Intake size

Demus
10-16-2005, 07:32 AM
I'm going to weld together a simple CAI and in the process of doing that I ran into a few questions. Should I try and keep the pipe the same size as the throttlebody? I have a 58mm throttle body, which works out to 52.8148 cm^2 surface area.

The MAF has a diameter of 8cm, and the divider has a width of 1cm in the middle. In total 3.14*4^2-8*1= 42.24 cm^2. My vortec intake elbow has a surface area of 48.145 cm^2 on the TB side, and 44.606 cm^2 on the other side.

In a perfect world would the MAF and elbow all be 52.8 cm^2 to match the intake? Or does it really not make the much of a difference?

Injuneer
10-16-2005, 12:09 PM
You don't need to match the area. You're stuck with the diameter of the MAF, the TB, and the elbow, but the connectinig piping can be as large as you want to make it. Pressure loss in a pipe is inversely proportional to (roughly) the square of the pipe diameter, so the bigger the pipe, the less pressure you lose. Similarly, the smoother the bends, and the fewer the number of bends, the less pressure you will lose. Where you do connect a larger diameter pipe to a smaller diameter device, you want a smooth transition. A sharp edge transition also causes more pressure loss.

There is no standing wave tuning possible in the elements in front of the TB, since the intake plenum effectively decouples the flow in the inlet track from the flow in the intake runners.