esses

When you romp on the throttle, you'll have this giant straw you're trying to suck air through.

Making it larger would just create a flow mismatch (impedence mismatch) and actually cause air to bounce BACK no?

Wouldn't the ideal solution be to have a smooth, constant diameter intake that's as absolutely short as possible?

0700

turbos make the impossible, possible.

esses

If you're not using torque (accelerating), your waste gate should be open and you shouldn't be charging/compressing your intake air.

So.... at a highway cruise, or in traffic. The instant you hit that gas pedal to pass someone, or to avoid something, the engine tries to gulp in air, and like a big giant inductor or straw, there's some lag time before it actually gets enough air.

I assume a big ol airbox right by the intake could help alleviate that to a large extent (do we have one?!). It'd act like a capacitor.

Right or am I on crack?

TipSter

The intake flow for each cylinder stops completely when the intake valve closes, versus a vacuum cleaner where the flow is constant all the time. Because the intake flow is continually starting and stopping with each valve cycle, you have to consider intake mass momentum when "tuning" the intake tract length. A long intake tract uses the momentum of the long tube of air to keep it moving along, waiting for the next opening cycle of the valve. In this way, when the valve does open, the mass of air is already moving towards the valve and you get more air into the cylinder. If the intake were very short, you'd have to re-accelerate the mass of air each time the valve opens.

However, this only works well at low engine RPM. At higher RPMs, the intake valve opening cycles are coming so fast that it's not effective any more to use the "resonance" of the intake tract. In this case, a shorter intake is the most effective.

This is why you see many cars, ours included, that have a "swithover" type intake tract. A long one for low RPMs and a short one for higher RPMs.

sans-audi

You want to stack all that air up for your low-rev stuff, and
that's just what your longer runners do. Lots of makers use
dual-runner configs to optimize the intake charge this way.

T.