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Dumb question here guys but, how close to a 1262r intake gasket are the ports on this intake?

I use a 2924 Super Victor now that has been port matched to a pair of AFR 225's. I'm thinking of making the switch to a 2828 for next years combination.

Thanks for your input.
 

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Discussion Starter #7
Dumb question here guys but, how close to a 1262r intake gasket are the ports on this intake?

I use a 2924 Super Victor now that has been port matched to a pair of AFR 225's. I'm thinking of making the switch to a 2828 for next years combination.

Thanks for your input.
It happens to be matched to a 1262r. Un-matched it's a little small!
 

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Chad,
I have a question regarding porting an Intake. Obviously you want to match with gasket /same or smaller than head port. How about the plenum such as this, do you have to have the heads at time of this plenum work. Seems as the transition to the runners is more from experience.....Tim
 

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Discussion Starter #11
Chad,
I have a question regarding porting an Intake. Obviously you want to match with gasket /same or smaller than head port. How about the plenum such as this, do you have to have the heads at time of this plenum work. Seems as the transition to the runners is more from experience.....Tim
I base it off intended RPM and engine size. However with stock type manifolds and without a welder, you stuck in some compromises. The transition is the key and most important, IMO.

 

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Discussion Starter #12
WAS/NOW

145/139
217/211
272/271
305/308
320/329
332/342
338/346
340/352
341/355


WAS Floor: 390...430..395

NOW Floor: 370...410...375

WAS Pinch: 1.240x2.000 (-.375)= 2.36 CSA (338 fps @.700)

NOW Pinch: 1.280x2.100 (-.375)= 2.57 CSA (320 fps @ .700)
 

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Discussion Starter #14
Chad, why is it important to reduce the airspeed? What happens when a head is too fast?
This says it well.

It's just the reality of any conventional port that the flow path has to make a turn from the runner down toward the valve into the cylinder. Moving air, like it or not, wants to travel in a straight line. The form at the turn is critical to how much air will ultimately make it through the runner, around the bend, and past the valves into the engine. The turn-in from the floor of the port down toward the valve seat is referred to as the shortside turn, while the opposite side (going down from the roof) is the long-side. The long-side, as the name implies, has a longer flow path, and naturally has a larger radius of curvature. The shortside is by definition a much sharper turn, and just like making a sharp turn around a corner in a car, going too fast will make it lose the turn and hit the wall. Similarly, air going around the shortside will reach a velocity at which it will miss the turn, or separate.
The velocity of air moving through the port is primarily a function of how much air it is moving vs. the port's volume (more accurately, its cross-sectional area). As the port moves more air, the velocity goes up; eventually getting so fast it blows the shortside turn and separates. When that happens, the port will typically stall, flowing no more or even less air no matter how much further the valve is opened. How much air will get through before the shortside separates and the port stalls will depend on the shape of this critical part of the port. The shortside form is a key limitation on the ultimate flow potential of a head. All ports aren't created equal, and some have a decent shortside form while others are handicapped in this area. A large radius turn represents a better flow path than a tight one. Some heads are compromised in how much material there is to work with, while others are generously endowed. Race heads are often designed with raised intake ports and a large meaty radius to help get the air around the bend without separating.
 

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Can anyone tell me if this intake has a cooling system crossover built into it?
Or does it have to be drilled and tapped for external lines?

Thanks
 

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This says it well.

As the port moves more air, the velocity goes up; eventually getting so fast it blows the shortside turn and separates. When that happens, the port will typically stall, flowing no more or even less air no matter how much further the valve is opened. How much air will get through before the shortside separates and the port stalls will depend on the shape of this critical part of the port.
Chad,

Question about this, I assume the separation and follow on stall is boundary layer, as happens on a wing or airfoil. Makes sense like a wing or airfoil and to high of an AOA at a given airspeed. Anyways, seems like focus on air delivery for intakes/carbs is on laminar flow. Some of the model airplane guys were having problems with boundary layer separation due to lower Reynolds numbers (smaller wings, as intakes have real small port sizes compared to airplane wings) and laminar flow (not having enough energy in the boundary layer in the laminar flow to stay attached to the wing). From what I understand they started "tripping" the flow forcing a turbulent boundary layer to energize the flow and reduce separation and the high drag laminar separation bubble. So on the short side has anyone considered or tested tripping the flow (or energizing the boundary layer) to reduce separation and increase the stall speed for more airflow (assuming it is laminar, maybe it is already somewhat turbulent, I'm way off and at its limit).

Andrew
 

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Andrew, like golf balls? How about like a F-117?
 
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