[charlie66]

Originally Posted by Tom Vaught

Charlie, once you get much past the 4th harmonic you are basically killing torque with an out of phase induction runner which is why torque is much lower.

Maybe Stan can explain why you would use a 8th harmonic runner design in a vehicle driven on the street NA for a period of time.

Tom V.

So Tom what harmonic should I chose then? Ur even a guess will be better then mine..

[charlie66]

Heres the link to the calculator im using. When they say (Optimum Intake Length 11.33 inches long (from valve head to plenum). Is that from the intake flange at the head to the plenum or from the actual valve including the runner in the head through the intake runner to the plenum?

http://www.wallaceracing.com/runnertorquecalc.php

[johnta1]

From seat at valve to plenum.
(subtract head valve distance from total to get actual intake runner length)

[charlie66]

how do I go about figuring the Smallest cross section without losing HP for my 4 cylinder ?

Im finding this a little hard to sink in.. sorry for all the questions..

[charlie66]

Originally Posted by johnta1

From seat at valve to plenum.
(subtract head valve distance from total to get actual intake runner length)

Ok so the answer there giving you is the total run and you have to subtract the head runner from that to get the length of the intake runner. So the 11.33 they gave me, I have to subtract the runner length from my Edelbrock head for my new runner size? That seems real short..

[charlie66]

Does anyone know the length of the runner in a Edelbrock round port?

[johnta1]

Around 5.16"

[charlie66]

Originally Posted by johnta1

Around 5.16"

So then I subtract that 5.16 from the 11.33 the calculator gave me and my intake runner now will be 6.17?

[johnta1]

Yes.

[charlie66]

Originally Posted by johnta1

Yes.

Thank you for clearing that up for me John!

[charlie66]

So here is a static flow simulation of the manifold im building . Keep in mind this is a static flow form throttle body to all cylinders. So this isn't how this manifold will flow under running condition. Its just to show air flow from throttle body to all cylinders at the same time.. Conditions are 30 psi into throttle body and atmospheric pressure at runners

https://www.youtube.com/watch?v=AiIEi2vduo0

[Tom Vaught]

Because you are only doing a 4 cylinder engine the Video actually makes some sense except that most of the air will hug the outer walls when they turn back and move towards the runner pairs. So 1 and 4 will be getting lots of air and 2 and 3 less air (so they will be fuel rich).

Better to let it bank off a flat surface and basically go everywhere which is what you want for even air distribution. The flat wall will kill the velocity too.

Tom V.

[charlie66]

Originally Posted by Tom Vaught

Because you are only doing a 4 cylinder engine the Video actually makes some sense except that most of the air will hug the outer walls when they turn back and move towards the runner pairs. So 1 and 4 will be getting lots of air and 2 and 3 less air (so they will be fuel rich).

Better to let it bank off a flat surface and basically go everywhere which is what you want for even air distribution. The flat wall will kill the velocity too.

Tom V.

I was thinking of putting a bump in the plenum ceiling around a half inch down to deflect the air downward earlier like a speed bump in the road so it goes to the inner runners. I do plan on doing a simulation with a square box/plenum too.

[Tom Vaught]

Do not need a square box plenum charlie as the corners just screw things up.
You just need a flat impact area for the air to bang into to disperse the air evenly.

Tom V.

[charlie66]

Originally Posted by Tom Vaught

Do not need a square box plenum charlie as the corners just screw things up.
You just need a flat impact area for the air to bang into to disperse the air evenly.

Tom V.

So you want me to take the 90 degree turns off and make them 45 or 22.5 degree corners?

[Tom Vaught]

Make the back wall shape like a "stop sign" Flat at the top and then angled in the corners, and straight on the sides. Pay no attention to the bottom portion of the shape on the image. Tom V.

[charlie66]

Originally Posted by Tom Vaught

Make the back wall shape like a "stop sign" Flat at the top and then angled in the corners, and straight on the sides. Pay no attention to the bottom portion of the shape on the image. Tom V.

understood..

[charlie66]

Here's the manifold in a running simulation..

https://www.youtube.com/watch?v=GSjq...ature=youtu.be

[charlie66]

Here's one with the square sides https://www.youtube.com/watch?v=MXW_...ature=youtu.be

[Tom Vaught]

You have some good videos out there Charlie.

Tom V.