Teach me about intake taper...basic questions inside.

[dgf2003]

Hi guys and gals,

I have a few questions about intake taper.

I see lots of post talking about taper in intakes.

Many of them talk in terms of percentages or degrees.

For example, in the Ford 302 world, I read that the Holley Systemax intake has 14" runners, and a 2* taper?

What exactly does this mean?

I have read somewhere that adding a taper to an intake runner has the effect of shortening the runner. The example I remember seeing said something to the effect of: a 2* taper on a 14 inch long intake runner will make the engine see an 11" runner. Is this correct?

How do you figure out intake taper if you have an intake and you want to measure it?

Thanks for any help with any of the questions...

David

 

[Bribyk]

I don't know what effect of taper would have on the intake pulse tuning but narrowing the runner speeds up the air flow due to decreased diameter and, thus, effectively "shortens" the runner.

 

[boostjunkie]

Look into Nozzles and Venturi's. The idea is to eliminate pressure loss and / or increase the flow rate.

 

[AboveRedline]

A runner with more taper will have a broader torque curve than a constant cross sectional area runner, not as dramatic as shortening the runner but more taper will make the runner look shorter. If you can live with a narrow power band then constant area is the way to go as you maximize the kinetic energy (m*v*v)in the runner.
There is no clear standard when defining the rate of taper. We use a percentage of area change and a side note of the runner length. A person talking about 2° of taper might be referring to the included angle of sidewalls and the included angle of floor and roof, or they might mean each wall. They are refering to the equivalent straight runner though.