That's what they do. IIRC, the SHO guys would frequently just tie the IMRC valves open.

 

I think the interesting part of the SHO manifold design is that the plenums fill both sides when the valves are open. I suppose that is why they need the balance tube.

 

Wallace Beiber a Ford Engineer with many many years of Intake Design experience was involved in a lot of the Ford Intake manifolds. The GT-40 Intakes, the SHO Intakes, the V-10 Intakes (including the Harley Davidson intake for the truck).

Notice how the air from the throttle body hits the "WALL" of the "Tee" right after it flows thru the throttle body to send the air evenly to both intake plenums. The Balance Tube also helps with even plenum pressures.

He really knew how the air actually reacted to the intake design.

Thanks for posting this new information.

Tom Vaught

 

I thought I would post up some pictures of a special Pontiac Intake manifold I will have to use on a Boosted Engine Project at some point, down the road. The pictures are of the Billet Prototype Pieces but the actual intake will be a Aluminum Cast piece.

Enjoy the quality CNC work on the intake.

Tom V.

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Hmm... no injector bosses....?

ks

 

Wet flow manifold don't need no injectors

 

That really is a good looking manifold! Are they going to make a batch? If you are not trying to mass produce them (I am not in the market) why not run the billet one? Second if for mass production why not include injector bosses for folks that want port injection?

 

How about showing the casting steps and process too?

ks

 

I will post some photos of 1963 Pontiac Parts, later 1990s race parts and 2022 modern technology parts.

Tom V. #ad
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The initial steps are "finger-printing" the Original Part, Making Stereo-lith plastic parts, glueing them together as molds for prototype casting evaluation, and dimensional matching vs original parts.

More to come.

Tom V.

 

As the owner/operator/programmer of a cnc machine I can certainly respect the time and effort that went into that billet chunk.

 

Interesting; after all that testing his conclusion was an admission of just how well developed oem intakes are, at least for modern era engines. Obviously if you are exceeding rpm range of oem design then you can build or buy better, but it will be a trade off. Pretty amazing just how good the oe ls, coyote, and hemi intakes are. even the 80's era tpi, ford 5.0 ho, mopar kegger intakes were impressive. My hat's off to you guys developing intakes for your individual combinations, the bar is high, and the results you guys are getting with basically no budget compared to oem design teams is nothing short of amazing.

 

Hi guys,

I'm doing Bachelor's thesis about Buick Stage 2 V6 Composite dual plenum intake.
I will be using new never used Kinsler Magnesium IMSA primary tubes and make them work on my turbo charged 1987 Buick Regal Turbo-T.

Airflow will be routed to larger main plenum from the under of the intake. The plenum tube, that changes the diameter from start to finnish will be 3D printed from Nylon/carbon mix and also then over layed with around 1mm of carbon fiber just for little extra stiffness.

The airflow hole to main plenum will also have it's own long/narrow bellmounth pointing at the top lid.

Air speed is increased when entering the plenum and it will smash to top lid of the plenum and divide from there to all the cylinders equally. CFD models are not done yet, but will be in near future.

Inner side of the Carbon fibre main plenum is made from Kevlar so that the aluminium flanges glued to it won't start to oxidize and if fuel fires up in the plenum, it will not blow up so easily.

I'm too lazy to write everything here super specific since i only have 4 weeks time to write over 25 pages text to my thesis lol.

Some pictures what i'm doing :

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What is your thinking about the convolutions around the intake horns?

 

Hi,

That's a good question, the grooves at the bellmouths. I don't have yet 100% sure facts, but i'm on the road to study more and more as my project goes forward.

This is design, that i would use for turbocharged application only.

On this dual plenum turbo intake design the bellmounths are placed in enclosed space, where the boosted air flow changes radically flow direction after collision to the plenum top lid. The air mass is spread on both sides, over top of the bellmounths (cylinder groups), because the top lid is shaped to do so. The airflow path to the primary tubes because of that will be very turbulent and the reason of the grooving i straighten the flow symmetrically to primary tubes and possibly pick up little extra volymetric flow from each grooves.

Grooves are of course designed to be in the line with the direction of the flow, because otherwise they would slow down the flowing air. The grooves generate possibly air speed differences at the boundary layer and because of the that, the grooves end after bellmounth and then it will be just big black 54mm diameter Kinsler after that.

I have tested many different bellmouth designs at superflow 1020 flow bench at my university and the differences are to be honest almost non-existent, as long as bellmounth is shaped correctly.

I will flow test these bellmounths compared to normal ones and i expect to seeing max 3cfm difference at max lift, but then again the flow bench doesn't tell everything.

