V-8 Int. Man. Design

[Paul Ruschman]

	Below is a question I posted some time ago and one of the replies I =
received. This is basically the same reply I received from several =
people. My new question to all this is.....

	 I have seen Cross Ram manifolds used with single and dual four barrel =
carbs.On the single four barrel the two plenums are kept seperate as are =
the dual four barrel setups. How would this differ in a EFI application?

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> From: Paul (BRAAP) Ruschman <prusch at ix.netcom.com>
> To: diy_efi at coulomb.eng.ohio-state.edu
> Subject: V-8 Int. man. design
> Date: Tuesday, 27 May, 1997 1:44 AM
>=20
> I am new to the list and am currently designing my own EFI Intake =
manifold for my Chev. 350 powered Datsun Z car. I plan on using the  =
L-jetronic or GM TPI electrics.
>       My question.
>       My plan is to make a manifold that utilizes two plenums, one per =
bank of cylinders. Knowing that the V-8 fires as if it were 4 V-twins =
stacked instead of two banks of four cylinder engines does this effect =
the intake air flow to the individual cylinders? Do I need to design the =
intake like a dual plane 180 degree carb manifold that plenums the two =
outer cylinders of one bank with the inner two cylinders of the other =
bank?
>       I feel that this being injected that it shouldn't make much=20
> difference fuel wise, but would one cylinder rob the available air the =
next cylinder is supposed to recieve?
>=20
>               Thank You,
>       Paul (BRAAP) Ruschman
	http://www.datsuns.com/cars/paulr.htm

=09

Uneven pulsation will affect the intake flow and the averaging that the =
air flow sensor sees.  Use two plenums but not for one bank only.  =
Instead, connect cylinders 1, 4, 6 and 7 to one plenum and 8, 3, 5, and =
2 to the other.  This will make each intake stroke at 180 degree =
intervals and provide balanced flow.  For best performance, the exhaust =
should also be connected this way but the gains are small.