Thank you very much for the information! This is a treasure trove!! I do have a few questions, for the street (where torque at lower rpm’s is more relevant) would you leave the opening smaller than the valve area for higher air speed or would opening it up still be better? Also if you would open the intake opening up, how much bigger would the port entry need to be in comparison to the valve? Do you rework your formulas to know how many millimeters to take out or do you just remeasure and calculate until you get to your target csa? Would you rather take material off of the top of the port entry rather than the floor? Lastly, how do you treat the short turn radius to mimic the ideal port (like you showed with the taper to accelerate the charge right up to the valve)? Sorry for the tons of questions, this type of information is very rare on TH-cam for 4 valve per cylinder engines. Any answer would be most appreciated!
No problem at all. First the opening really depends on how much choke it was creating and what our "total" average velocity across the whole length of the primary induction length and wherever any of those points are under or too tight for our targeted HP and torque range. As a general rule... The more we make to flow path from radius entry of the runner to the seat, the better as far as obstacles go, the more it helps both torque and hp. As long as we are focused on shape and just improving the problem areas. The other factor here that can help with torque is our turbulent shear factor. So the factory leaking down here can help with the fuel shearing mechanism. But higher higher in the runner also improves this. Also, remember that the manifold is already at the window size. So, we are also stabilising the consistency in our inertia mechanism. And as far as CSA at the window, in all top race heads. The window is generally around 3-5% bigger, and the MCSA is at the throat. This is how we optimise the massive effects of our inertia supercharged mechanism. Even the billet RB26 we designed for sema last year is based on this math. Hope that helps mate. Sorry, mate. I've been away so a bit slow at relying, I started days ago, lol.
Thank you very much for the information! This is a treasure trove!!
I do have a few questions, for the street (where torque at lower rpm’s is more relevant) would you leave the opening smaller than the valve area for higher air speed or would opening it up still be better? Also if you would open the intake opening up, how much bigger would the port entry need to be in comparison to the valve? Do you rework your formulas to know how many millimeters to take out or do you just remeasure and calculate until you get to your target csa? Would you rather take material off of the top of the port entry rather than the floor? Lastly, how do you treat the short turn radius to mimic the ideal port (like you showed with the taper to accelerate the charge right up to the valve)?
Sorry for the tons of questions, this type of information is very rare on TH-cam for 4 valve per cylinder engines. Any answer would be most appreciated!
No problem at all.
First the opening really depends on how much choke it was creating and what our "total" average velocity across the whole length of the primary induction length and wherever any of those points are under or too tight for our targeted HP and torque range.
As a general rule... The more we make to flow path from radius entry of the runner to the seat, the better as far as obstacles go, the more it helps both torque and hp. As long as we are focused on shape and just improving the problem areas.
The other factor here that can help with torque is our turbulent shear factor. So the factory leaking down here can help with the fuel shearing mechanism. But higher higher in the runner also improves this.
Also, remember that the manifold is already at the window size. So, we are also stabilising the consistency in our inertia mechanism.
And as far as CSA at the window, in all top race heads. The window is generally around 3-5% bigger, and the MCSA is at the throat. This is how we optimise the massive effects of our inertia supercharged mechanism. Even the billet RB26 we designed for sema last year is based on this math.
Hope that helps mate.
Sorry, mate. I've been away so a bit slow at relying, I started days ago, lol.
great content as always sir, happy new year
Cheers man! Happy New Year to you too!
On four valve engines? Don't you have to consider both valves as a big single valve in doing the math? Both Valves do open at the same exact time.
Yep exactly! That's why we doubled the area of one throat 👍