Intake Modifications (pics)

on my inverted with its 4x4 inlet i saw a 2 point raise in boost loosing the ic tubes and blower top ic ect,

i beleive this will show you a raise in boost also.

and a cooler boost as less turbulance in intake stream now,

I also have a revised return plenum using 3" tube and my intake plenum is also 3" so your boost should increase maybe 2 lbs as mine did . I really like that return plenum . good work finaly we are getting some parts going here . good job .

JJ the thing with the boost is kind of technical. The volume of air that passes through will be the same but there will be less pressure since there is not as much restriction.


Chris

At least for flowing water in a ideal situation, the equations for pressure and cross sectional area are such:

P1A1 = P2A2

By increasing the cross-sectional area, pressure decreases.

I was just trying to get a handle on this whole before or after the boost gauge thing. I've talked with Damon about it before.

Air Flow is affected by any obstruction in the system. The raised top only offers a 2" cross sectional area. The lower IC tube is pinched and the center triangle in the intake is another. Single plain intakes don't have individual runners (not these). We are not concerned about atomizing the air and fuel since the injectors add fuel to each intake port inside the cylinder head. The design goal is to provide the best source of air flow to the intake valves. Even intake pressure provides that and the triangle in the intake does not. Each time the intake valve opens air is forced in and the amount of air each cylinder gets depends on the air pressure inside the intake. As air flow velocity increases any obstruction causes air turbalance and eventually backpressure also called cavatation. Greater air pressure backing up inside the intake causing the supercharger to make less power. Backpressure increases the HP it takes to run the supercharger. You see the result of backpressure when your SC belt slips. 5 speed cars are the worst due to the ability to sping the SC faster than the auto cars. The bypass valve begins to close at 5in vacuum and is completely closed at 0 vacuum but a fast reving engine can and will beat the bypass valve closing. This will cause the backpressure that causes the belt to slip. Once the belt begins to slip it may take a few seconds for the belt to stop as the load (backpressure) is reduced when the airflow is redirected through the larger SC intake. Ford installed a vacuum balance tube between the inlet plenum and out plenum to reduce backpressure in the system. The vacuum hose is the only rubber 3/8" hose connecting the two and sits on the very top.

Rich

CAvitation is defined as ,the formation of partial vacuums in a fluid by a swiftly moving solid body (as a propeller) or by high-intensity sound waves. So that would only happen on the inlet side of the blower. So back pressure and cavatation are 2 different things.

I don't really agree that the bypass valve will be slow in response to the increase in airflow, because the bypass is forced closed (plus the added spring pressure in the unit). When you rev the engine that has no load on it it's going to react slow but in a car that has a load on it it snaps shut.

"This will cause the backpressure that causes the belt to slip. Once the belt begins to slip it may take a few seconds for the belt to stop as the load (backpressure) is reduced"

Once a belt starts to slip, the reason it takes time to stop is also patrially due to hysteresis. In other words once it starts to slip it is going to slip for a longer time. Kinda when spin your tires you have to back way out to stop the spinning.


The crosstalk tube (that connects the inlet and outlet plenums) allow air to bleed into the back of the SC to give it something to "bite" on. With the original 55mm MAF and 60mm TB they become a restriction and cause the air entering the SC to cavitate. This will beat the blower up hammer on the bearings and such. The rotors weigh exactly 4 lbs a piece and that's a lot of weight spinning in there so beating on the bearings is not a good thing.

The fact that the blowers are driven at better than 2.5 times the engine speed doesn't help either.

I like what you guys are doing and wish I had the time to work on mine. too many irons in the fire...

Jeff

Single plain intakes don't have individual runners

Click to expand...

Actualy they still do have runners...Just not as long..And nothing like an SC intake which truly has no runners at all

Time for the reserection. Who has had the mod done? Who can give some good solid numbers? Who cant give good solid numbers and just wants to talk more about it? Who can give a GOOD seat of the pants "Only mod I made and drove it again" feel?

Rich, What does your porting job consist of?

Chris

Coy Miller removes the center triangle on his stage 2-3 engines. Coy did the porting on my intake and he removed the triangle inside the intake per my request. I had asked Coy to flow the intake before and after but he was unable to get it on the bench and back to me fast enough. As for before and after tests I have none. I have driven my project car with the intake but with all the other mods I cannot give an accurate response to doing just the intake mod. Single plane intakes traditionally do not have a air divider inside them. This OEM intake from Ford used on the SC is the first I have seen. As for just porting the intake Coy does this to all his engines. Gasket matching and porting will always promote better air flow. The term laminar flow is a result of smoothing the air flow across a surface. Laminar air always flows faster than turbulent air flow. I'm sure someone eventually will have a controlled before and after intake test.

Rich

Siiiiiiiiigggggggggggghhhhhhhhhh...another dead end... ...Oh well. Time to pull the spare engine outta the car..

Thanks rich

Chris