Paul

 I noticed many intake designs have constant diameter intake pipes while
Guru Racing and a few others taper theirs down to the intake port.

I will make my intake manifold out of carbon or some other heat resistant
glass epoxy GRP so I am free at the moment as to the course and profile they
will be.

I thought to go from 60mm id at the intake plenum with the adjustable length
portion being able to extend another 120mm within the intake intake plenum.
From the plenum  to the slide throttle, a distance of about 320mm I would
like to taper the tubes down to 50mm gradually over their length.

Injectors are right after the slide throttle so fuel mist separation is not
an issue.  Other than being a pain in the butt to construct the tapered pipe
are their any disadvantages or advantages to such a design?


Thanks

Doug

It is mentioned in:
Scientific Design of Exhaust and Intake Systems. Philip H. Smith
and John C. Morrison Published by Robert Bentley. ISBN 0-8376-0309-9

http://www.rb.com


-- 
Paul Lamar ...No rotor no motor.

Doug,
Concerning information given to me on inlet manifolds.
My understanding is that any reduction (such as a Venturi) in an inlet is a
restriction. However if a small restriction increases velocity without
choking the flow, it has an advantage for VE.
Alternatively any increase in size (especially toward the engine end) the
flow will slow and will be a disadvantage.

I'm advised that THE OPTIMUM SHAPE is a megaphone shape starting larger at
the outmost end and ending at the port, in a even taper. The air flow starts
out larger than the port, builds pressure and speed, but like you said, the
hard part is building the darn thing!.

Probably the same reason why those tapered exhausts work so well in 2
strokes .
George ( down under)


Do you have any mathematical theory to support this contention or is it  an
opinion? If it is an opinion do you have (or the person that expressed their  opinion
to you) have any empirical data to support their contention.


Paul Lamar ...No rotor no motor.

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