B3 Sheetmetal Intake! PICS

[bobbyspider]

^ word!

[mattdickmeyer]

I should have it finished this weekend, I'll post all the pics after.

[sasquatch]

sweet, cant wait

[bhearts]

Do festivas not have idle bypass valves. It doesn't look like this intake has one.

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[rmoltis]

They do, but he wanted it to look clean so he didn't cut a hole and attach it.
He said on warm up you gotta manually hold the throttle open until its warmed up.

[bhearts]

Huh, how about that pcv valve, where did that hook in at? I'm super interested in making one of these myself, no offence Matt, but this piece looks relatively easy with some goods planning. I'd prefer to do a plenum out of circle pipe, instead of that square design, mainly to not copy Matt's design. But where does one find intake trumpets like that, ands what size were they at the base

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[sketchman]

Consider doing it in steel. That's my plan. Square is a more volume efficient shape. You can also make your own dies to shape trumpets out of straight pipe, with a press.

Here.

[bhearts]

One diy intake manifold website only had round plenums for sale. What gives square an advantage

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[rmoltis]

Physically making an intake is simple.
But the science involved in choosing plenum size, and intake primarily lengths and sizes.
Plenum taper/shape/length etc.
In order for it to resonate within the expected rpm bands is another story.

I'm pretty sure matt won't divulge any info pertaining to his design.
Seeing how much time and effort probably went into the design aspect finding the right combo.

But those "trumpets" are velocity stacks.
They help smooth out air into a tube for a more complete fill by reducing flow and increasing pressure.

[sketchman]

Dimension vs volume. A 3" wide square plenum will hold more than a 3" diameter round one. So for instance you want a ( engine displacement x 110% ) volume plenum. A 3" square plenum will get you there well with a ~9" length. A 3" round one takes ~11.5" to do it. The calcs were done using the same wall thickness on both shapes to give a 2.76" inner width from wall to wall.

While it's true designing the perfect or at least ideal manifold is an art and science, making a better one than stock is not hard. Use common sense. Straighten the runners as much as possible, use a good sized plenum (at least 110% of engine displacement), and make sure it's airtight. Win.

Here's some details.

total pleneum volume comes in at 88 ci which gives ten percent over cylinder volume. total runner length is 18.5 inchs , which make its volumetric efficency (the rpm at which peak torque occours) between 4500-5000 rpm. this length combined with my cam installed at 104 degree centerline will offset the normal reduction in low rpm torque that usually happens small ci engines will a high flow ported head.this will also make peak hp around a usable 6500 rpm instead of the normal 8500rpm for an engine of this capacity.

[bhazard]

I doubt it would be hard to add.

[bhearts]

Plenum volume is the whole volume past the throttle body?

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[sketchman]

From the throttle body to the beginning of the intake runners excluding any bits that stick into the plenum.

[bhearts]

So at least on my aspire, it looks like there coolant line coming from my tb. I've heard this is to warm up a wax in it when the coolant warms up for normal operation. How would this get deleted off of a different intake is added

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[getnpsi]

If you make a new b3 plenum, please make a 1.6 usdm zm...just for my amusement...i gotz paypal...