though so if you want it to edit I can share it too). I am also in the process of printing another adapter for the R1 throttle body set which is pretty much a port-matched setup with the Miata port so I should get the real gains soon. But yeah 3D printing has been so handy. Instead of buying a $1,000 ITB setup I was able to make my own for $300 (literally everything that I needed).

If you ever want to do one for shits, giggles, and driving around I can get at this guy (https://markforged.com/mark-two/) and this guy (https://www.desktopmetal.com/products/studio) for just cost of materials.

Here it is. STL file, solidworks part file, and an NB intake port drawing.

You're actually driving around on a 3d printed manifold?

All about those print settings and porosity.

We used to use a thin SLS manifold in SAE for that exact reason. Idled like shit, but you can get an extra 20% airflow past the restrictor by sucking air through the plastic