DIY_EFI Digest       Thursday, October 21 1999       Volume 04 : Number 593



In this issue:

	Re: DIY_EFI Digest V4 #591

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Date: Wed, 20 Oct 1999 23:17:57 -0700
From: Doug Dayson <djdayson@xxx.com>
Subject: Re: DIY_EFI Digest V4 #591

> Date: Wed, 20 Oct 1999 07:44:46 -0600
> From: bearbvd@xxx.net (Greg Hermann)
> Subject: Re: DIY_EFI Digest V4 #591
> 
> >
> >Currently my engine only consumes somewhere around 625 cfm max...I believe
> >that the BB TBI's flow 670 cfm so I too have thought about a BB TBI...Holley
> >makes a SB TBI manifold good for 6000 rpm as well...I'll have to check it's
> >height though?
> >
> Hi Doug--
> 
> Watch out for the flow on things like Holley Pro-Jection. 2 barrel carbs
> are rated for flow (in cfm) at 3 inches of Hg pressure drop. 4 barrel carbs
> are rated for flow at 1.5 in. Hg pressure drop--NOBODY seems to publish the
> pressure drop at which things like pro-jection are flow rated---BUT--I have
> talked to folks who have tried the pro-jection, and found, by
> experience--their engine does _ NOT _ flow nearly as well as with a 4
> barrel of similar flow rating--that Holley must be rating the projection
> units at some (unknown) higher pressure drop!!!
> 
>  (Just for general info, the multiplier for comparing 2 barrel carbs to 4
> barrels is .707. A 350 cfm rated 2 barrel only flows 247.5 cfm if rated
> using the same test conditions which are used for rating a 4 barrel!)
> 
> Regards, Greg

Thanks Greg...I had completely forgotten that fact...quite right you are!

I'll try Holley's Tech Support and report back...

Doug

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