Like this.

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If that is a compressor By-pass Valve on the outside radius of your bend going into the throttle body, I think you have a good design. Normally you would have more air going around the outside of the bend so having the valve there lets the air have a straight shot out of the plumbing when you close the throttle. Air Distribution also follows that outside bend but if you have two air discharges across from each other that effect quickly goes away in reality as the air smashes into the air discharge on the opposite side of the plenum and the air to the runners is really good.
Tom V.

 

I was wondering what the pros and cons are between having the air come in the intake from the bottom or the air coming in from the top front of the intake

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Here's another picture of an intake that seems to take up a lot of space under the hood

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This intake manifold that I have on my car right now the only thing I don't like about it is you have to remove some plumbing and throttle body to get the valve cover off.

 

If you read thru the whole thread there is a lot of discussion about the right way and the wrong way to do a bottom feed intake manifold design.

The bottom feed intake (if you have the room in the valley) has some advantages "package wise" vs the Marcella or Wilson style intake manifold.

The bottom feed design with the slot between the two plenums DOES NOT work well. The air packs up at the back and the flow is uneven to the upper plenum. The bottom feed intake with the throttle body then a Elbow that bounces the air off the plenum roof works very well.

Tom V.

 

We talked about the elbow after the throttle body are you talking about this design?

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NO! TOO MANY SHARP 90 DEGREE BENDS WHICH JUST CAUSES HIGH TURBULENCE!

Go to Post #23 of this topic and you will see two pictures of the "elbow" and what I am talking about.
An excellent Visual Explanation. The air goes thru the throttle body, makes an upward turn, then the air bounces
off the roof of the plenum, disperses evenly to the runners, and make even power to all of the cylinders.

Tom V.

 

Ran across an old Hot Rod Magazine article I had on the shelf.
In the 2007-2008 time frame GM Engineering wanted to prove that their LS-X engine could handle 2000 HP like their Advertising claimed.
So (according to the article) they contacted Thomson Automotive in Redford Michigan to test a boosted engine for them.
At the end of the day the engine made 2050 HP according to the Article.

The point of this is:
1) GM Engineering designed a "low profile -SMALL PLENUM" Intake manifold for the engine.
The intake was a one piece billet intake from a raw chunk of aluminum. Beautiful piece of machining.
It was designed for a Throttle Body Mount right on the front of the "V' portion of the lower intake (See Picture)
It also had dual injector bosses on the intake.
Thomson ran the intake (see pictures #1 and #1A) but unfortunately the intake did not work as planned. (More on that later) Sorry for the double picture post.

So then Thomson Automotive installed a more conventional Tunnel Ram (LARGE PLENUM) style intake with one set of 160 lb/hr injectors,
two large throttle bodies and a dual carb "Bonnet" on the top of the Throttle Bodies. See Picture 2.

This worked very well and made 2050 HP with a very large Water to Air Inter-cooler and using 40 degree city water.

So the point of this post (in the Intake Manifold Design thread) is that the air coming into the "V" section of the GM SMALL PLENUM intake (picture #3) was not providing proper air distribution to the runners and most likely was sending the majority of the air mass to the rear cylinders. Poor AIR DISTRIBUTION, POOR POWER PRODUCTION

The Tunnel Ram Design slowed down the air in the Bonnet, fed it to the twin throttle bodies, sent it into a more conventional LARGE Tunnel Ram plenum, and finally the air flowed more evenly into the runners and made a lot more horsepower on the dyno.

So you can't just carve out a intake out of billet material and expect it to work properly every time. There is a reason why a MARCELLA INTAKE has the TB Inlet where it is and the TB Angle it is, and the Plenum Shape it has.
CLICK ON THE PICTURES TO MAKE THEM LARGER TO SEE THE TB POSITION ON THE INTAKES

Tom V.

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That picture number 3, the plenum is gigantic you would need quite a large cowl induction hood to cover that. That's good information there Tom

 

Here's something I thought about doing and I want to see if it will help. It would involve putting a small funnel style box on the side of the plenum. It would still have two throttle bodies one on each side. I believe this might help to allow the air to slow down when it reaches the plenum.

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Good Thought.
If you position the inlets to the Plenum PROPERLY, The air from one Inlet's air flow smashes into the other inlet's air flow and the velocity of both inlets air flow goes to almost zero. It also expands over the whole plenum evenly.

The 406 Pontiac Engine that ran 6s in 1996, had a inlet design as described and also a plenum volume of twice what the engine displacement was.
A normal NA carb plenum inlet volume is about 70% of displacement. Good Tunnel Rams are typically over 100% of displacement.
Boosted Engines with distribution issues typically have too small of a plenum volume or air velocity issues.

Tom V.

