different throttle body?

[FIND]

Your math is funny.

The surface area of a 60 mm throttle plate would be A=3.14R or area equals pi (3.1415926) times the radius. That works out to 94.2 square mm (30 x 3.14).

Now if your are trying to subtract out the area of the throttle shaft and the cross section of the throttle plate that isn't going to be much. Then add back in what gets removed when you optimize the throttle body (sharpen the edge of the throttle plate and remove half of the shaft), and that still isn't much. I would need to measure the diameter of the throttle shaft and the thickness of the throttle plate to actually see the difference.

area=3.14159 * R^2 circumference = 3.14159 * diameter.

area of a throttle plate that is 60 mm in diameter is ~2827 MM^2

Anyways, it doesnt matter what the surface area of the plate is, because halfshafting does not change the surface area. It changes the amount of surface area that is exposed, however we are looking for a volumetric change by removal of that shaft. That change is miniscule, although I cant remember the exact dimensions of half of the shaft.

Moving on. The area at the exit point is more important though than the area at the smallest point because the exit point is where vacuum is derived. Now since you can only create so much vacuum, air will fill that area, which means that you have to consider what is the absolute velocity air can travel. I dont remember and I dont feel like looking up stuff and doing equations to figure out what speed air can travel at such altitude/temperature whatnot. Anyways, if you have a 65mm thottle body that flows ~236 CFM then your air is moving through the open area at 7763 feet per minute which sounds perfectly reasonable (thats 88mph if you are counting, break out the flux capacitor). Now here is where I run into a problem, cause I dont remember the formulas to determine further air flow.

Anyhow it seems I have digressed. I was originally gonna tell you what the real benefit to halfshafting is. Have you heard of the Bernoulli effect? Ok, think of the shaft like an airfoil. As air moves over it, it has to move at a higher velocity, creating an area of high pressure. Now we are going to apply that to aerodynamics. As air moves off of the shaft, it leaves a low pressure area directly in the wake of the shaft. This causes turbulence which reduces air speed requiring more vacuum pressure to pull air past. Now bear in mind the differences are still minuscule, but removing half of the shaft means that you reduce the amount of turbulent air over the throttle plate which means it requires less energy to pull air through the throttle body.

The actual benefit of halfshafting is not additional flow area since it is minuscule anyways, and overall I think the difference is negligible. I believe if I had the formulas available right now I could demonstrate to you that the benefit of halfshafting is actually an aerodynamic benefit, and you could achieve the same results by shaping the shaft like a water drop cross-section.

I did not stay at a holiday in express last night though, so I could be wrong.

Harrry you are thinking of the diameters, not surface area

 

[Big Jim]

area=3.14159 * R^2 circumference = 3.14159 * diameter.

area of a throttle plate that is 60 mm in diameter is ~2827 MM^2

Anyways, it doesnt matter what the surface area of the plate is, because halfshafting does not change the surface area. It changes the amount of surface area that is exposed, however we are looking for a volumetric change by removal of that shaft. That change is miniscule, although I cant remember the exact dimensions of half of the shaft.

Moving on. The area at the exit point is more important though than the area at the smallest point because the exit point is where vacuum is derived. Now since you can only create so much vacuum, air will fill that area, which means that you have to consider what is the absolute velocity air can travel. I dont remember and I dont feel like looking up stuff and doing equations to figure out what speed air can travel at such altitude/temperature whatnot. Anyways, if you have a 65mm thottle body that flows ~236 CFM then your air is moving through the open area at 7763 feet per minute which sounds perfectly reasonable (thats 88mph if you are counting, break out the flux capacitor). Now here is where I run into a problem, cause I dont remember the formulas to determine further air flow.

Anyhow it seems I have digressed. I was originally gonna tell you what the real benefit to halfshafting is. Have you heard of the Bernoulli effect? Ok, think of the shaft like an airfoil. As air moves over it, it has to move at a higher velocity, creating an area of high pressure. Now we are going to apply that to aerodynamics. As air moves off of the shaft, it leaves a low pressure area directly in the wake of the shaft. This causes turbulence which reduces air speed requiring more vacuum pressure to pull air past. Now bear in mind the differences are still minuscule, but removing half of the shaft means that you reduce the amount of turbulent air over the throttle plate which means it requires less energy to pull air through the throttle body.

The actual benefit of halfshafting is not additional flow area since it is minuscule anyways, and overall I think the difference is negligible. I believe if I had the formulas available right now I could demonstrate to you that the benefit of halfshafting is actually an aerodynamic benefit, and you could achieve the same results by shaping the shaft like a water drop cross-section.

I did not stay at a holiday in express last night though, so I could be wrong.

Harrry you are thinking of the diameters, not surface area

Dakota,

I screwed up. I have not had to calculate the area of a circle probably since college. Anyway, the correct formula is Area = pi (3.14) times the radius squared.

Here is a link. I should have looked it up.

http://www.worsleyschool.net/science/files/circle/area.html

I absolutely agree that the benefit of optimizing the throttle body is to improve aerodynamics to provide less disturbance to the airflow.

 

[FIND]

Dakota,

I screwed up. I have not had to calculate the area of a circle probably since college. Anyway, the correct formula is Area = pi (3.14) times the radius squared.

Here is a link. I should have looked it up.

http://www.worsleyschool.net/science/files/circle/area.html

I absolutely agree that the benefit of optimizing the throttle body is to improve aerodynamics to provide less disturbance the the airflow.

Lol completely understandable. You should have seen how bad I bombed my placement exams after 10 years of being out of school when I went back to college. Math isnt a problem for me and I scored 33 on my ACT, but when I went back to college and had to take placement exams being my ACT scores were so old, I barely escaped having to take remedial english and barely met the requirements to take college algebra. Gawd the stuff is easy to forget if you dont use it every day.