All the mechanical fluid flow laws have been true when i have been inspecting the results

From the results you can see, that the rectangular intake had much greater air speed at any lift than the round intake which indicates, that the tube diameter is smaller, but by my calculations the inner volume was still the same.

At the max lift (19mm) the rectangular intake lost it's touch. While the port had still guts to flow little more, the air speed in the intake got so great, that the CFM number went lower because of the very turbulent flow messed up the max flow potential. Every other same size intake flowed better at 19mm than the rectangular (smaller 50mm diameter intakes flowed less).

Rectangular intake had pretty laminar flow at the corners, even took pictures of it, but very violent stuff happening at the middle. It's easily explained by the bondary layer differences, because the shape to primary tube isn't round.

Pyöreä = Round
This intake changes it's profile very smoothly from rectangular intake port to completely ROUND singe intake runner with just normal bellmounth at it's end.

Suorakulmainen = Rectangular intake, that keeps the rectangular shape all the way from intake port to it's end. The dimensions of it of course change to larger from the start to end, but the inside volume is same than the round one.

First picture is results of flow test with Superflow 1020 flowbench (some finnish lesson for you guys also). The valve lift is in millimeters just like i like it.

Second picture, bellmounth designs

Third picture CFM results for the designs. MAX valve lift 19mm = 0,748031 inch

Fourth picture= Air speeds taken from the middle of the bellmouth with pitot tube

The overall best results for my Buick Stage 2 V6 head at 28" test pressure
was achieved with intake port shaped rectangular intake manifold design. CFM was not the greatest at the test points, but air speed was amazing all the way to intake port.
I calculated, that the volume of the circle port intakes were completely same, but still the rectangular flowed more than the round ones with any bellmounths installed to it.

Kinsler engineers already in the 80's knew what they were doing since the inner diameter of the primary tubes (54mm) give nice fast airflow to engine and they also flow easily the maximum flow capacity of the cylinder heads that i have.

Bellmounth designs effects much less to CFM than the total length and shape of the intake manifold.

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This chart might be the easiest to read.

The 1-7 models have 60mm diameter primary tubes (pretty damn large)
Number 8 is the completely rectangular intake

Under them is tests done with 50mm diameter intake.
Applied to 50mm round intake was:
Pyöreä = Round bell mounth
Suorakulmainen = Rectangular bell mounth (to circlular intake yes)
As weird as it is the rectangular flowed more CFM even installed to circular shape intake manifold.

From the previous post you can check what number is what bellmounth.

How ever the difference is so small and the flow bench tests won't tell us everything, so i will go with the round design at my Bachelor's thesis.

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Thanks for the pictures and the excellent write up of your project to date.

Tom Vaught "Retired" Senior Engineer Ford Motor Company Research Lab.

 

Thank you for the excellent report, and interesting study EngineeRick. I am very interested in your CFD results on the grooved bellmouth. It is an interesting approach and I hope there is some benefit.

Since the boundary layer is essentially static, the depth (or height) of your grooves will have to be at least greater than the boundary layer thickness. They need to be sticking up through the boundary layer into what you suggest is turbulent air. An issue I see is at the end of the grooves, or the transition area where the groves go to a smooth surface. I don’t know if you will have laminar flow at the groove-to-smooth transition area. In fact, you may be introducing turbulence. If that is the case you will have a ring of turbulence around the initial smooth area almost acting as a choke reducing flow in that area. I’m hoping that is not the case. Your CFD results, especially in that area, will be quite interesting.

I am going to study your data again. Thank you for the nice contribution.
All the best.

 

EngineeRick, the bell mouth shape and taper also plays a big role in the shape of the waves in the inlet system, flow is only part of the answer, do you plan to investigate that?

 

Thank you for the questions,

My predictions for the flow-parallel grooves are that the possibility of messing up the boundary layer flow certainly exists. For this reason, the grooves end immediately after the bellmounth area and the primary tubes are just normal round tube.

At the main plenum when the flow direction changes after it bounces down from the intake top-lid, it will really slow down the flow speed dramatically, which is good thing in terms of air distribution equally to all the cylinders. Still from my point of view it would be always good to have the same flow direction all the way from the airbox or charge pipe to intake runners!

I don't have space for that kind of intake under my 1987 Buick Regal good, so that's why i ended up doing the design, that i have now.

I hate, that i only have this spring time (really only 5 weeks) to study this subject and when i graduate from the University, i don't have access for the flow bench or even Catia V5 etc. anymore depending where i go to work after studies.

2021 Honda V6 F1 engine variable length intake:

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