M20 intake manifold design thread

[B C]

smooth surface finish, but plenty of ledges for air to "trip" on and become more turbulent. 
Probably weighs the same as the cast aluminum manifold to boot. 

Looks like garbage.  Someone needs to start an  "E30 engine bays that look like crap" thread.

[Rowleym]

I really like where this is going! We have a unique opportunity here I have all the tools to build an awesome manifold for us, but we simply need to design it! I think it would be cool to post all the files publicly as well so people could have them built. I can only fathom building 5 or so at first  

We can do this at an extremely affordable cost too! I could even build a die to form the velocity stacks, to save mucho moneys(or not). 
There are many ways we can make this really affordable! I want to kill as many crab manifolds as I can....

[B C]

Right now im  on board with what Jeff is doing. Lop the flanges off, weld on some 6061 tubing for the runners and probably pipe, plate, or a combination of both for the plenum. Super simple stuff.

[Jeff]

I like simple. I have to sit the flange in half so I can cast it to make duplicates for different manifolds. We need to figure out the optimum runner length and plenium size. Also shape or the plenium has factor too round oval square triangle what makes what difference. The volume inside the plenium is also needed

[B C]

My design priorities are

-Equal cylinder filling

-Minimal flow loss

-Plenum size and runner length beneficial for low rpm off-boost performance if possible. 

-Manufacturability

-Low weight

-Acoustics

-Engine bay cleanup/ease of maintenance

[Rowleym]

Snap said:

My design priorities are

-Equal cylinder filling

-Minimal flow loss

-Plenum size and runner length beneficial for low rpm off-boost performance if possible. 

-Manufacturability

-Low weight

-Acoustics

-Engine bay cleanup/ease of maintenance

Perfect! Exactly what I'm after.

Can't wait to see some numbers so I can order the runners that's all I need to build 3 or 4 of them.

[B C]

If at all possible I would like to use the stock throttle cable as well

[Rowleym]

Snap said:

If at all possible I would like to use the stock throttle cable as well

No front(angled) entry?

[B C]

I havent looked into generic throttle cables much but yes id like the tb to be front mounted

[Jeff]

Why front mounted vs side mount?

[Rowleym]

Jeff said:

Why front mounted vs side mount?

I personally like it for packaging reasons, and long radius(and short in length)  intercooler piping

[Jeff]

I think there needs to be two different ones designed here 1 for the guy that is going n/a and one for the turbocharged monsters

[Earl]

^Agreed=) There should be an m42 manifold made too=D

[B C]

Dear Earl,

2 nights ago I had a dream that I swapped a rebuilt M42 into my car (with my current turbo and such).

It sucked. true story. 

sincerely,

Snapple

[Rowleym]

Jeff said:

I think there needs to be two different ones designed here 1 for the guy that is going n/a and one for the turbocharged monsters

I would hope so! They are two totally different beasts(not exactly)

If i wasn't FI I would definitely use ITB's or triple webbers or something

[ClassE]

I'll be supplying the chips and soda for this debacle - so let's start with the hard questions:

Doritos or Sun Chips?

[ClassE]

On a more serious note: I'm 100000% in for this.

-I like the "front" TB inlet to allow for easy integration of IC cooler piping later (wink-wink).

-My previous SRI was built by a gentleman on the east coast who specialized in such things. Acouple design things to consider: vacuum ports and locations. TB flange variations. Integral fuel rail mounts.

-I'll have to find the data - but I recall reading a lot of research on having the full bell radius stacks "flush" with the plenum side VS extending "into" the plenum when researching my previous mani. Extending "into" was the winner for all applications.

-Gotta look good (design/fitment/welds). I pretty stuff.

My previous SRI off my MK3 ABA:

[ClassE]

^^^That manifold had the full bell radius stacks extending into the plenum. Sounded AMAZING at WOT, nice gains in upper RPMs as well.

[B C]

On my manifold Id like the TB flange to be such that it can be easily cut off and a larger one re-welded, or simply re-drilled for a larger TB if I ever find that I am in need of one.

[Rowleym]

Snap said:

On my manifold Id like the TB flange to be such that it can be easily cut off and a larger one re-welded, or simply re-drilled for a larger TB if I ever find that I am in need of one. 

the manifold I will be building with definitely have the stock bolt pattern for the TB. Can always redrill for a different one