 

Hello all. A longtime lurker here. I have read through this thread a number of times. I have a thread under the Tech questions that everyone has been really helpful. I have been building and acquiring parts for my first turbo build for a number of years. The latest project is to add Twin 78mm Borg Warner turbos to a 565 big block Chevy in a C10 long bed pickup. I am designing a top for an Edelbrock 70855 (fuel injection) tunnel ram intake manifold that will fit under the stock hood and incorporate two inter coolers, one on either side of the manifold. This design would require two forward facing throttle bodies, feeding air to the top sides through two 4.5”X4.1”X18” bell water to air intercoolers. The question I would like to ask is; with this setup what would be the best direction in the design of the upper potion of the intake. Is allowing the air to slow down through the intercoolers and mix in the plenum be the best? I can add a divider plate or a half pipe to re-direct the air downward toward the ports. The half pipe might reduce the volume slightly. Any suggestions are appreciated. I have attached a few pictures of the manifold and an article I came across where they are using a similar design.

Thanks! Joe

A copy of the specs from the other Thread:

565 BRC 4.25" crank, supposed to be Oliver rods (look like Howard rods). Wiseco 5103H100 pistons (15cc dome 10.75:1- can be milled flat to 9.2:1).
Brodix BB2 plus heads with 2.3" intakes and high temp exhaust valves added. 292.8/385.2 flow @0.700 lift.
Straub custom turbo solid roller cam .663/.689-256/256 at 0.050".
Edelbrock 70855 EFI manifold.
(2) S478 Borg Warner Turbos 1.32/96mm T6.
Stainless Works 2.25" 3.5" up and forward turbo headers.
(2) JGS500 50mm waste gates.
(2) JGS600 Blow-off valves.
FAST XFI fuel injection with traction control.
FAST distributor-less ignition.

http://www.superchevy.com/features/ghtp-1107-1986-pontiac-trans-am/


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The inter-coolers will, for sure, reduce the intake charge velocity going on to the intake plenum.
That being said, your question about using a divider plate: I have never seen where the divider plate did a better job of creating better air distribution to the runners vs the air charges blasting into each other.

Can you position the inter-cooler components on the floor or a table how you want to mount them under the hood?

Tom V.

 

Thank you for responding Tom. The position of the intercoolers is shown below. Sorry for the lack of detail, I am just starting to position components and developing the CAD file. The intake manifold and the turbo parts are already purchased, but not the intercoolers and throttle bodies. Any parts will be purchased as needed to digitize and complete the design. Currently with the engine in the stock location there is about one inch of clearance to the bottom of the hood. The plan would be to move the engine rearward and down, but the amount of movement will depend a lot on the intake design. The inlet is angled to match the valve cover angle mostly for looks. I really appreciate your input!
Joe

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Hey Tom take a look at this newest article from Bennett racing
https://www.dragzine.com/tech-stori...from-new-intake-manifold-technology-from-cfe/

 

Tom take a look at this article from Bennett racing
https://www.dragzine.com/tech-stori...from-new-intake-manifold-technology-from-cfe/

 

That's a pretty cool design so it will have to throttle bodies I'm assuming one on each side of the angled inlet and then to intercoolers one on each side of the intake over top of the valve covers.

 

Thanks Ron. Yes it will have two throttle bodies on it. Not too far off what you have done, just added the intercoolers into it and re-positioned the throttle bodies. The idea was to keep the plumbing on the boost side short for throttle response, and still be able to fit it under the hood. This project started with a 1967 Camaro convertible, and the hood clearance is really tight. One day I woke up and it really didn't sound very smart. That was when I revised the plan to use the C10. Lots of room for a tunnel ram manifold. I would have liked a shorter manifold, but I could not find a suitable intake. my budget doesn't include funds for a Marcella or other custom manifold. I think if I was needing a shorter intake I would cut the top off of a tunnel ram and build a plenum to clear the hood. This intake conveniently comes set up for fuel injection, but they are placed so high on the manifold you would have to add new bungs anyway. One of the drawbacks I see in my design, is that in order to get the square inches of area for the intercoolers, they are almost 18 inches long. I worry that over the length of the intercooler the coolant will become heated to the point of reducing the efficiency. I could break it into four intercoolers, and either feed or exit in the middle. The article I attached earlier, I believe, stated that they were using four intercoolers. I am not above using their ideas!
Joe

 

Water is a great Temp Equalizer in a intercooler brick.
Some inter-cooler bricks have both water flow coming into the brick and coming out of the brick on the same end.
I have attached a picture of what a double pass water to air intercooler looks like.
The advantages are:
1) The water inlet and outlet are on the same side of the brick.
2) The cooled water comes into the brick on the pass closest to the Intake plenum
3) The water that has removed some heat then passes back thru the brick closer to the hot air side but because the water
is still much cooler vs the intake charge it does so pre-cooling of the air before the air gets to the coldest water passage.

And the long length make no difference because the water temp averages out over the two passes thru the inter-cooler brick.
Tom V.

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