Re: Manifold Question

[GLewis4457@domain.elided]

In a message dated 4/28/99 3:08:14 AM Central Daylight Time, 
owner-alfa-digest@domain.elided writes:

> It sure does, Tom, and very strongly. Has to do with sonic waves and such
>  bouncing back and forth along the length of the intake runners, as well as
>  with the momentum of the gas in the runners. Longer runners = lower rpm
>  torque peak. Smaller diameter runners usually goes together with longer--I
>  have long felt that runner volume should bear some definite relationship to
>  individual cylinder displacement. Same stuff applies to exhaust header tube
>  diameter and length, and with pretty much the same ralationships holding
>  true--longer and smaller for a lower torque peak.

In some of the more recent hot cars on the market (the Ford SHO is one) there 
are actually solenoid controlled flappers that open and close changing the 
length of the runners depending on engine speed, throttle position, etc...  I 
think that there are actually 2 different length runners going to each intake 
and the flapper determines which one is being used.

Jerry in Houston

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